International Journal of Developmental Science 8 (2014) 3–24DOI 10.3233/DEV-140129IOS Press

Systematic Review – Target Article

Bullying, Romantic Rejection, and Conflictswith Teachers: The Crucial Role of SocialDynamics in the Development of SchoolShootings – A Systematic Review†Friederike Sommer∗, Vincenz Leuschner and Herbert ScheithauerDepartment of Educational Science and Psychology, Freie Universitat Berlin, Berlin, Germany

AbstractA plethora of studies have appeared which argue that, prior to their attack, the perpetrators of school shootings had experienced intense conflictsand problematic relations (e.g. bullying) with peers and teachers, and were on the periphery of the schools’ social life. This in turn resulted inthe perpetrators’ view of themselves as marginalized victims. However, methodological problems and inconsistencies mark many studies, andfindings vary. In an attempt to clarify the role of perpetrators’ negative social experiences with peers and teachers prior to their attack, we haveundertaken a systematic search of the literature, including 35 international primary studies on school shootings. In selecting the studies we limitedourselves to ones which deal with at least two (Range: 2–39) cases in which a violent targeted attack was carried out by a current or formerstudent who chose their school or university as the site of the attack. A total of 126 cases (128 perpetrators) from 13 countries (USA, Canada,Germany, Finland, Brazil, Argentina, Australia, Bosnia, Greece, Hungary, Netherlands, Sweden, and Thailand) were examined. The mean ageof the perpetrators was 19 (Range: 6–62 years, SD = 8.72), and in 121 cases the perpetrators were males. Detailed information relating on thesocial dynamics that contributed to the attack was found in 67 case reports. Our analysis revealed that in 88.1% of cases the future perpetratorexperienced social conflict within the school environment. A minority of perpetrators (29.9%) were physically bullied, while 53.7% experiencedpeer rejection, verbal and otherwise. Romantic rejection was only found in 29.9% of cases. Conflicts with teachers (43.3%) proved a decisivefactor. In order to better understand the role of social dynamics in the developments leading up to school shootings, it is necessary to analyze theperpetrators’ position within their social network and the ways in which they experienced interaction with their peers and others at the school. Inaddition we must obtain precise information on their views of themselves as victim over a period of time.

Keywordsschool shooting, bullying, social rejection, severe targeted school violence, systematic review

Introduction

The main question asked in the wake of school shoot-ings is always why they happened, and mental healthprofessionals, policy makers and researchers have

∗Address for correspondenceFriederike Sommer, Freie Universitat Berlin, Department of Edu-cational Science and Psychology, Habelschwerdter Allee 45, 14195Berlin, Germany. E-mail: friederike.sommer@fu-berlin.de†See endnote at the end of the manuscript.

worked hard to explain why adolescents commit massmurder at their schools. While some have approachedthe question from the angle of individual pathology(Harding, Mehta, & Newman, 2003; Langman, 2009) orculture (Brown, Osterman, & Barnes, 2009; Kimmel,2008), others have focused on the “social dynamics”that eventually culminated in shootings (Newman, Fox,Harding, Mehta, & Roth, 2004).

Empirical evidence shows that violent attacks atschools and university campuses are rarely sudden,

ISSN 2192-001X/14/$27.50 © 2014 – IOS Press and the authors. All rights reserved 3

F. Sommer et al. / Bullying, Romantic Rejection, and Conflicts with Teachers

impulsive acts, but are rather the result of a longdevelopment involving a multitude of interacting fac-tors (Leuschner et al., 2011; Vossekuil, Fein, Reddy,Borum, & Modzeleski, 2002). Verlinden, Hersen, andThomas (2000) reviewed studies which looked at youthviolence in general and the risk factors which can leadto it. The list they proposed included amongst othersimpulsiveness, hyperactivity, abuse in childhood, aca-demic failure, access to weapons, and the experienceof being bullied. In examining the role of these fac-tors, they selected nine cases involving violent massassaults carried out in schools. In addition to individualrisk factors such as the feeling of being let down bytheir families, adverse social and environmental condi-tions, and acute strain arising from various sources, theyfound problem-laden social relationships in the schoolenvironment in the perpetrators’ histories, for which weuse the term social dynamics.

Detailed investigation of perpetrators’ social rela-tionships in the school they attended makes sense, asthe perpetrators deliberately chose it as the scene oftheir violent act. When it comes to social dynamics, theprimary factor discussed is the perpetrators’ perceptionof themselves as victims of physical or verbal bullyingprior to their attack. Bullying is defined as long-termrepeated victimization, with an imbalance of powerbetween the bully and victim (Olweus, 1994). It canbe physical, verbal or psychological in nature. A multi-tude of studies have revealed that bullying can result infeelings of helplessness, loneliness, anxiety and depres-sion, and can lead to psychosomatic disorders, eatingdisorders or even suicide (also referred to as bully-cide). Truancy and a decline in academic performanceare also common as are problems in relationships;aggressive, delinquent and anti-social behavior; datingviolence and excessive risk-taking (for a summary seee.g. Hess & Scheithauer, in press; Scheithauer, Hayer,& Petermann, 2003; Ttofi, Farrington, & Losel, 2012).Research has confirmed that being bullied has a stronglynegative effect on children’s psychosocial development,thus it is reasonable to assume that it plays a role inschool shootings. On the website StopBullying.gov itis stated that “a very small number of bullied childrenmight retaliate through extremely violent measures. In12 of 15 school shooting cases in the 1990s, the shootershad a history of being bullied” (“Effects of Bullying”,2014). Indeed, many case studies, especially from theU.S., have indicated that peer rejection is most likelythe key risk factor in the development of future per-petrators (Fast, 2009; Kidd & Meyer, 2002; McGee &DeBernado, 1999). According to Larkin (2009), more

than half of the perpetrators he studied were seekingrevenge for mistreatment they had suffered at the handsof their peers and that they specifically targeted peo-ple who had tormented them. The perceived socialrejection might have been linked to a lack of socialskills, which caused the future perpetrator to founderin social situations, setting him or her off on a down-ward spiral of increasing isolation and rejection (Kidd& Meyer, 2002; Nansel et al., 2001). This assumptionis confirmed by results obtained in a case study pre-sented by Leary, Kowalski, Smith, and Phillips (2003),who described the strong link between interpersonalrejection and aggressive behavior in general, therebysupporting the thesis that school shootings are com-monly provoked by real or imagined rejection in theform of teasing, ostracism, or unrequited love. In onlytwo of the fifteen incidents they analyzed there was noperceivable pattern of ongoing ostracism, bullying, ormalicious teasing. Thus, the authors argued that rejec-tion alone does not suffice as a cause of violence, butwhen it appears along with other factors such as psy-chological problems, fascination with weapons and/orthemes of death, the risk of violence is higher.

These findings are consistent with those obtained bythe U.S. Secret Service, who found evidence of bully-ing, ostracism, and social rejection in over two-thirdsof the 37 cases they reported in their Safe School Initia-tive (Vossekuil et al., 2002). The authors argued that theexperience of being bullied most likely had a significantimpact on the perpetrators’ motivation in committingtheir attack. Leary et al. (2003) agreed on this, statingthat the key findings in the U.S. Secret Service reportsuggest that prior to the shooting, the future perpetratorshad experienced repeated bullying, reportedly border-ing on torment. In a study carried out by Newman etal. (2004), social marginality – the shooter’s percep-tion of himself as extremely marginalized in the socialworld that matters to him – was discussed as one of fivekey factors on the path to school shootings. There wasevidence of social marginality in all but one of the 25cases studied by Newman et al. (2004): 67% had feltmarginalized and 63% had been bullied or teased. Oneparticular type of bullying is discussed by Kimmel andMahler (2003), who support the thesis that future perpe-trators failed to measure up to prevailing norms of mas-culinity. They found that nearly every one of the 31 per-petrators they analyzed in their study had been accusedof being gay because they were not tough enough. Thisfinding lends credence to the claim that most of theshootings represented a violent response to what theperpetrator perceived as attacks on his masculinity.

4 International Journal of Developmental Science 8/2014, 3–24

F. Sommer et al. / Bullying, Romantic Rejection, and Conflicts with Teachers

Since most school shootings have been carried outby males, it is important to investigate the role of gen-der in school shootings. In the work by Leary et al.(2003) mentioned above, it is argued that one particularform of rejection, namely unrequited love, can serveas a risk factor culminating in a violent act. Klein’s(2012) finding revealed that in about half of the casesshe discussed, the future perpetrator had suffered from aromantic breakup or unrequited love. Klein found thatthe shooters’ motives were at least partly linked withrejection, jealousy, frustration, perceived failure withgirls or a desire to protect them. Thus, in numerousincidents, the perpetrators targeted and killed girls theyfelt had rejected them.

In general, school shooters have been commonlydescribed as loners (Meloy et al., 2001; Newman et al.,2004) with few friends or none at all. As Levin andMadfis (2009) stated in their description of mountingstrain in the personal development of school shooters,long-term frustration experienced early in life can leadto social isolation. With social support systems lacking,strain can become unbearable. Newman et al. (2004)argued that the perpetrators were not loners so muchas “failed joiners, who always tried to fit in” (New-man & Fox, 2009, p. 19). By contrast, in shootingsthat occurred on college campuses the perpetrators wereapparently more disconnected and had stopped tryingto integrate into groups (Newman & Fox, 2009).

Recently, Dumitriu (2013) divided school shoot-ers into three distinct groups. Interestingly 71 of the163 school shooters she analyzed had no friends,experienced difficult relationships with girls, and suf-fered repeated bullying at school. In contrast, 22 weredescribed as “perfect students” who had friends andgenerally normal relationships, and who did not sufferbullying. The third type (n = 70), typically 31 years oldor over, a former student who had been an outsider atthe school, is not discussed in detail by Dumitriu’s, whodrew the following conclusions from her study:

“School shootings are more complex than usuallyportrayed in many studies and especially in mediaaccounts which proceed from the assumption that aschool shooter is a shy student who had been bulliedby some of his peers and whom he or she shot in anepisode of rage” (Dumitriu, 2013, p. 306).

The precise role of social rejection in school shoot-ings remains a matter of controversy (Rocque, 2012).While the studies cited above give evidence of the cru-cial role social rejection plays in the development ofschool shooters, others do not consider social dynamics

in their list of key risk factors. For example, Langman(2009) argued that only 6% of the 35 attackers in hiscase study targeted specific students who had picked onthem. Thus, even if the shooters were victims of bully-ing, this did not necessarily mean that the mistreatmentcaused the attack. Dutton, White, and Fogarty (2013)found evidence of paranoid thinking in self-reports ofmass shooters who explained that they had sufferedpsychologically from rejection. While there was littleevidence of actual bullying incidents, offenders seemedobsessed with the idea that they had been rejected bytheir peers (Dutton et al., 2013). The three types of rejec-tion listed by Leary et al. (2003) – ostracism, bullying,and romantic rejection – were less evident in inves-tigations of more recent school shootings (Weatherby,Strachila, & McMahon, 2010). In fact, some researcherssuggested that in a number of cases school shooters hadbeen bullies themselves, and that others seemed quitepopular among their peers (Dumitriu, 2013; Fast, 2009;Langman, 2009; Newman et al., 2004). At least 41% ofthe shooters in the study done by Vossekuil et al. (2002)socialized with mainstream students or were consideredmainstream students themselves.

Another form of marginalization still not properlyunderstood involves teachers and school administra-tors (see also Bondu & Scheithauer, 2014). Given thefact that at least 150 parents, teachers, administrators,coaches and other adults were killed or wounded in166 school shootings that occurred between 1979 and2009 (Klein, 2012), we need to explore more closelythe relationship between the perpetrators and their adultvictims. The conflicts between perpetrators and theirteachers and other school staff varied in manner andintensity. In some cases teachers and administrators hadmerely ignored or dismissed the bullying suffered by thefuture schoolyard assailant and had failed to intervene,while in others the teachers played a more active role, atleast in the eyes of the perpetrators. Klein (2012) statedthat in at least 24 of the 166 incidents she had studied,the perpetrators said they were responding to what theysaw as academic or disciplinary injustices inflicted onthem. In particular, European shooters and perpetratorson college campuses had frequently received negativeschool reports or punishment of various kinds (Bondu,2012; Bondu & Scheithauer, 2014; Fox & Savage, 2009;Hoffman, Roshdi, & Robertz, 2009). Thus, being sus-pended from school may have been the reason for someshootings in which the attackers targeted teachers andadministrators (Newman et al., 2004).

As most students who experience rejection, eventhose who are bullied and ostracized by peers or teach-

International Journal of Developmental Science 8/2014, 3–24 5

F. Sommer et al. / Bullying, Romantic Rejection, and Conflicts with Teachers

ers, do not resort to lethal violence, it seems likely thatadditional risk factors play a role. Nevertheless mostof the primary studies conducted thus far confirm thatmany perpetrators had experienced some kind of socialrejection.

The purpose of this paper is to systematically reviewand summarize research findings on school shootings,focusing on the role of social dynamics. We have con-sidered all primary studies which deal with at least twocases of school shootings, defined as offenses commit-ted by a current or former student who deliberatelychooses his or her school or university as the site of anattempt to kill one or more people (cf. Bondu, 2012).Sincefindings relating to socialdynamics in the researchon school shootings remain inconsistent, we have notformulated any hypotheses in advance, but remain opento any links that might become apparent in the data.

Method

Our review of the literature is based on criteria for-mulated in the PRISMA statement (Moher, Liberati,Tetzlaff, Altman, & the PRISMA Group, 2009), our aimbeing to identify and examine all the relevant researchstudies in a systematic manner. Hopefully this will helpresolve disagreements arising from contradictory find-ings in the various studies (Klassen, Jadad, & Moher,1998) and will contribute to a more objective appraisalof research results (Egger, Smith, & O’Rourke, 2001).

