Group Dynamics: Theory, Research, and Practice1999, Vol. 3, No. 4,291-302

Copyright 1999 by the Educational Publishing Foundation1089-2699/99/S3.00

Does Stress Lead to a Loss of Team Perspective?

James E. DriskellFlorida Maxima Corporation

Eduardo SalasUniversity of Central Florida

Joan JohnstonNaval Air Warfare Center Training Systems Division

One of the more well-established findings in the research literature is that stress leads toa restriction or narrowing of attentional focus. In the present study, we extend thisresearch to the group context. We propose that, in a team environment, the narrowing ofattention induced by stress may result in a shift in perspective from a broad teamperspective to a more narrow or individualistic self-focus, and this loss of teamperspective may result in degraded team performance. The results of an empirical studyfound that stress resulted in a narrowing of team perspective and that team perspectivewas a significant predictor of team performance. Moreover, when the effects of teamperspective were controlled, the effects of stress on team performance were substan-tially weakened. These results suggest that one way in which stress impacts teamperformance is by narrowing or weakening the team-level perspective required foreffective team behavior.

Research indicates that individuals respond tostress by a restriction or narrowing of attentionalfocus (Cohen, 1980; Combs & Taylor, 1952;Easterbrook, 1959). For example, Salovey(1992) showed that unexpected events mayresult in a shift of individual attention fromexternal cues to a more internal self-focus. If weassume that this restriction of attention extendsto social cues as well, then we may expect anarrowing of social perspective to occur at thegroup level. More specifically, we propose that anarrowing of attention at the group level isaccompanied by a shift from a broader, teamperspective to a more narrow, individualisticfocus. Furthermore, in a team task environment,we expect this narrowing of perspective to leadto a degradation of performance. However,although considerable research has examined

James E. Driskell, Florida Maxima Corporation, WinterPark, Florida; Eduardo Salas, Department of Psychology,University of Central Florida; Joan Johnston, Naval AirWarfare Center Training Systems Division, Orlando, Florida.

The views expressed herein are those of the authors anddo not reflect the opinion, policy, or views of the Departmentof Defense.

Correspondence concerning this article should be ad-dressed to James E. Driskell, Florida Maxima Corporation,507 North New York Avenue, R-l, Winter Park, Florida32789. Electronic mail may be sent to james.driskell @rollins.edu.

individual reactions to stress, comparativelylittle work has examined the effects of stress ongroup performance (see Driskell & Salas, 1991).The purpose of this study is to examine therelationship between stress, team perspective,and performance in task groups.

Group Performance Under Stress

Real-world incidents provide anecdotal butoften vivid illustrations of team effectivenessand ineffectiveness under stress. On July 19,1989, United Airlines Flight 232 experiencedthe failure of an engine and complete loss ofhydraulic pressure, leaving the airplane withvirtually no flight controls. The airplane crashedduring an attempted landing at Sioux City, Iowa,and 111 of the 296 passengers and crewmembers were fatally injured. However, expertsnoted that the crew's performance in landing theplane under at least some measure of controlwas just short of a miracle. The report of theNational Transportation Safety Board (NTSB,1990) and subsequent evaluations of the cockpittranscripts (Predmore, 1991) suggested that onereason for the crew's effectiveness was that theymaintained a hiigh level of team coordination,interaction, and communication during theemergency.

To provide a contrasting example, United

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Airlines Flight 173 crashed near Portland,Oregon, in December 1978, as it ran out of fuelwhile the crew attempted to deal with a landinggear malfunction. The NTSB report (1979) citeda breakdown in teamwork as a primary cause ofthis accident. The report indicated that thecaptain was preoccupied with an individual task,that "the first officer's main responsibility is tomonitor the captain" and this was not done, andthat "the flight engineer's responsibility is tomonitor the captain's and first officer's actions"and this was not done (p. A-5). In a review ofcrew performance in aviation, Foushee (1984)noted that a majority of accidents are related tobreakdowns in crew or team coordination.Foushee (1982) reported one commercial avia-tion incident in which, after ignoring repeatedinquiries from a copilot, the captain responded,"Just look out the damn window" (p. 1063).

Why does group coordination become moreproblematic under stress or emergency condi-tions? Research examining individual reactionsto stress suggests that individuals' focus ofattention shifts from a broader to a narrowerperspective when under stress, and we believethis phenomenon may have significant implica-tions for group interaction. One of the morewell-established findings in the stress literatureis that as stress or arousal increases, theindividual's breadth of attention narrows (Combs& Taylor, 1952; Easterbrook, 1959). Perhaps theearliest statement of this phenomenon wasWilliam James's (1890) belief that the individu-al's field of view varied from a broaderperspective under normal conditions to a morenarrow, restricted focus under stress. Pen-nebaker, Czajka, Cropanzano, and Richards (1990)provided an empirical test of the hypothesis thatnormal thought processes and attentional focusare restricted under stress, finding that individu-als confronted with uncontrollable noise tendedto move from high to lower levels of thought,from a broad to a narrow perspective, whenunder stress. Other research showed that stressmay increase individual self-focus. Baumeisterand colleagues (Baumeister, 1984; Butler &Baumeister, 1998) showed that performancepressure engenders higher levels of self-focusedattention. This research adopts an attentionaltheory approach that assumes that performancepressure focuses an individual's attention in-ward. This may increase self-awareness butdisrupt the performance of skilled tasks by

diverting attention from external task-relevantinformation or by. inhibiting automated perfor-mance processes (Lewis & Linder, 1997).

Does this phenomenon occur at the grouplevel? The analogue to this process at the grouplevel is that group members under stress maybecome more self-focused and less groupfocused. Indeed, some evidence suggests thismay occur. Several studies showed that stressleads to a decrease in prosocial behaviors, suchas helping. For example, Mathews and Canon(1975) found that individuals were less likely tohelp or assist others when exposed to loudambient noise. Rotton, Olszewski, Charleton,and Soler (1978) found that loud noise reducedparticipants' ability to discriminate amongpeople occupying different roles. Cohen (1978,1980) concluded that the narrowing of attentionthat occurs under stress may include socialphenomena as well and that stress may lead to aneglect of social or interpersonal cues anddecreased sensitivity to others.

Some preliminary evidence on attentionalfocus in groups lends peripheral support to thisanalogy. For example, Mullen (1991) showedhow group composition has consequences forattentional focus in groups. Yet despite theexplosion of research on cognition, attention,and decision making in the past several decades,relatively little work has addressed stress andteam performance. Certainly, the debilitatingeffect of stress on team performance has beenrecognized in the work of Cannon-Bowers andSalas (1998), Karau and Kelly (1992) andothers, and interventions have been developedto enhance individual and team decision makingunder stress (Hartel & Hartel, 1997). However,as Littlepage and Karau (1997) noted, despitethese efforts, a number of fundamental questionsremain unanswered. Most lacking is an under-standing of the processes by which stress affectsteam performance.

In summary, a large body of researchindicates that the individual's breadth of atten-tion narrows, and individuals tend to becomemore self-focused when under stress. In thepresent study, we extend this research toexamine group performance by arguing thatstress decreases group focus. We argue that,under stress, group members adopt a narrower,more individual perspective of task activity.With this narrowing of perspective, teammembers' cognitions shift from a broader, team

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perspective to a more narrow, individualisticfocus.