Literature Search

We only included those primary studies in our reviewwhich (1) focused on school shootings, (2) containedinformation on the personal development of the perpe-trators, providing both qualitative as well as aggregateddata, (3) appeared between January 1990 and Decem-ber 2013. We began our search with the help of theelectronic databases PsychNET, PsychINFO, Pubmed,Scopus, Google Scholar, and ScienceDirect, using thesearch terms school shooting, homicidal violence, ram-page, severe targeted school violence, and amok. Nextwe went through the reference lists we found in thosestudies which met our criteria, and contacted experts inthe field. In the end we collected a total of 454 journalarticles.

Inclusion Criteria and Study Selection

In a second step two raters read the abstracts of the454 publications and gathered further information fromthe full publication to decide whether a certain publi-

cation was eligible. Studies were included if they metthe following criteria: (1) they dealt with at least twoschool shootings committed by a current or former stu-dent who deliberately chose their school or university asthe site of their planned attack, (2) they were publishedin English or in German, (3) they met certain researchstandards (we excluded articles and papers which sim-ply listed incidents or had appeared in newspapers oron the Internet). Studies were excluded if (1) the casesdiscussed did not involve at least two incidents thatoccurred in an academic institution, but instead focusedin incidents like family killings, (2) secondary analyseswere not based on a sampling of cases, but simply sum-marized previous research, (3) they were dissertations,(4) they focused exclusively on global questions con-nected with school shootings, like prevention efforts orprevalence.

All the studies that fulfilled our criteria were markedfor review. The final decision on whether to include aparticular article was made after reading the full text. Inthe end a total of 35 studies were selected. Table 1 givesreference information and lists the key characteristicsof the studies.

Characteristics of Primary Studies Reviewed

Twenty nine of the 35 primary studies were in Englishand dealt primarily with cases in the U.S., only occa-sionally discussing cases elsewhere [primary studies1:1–18, 20–22, 24, 28, and 30–35]; five were in German,four of which focused exclusively on cases in Germany[19, 23, 25, and 29], one on cases in other countries [26].One of the studies in English focused on Finnish cases[27]. Twenty five primary studies [1, 4, 7, 8, 10–14,16, 17, 20–27, 29–33, and 35] contained detailed qual-itative data for each incident analyzed, while ten otherstudies named the cases they analyzed, but did not pro-vide detailed information on the incidents [2, 3, 5, 6,9, 15, 18, 19, 28, and 34]. In examining these studieswe only considered aggregated information relating tosocial conflicts experienced by the perpetrators.

The data sources referred to in the primary stud-ies varied considerably. In four studies no informationcould be obtained on data sources [2, 8, 15, and 23]. Theanalyses in six primary studies relied solely on mediaaccounts [6, 10, 12, 22, 24, and 33], while in six studiesthe data was collected from the media, scientific articlesand previous research [11, 16, 21, 26, 30, and 32]. In atotal of 19 studies [1, 3–5, 7, 9, 13, 14, 17–20, 25, 27–29,

1Number of primary study according to Table 1

6 International Journal of Developmental Science 8/2014, 3–24

F. Sommer et al. / Bullying, Romantic Rejection, and Conflicts with TeachersTa

ble

1In

clud

edP

rim

ary

Stud

ies

Ref

eren

ceD

ata

sour

cefo

ran

alys

isD

efini

tion

for

inci

dent

sN

umbe

rof

case

san

alyz

edG

ener

alpo

sitio

non

soci

aldy

nam

ics

inin

form

atio

nsc

hool

shoo

tings

1.M

cG

ee&

DeB

erna

do(1

999)

“Lim

ited

amou

ntof

frag

men

tary

data

and

unco

nfirm

edan

ecdo

tala

ccou

nts

deri

ved

from

offic

ialp

olic

ere

port

san

dth

epo

pula

rm

edia

”(p

.7)

Non

-tra

ditio

nals

hoot

ing

inci

dent

sw

hich

occu

rred

inth

eU

.S.m

iddl

ean

dhi

ghsc

hool

s

18ca

ses

(199

3–20

01)

Prec

ipita

ntdi

scip

line/

reje

ctio

n,bu

llyin

g:10

0%;s

ocia

lout

cast

:100

%;t

ease

d/fe

ltvi

ctim

ized

:100

%

2.B

and

&H

arpo

ld(1

999)

No

info

rmat

ion

avai

labl

eN

oin

form

atio

nav

aila

ble

8ca

ses

“The

yfe

ltre

ject

edby

othe

rsan

dso

ught

reve

nge

orre

talia

tion

for

real

orpe

rcei

ved

wro

ngs

done

toth

em.T

hey

appe

ared

tobe

lone

rs,a

vera

gest

uden

ts,a

ndsl

oppy

orun

kem

ptin

dres

s.T

hey

had

apr

open

sity

todi

slik

epo

pula

rst

uden

tsor

stud

ents

who

bully

othe

rs.”

(p.1

4)3.

O’T

oole

(199

9)“A

sum

mar

yof

the

inci

dent

,tap

esor

tran

scri

pts

ofin

terv

iew

sw

ithth

eof

fend

er(s

),w

itnes

sst

atem

ents

,in

terv

iew

sw

ithpe

rson

sw

hokn

ewth

est

uden

tsan

dfa

mili

esan

dpr

ovid

edin

form

atio

nab

outo

ffen

ders

’ba

ckgr

ound

,cou

nsel

ing

and

psyc

hiat

ric

repo

rts

and

eval

uatio

ns,

scho

olre

cord

san

dcl

ass

wor

k,in

terv

iew

sw

ithla

wen

forc

emen

tand

scho

olpe

rson

nel.”

(p.3

4)

“18

scho

olsh

ootin

gca

ses

arou

ndth

eco

untr

y(i

n4

the

stud

ento

rst

uden

tsin

volv

edpl

anne

da

shoo

ting

and

mad

esi

gnifi

cant

prep

arat

ions

,but

wer

ede

tect

edan

dpr

eem

pted

byla

wen

forc

emen

t).T

heca

ses

invo

lved

sing

lean

dm

ultip

leof

fend

ers.

”(p

.34)

18ca

ses

(14

actu

al,4

pree

mpt

ed)

The

thre

atas

sess

men

tmod

ellis

tsce

rtai

nty

pes

ofbe

havi

or,p

erso

nalit

ytr

aits

,and

circ

umst

ance

sin

the

fam

ily,s

choo

l,an

dco

mm

unity

envi

ronm

entt

hats

houl

dbe

rega

rded

asw

arni

ngsi

gns.

Soci

aldy

nam

ics

conn

ecte

dto

scho

olsh

ootin

gsm

ight

be:F

aile

dlo

vere

latio

nshi

p,in

just

ice

colle

ctor

,clo

sed

soci

algr

oup,

peck

ing

orde

ram

ong

stud

ents

,pee

rgr

oups

.

4.V

erlin

den,

Her

sen,

&T

hom

as(2

000)

Con

vict

ions

in4

case

s,in

form

atio

nob

tain

eddi

rect

lyfr

omth

eco

urts

(int

ervi

ews,

vide

otap

es,c

ourt

docu

men

ts)

in2

case

s,se

arch

oflo

cal

and

natio

nalm

edia

“Mul

tiple

vict

imvi

olen

tass

aults

insc

hool

sth

atha

veoc

curr

eddu

ring

the

past

3sc

hool

year

san

dha

vein

volv

edus

eof

firea

rms.

”(p

.27)

10ca

ses

(199

6–19

99)

Inni

neof

ten

case

sth

epe

rpet

rato

rfe

ltre

ject

edby

peer

san

dpe

rsec

uted

;in

eigh

tof

ten

case

sth

epe

rpet

rato

rw

asso

cial

lyis

olat

ed.

5.M

eloy

,Hem

pel,

Moh

andi

e,Sh

iva,

&G

ray

(200

1)

Cou

rtro

omte

stim

ony,

scie

ntifi

car

ticle

s,ac

adem

icbo

oks,

vide

oan

dau

diot

apes

,in

terv

iew

s,m

edia

Ado

lesc

entm

ass

mur

der:

“Int

entio

nal

killi

ngof

atle

astt

hree

vict

ims

(oth

erth

anth

epe

rpet

rato

r)in

asi

ngle

inci

dent

byan

indi

vidu

al19

year

sol

dor

youn

ger.

Indi

vidu

als

who

used

afir

earm

,cut

ting

inst

rum

ent,

orbl

unt

obje

ctw

ithor

with

outo

ther

wea

pons

.”(p

.720

)

34(8

scho

olsh

ootin

gsin

the

sam

ple)

adol

esce

ntm

ass

mur

der

(195

8–19

99)

70%

lone

rs(“

self

-lab

elin

g,if

hesh

owed

am

arke

dte

nden

cyto

spen

dtim

eal

one

rath

erth

anw

ithot

hers

”),1

7%hi

stor

yof

bully

ing

othe

rs,4

3%w

ere

bulli

edby

othe

rs(“

long

-ter

mvi

ctim

izat

ion

ofa

stud

entb

yhi

spe

ers,

incl

uded

both

phys

ical

and

psyc

holo

gica

latta

cks”

).(p

.721

)6.

Dan

ner

&C

arm

ody

(200

1)M

ajor

new

spap

ers,

artic

les

publ

ishe

dw

ithin

two

wee

ksof

the

even

tSa

mpl

eof

infa

mou

ssc

hool

viol

ence

case

sin

clud

edhe

rein

med

iaac

coun

tsof

the

Jone

sbor

osh

ootin

gs.

9ca

ses

(199

7–19

99)

“The

mos

tfre

quen

texp

lana

tion

for

the

shoo

tings

was

“res

pons

eto

bully

ing”

.Thi

sfr

ame

capt

ures

expl

anat

ions

that

desc

ribe

dth

eof

fend

ers’

viol

ence

asa

resp

onse

tobe

ing

pick

edon

orbu

llied

byfe

llow

stud

ents

.”(p

.103

)

International Journal of Developmental Science 8/2014, 3–24 7

F. Sommer et al. / Bullying, Romantic Rejection, and Conflicts with TeachersTa

ble

1(C

onti

nued

)

Ref

eren

ceD

ata

sour

cefo

ran

alys

isD

efini

tion

for

inci

dent

sN

umbe

rof

case

san

alyz

edG

ener

alpo

sitio

non

soci

aldy

nam

ics

inin

form

atio

nsc

hool

shoo

tings

7.K

idd

&M

eyer

(200

2)“I

nter

view

sw

ithof

fend

ers,

fam

ilym

embe

rs,v

ictim

s,w

itnes

ses,

orot

hers

clos

ely

invo

lved

inth

eca

se,r

epor

tsfr

omth

em

ore

repu

tabl

ena

tiona

l,re

gion

al,o

rlo

caln

ews

sour

ces.

”(p

.5)

Off

ense

sin

aru

ralo

rsm

allt

own

com

mun

ity:“

Cas

esw

ere

limite

dto

thos

ew

hich

invo

lved

mul

tiple

stud

ent

fata

litie

son

scho

olca

mpu

ses

duri

ngno

rmal

oper

atin

gho

urs.

”(p

.3)

8ca

ses

(199

6–19

99)

“Afe

elin

gof

peer

reje

ctio

nw

asa

char

acte

rist

icsh

ared

amon

gsi

xof

the

eigh

toff

ende

rs.A

few

offe

nder

sta

rget

edpa

rtic

ular

vict

ims

who

had

teas

edth

em,o

rth

eyre

port

edse

ekin

gre

veng

efo

rth

ela

ckof

resp

ecta

ndm

altr

eatm

entt

hey

rece

ived

from

peer

s.Fe

elin

gsof

reje

ctio

nal

sooc

curr

edaf

ter

seve

ralo

ffen

ders

wer

eap

pare

ntly

spur

ned

bya

love

inte

rest

.”(p

.7)

8.W

ater

man

(200

2)N

oin

form

atio

nav

aila

ble

“The

rece

ntsc

hool

shoo

tings

wer

epr

emed

itate

dhi

gh-p

rofil

eaf

fair

sin

whi

chvi

ctim

sw

ere

mor

eor

less

chos

enat

rand

om.”

(p.4

)

8ca

ses

“In

each

case

,bul

lyin

gan

dto

rmen

ting

occu

rred

ona

daily

basi

s,ye

ttea

cher

san

dad

min

istr

atio

nsdi

dno

thin

g,or

even

wor

se,p

unis

hed

the

vict

ims

for

reta

liatin

g.”

(p.1

9)9.

Vos

seku

il,Fe

in,

Red

dy,B

orum

,&

Mod

zele

ski

(200

2)

Inve

stig

ativ

e,sc

hool

,cou

rt,a

ndm

enta

lhe

alth

reco

rds,

supp

lem

enta

lin

terv

iew

sw

ith10

ofth

epe

rpet

rato

rs.

“Inc

iden

tsof

targ

eted

viol

ence

insc

hool

setti

ngs:

Scho

olsh

ootin

gsan

dot

her

scho

olba

sed

atta

cks

whe

reth

esc

hool

was

delib

erat

ely

sele

cted

asth

elo

catio

nfo

rth

eat

tack

and

was

not

sim

ply

ara

ndom

site

ofop

port

unity

.C

urre

ntst

uden

tor

rece

ntfo

rmer

stud

enta

ttack

edso

meo

neat

his

orhe

rsc

hool

with

leth

alm

eans

(agu

nor

akn

ife)

and

the

stud

enta

ttack

erpu

rpos

eful

lych

ose

his

orhe

rsc

hool

asth

elo

catio

nof

the

atta

ck.”

(p.1

3)

37ca

ses,

41pe

rpet

rato

rs(1

974–

2000

)“4

1%so

cial

ize

with

mai

nstr

eam

stud

ents

orw

ere

cons

ider

edas

mai

nstr

eam

stud

ent

them

selv

es,2

7%w

ere

cons

ider

edto

bea

part

ofa

frin

gegr

oup,

12%

had

nocl

ose

frie

nds,

24%

lone

rs,7

1%fe

ltpe

rsec

uted

,bu

llied

,thr

eate

ned,

atta

cked

orin

jure

dby

othe

rspr

ior

toth

ein

cide

nt.”

(p.2

4)

10.H

arte

r,L

ow,&

Whi

tese

ll(2

003)

Med

iaac

coun

tsM

ajor

Scho

olsh

ootin

gssi

nce

1996

10ca

ses,

12pe

rpet

rato

rs“A

com

mon

feat

ure

inth

ehi

stor

ies

ofth

esc

hool

shoo

ters

has

been

that

they

each

had

ahi

stor

yof

bein

ghu

mili

ated

bype

ers,

aro

man

ticot

her,

ora

teac

her.

Ince

rtai

nca

ses,

the

actu

alpr

ecip

itatin

gev

entw

assu

chvi

ctim

izat

ion,

lead

ing

tore

veng

e.”

(p.5

)11

.Kim

mel

&M

ahle

r(2

003)

Ana

lysi

sof

the

exta

ntco

mm

enta

ryan

dlit

erat

ure

onsc

hool

viol

ence

and

seco

ndar

ym

edia

repo

rts

“Ran

dom

scho

olsh

ootin

gs:A

youn

gst

uden

tope

nsfir

eon

scho

olgr

ound

s,ap

pare

ntly

rand

omly

,and

shoo

tste

ache

rsan

dst

uden

ts.”

(p.1

456)

31ca

ses

(198

2–20

01)

“Nea

rly

allo

fth

esc

hool

shoo

ters

had

stor

ies

ofbe

ing

cons

tant

lybu

llied

,bea

tup,

and,

mos

tsig

nific

antly

for

the

anal

ysis

“gay

-bai

ted”

.Fiv

eof

the

scho

olsh

oote

rsha

dw

hatt

hey

felt

was

seri

ous

girl

trou

ble,

espe

cial

lyre

ject

ion.

”(p

.144

5,p.

1454

)

8 International Journal of Developmental Science 8/2014, 3–24

F. Sommer et al. / Bullying, Romantic Rejection, and Conflicts with Teachers

12.L

eary

,K

owal

ski,

Smith

,&Ph

illip

s(2

003)

Nat

iona

lnew

sm

edia

,new

spap

ers

from

the

loca

lare

a,w

orld

wid

ew

ebsi

tes

“All

wel

l-do

cum

ente

dca

ses

ofsc

hool

viol

ence

inth

eU

.S.S

hoot

ing

inci

dent

mus

thav

eoc

curr

edat

asc

hool

duri

ngth

esc

hool

day,

mus

thav

ebe

enpe

rpet

rate

dby

stud

ents

and

resu

lted

inin

jury

orde

ath

toat

leas

tone

stud

ent.

Inci

dent

sin

whi

chth

eon

lyvi

ctim

sw

ere

nons

tude

nts

wer

eno

tcon

side

red

beca

use

we

wer

eex

plic

itly

conc

erne

don

lyw

ithst

uden

t’sag

gres

sion

tow

ard

thei

rpe

ers.

”(p

.204

)

15ca

ses

(199

5–20

01)

“Mos

tof

the

shoo

ters

(12

of15

)ha

dex

peri

ence

dan

unus

ually

high

amou

ntof

bully

ing

and

ostr

acis

m,t

hatw

aspa

rtic

ular

lyre

lent

less

,hum

iliat

ing,

and

crue

l.In

addi

tion

man

yca

ses

invo

lved

ongo

ing

ostr

acis

mth

atle

ftth

epe

rpet

rato

ron

the

peri

pher

yof

the

scho

ol’s

soci

allif

e.In

abou

thal

fof

the

epis

odes

the

perp

etra

tor

had

also

expe

rien

ced

are

cent

reje

ctin

gev

ent.

Inon

lytw

oca

ses

was

ther

eno

evid

ence

wha

tsoe

ver

that

the

perp

etra

tor

had

been

reje

cted

orm

istr

eate

dby

othe

rpe

ople

.”(p

.210

)13

.Moo

re,P

etri

e,B

raga

,&M

cLau

ghlin

(200

3)

Rec

ords

,cou

rtre

port

s“Y

oung

peop

lear

min

gth

emse

lves

and

open

ing

fire

onth

eir

scho

olm

ates

and

teac

hers

,kill

ing

orse

riou

sly

inju

ring

them

.The

inci

dent

soc

curr

edin

the

hallw

ays

and

com

mon

area

sof

scho

ols

and

ata

scho

ol-s

pons

ored

even

t.”(p

.249

)

8ca

ses

(199

1–19

99)

“In

4of

8ca

ses

the

perp

etra

tor

was

avi

ctim

ofbu

llyin

g,in

the

sam

eam

ount

ofca

ses

hew

asa

bully

him

self

,and

inth

ree

case

she

suff

ered

from

are

cent

peer

reje

ctio

n.Y

etth

esh

oote

rspe

rcep

tions

seem

edto

have

little

basi

sin

real

ity,o

r,if

they

wer

ere

al,t

hey

wer

eno

twid

ely

unde

rsto

odan

dsh

ared

byot

hers

.The

yw

ere

notb

eing

thre

aten

edw

ithph

ysic

alvi

olen

ceat

the

time

they

shot

.In

thre

eca

ses

ther

eha

vebe

endi

scip

linar

ypr

oble

ms

with

teac

hers

.”(p

.251

)14

.New

man

,Fox

,H

ardi

ng,M

ehta

,&

Rot

h(2

004)

Nat

iona

lDat

abas

eof

scho

ol-a

ssoc

iate

dvi

olen

cede

aths

byth

eC

ente

rsfo

rD

isea

seC

ontr

olan

dPr

even

tion,

repo

rtby

the

U.S

.sec

rets

ervi

ce,o

wn

data

set

bym

edia

acco

unts

and

othe

rca

sest

udie

s

“Dea

dly

assa

ults

onan

inst

itutio

n-th

esc

hool

.An

inst

itutio

nala

ttack

take

spl

ace

ona

publ

icst

age

befo

rean

audi

ence

,is

com

mitt

edby

am

embe

ror

afo

rmer

mem

ber

ofth

ein

stitu

tion,

and

invo

lves

mul

tiple

vict

ims,

som

ech

osen

for

thei

rsy

mbo

licsi

gnifi

canc

eor

atra

ndom

.”(p

.232

)

29ca

ses

(197

4–20

02)

Asc

hool

shoo

ters

are

nota

lllo

ners

and

they

are

nota

llbu

llied

,but

near

lyal

lex

peri

ence

dos

trac

ism

and

soci

alm

argi

nalit

y:5%

wer

epo

pula

r,pr

eppi

es,

jock

s,or

athl

etes

;Lon

er11

–34%

;no

clos

efr

iend

s:12

%;F

ring

eor

outc

ast:

52%

;M

argi

nal7

8–96

%;V

ictim

ized

:53%

;B

ullie

dor

teas

ed:6

3%;F

elt

vict

imiz

ed/m

argi

naliz

ed:6

7–71

%;

Mas

culin

itych

alle

nged

:63%

.The

reis

anot

her

form

ofm

argi

naliz

atio

n:B

eing

push

edou

tof

the

inst

itutio

nal

toge

ther

,w

hich

expl

ain

som

esh

ootin

gsin

whi

chth

eat

tack

ers

mor

eex

plic

itly

targ

eted

teac

hers

and

adm

inis

trat

ors.

”(p

p.23

9–24

2)15

.Fox

,Lev

in,&

Qui

net(

2005

)N

oin

form

atio

nav

aila

ble

Tabl

ew

ithse

lect

edsc

hool

mas

sacr

es:

Ada

pted

and

repr

inte

dw

ithpe

rmis

sion

from

Tim

eM

agaz

ine,

31.5

.199

9.

8ca

ses

The

reha

sbe

ente

asin

gin

six

ofei

ghtc

ases

,ro

man

ticre

ject

ion

inha

lfof

the

case

san

din

one

case

the

perp

etra

tor

was

expe

lled

from

scho

olbe

fore

hew

ento

nth

em

assa

cre.

International Journal of Developmental Science 8/2014, 3–24 9

F. Sommer et al. / Bullying, Romantic Rejection, and Conflicts with Teachers

Tabl

e1

(Con

tinu

ed)

Ref

eren

ceD

ata

sour

cefo

ran

alys

isD

efini

tion

for

inci

dent

sN

umbe

rof

case

san

alyz

edG

ener

alpo

sitio

non

soci

aldy

nam

ics

inin

form

atio

nsc

hool

shoo

tings

16.K

lein

(200

6)“A

llne

ws

cove

rage

and

rese

arch

was

syst

emat

ical

lyga

ther

edon

scho

olsh

ootin

gca

ses.

”(p

.45)

“Cas

esw

ere

atle

astt

wo

peop

leha

vebe

enki

lled

and/

orth

ere

wer

efo

uror

mor

evi

ctim

s.”

(p.4

5)

10ca

ses

(199

6–20

01)

“Gay

hara

ssm

entc

onsi

sten

tlyap

pear

sas

am

otiv

atin

gfa

ctor

.In

five

ofth

ete

nca

ses,

stud

ents

wer

ero

utin

ely

calle

dga

y,fa

ggot

,an

dth

elik

e.In

near

lyal

lof

the

shoo

tings

,bo

y’s

mas

culin

ityw

assy

stem

atic

ally

chal

leng

edvi

aha

rass

men

tand

/or

nam

e-ca

lling

.”(p

.46)

17.F

ast(

2008

)D

ocum

enta

ryev

iden

ce,a

rtic

les

from

com

mun

ityne

wsp

aper

s,le

gal

docu

men

ts,a

ndpe

rson

alac

coun

ts

“The

shoo

ter

and

the

vict

ims

had

tobe

onsc

hool

grou

nds

duri

ngth

ecr

ime,

the

assa

ilant

sha

dto

bead

oles

cent

s,an

dth

evi

ctim

sha

dto

num

ber

two

besi

des

the

shoo

ter,

had

heco

mm

itted

suic

ide,

too.

”(p

.14)

15ca

ses

“Nea

rly

ever

yca

sein

volv

esbu

llyin

g,an

dth

eob

viou

sch

ain

ofca

usat

ion,

from

bully

ing

tohu

mili

atio

nto

rage

tore

veng

e,m

ade

this

one

ofth

efir

stch

arac

teri

stic

sof

scho

olra

mpa

gesh

oote

rsto

beid

entifi

ed.”

(p.1

3)18

.Fox

&Sa

vage

(200

9)“D

ata

glea

ned

from

the

FBI’

sU

nifo

rmC

rim

eR

epor

ting

prog

ram

and

the

U.S

.D

epar

tmen

tof

Edu

catio

n’s

reco

rds

man

date

dby

the

Cle

ryA

ct,a

sw

ella

sde

taile

dm

edia

repo

rts

gath

ered

from

sear

chin

gel

ectr

onic

new

spap

erda

taba

ses.

”(p

.146

7)

“Sho

otin

gin

volv

ing

mul

tiple

fata

litie

son

colle

geca

mpu

ses

inth

eU

nite

dSt

ates

.”(p

.147

6)

76ca

ses

(199

0–20

08),

13ar

ena

med

“Sho

otin

gsat

high

scho

ols

ofte

npr

ecip

itate

dw

hen

stud

ents

feel

bulli

edor

pers

ecut

edby

thei

rcl

assm

ates

and/

orte

ache

rs.H

owev

er,

the

perp

etra

tors

ofm

ass

shoo

tings

atco

llege

san

dun

iver

sitie

sar

eof

ten

grad

uate

stud

ents

-old

erin

divi

dual

sw

hotu

rnto

viol

ence

inre

spon

seto

wha

tthe

ype

rcei

veto

beun

bear

able

pres

sure

tosu

ccee

dor

the

unac

cept

able

real

ityof

failu

re.”

(p.1

475)

19.H

offm

ann,

Ros

hdi,

&R

ober

tz(2

009)

Cri

me

and

cour

trec

ords

Seve

reta

rget

edsc

hool

viol

ence

isde

fined

asan

inte

ntio

nally

dead

lyof

fens

eag

ains

tspe

cific

pers

ons

orgr

oup

ofpe

ople

.The

scho

olas

the

site

toca

rry

outt

heat

tack

isch

osen

bypu

rpos

e.

7ca

ses

(199

9–20

06)

71.4

%of

the

Ger

man

offe

nder

sha

vebe

ente

ased

and

hum

iliat

ed(a

ndha

vebe

ense

nsiti

veto

this

),57

.1%

have

been

perc

eive

das

lone

rs(b

utha

dfe

wfr

iend

sfr

omtim

eto

time)

,57.

1%w

ithdr

awal

from

thei

rso

cial

cont

acts

prio

rto

the

atta

ck,8

5.7%

had

disc

iplin

ary

confl

icts

with

teac

hers

.Im

min

entt

oth

eho

mic

ide

the

perp

etra

tor

expe

rien

ced

are

ject

ion

(by

agi

rl,c

lass

mat

esor

susp

ensi

onfr

omsc

hool

).20

.New

man

&Fo

x(2

009)

“Lis

tsof

shoo

tings

from

the

Vir

gini

aTe

chR

evie

wPa

nel’s

com

pend

ium

offa

tals

choo

lsho

otin

gsin

the

Uni

ted

Stat

esan

da

vari

ety

ofm

edia

com

pila

tions

ofsu

chev

ents

.”(p

.3)

“The

loca

tion

ofth

ein

cide

ntis

apu

blic

stag

e,ei

ther

onth

esc

hool

prop

erty

orat

asc

hool

rela

ted

func

tion,

the

shoo

ters

mus

tbe

curr

ento

rfo

rmer

stud

ents

ofth

esc

hool

,the

rem

ustb

em

ultip

levi

ctim

s(a

lthou

ghth

ein

juri

esdo

noth

ave

tobe

fata

l)or

atth

eve

ryle

ast,

mul

tiple

targ

ets.

”(p

.2)

9ca

ses

(200

2–20

08)

Soci

alm

argi

naliz

atio

nis

one

ofth

efiv

eke

yfa

ctor

s:“T

hepr

otag

onis

tsw

ere

lone

rsor

frin

gefig

ures

(cer

tain

lyno

tpop

ular

),te

ased

/bul

lied,

subj

ecte

dto

mas

culin

ityte

sts

that

they

faile

d,or

felt

mar

gina

lized

even

ifth

ere

islit

tleev

iden

ceto

this

effe

ct.”

(p.9

)

10 International Journal of Developmental Science 8/2014, 3–24

F. Sommer et al. / Bullying, Romantic Rejection, and Conflicts with Teachers

21.L

arki

n(2

009)

Aca

dem

icre

sear

ch,v

ario

usm

edia

outle

tsan

dIn

tern

etsi

tes,

arch

ives

oflo

cala

ndre

gion

alne

wsp

aper

s

“Ast

uden

tor

afo

rmer

stud

entb

ring

sa

gun

tosc

hool

with

the

inte

ntio

nof

shoo

ting

som

ebod

y,th

egu

nis

disc

harg

edan

dat

leas

tone

pers

onis

inju

red,

and

the

shoo

ter

atte

mpt

sto

shoo

tmor

eth

anon

epe

rson

,atl

east

one

ofw

hom

was

nots

peci

ally

targ

eted

.”(p

.131

0)

36ca

ses,

38pe

rpet

rato

rs,2

are

nam

ed(1

974–

2012

)52

.6%

wer

em

otiv

ated

byre

veng

eag

ains

tbu

llyin

g,ha

rass

men

t,an

din

timid

atio

nby

thei

rpe

ers.

The

shoo

ters

peer

stat

usw

asde

term

ined

in25

of38

case

s.O

fth

ose

84%

wer

eei

ther

outc

asts

orlo

ners

who

wer

ere

ject

edby

thei

rpe

ers

eith

eras

indi

vidu

als

oras

mem

bers

ofid

entifi

able

low

-sta

tus

colle

ctiv

ities

.22

.Kal

ish

&K

imm

el(2

010)

Sam

plin

gof

med

iare

port

s“A

whi

tebo

y(o

rbo

ys)

brin

gsse

mi-

auto

mat

icri

fles

oras

saul

tw

eapo

nsto

scho

olan

dop

ens

fire

oncl

assm

ates

and

teac

hers

,see

min

gly

atra

ndom

.Sch

ools

hoot

ings

that

culm

inat

ein

the

suic

ide

ofth

eas

saila

nt(s

).”(p

.452

)

3ca

ses,

4pe

rpet

rato

rs(1

999–

2008

)“N

earl

yal

lhad

stor

ies

ofbe

ing

cons

tant

lybu

llied

,bea

ten

up,a

nd“g

ayba

ited”

.”(p

.455

)“I

nal

lthr

eeca

ses,

the

shoo

ters

felt

both

vict

imiz

edby

othe

rsan

dsu

peri

orto

them

.”(p

.459

)“I

twas

notj

ustt

hatt

hey

wer

ebu

llied

and

hara

ssed

and

intim

idat

edev

ery

day,

itw

asth

ead

min

istr

atio

ns,

teac

hers

,and

com

mun

ityco

llude

dw

ithit.

”(p

.462

)23

.Wie

czor

ek(2

010)

No

info

rmat

ion

avai

labl

eD

eadl

yvi

olen

ceth

atoc

curr

edin

scho

ols

9ca

ses

(196

4–20

09)

Inse

ven

ofni

neca

ses

soci

alri

skfa

ctor

s(m

ostly

disc

iplin

ary

prob

lem

s)co

uld

beco

nduc

ted.

24.W

eath

erby

,St

rach

ila,&

McM

ahon

(201

0)

New

spap

ers

from

the

day

ofth

esh

ootin

gto

seve

nda

ysla

ter

Eac

hca

seex

amin

edw

asco

mm

itted

bya

mid

dle

scho

olor

ahi

ghsc

hool

stud

ent

ina

lear

ning

envi

ronm

entw

ithin

the

Uni

ted

Stat

es.

12ca

ses

(200

1–20

08)

“The

reis

less

evid

ence

ofex

trem

ete

asin

gor

ostr

acis

mth

anL

eary

,eta

l.(2

003)

foun

din

thei

rst

udy.

Whi

leth

ese

findi

ngs

diff

er,

both

stud

ies

doill

ustr

ate

that

reje

ctio

n,te

asin

g,an

dos

trac

ism

can

bepr

omin

ent

fact

ors

insc

hool

shoo

tings

.The

rem

aybe

othe

rfa

ctor

s,ho

wev

er.”

(p.1

1)25

.Ros

hdi&

Hof

fman

n(2

011)

Cou

rtre

cord

s,in

terv

iew

sSe

eV

osse

kuil

etal

.(20

02)

10ca

ses

(199

9–20

09)

Six

outo

fte

npe

rpet

rato

rsfa

ced

prob

lem

sw

ithin

the

scho

olco

ntex

t(di

scip

linar

ypr

oble

ms,

confl

icts

with

teac

hers

),tw

ope

rpet

rato

rsex

peri

ence

dbu

llyin

g,an

dth

ree

perp

etra

tors

wer

epe

rcei

ved

aslo

ners

.26

.Bru

mm

e(2

011)

Scie

ntifi

cre

sear

ch,m

edia

acco

unts

Cur

rent

orre

cent

form

erst

uden

t,w

hopu

rpos

eful

lyse

lect

edan

dta

rget

edhi

sor

her

scho

ol.M

ultip

levi

ctim

s(t

arge

ted

orki

lled

byra

ndom

),th

atw

ere

chos

enby

thei

rsy

mbo

licco

nnec

tion

toth

ein

stitu

tion.

14ca

ses

(199

5–20

09)

Mos

tof

the

perp

etra

tors

had

been

teas

edor

hum

iliat

edby

peer

s.N

otal

lwer

elo

ners

,m

ostly

they

had

afe

wbu

tluk

ewar

mfr

iend

ship

s.O

ffen

ders

felt

isol

ated

and

mar

gina

l.

27.K

iilak

oski

&O

ksan

en(2

011)

“Pre

-inv

estig

atio

nre

port

sby

the

Finn

ish

polic

ean

dth

ere

port

sby

the

gove

rnm

entc

omm

issi

ons

crea

ted

toin

vest

igat

eth

esh

ootin

gspr

ovid

edba

ckgr

ound

mat

eria

l”(p

.32)

No

info

rmat

ion

avai

labl

e2

case

s(2

007–

2008

)“A

llFi

nnis

hsc

hool

shoo

tings

wer

eas

soci

ated

with

nega

tive

and

viol

ent

expe

rien

ces

insc

hool

.The

shoo

ters

tend

edto

feel

mar

gina

lized

and

tola

ckpe

ergr

oup

appr

oval

inth

eir

scho

olca

reer

s.”

(p.3

3)

International Journal of Developmental Science 8/2014, 3–24 11

F. Sommer et al. / Bullying, Romantic Rejection, and Conflicts with Teachers

Tabl

e1

(Con

tinu

ed)

Ref

eren

ceD

ata

sour

cefo

ran

alys

isD

efini

tion

for

inci

dent

sN

umbe

rof

case

san

alyz

edG

ener

alpo

sitio

non

soci

aldy

nam

ics

inin

form

atio

nsc

hool

shoo

tings

28.L

ankf

ord

(201

2)Pr

evio

ussc

hola

rshi

p,go

vern

men

tre

port

s,m

edia

repo

rts

“The

stud

yw

asde

sign

edto

anal

yze

terr

oris

m,r

ampa

ge,w

orkp

lace

,and

scho

olat

tack

sth

atin

volv

edsu

icid

eat

tem

pts

and

occu

rred

inth

eU

.S.”

(p.2

57)

Defi

nitio

nof

scho

olsh

ootin

gs:“

Indi

vidu

als

who

atta

cked

ata

scho

ol,c

olle

ge,o

run

iver

sity

that

they

had

ever

atte

nded

.”(p

.258

)

16ca

ses

(199

1–20

08)

75%

Soci

alM

argi

naliz

atio

n(l

oner

s,bu

llied

,te

ased

,did

noth

ave

clos

efr

iend

s,fe

ltso

cial

lym

argi

naliz

edor

soci

ally

isol

ated

);88

%W

ork/

scho

olPr

oble

ms

(str

uggl

ing

tosu

ccee

din

wor

kor

scho

ol,w

ere

angr

yor

upse

tabo

utst

h.at

wor

kor

scho

ol,o

rha

dbe

ensu

spen

ded,

fired

orot

herw

ise

disc

iplin

edat

wor

kor

scho

ol).

29.B

anne

nber

g(2

012)

Polic

ean

dco

urtr

ecor

dsR

ampa

gesh

ootin

gsof

adol

esce

nts

with

unkn

own

mot

ive

18ca

ses

ofad

oles

cent

mas

sm

urde

rer,

11ca

ses

occu

rred

inan

inst

itutio

n(1

992–

2009

)

Perp

etra

tor

felt

hum

iliat

edan

dbu

llied

,but

also

with

draw

nfr

omso

cial

cont

acts

and

did

notw

antt

ofit

in.I

nso

me

case

sdi

scip

linar

ypr

oble

ms

with

teac

hers

occu

rred

.In

four

ofel

even

case

s,sh

oote

rsw

ere

perc

eive

das

lone

rs,t

wo

expe

rien

ced

aro

man

ticre

ject

ion

prio

rto

the

atta

ck.

30.S

chill

er(2

013)

Art

icle

s,bi

ogra

phie

s,bo

oks,

med

ia,

inte

rvie

ws,

docu

men

tari

es,r

epor

ts,

and

Secr

etSe

rvic

efin

ding

s

“Any

inci

dent

whe

rea

curr

ents

tude

ntor

rece

ntfo

rmer

stud

enta

ttack

edso

meo

neat

his

scho

olw

ithle

thal

mea

ns,a

ndw

here

the

stud

enta

ttack

erpu

rpos

eful

lych

ose

his

scho

olas

the

loca

tion

ofth

eat

tack

.”(p

.102

)

12ca

ses

(197

8–20

00)

“Sho

oter

sar

ety

pica

llyyo

ung

men

who

feel

mar

gina

lized

.Man

yof

the

shoo

ters

stat

eth

atth

eyw

ere

bulli

edor

hum

iliat

edat

scho

olby

thei

rpe

ers

orbe

little

dby

adul

tsw

how

ere

clos

eto

them

.In

11of

17ca

ses

bully

ing

was

foun

d,in

one

case

the

perp

etra

tor

was

seek

ing

reve

nge

for

the

puni

shm

ento

fa

teac

her.”

(p.1

05)

31.L

angm

an(2

013)

Stud

entj

ourn

als,

polic

ere

cord

s,co

urt

docu

men

ts,o

ffici

alre

port

s,bo

oks,

and

artic

les

inbo

thsc

hola

rly

jour

nals

and

new

sou

tlets

“Atta

cks

atsc

hool

sin

whi

chth

ere

wer

em

ultip

levi

ctim

s.T

hevi

ctim

sin

clud

edpe

ople

who

wer

esh

otra

ndom

ly,a

sw

ella

sso

me

who

wer

esp

ecifi

cally

targ

eted

.The

perp

etra

tors

inal

mos

tev

ery

case

wer

eei

ther

curr

ento

rfo

rmer

stud

ents

atth

esc

hool

sth

eyat

tack

ed.I

ntw

oca

ses

the

perp

etra

tors

wer

eno

tstu

dent

sof

the

scho

ols

they

atta

cked

.”(p

.131

)

35ca

ses

(197

5–20

11)

“Onl

y6%

targ

eted

asp

ecifi

cst

uden

twho

had

pick

edon

them

,mor

efr

eque

ntly

they

targ

eted

fam

ilym

embe

rs,f

emal

es,a

ndsc

hool

pers

onne

l.E

ven

ifth

eyw

ere

teas

edan

d/or

bulli

ed,t

his

does

notm

ean

that

the

mis

trea

tmen

tcau

sed

the

ram

page

.”(p

.145

)

12 International Journal of Developmental Science 8/2014, 3–24

F. Sommer et al. / Bullying, Romantic Rejection, and Conflicts with Teachers32

.Dut

ton,

Whi

te,

&Fo

gart

y(2

013)

Perp

etra

tors

’di

arie

san

dw

eb-s

ites

No

info

rmat

ion

avai

labl

e4

case

s,3

ofth

emsc

hool

/un

iver

sity

shoo

ter

(199

9–20

11)

“The

rear

ese

vera

lele

men

tsin

the

thin

king

ofsc

hool

shoo

ters

that

sugg

esta

para

noid

pers

onal

itydi

sord

erbl

ende

dw

ithm

alig

nant

narc

issi

sm.P

aran

oid

pers

onal

ities

have

ape

rvas

ive

mis

trus

tof

othe

rs,a

resu

spic

ious

and

hype

r-vi

gila

ntfo

r“d

isre

spec

t”an

dac

tivel

yse

ek“e

vide

nce”

.The

ype

rsis

tent

lyfe

elw

rong

ed-

avi

ctim

ofso

cial

inju

stic

ean

dar

ese

ethi

ngw

ithan

ger

whe

nth

eyre

coun

tth

ese

inju

stic

es.T

here

islit

tlere

fere

nce

tosp

ecifi

cex

peri

ence

sof

bein

ga

vict

imof

bully

ing.

”(p

.551

)33

.Mad

fis&

Lev

in(2

013)

Med

iaac

coun

ts“A

naly

ses

incl

udes

only

thos

epe

rpet

rato

rsw

hoth

emse

lves

,att

hetim

eof

the

atta

ck,w

ere

enro

lled

inor

wer

ere

cent

lyw

ithdr

awn

from

the

mid

dle

scho

ol,h

igh

scho

olor

colle

geth

atth

eyta

rget

ed.M

ultip

lehu

man

targ

ets

wer

eki

lled

orin

jure

don

scho

olpr

oper

tyby

ast

uden

tor

rece

ntfo

rmer

stud

ento

fth

eta

rget

edsc

hool

.”(p

.80)

12ca

ses

(199

9–20

11)

“The

cata

lyst

for

scho

olsh

oote

rsis

mos

tof

ten

ahu

mili

atin

glo

ssof

face

,are

ject

ion

bya

girl

frie

nd,a

loss

ofac

adem

icst

andi

ng,a

nev

ictio

nfr

oma

com

mun

ityof

peer

s,or

even

am

ajor

illne

ss.A

tlea

st7

ofth

e12

inci

dent

sin

volv

edlo

ng-t

erm

bully

ing

asan

expr

essi

onof

the

kille

r’s

chro

nic

stra

inan

dlo

ngst

andi

ngde

sire

toge

teve

n.B

ully

ing

was

not,

how

ever

,the

only

form

oflo

ng-t

erm

frus

trat

ion

expe

rien

ced

bysc

hool

ram

page

shoo

ters

inth

ein

tern

atio

nals

ampl

e.”

(pp.

82ff

.)34

.Dum

itriu

(201

3)G

over

nmen

talr

epor

tsof

inqu

irie

sin

toth

ese

even

ts,p

olic

ere

port

s,co

urt

reco

rds,

scho

olre

cord

s,ne

wsp

aper

artic

les

and

arch

ival

docu

men

ts,fi

eld

data

(int

ervi

ews

and/

orfo

cus-

grou

ps)

“Mul

tiple

-vic

timac

tof

extr

eme

viol

ence

perp

etra

ted

onsc

hool

prem

ises

,ge

nera

llyby

asc

hool

-rel

ated

perp

etra

tor

who

care

fully

plan

sth

eac

tin

adva

nce.

”(p

.301

)

160

case

s,10

sele

cted

for

inde

pth-

qual

itativ

eca

sest

udie

s(1

900–

2013

),31

perp

etra

tors

are

refe

rred

“The

resu

ltsre

veal

edth

atsc

hool

shoo

tings

are

muc

hm

ore

com

plex

than

are

port

raye

din

mos

tres

earc

hst

udie

san

dof

ficia

lre

port

sin

the

field

,and

acco

rdin

gto

whi

chth

ece

ntra

lcha

ract

eris

ash

yst

uden

twho

had

been

bulli

edby

som

eof

his

peer

san

dw

hom

hesh

otin

anep

isod

eof

rage

.”(p

.306

)35

.Mal

kki(

2013

)“P

ublic

lyav

aila

ble

com

mun

icat

ion

byth

epe

rpet

rato

rs,o

ffici

alre

port

san

dpo

lice

inve

stig

atio

ndo

cum

ents

inth

ein

cide

nts,

med

iare

port

sas

wel

las

prev

ious

rese

arch

onth

ein

cide

nts.

”(p

.188

)

“Atl

east

part

lyin

disc

rim

inat

esh

ootin

gspe

rpet

rate

dby

form

eror

curr

ent

stud

ents

ofth

atsc

hool

.The

stud

ent

has

brou

ghtt

hegu

nto

the

scho

olw

ithth

ein

tent

ion

ofsh

ootin

gso

meb

ody,

atle

asto

nepe

rson

(oth

erth

anth

esh

oote

r)ha

sto

bein

jure

dby

abu

llet,

and

that

the

shoo

ter

atte

mpt

sto

shoo

tm

ore

than

one

pers

on,a

tlea

ston

eof

who

mw

asno

tspe

cific

ally

targ

eted

.”(p

.188

)

28ca

ses

(199

9–20

11)

Thr

eety

pes

ofsc

hool

shoo

ters

:“1.

Polit

ical

scho

olra

mpa

gesh

ootin

gs:T

hepe

rpet

rato

rsex

pres

san

grily

thei

rre

sent

men

tof

the

way

they

have

been

trea

ted,

argu

ing

that

they

wer

epu

shed

toth

eir

acto

fve

ngea

nce.

From

the

desc

ript

ion

ofth

epe

rson

alsi

tuat

ion

emer

ges

anim

age

ofa

faile

djo

iner

,who

trie

dto

fitin

butw

asbu

llied

,tea

sed,

and

reje

cted

.Ats

ome

poin

t,th

eyun

ders

tood

that

they

did

note

ven

wan

tto

fitin

toth

em

ajor

ityan

dliv

ein

aw

orld

like

that

.”(p

.200

)2.

Col

umbi

ne-I

nflue

nced

Shoo

tings

.3.I

sola

ted

shoo

tings

.

International Journal of Developmental Science 8/2014, 3–24 13

F. Sommer et al. / Bullying, Romantic Rejection, and Conflicts with Teachers

31, 34, 35] analyses of cases were based on officialprimary sources including police-, school-, court- andmental health records. In addition, personal accountswere consulted, along with interviews with familymembers, school staff and perpetrators themselves.

In reviewing the 35 selected studies, we identified 126different cases of school shootings, involving 128 per-petrators. Of these 126 attacks, 112 attacks occurred inschools, (88.9%), 14 (11.1%) on university campuses.The earliest case included in the primary studies tookplace in Volkhoven (Germany) in 1964, the latest inNewtown (USA) in 2012. The mean age of perpetratorswas 19 (SD = 8.72) and the median age of perpetratorswas 16. The youngest perpetrator was six years old, theoldest 62. A total of 121 shooter were males (94.5%)while seven offenders were females (5.5%). Most of theattacksoccurred(n = 97) in theU.S. (75.3%).Therewere14 in Germany (10.9%), four in Canada (3.1%), three inFinland (2.3%), two in Brazil, and one shooting each ineightadditionalcountries (Argentina,Australia,Bosnia,Greece, Hungary, Netherlands, Sweden, and Thailand).

One important task was to determine how often indi-vidual perpetrators were included in the various primarystudies selected. Our results showed an unequal dis-tribution of cases: 63 of the 128 perpetrators (49.2%)were included in one study only, 22 (17.2%) in two,33 in three to ten studies (25.8%), and, finally, tenperpetrators were included in more than ten studies(7.8%). The ten most frequently reported cases wereEric Harris: Columbine 1999 (included in 22 stud-ies); Dylan Klebold: Columbine 1999 (20 studies);Luke Woodham: Pearl 1997; Michael Carneal: WestPaducah 1997; Andrew Golden and Mitchell Johnson:Jonesboro 1998; Kipland Kinkel: Springfield 1998 (17studies); Barry Loukaitis: Moses Lake 1996 (14 stud-ies); Thomas Solomon: Conyers 1999 (13 studies) andEvan Ramsey: Bethel 1997 (11 studies).

Categories and Content Analysis

In order to analyze the social dynamics which mighthave played a role in the various cases, we chose thosewhich contained detailed information on social posi-tion, as well as on personal relationships and conflicts–questions like whether the perpetrator had been a loner,had been bullied or had experienced conflicts withteachers. As ten studies presented only aggregated data[2, 3, 5, 6, 9, 15, 18, 19, 28, and 34] particular categorieswere not applicable in all of the 126 cases. We excludedthose studies which contained either no detailed quali-tative information on the cases or only aggregated data.

In addition, four cases were excluded from analysis,either because they did not fit our definition of a schoolshooting. In addition, four cases were excluded fromanalysis, either because they did not fit our definition ofa school shooting or the attack had been thwarted. Asstated in the introduction, we define school shootingsas offenses committed by a current or former studentwho purposely chooses his or her school or universitycampus as the site of an attempt to kill one or morepersons.

The list was narrowed down to 65 school shootings,committed by 67 perpetrators discussed in 25 studies,including 59 attacks in schools (90.8%) and six on uni-versity campuses (9.2%). The mean age of perpetratorsincluded in this reduced sample was 18 (SD = 7.38)and the median age of perpetrators was 16 years. Theyoungest perpetrator was 11 years of age, the oldest62. Sixty three perpetrators were males (94.0%) andfour were females (6.0%). The percentage of casesfrom the USA was slightly lower compared to the ini-tial sample (46 cases = 70.8%), and the perpetrators inthe reduced sample came from a smaller number ofcountries (Germany: nine cases = 13.8%; Finland: threecases = 4.6%; Canada and Brazil: two cases = 3.0%;Australia, Greece, and Thailand: one case each). Theaverage case involved 2.83 fatalities (excluding perpe-trators’ suicide) and 5.81 injuries. Twenty perpetrators(29.9%) committed suicide.

In the most recent list to be published, Bockler,Seeger, Sitzer, and Heitmeyer (2013) attributed 63% ofschool-shootings worldwide to the U.S. In our samplethe proportion is slightly higher, at 70.8%. In contrastto many primary studies (e.g. McGee & DeBernardo,1999; Newman et al., 2004; Vossekuil et al., 2002)we included female perpetrators in our sample (n = 4).The majority of perpetrators (83.6%) were adolescents(between 12 and 21 years of age) – a common find-ing in the literature on school shootings. The averageof 2.83 dead and 5.81 injured victims per attack corre-sponds roughly to the average rate of victims per offensebetween 2000 and 2010 as reported by Bockler et al.(2013). Likewise, the proportion of perpetrators in oursample who committed suicide (29.9%) was approx-imately the same as that reported by Bockler et al.(2013), with 33 out of 123 perpetrators (27%) takingtheir own lives. Thus we can conclude that our sampleis in line with findings which are commonly found inthe literature on school shootings.

In analyzing the contents of case reports, we devel-oped a coding scheme based on descriptions of riskfactors which frequently appear in the literature. All

14 International Journal of Developmental Science 8/2014, 3–24

F. Sommer et al. / Bullying, Romantic Rejection, and Conflicts with Teachers

categories and concepts bearing on the perpetrator’ssocial position, personal relationships and conflictswere collected from the literature and consolidated ina coding scheme.

The first step in our analysis was to select fromthe primary studies all qualitative information relatingto social dynamics and to list it according to case. Iftwo perpetrators carried out an attack, we analyzed thesocial dynamics observable in each one. Thus, in the fol-lowing remarks the term “cases” refers to the number ofperpetrators, rather than the number of incidents. Sec-ondly, two experts on school-shooting research workedindependently, using our coding scheme in rating infor-mation. Subsequently they discussed the ratings theyobtained, case by case, until they reached consen-sus. Thus, analyzing the reliability of ratings was notappropriate. In reconstructing the perpetrator’s profile,specific categories like “loner” or “bullying victim”were described as either “present” or “not present”. Weapplied the classification “inconsistent data” in caseswhere the information contained in the primary studieswas contradictory.

In examining the social dynamics in each case, welooked at the following categories:

• Loner (self-report): The perpetrator sees him- orherself as someone who prefers to be alone andconsequently either does not actively seek humaninteraction or deliberately avoids it. The sources weconsulted included diaries and interviews.

• Loner (external report): Here we consulted externalsources, including the accounts of peers, teachers,and other individuals in the case descriptions.

• No friends: In describing the social relationships ofschool shooters, many researchers have stated thatthey had no friends at all. As cultural differences canbe reflected in definitions of what a friend is, we onlyapplied this category when there was evidence incase descriptions that the perpetrator had no friends.

• Physical bullying: Any kind of bullying resulting inphysical pain or damage to property. There was noway of knowing exactly how the term was defined inthe various primary studies we examined, (e.g. as ithas been defined by Olweus, 1994), so we acceptedthe researchers’ use of the word in describing a per-petrator or in referring to beatings suffered by theperpetrator at the hands of peers.

• Verbal and/or relational peer rejection: Thisincludes teasing, name calling, gay bating, andostracism. Whether or not these forms of peer rejec-tion are covered by the definition of bullying used

in the individual case studies remains unclear. Mostgive no detailed information on the frequency orduration of such incidents or on the relationship ofthe perpetrator to those who rejected him or her. Weapplied the term if the perpetrator had been teased,picked on, “gay-baited”, or otherwise rejected by hisor her peers according to the information containedin the primary studies.

• Romantic rejection: This describes a romanticbreakup or a case of unrequited love prior to theschool shooting, which apparently had a bearing onit.

• Conflict with teachers or school system: Open con-flicts with an individual teacher or other schoolauthorities, including the school principal (disci-plinary or academic injustices, personal conflicts,suspension from school).

• Bully: Evidence that the shooter had bullied others.• Model student: We borrowed this category from

Dumitriu (2013), who described perfect (honored)students as well-socialized individuals (male), whohave friends as well as relationships with girls,and who are generally regarded as polite, mild-mannered, respected, model students.

• Social marginality (self-report): Social marginality,the most important feature postulated in the workof Newman et al. (2004), refers to the perpetrator’sown self-perception as extremely marginal in thesocial world that matters to him.

• Urge for revenge: Revenge as a motive can provideinformation on perpetrators’ suffering as a resultof social exclusion and/or personal conflicts. Thisfeature was included if studies explicitly mentionedthat revenge was a motive in the shooting.

In addition to these categories, we also reviewedevidence for concepts often used in school shooting lit-erature. Concepts combined several categories within atheoretical framework:

• Any marginalization: Under this category, Newmanet al. (2004) list evidence that the “protagonist was(a) loner or fringe figure (certainly not popular), or(b) teased/bullied, or (c) subjected to ‘masculinitytests’ that he failed, or (d) felt marginalized evenif there is little evidence for this effect” (Newman& Fox, 2009, p. 9). In order for us to give a rat-ing on this, information relating to the categories“loner” (either self or external description) and/or“physical bullying” and/or “verbal and/or relationalpeer rejection”, and/or “social marginality” had tobe evident from the case descriptions.

International Journal of Developmental Science 8/2014, 3–24 15

F. Sommer et al. / Bullying, Romantic Rejection, and Conflicts with Teachers

• Peer rejection: Here Leary et al. (2003) includephysical bullying, teasing and other forms of peerrejection (verbal, romantic, and other). We con-cluded that this applies when there is evidence of“physical bullying”, and/or “verbal and/or relationalpeer rejection”, and/or “romantic rejection” in thecase description.

• Any interpersonal conflicts: This includes all inci-dents that we interpreted as personal conflicts(“physical bullying”, and/or “verbal and/or rela-tional peer rejection”, and/or “romantic rejection”,and/or “conflict with teachers or school system”).

Findings

The rating of information – and subsequently the inter-pretation of our findings – was hampered by the fact thatthe primary studies we selected did not always includeinformation for every category which was of interest tous. In such cases there was no way of knowing whetherthe researchers were unable to access the informationwe wanted or whether they had found no evidence ofcertain features relating to social dynamics. For thisreason we decided to pursue a two-pronged strategyin analyzing individual studies. In a so-called “con-servative analysis” we interpreted only the informationwhich the authors of the primary studies provided. In a“progressive analysis” we assumed that if the authorsof the primary studies did not report any informa-tion which fell under a specific category that meantthat they did not find any evidence of its presence.In this case we rated “no information”, meaning “noevidence”. Assuming that the authors of such primarystudies would normally report all of the informationthat emerged and was regarded as relevant, we use the“progressive analysis” in the following description andinterpretation.

Regarding the perpetrators’ social position withintheir respective social networks, discrepancies werediscovered between their self-appraisals and thosegiven by others. In 47.8% of cases, perpetrators weredescribed as loners or social outcasts. Some degree ofsocial marginalization, as reported in external descrip-tions, was found in 85.1% of cases. In contrast to theseexternal reports, only in 23.9% of cases did perpetra-tors describe themselves as loners, and in only 55.2% ofcases was there evidence that perpetrators themselveshad felt socially marginalized. In addition, in eight cases(11.9%) feelings of marginalization, in five cases feel-ings of being a loner were explicitly excluded in theprimary studies. Thus, an all-encompassing social iso-

lation/marginalization of the perpetrator is apparentlyrelatively rare. Additionally, there was almost no casein which the perpetrator had no friends at all (4.5%,n = 3). However, this finding does not mean that perpe-trators were popular among their peers. In most studiesresearchers found that the perpetrators had few friends,with only two out of 67 perpetrators (3.0%) describedas being a model student (cf. Dumitriu, 2013).

We found little evidence that there had been physicalbullying (29.9%), and in 31.3% of the cases, physicalbullying was explicitly excluded. Other forms of peerrejection such as teasing, provoking, name calling and“gay bating” were reported more often (53.7%). In only10 cases (14.9%) they were explicitly excluded. Theseresults indicate that there are school shooting cases inwhich bullying definitely played no role, while in ninecases (13.4%) perpetrators were described as bullies,without being bullied themselves.

In connection with peer rejection, romantic rejectionmust also be considered. Leary et al. (2003) mentionedromantic rejection as a third category of peer rejection– alongside teasing and ostracism – and found this formof rejection in about half of the cases analyzed. In ourreview we found evidence for romantic rejection in only29.9% of the cases. It is worth noting that in some cases(n = 6), romantic rejection was apparently the only formof interpersonal conflict within the network of relation-ships at school prior to attack. Altogether, in 67.2%of the cases, we concluded that peer rejection cursiveinstead in some form – whether physical bullying, ver-bal abuse, or romantic rejection – was present.

Researchers have commonly neglected the signif-icance of student-teacher problems and interaction(Bondu & Scheithauer, 2014). In our review we foundthat conflicts with teachers (in 43.3% of the cases)prior to the attack might have been a key factor influ-encing the negative development of a future assailant.In 88.1% of the cases there were interpersonal prob-lems/conflicts in some form (bullying, teasing, romanticrejection, and/or conflicts with teachers) within theschool environment. In four cases (6.0%), findings wereinconsistent, and in only two cases was there no evi-dence of such problems or conflicts.

Analyzing possible motivating factors can also tell ussomething about the self-perception of the perpetratorswith regard to social dynamics prior to their attack. Ifperpetrators saw their shooting as revenge for mistreat-ment suffered at the hands of significant people in theirsocial environment, we can assume that social relation-ships were a source of suffering. In our review, scholarsdescribed urge for revenge as a motive for 26 perpe-

16 International Journal of Developmental Science 8/2014, 3–24

F. Sommer et al. / Bullying, Romantic Rejection, and Conflicts with Teachers

trators (38.8%). In one case revenge as a motive wasexplicitly excluded. In the majority of cases (59.7%)no information was given on the perpetrator’s motives.

Discussion

Our study indicates that, in analyzing the impact ofsocial dynamics prior to a school shooting, it is impor-tant to include different kinds of relationships and toexamine how they are interconnected. As stated above,bullying and peer rejection are very important, but theyare not the only forms of conflict. Conflicts with teach-ers – and with the school system as a whole – arealso of key significance. In addition, the perpetrators’social position and subjective perception of victimiza-tion and marginality can be crucial factors on the pathtoward violent school attacks. For our content analysisof school shooting cases reported in primary studies, weused common categories and concepts of risk factorsrepresenting significant experiences within the domainof “social dynamics”. From our perspective, these cate-gories rated with our coding scheme can be allocated to– at least – three different superior classes of concepts:

Under one superior class we place conflicts and otherforms of negative interaction experienced by the per-petrators (conflicts with peers and teachers, bullying,romantic rejection); a second class includes their socialposition within the social network at school (whetherloner, outcast, or model student) and finally perceptionsof the perpetrators themselves serve as a third superiorclass of concepts (feelings of marginalization, of beinga loner, of wanting revenge).

From our perspective it seemed useful to discuss ourfindings along these classes in order to allow a greaterunderstanding of the social dynamics prior to an inci-dent of school shooting and to find categories whichcould be functional equivalent.

Negative Interaction and Conflict

There is general consensus in the literature on schoolshootings on the key role of negative events and dis-turbed personal interaction prior to school shootings.Our findings suggest that a broad constellation of eventsand developments must be included in our analyses.Only a minority of perpetrators (29.9%) experiencedactual physical bullying and/or other extreme formsof mistreatment. More frequently perpetrators sufferedfrom a general feeling of being rejected by peers.However, the overall rate of verbal and relational peer

rejection we discovered was slightly lower (53.7%) thanreported in some of the individual studies included inour review. Thus our findings are more in line with thoseof Weatherby et al. (2010), who found ongoing teasingor ostracism in only half of the cases in their sample.

Considering the prevalence of rejection in general,expressed in various ways, (e.g. Hess & Scheithauer, inpress; Scheithauer, Haag, Mahlke, & Ittel, 2008; Scheit-hauer, Hayer, Petermann, & Jugert, 2006), the questionarises as to whether this particular kind of negative inter-action with peers might be a significant and necessaryrisk factor in the development of the school shooter, asis commonly maintained in the literature on the sub-ject and in the media. It is important to note here thatsome of the perpetrators were described as being bul-lies themselves (13.4%). This finding casts doubt onmodels which place sole emphasis on the victim sta-tus of perpetrators (Levin & Madfis, 2009). Researchon bullying confirms that bullies are or were also vic-tims (so called bully-victims; e.g. Hess & Scheithauer,in press; Scheithauer et al., 2003; Scheithauer et al.,2006). In our sample we found only one perpetrator outof nine who was described as a bully and whose actionsincluded physical abuse, while five had experiencedpeer rejection in some form.

Another form of negative social interaction whichmight play a role is romantic rejection, often catego-rized under the term “peer rejection”. In the cases weinvestigated, romantic rejection (29.9%) did not appearto be as widespread as Leary et al. (2003) stated intheir study (in about half of the cases). Nevertheless,in some of the cases, romantic rejection and unrequitedlove were the only forms of interpersonal conflict inthe perpetrator’s history (n = 6). Nor did our findingson peer rejection (in 67.2% of the cases) correspond tothose of Leary et al. (2003), who found peer rejection in13 of 15 cases (86.6%). Instead they were in line withthe findings of Vossekuil et al. (2002), who discoveredevidence of bullying, ostracism, and social rejection inover two-thirds of the cases analyzed.

Apart from peer rejection or disturbed relationswith friends, our findings suggest that another typeof negative social interactions within the school envi-ronment must be taken into account (cf. Bondu &Scheithauer, 2014): In 43.3% of the cases, perpetra-tors experienced ongoing conflicts with teachers andschool officials. This finding was remarkable, con-sidering that researchers have commonly overlookedstudent-teacher problems and interaction as a signifi-cant risk factor in the development of later perpetratorsleading up to a school shooting. Furthermore, despite

International Journal of Developmental Science 8/2014, 3–24 17

F. Sommer et al. / Bullying, Romantic Rejection, and Conflicts with Teachers

Table 2Findings1

Categories No Any Inconsistent Sum No Sumevidence evidence finding2 conservative information progressive

Loner (self report) N 5 16 21 46 673

Conservative 23.8% 76.2% 100.0%Progressive 7.5% 23.9% 68.7% 100.0%

Loner (external report) N 8 32 4 44 23 67Conservative 18.2% 72.7% 9.1% 100.0%Progressive 11.9% 47.8% 6.0% 34.3% 100.0%

No friends N 29 3 4 36 31 67Conservative 80.6% 8.3% 11.1% 100.0%Progressive 43.3% 4.5% 6.0% 46.3% 100.0%

Physical bullying N 21 20 7 48 19 67Conservative 43.8% 41.7% 14.6% 100.0%Progressive 31.3% 29.9% 10.4% 28.4 100.0%

Verbal or relational peer rejection N 10 36 8 54 13 67Conservative 18.5% 66.7% 14.8% 100.0%Progressive 14.9% 53.7% 11.9% 19.4% 100.0%

Romantic rejection N 5 20 1 26 41 67Conservative 19.2% 76.9% 3.8% 100.0%Progressive 7.5% 29.9% 1.5% 61.2% 100.0%

Conflicts with teacher/school N 3 29 32 35 67Conservative 9.4% 90.6% 100.0%Progressive 4.5% 43.3% 52.2% 100.0%

Bully N 8 9 1 18 49 67Conservative 44.4% 50.0% 5.6% 100.0%Progressive 11.9% 13.4% 1.5% 73.1% 100.0%

Model student N 10 2 2 14 53 67Conservative 71.4% 14.3% 14.3% 100.0%Progressive 14.9% 3.0% 3.0% 79.1% 100.0%

Urge for Revenge N 1 26 27 40 67Conservative 3.7% 96.3% 100.0%Progressive 1.5% 38.8% 59.7% 100.0%

Social marginality (self report) N 8 37 4 49 18 67Conservative 16.3% 75.5% 8.2% 100.0%Progressive 11.9% 55.2% 6.0% 26.9% 100.0%

Any marginalization N 4 57 61 6 67Conservative 6.6% 92.4% 100.0%Progressive 6.0% 85.1% 9.0% 100.0%

Peer rejection N 9 45 6 60 7 67Conservative 15.0% 75.0% 10.0% 100.0%Progressive 13.4% 67.2% 9.0% 10.4% 100.0%

Any interpersonal conflict N 2 59 4 65 2 67Conservative 3.1% 90.8% 6.1% 100.0%Progressive 3.0% 88.1% 6.0% 3.0% 100.0%

1Findings are presented in the table as follows: The first line of every category shows the frequencies. The second line (conservative) indicates thepercentage for a conservative analysis of frequencies, interpreting “no information” to mean that information was lacking. The second line showsthe percentage for a progressive analysis of frequencies, interpreting “no information” as no evidence for the particular category. 2“Inconsistentfinding” = scholars made divergent statements about the evidence of an individual factor. 3N = 67 cases (perpetrators) with detailed informationregarding social dynamics.

all the literature on school shooters and their relation-ship to the school system in general (Adams, 2000;Staples, 2000; Thompkins, 2000), little attention hasbeen given to teacher-perpetrator relations in case stud-ies on school shootings in the U.S. In contrast, in variousGerman studies (Bondu 2012; Bondu & Scheithauer,2014; Hoffmann et al., 2009; Wieczorek, 2010) con-flicts between teachers and future perpetrators, along

with feelings of injustice suffered at the hands of schoolstaff, are well documented. Thus, the German cases sug-gest that loss of status within the school environmentas reference system is an important key factor. In ourreview, we found evidence of this in U.S. cases as well(41.7% of U.S. cases).

In conclusion, in most of the cases analyzed (88.1%),perpetrators experienced conflicts and other forms of

18 International Journal of Developmental Science 8/2014, 3–24

F. Sommer et al. / Bullying, Romantic Rejection, and Conflicts with Teachers

negative social interaction within the school environ-ment as reference system. Such negative interactionincluded (1) physical mistreatment and/or social exclu-sion by peers, expressed verbally or otherwise, (2)romantic rejection, (3) feelings of being treated unjustlyby teachers and school officials. While in a few cases(n = 7) all three types of negative interaction werepresent, in 41 of the 67 cases examined only onewas found (bullying/verbal and relational peer rejectionn = 19; romantic rejection n = 6; conflicts with teachersn = 16). As these results indicate, it remains to be seenwhether these three types of negative interaction arefunctionally equivalent on the development of perpetra-tors. This is a hypothesis which might be investigatedin further research, in which case analysis should focuson the personal relationship between the perpetrator andselected victims before and during the act of violence.

Social Position

Typically school shooters are described as marginalizedloners, or social outcasts. Our results only partially con-firmed these descriptions. While 47.8% of perpetratorswere characterized as loners or outcasts, 11.9% werenot. Thus, perpetrators were not completely isolated,but in fact had social contacts and were not as lonely asone would normally expect a “loner” to be. Moreover,there is evidence that, in some cases, the perpetrators’friends could be labeled “deviant”. Sometimes thesefriends played a significant role in the social dynamicsthat lead up to the attack, in that they either directlyor indirectly expressed support for the future perpe-trator, either by procuring weapons, placing bets onwhether the attack would be carried out and/or increas-ing the pressure to act by making light of threats. Thus,in line with Vossekuil et al. (2002), we can concludethat peer interaction and friendship patterns varied allthe way from being socially isolated to being popular.On the other hand we disagree with Dumitriu (2013),who claimed that a relevant number of school shoot-ers were “perfect (honored) students”: in our sampleonly two perpetrators fitted the description model stu-dent. In contrast, Dumitriu identified 22 (13.5%) outof a total of 163 school shooters as model students. Itshould be noted, however, that methodological differ-ences between her study and our review2 make directcomparison difficult.

2Her study did not allow for a direct assignment from character-istics to cases, she included cases from 1900 to 2013.

Our findings confirmed the concept of “marginaliza-tion” developed by Newman et al. (2004), with 85.1%of the cases in our review fitting that concept. At thesame time, Newman combines self-reports of marginal-ization and bullying on the one hand, and externaldescriptions of the perpetrator as being a loner, onthe other, in one single concept. In our opinion, thisis problematic, as it prevents us from seeing how thetwo are interrelated. It becomes impossible to deter-mine whether the marginal position of the perpetratorwas the result of peer rejection or whether it was “self-chosen withdrawal”. Thus, marginalization becomes a“catch-all” category, which is very difficult to interpret.Overall, there is some evidence that a majority of attack-ers were marginalized among their peers, but we mustbe careful in making generalizations. In our review weeven found descriptions which suggested that the per-petrators were by no means loners or outcasts and werenot at all marginalized.

Subjective Perception of Perpetrator

Some authors argued that there was no objectiveevidence of peer rejection in some cases, while the per-petrators themselves felt rejection, a factor which mighthave played a role in the decision to attack (e.g. Duttonet al., 2013; Langman, 2013). This divergence might beexplained by personality traits such as narcissistic ten-dencies or excessive sensitivity to perceived injustice(Hoffmann et al., 2009). Following this presumptionone would expect reports of self-reported victimizationto outnumber external ones. However, our findings sug-gest the opposite: Perpetrators described themselves asloners less often than others perceived them as such(23.9% self-report vs. 47.8% external report), and lessoften as marginalized (55.2% self-report of marginal-ization vs. 85.1% report of any marginalization; cf.findings by Newman et al., 2014, who found the self-description “loner” in 34% of the cases, “marginalized”in 67%). Thus, from the perspective of the perpe-trator, revenge resulting from interpersonal conflictsmight have been a driving motive. In fact, in 38.8%of cases perpetrators cited revenge as a motive – asomewhat lower rate than that reported by Vossekuilet al. (2002), who concluded that more than half ofthe attackers were driven by revenge. In our analysiswe were unable to determine, in retrospect, whetherperpetrators themselves cited “revenge” as a motive orwhether researchers did so. Here we must rememberthat in many cases there were no self-reports, as theperpetrators had died at the scene of the violent act.

International Journal of Developmental Science 8/2014, 3–24 19

F. Sommer et al. / Bullying, Romantic Rejection, and Conflicts with Teachers

Additional Findings

Additionally to the content-related findings, we havefound some other noteworthy aspects in the primarystudies:

First, as conceded by the researchers themselves (e.g.Harding, Fox, & Mehta, 2002), studies on school shoot-ings have been largely limited to small samples, withall the consequent methodological difficulties. Manyof the primary studies we reviewed investigated moreor less the same ten cases (Moses Lake, Bethel, Pearl,West Paducah, Erfurt, Jonesboro, Littleton). All of thesecases dated from the late nineties, occurred in the U.S.and were analyzed in the first wave of school shootingresearch published between 1999 and 2004. Thus mostof our knowledge of school shootings stems from justa few case studies from the same time and place. Sixtythree out of a total of 128 perpetrators (49.2%) wereincluded in only one single study, which means thatlittle consideration was given to half of all cases thatqualified. Integrating these cases into one comprehen-sive review might lead to different results, especiallyas it is not clear why some cases were included in theprimary studies and others were not. It is possible thatthose cases were selected that were prototypical, whilethose which deviated from the perceived norm weredisregarded.

Second, the mode of data collection is potentiallybiased, as information was mainly obtained from pressreports, which may reflect reporters’ personal theoriesregarding the causes and dynamics of the shootings,instead of delivering objective information. Journaliststend to look for the typical, for prototypes that rein-force existing images and stereotypes. In doing so, theysometimes ignore or downplay other explanations ofviolence (Danner & Carmody, 2001). These limitationsaffect a total of 12 primary studies in our review whichmostly relied on media accounts. Furthermore, due tothe need for retrospective analysis focusing on this phe-nomenon, the data that was obtained by court-, police-,or school reports may also be biased.

Third, definitions proved a problem in carrying outour review. In most of the primary studies, the term“school shootings” is defined in advance, and casesare selected accordingly. The definitions vary widely– resulting in very different lists of cases regardedas “relevant”. There was disagreement with regard tothe number of victims (multiple vs. single casualties),choice of weapon (solely firearms vs. lethal means ingeneral), the question whether the attack was premed-itated or spontaneous (school deliberately chosen vs.

random selection), the status of perpetrator (studentor former student vs. non-student), the outcome of theattack (thwarted vs. carried out), and the country whereit took place. The only feature common to all the defi-nitions is the site of the violent act, which is a school oruniversity. In short, we realized that the cases we under-took to compare probably differed in many respects.Thus we were careful to include only those cases whichfit our basic definition of a school shooting. We left openthe questions as to the country where the attack tookplace, the choice of weapon, the number of victims andthe outcome.

Conclusion: From Risk Factors Towards aDevelopmental Perspective

The comprehensive review we have undertaken revealsthat the social dynamics which can play an importantrole in school shootings are much more varied thanindicated in any one primary study. Although there aremany similarities between the individual cases (perpe-trator felt marginalized, experienced peer rejection, andsaw his or her attack as an act of revenge) there werealso cases which do not fit this description (perpetra-tor was a bully, had not experienced peer rejection, hadbeen characterized as model student). These atypicalcases merit particular attention and analysis. Thus, inexamining the social dynamics as they developed priorto a school shooting, we found numerous differencesamong perpetrators and discovered that differing pathshad led them to the shooting incident (equifinality; cf.Cicchetti & Rogosch, 1996). Having taken a close lookat the literature, we concluded that, among the factorsinvestigated, there was no single one which was presentin all cases, which means that these are no necessaryconditions when it comes to school shootings. Whatwe see instead are multiple risk factors from differ-ent domains, interacting with each other in a complexmanner, including such things as individual person-ality traits and specific situations. Grouping togetherindividual factors into more “general” concepts suchas “social marginality of the perpetrator” (85.1% ofcases) or “negative social interaction within the schoolenvironment” (88.1% of cases) we can conclude thatmost of the cases fulfilled the criteria. Further studiesshould investigate if all social dynamics perform thesame function in the developments which culminatein a school shooting, including factors like bullying,romantic rejection, and conflicts with teachers.

With the exception of several in-depth case studies(e.g. Fast, 2009; Larkin, 2009; Newman et al., 2004)

20 International Journal of Developmental Science 8/2014, 3–24

F. Sommer et al. / Bullying, Romantic Rejection, and Conflicts with Teachers

the primary studies we included approached risk fac-tors as “existent” or “non-existent”, without asking forexample who had assessed them (perpetrator, special-ists, scientist, etc.) or what time frame was involved(early childhood, the period leading up to the shoot-ing). All of the risk factors are looked at individuallyand analyzed separately in determining whether theyincrease or reduce risk. Thus, complex social dynamicsare divided up into isolated parts in an “a-theoretical”manner (Fox & Burstein, 2010). Real understandingof the factors leading to violent acts such as schoolshooting we will require a careful analysis of the linksconnecting social position, social interaction, and thesubjective self-perception of the future perpetrator overa period of time. Whether or not romantic rejection, forexample, can be considered a contributing factor, willdepend on the perception of the perpetrator. Thus, anapproach is needed which takes into account the vari-ous contributing factors and their respective impacts onthe psychosocial development of the individual.

Limitations and Prospects

Research on school shootings has been commonlybased on retrospective, incomplete data, and these lim-itations hamper any content analysis of the primarystudies. Some researchers supply a great deal of infor-mation on certain cases, while others provide little ornone. Thus, giving ratings on the basis of a codingscheme was quite simple in some cases, but challeng-ing in others. Without knowing whether, for example,bullying involved repeated physical, verbal or psycho-logical attacks or some other form of intimidation whichwent on for a long period and reflected an imbalanceof power, we cannot speak of bullying per definition.The extent to which the victimization experience neg-atively impacts on the psychosocial development ofan individual depends in part on his or her copingstrategies, emotional regulation, and further contextualfactors (Mahady Wilton, Craig, & Pepler, 2000). Fur-ther research on the impact of bullying experiences orother social difficulties on the perpetrator’s develop-ment to violence should therefore focus more on theimpact of victimization perceived by the perpetratorthan on the bullying experience itself.

The present comprehensive review was conductedwith the aim of shedding light on the crucial role ofsocial dynamics in school shootings. Other individ-ual and contextual factors were left out of the picture,although they no doubt also contribute to social con-flicts and emotional strain. Investigating these factors

and the ways in which they interact over time will benecessary if we are to gain a comprehensive understand-ing of school shooting cases. Finally, it is likely that wehave not given due consideration to cultural factors.What is seen as social marginalization and conflict inone country or culture might not be seen as such inanother, a fact which should be born in mind when themedia and court reports in one country register fewersigns of social marginalization and conflict than else-where, in attempting to explain school shootings (cf.Lankford, 2012). Further analyses should address thedifferences between cases in the U.S. and those thatoccurred in other countries, in attempting to clarify therole of cultural influences in the developments that leadto school shootings. Recent research has delivered anal-yses of school shootings, comparing them with otheracts of homicide (Lankford, 2012). These are promis-ing efforts which should contribute to our understandingof the phenomenon, by specifying the particular con-stellation of causes and contributing factors which turnyoung people into school assassins.

Acknowledgments

The present study is part of the interdisciplinary three-year research project TARGET (2013–2016), fundedby the Federal Ministry of Education and Research(BMBF) of Germany (funding code 13N12646).

Conflicts of Interest

There are no conflicts of interest.

References3

Adams, A. T. (2000). The status of school discipline and violence.The ANNALS of the American Academy of Political and SocialScience, 567, 140-156.

*Band, S. R., & Harpold, J. A. (1999). School violence. Lessonslearned. FBI Law Enforcement Bulletin, 68, 9-16.

*Bannenberg, B. (2012). Sogenannte Amoklaufe junger Tater –Mehrfachtotungen aus unklarem Motiv. [So-called rampageshootings of young perpetrators – Multiple homicides withunknown motive]. In H. Remschmidt (Ed.), Totungs- und Gewalt-delikte junger Menschen. Ursachen, Begutachtung, Prognose (pp.77-104). Berlin, Heidelberg: Springer.

Bockler, N., Seeger, T., Sitzer, P., & Heitmeyer W. (Eds.). (2013).School shootings. International research, case studies, and con-cepts for prevention. New York: Springer.

Bondu, R. (2012). School Shootings in Deutschland. Inter-nationaler Vergleich, Warnsignale, Risikofaktoren, Entwick-lungsverlaufe [School shootings in Germany. International

3References with a * were included in the systematic review

International Journal of Developmental Science 8/2014, 3–24 21

F. Sommer et al. / Bullying, Romantic Rejection, and Conflicts with Teachers

comparison, warning signs, risk factors, developmental path-ways]. Retrieved from Freie Universitat Berlin’s electronic The-ses and Dissertations Archive: http://www.diss.fu-berlin.de/diss/receive/FUDISS thesis 000000037683

Bondu, R., & Scheithauer, H. (2014). Peer and teacher relationships inGerman school shooters. International Journal of DevelopmentalScience, 8, 57-63.

Brown, R., Osterman, L., & Barnes, C. (2009). School violenceand the culture of honor. Psychological Science, 20, 1400-1405.

*Brumme, R. (2011). School Shootings. Soziologische Analysen[School Shootings. Sociological analysis]. Heidelberg: Springer.

Cicchettia, D., & Rogoscha, F. A. (1996). Equifinality and mul-tifinality in developmental psychopathology. Development andPsychopathology, 8, 597-600.

*Danner, M. J. E., & Carmody, D. C. (2001). Missing gender in casesof infamous school violence: Investigating research and mediaexplanations. Justice Quarterly, 18, 87-114.

*Dumitriu, C. (2013). School violence around the world: A socialphenomenon. Procedia – Social and Behavioral Sciences, 92,299-308.

*Dutton, D. G., White, K. R., & Fogarty, D. (2013). Paranoid think-ing in mass shooters. Aggression and Violent Behavior, 18, 548-553.

Effects of Bullying (2014). Retrieved April 16, 2014, fromhttp://www.stopbullying.gov/at-risk/effects/

Egger, M., Smith, G. D., & O’Rourke, K. (2001). Rationale, potentialsand promise of systematic review. In Egger, M., Smith, G. D., &Altman, D. G. (Eds.) Systematic reviews in health care: Meta-analysis in context (pp. 3–19). London: BMJ Books.

*Fast, J. (2008). Ceremonial violence. A psychological explanationof school shootings. Woodstock: The Overlook Press.

Fox, J. A., & Burstein, H. (2010). Violence and security on campus:From preschool to college. Westport: Praeger.

*Fox, J. A., Levin, J., & Quinet, K. (2005). The will to kill: Makingsense of the senseless murder. Boston: Allyn and Bacon.

*Fox, J. A. & Savage, J. (2009). Mass murder goes to college: Anexamination of changes on college campuses following VirginiaTech. American Behavioral Scientist, 52, 1465-1485.

Harding, D. J., Fox, C., & Mehta, J. D. (2002). Studying rare eventsthrough qualitative case studies: Lessons from a study of rampageschool shootings. Sociological Methods and Research, 31, 174-217.

Harding, D., Mehta, J., & Newman, K. (2003). No exit: Mental illness,marginality, and school violence in West Paducah, Kentucky. InM. H. Moore, C. V. Petrie, A. A. Braga, & B. L. McLaughlin(Eds.), Deadly lessons: Understanding lethal school violence (pp.132-162). Washington, DC: The National Academies Press.

*Harter, S., Low, S. M., & Whitesell, N. R. (2003). What we havelearned from Columbine. The impact of the self-system on sui-cidal and violent ideation among adolescents. Journal of SchoolViolence, 2, 3-26.

Hess, M., & Scheithauer, H. (in press). Treatment and preventionof bullying. In T. Gullotta, M. Evans, & R. Plant (Eds.), Thehandbook of adolescent behavioral problems, 2nd edition. NewYork: Springer Academic Publishing.

*Hoffmann, J., Roshdi, K., & Robertz, F. J. (2009). Zielgerichteteschwere Gewalt und Amok an Schulen. Eine empirische Studiezur Pravention schwerer Gewalttaten. [Severe targeted violenceand rampage at schools. An empirical study for the prevention ofsevere violence.]. Kriminalistik, 63, 196-204.

*Kalish, R., & Kimmel, M. (2010). Suicide by mass murder: Mas-culinity, aggrieved entitlement, and rampage school shootings.Health Sociology Review, 19, 451-464.

*Kiilakoski, T., & Oksanen, A. (2011). Cultural and peer influenceson homicidal violence: A Finnish perspective. New Directions forYouth Development, 129, 31-42.

Kimmel, M. S. (2008). Profiling school shooters and shooters’schools: The cultural contexts of aggrieved entitlement andrestorative masculinity. In B. Agger, & D. Luke (Eds.), Thereis a gunman on campus: Tragedy and terror at Virginia Tech (pp.65–78). Lanham: Rowman and Littlefield.

*Kimmel, M. S., & Mahler, M. (2003). Adolescent masculinity,homophobia, and violence. American Behavioral Scientist, 46,1439-1458.

*Kidd, S. T., & Meyer, C. L. (2002). Similarities of school shootingsin rural and small town communities. Journal of Rural CommunityPsychology, E5 (1).

Klassen, T. P., Jadad, A. R., & Moher, D. (1998). Guides for readingand interpreting systematic reviews: I. Getting started. Archivesof Pediatrics & Adolescent Medicine, 152, 700-704.

*Klein, J. (2006). Cultural capital and high school bullies: How socialinequality impacts school violence. Men and Masculinities, 9,53-75.

Klein, J. (2012). The bully society. School shootings and the crisis ofbullying in America’s schools. New York: New York UniversityPress.

Langman, P. (2009). Rampage school shooters: A typology. Aggres-sion and Violent Behavior, 14, 79-86.

*Langman, P. (2013). Thirty-five rampage school shooters: Trends,patterns, and typology. In N. Bockler, T. Seeger, P. Sitzer, & W.Heitmeyer (Eds.), School shootings: International research, casestudies, and concepts for prevention (pp. 131-156). New York:Springer.

*Lankford, A. (2012). A comparative analysis of suicide terroristsand rampage, workplace, and school shooters in the United Statesfrom 1990 to 2010. Homicide Studies, 17, 255-274.

*Larkin, R. W. (2009). The Columbine legacy: Rampage shootingsas political acts. American Behavioral Scientist, 52, 1309-1326.

*Leary, L. M., Kowalski, R. M., Smith, L., & Philips, S. (2003). Teas-ing, rejection, and violence: Case studies of the school shootings.Aggressive Behavior, 29, 202-214.

Leuschner V., Bondu, R., Schroer-Hippel, M., Panno, J., Neumetzler,K., Fisch, S., Scholl, & J., Scheithauer, H. (2011). Preventionof homicidal violence in schools in Germany: The Berlin Leak-ing Project and the Networks Against School Shootings Project(NETWASS). New Directions for Youth Development, 129, 61-78.

Levin, J., & Madfis, E. (2009). Mass murder at school and cumulativestrain: A sequential model. American Behavioral Scientist, 52,1227-1245.

*Madfis, E., & Levin, J. (2013). School rampage in international per-spective: The salience of Cumulative Strain Theory. In N. Bockler,T. Seeger, P. Sitzer, & W. Heitmeyer (Eds.), School shootings:International research, case studies, and concepts for prevention(pp. 79-104). New York: Springer.

Mahady Wilton, M. M., Craig, W. M., & Pepler, D. J. (2000). Emo-tional regulation and display in classroom victims of bullying:Characteristic expressions of affect, coping styles and relevantcontextual factors. Social Development, 9, 226-245.

*Malkki, L. (2013). Political elements in post-Columbine schoolshootings in Europe and North America. Terrorism and PoliticalViolence, 26, 185-210.

22 International Journal of Developmental Science 8/2014, 3–24

F. Sommer et al. / Bullying, Romantic Rejection, and Conflicts with Teachers

*McGee, J. P., & DeBernardo, C. R. (1999). The classroom avenger.The Forensic Examiner, 8, 1-16.

*Meloy, J. R., Hempel, A. G., Mohandie, K., Shive, A. A., & Gray, B.T. (2001). Offender and offense characteristics of a non-randomsample of adolescent mass murderers. Journal of the Ameri-can Association of Child and Adolescent Psychiatry, 40, 719-728.

Moher, D., Liberati, A., Tetzlaff, J., Altman, D. G., & the PRISMAGroup (2009). Preferred reporting items for systematic reviewsand meta-analyses: The PRISMA Statement. Annals of InternalMedicine, 151, 264-269.

*Moore, M. H., Petrie, C. V., Braga, A. A., & McLaughlin, B. L.(2003). Deadly lessons: Understanding lethal school violence.Washington, DC: National Academies Press.

Nansel, T. R., Overpeck, M., Pilla, R. S., Ruan, W., Simons-Morton,B., & Scheidt, P. (2001). Bullying behaviors among US youth:Prevalence and association with psychosocial adjustment. Jour-nal of the American Medical Association, 285, 2094-2100.

*Newman, K. S., & Fox, C. (2009). Repeat tragedy: Rampage shoot-ings in American high school and college settings, 2002-2008.American Behavioral Scientist, 52, 1286-1308.

*Newman, K. S., Fox, C., Harding, D. J., Mehta, J., & Roth, W.(2004). Rampage. The social roots of school shootings. New York:Perseus Books.

Olweus, D. (1994). Annotation: Bullying at school: Basic facts andeffects of a school based intervention program. Journal of ChildPsychology and Psychiatry, 35, 1171-1190.

*O’Toole, M. E. P. D. (1999). The school shooter: A threat assessmentperspective. Quantico, VA: National Center for the Analysis ofViolent Crime, Federal Bureau of Investigation.

Rocque, M. (2012). Exploring school rampage shootings: Research,theory, and policy. The Social Science Journal, 49, 304-313.

*Roshdi, K., & Hoffmann, J. (2011). Ein Vergleich von Taten ziel-gerichteter Gewalt an Schulen mit und ohne Amok-Dynamik. [Acomparison of cases of severe targeted school violence with andwithout amok dynamics]. In C. Lorei (Ed.), Polizei und Psycholo-gie 2009: Kongressband der Tagung Polizei und Psychologie am27. und 28. Oktober 2009 in Frankfurt am Main (pp. 83-104).Polizeiwissenschaft: Frankfurt.

Scheithauer, H., Haag, N., Mahlke, J., & Ittel, A. (2008). Gender-differences in the development of relational aggression –Evidence for an age effect? Preliminary results of a meta-analysis.European Journal of Developmental Science, 2, 176-189.

Scheithauer, H., Hayer, T., & Petermann, F. (2003). Bullying unterSchulern –Erscheinungsformen, Risikobedingungen und Inter-ventionskonzepte [Bullying among students – forms, risk factors,and interventions]. Gottingen: Hogrefe.

Scheithauer, H., Hayer, T., Petermann, F., & Jugert, G. (2006). Phys-ical, verbal and relational forms of bullying among students fromGermany: Gender-, age-differences and correlates. AggressiveBehavior, 32, 261-275.

*Schiller, J. (2013). School shootings and critical pedagogy. TheEducation Forum, 77, 100-110.

Staples, J. S. (2000). Violence in schools: Rage against a brokenworld. The ANNALS of the American Academy of Political andSocial Science, 567, 30-41.

Thompkins, D. E. (2000). School violence: Gangs and a culture offear. The ANNALS of the American Academy of Political andSocial Science, 567, 54-71.

Ttofi, M., Farrington, D., & Losel, F. (2012). School bullying asa predictor of violence later in life: A systematic review and

meta-analysis of prospective longitudinal studies. Aggression andViolent Behavior, 17, 405-418.

*Verlinden, S., Hersen, M., & Thomas, J. (2000). Risk factors inschool shootings. Clinical Psychology Review, 20, 3-56.

*Vossekuil, B., Fein, R. A., Reddy, M., Borum, R., & Modzeleski, W.(2002). The final report and findings of the Safe School Initiative:Implications for the prevention of school attacks in the UnitedStates. Washington DC.

*Waterman, B. T. (2002). Terror in our schools: An exam-ination of the recent school shootings. Retrieved fromhttp://www.bedrugfree.net/Terror.pdf

*Weatherby, G. A., Strachila, S., & McMahon, B. (2010). Schoolshootings: The deadly result of teasing and ostracism. Journal ofCriminal Justice Education, 2, 1-15.

*Wieczorek, A. (2010). Schulerattentate an deutschen Schulen.Mythen, Fakten und Schlussfolgerungen fur die polizeilichePraxis. [Student attacks on German schools. Myths, facts andimplications to police practice.]. Kriminalistik, 3, 153-160.

Bio Sketches

Friederike Sommer is a psychologist working as a research asso-ciate in the TARGET project at Freie Universitat Berlin, DivisionDevelopmental Science and Applied Developmental Psychology.

Dr. Vincenz Leuschner is a social scientist working as coordi-nator of the TARGET project at Freie Universitat Berlin, DivisionDevelopmental Science and Applied Developmental Psychology.

Dr. Herbert Scheithauer is Professor for Developmental and Clin-ical Psychology at Freie Universitat Berlin and Head of the DivisionDevelopmental Science and Applied Developmental Psychology.

Endnote: Errata

In an earlier version of this target article we describedthe category “conflicts with teacher and the school” asfollows:

“Open conflicts with an individual teacher or otherschool authorities, including the school principal,which were not related to academic performance.”Consequently, Jessie Klein criticized in her commen-tary on the target article:

“In short the paper misses (…) (3) The impact ofperceived academic failure (…)”

“Sommer et al. include school shooting cases relatedto rage at being suspended or otherwise punished; butexclude cases related to academic performance.”

“Nonetheless, in their study the authors onlyincluded: “Open conflicts with an individual teacheror other school authorities, including the school princi-pal, which…” were explicitly “not related to academicperformance”

International Journal of Developmental Science 8/2014, 3–24 23

F. Sommer et al. / Bullying, Romantic Rejection, and Conflicts with Teachers

After reading Klein’s critique, we realized that we useda misleading description of the category. Thus, we mod-ified the description in the final version of the targetarticle to make sure that the category is not describ-ing the decline in school performance only (which isoften described as a risk factor present in later perpe-trators), but rather also includes conflicts with teachersthat result from poor academic performance.

Thus, we changed the description of the categoryin the present version of the target article as follows:“Open conflicts with an individual teacher or otherschool authorities, including the school principal (dis-ciplinary or academic injustices, personal conflicts,suspension from school)”.

24 International Journal of Developmental Science 8/2014, 3–24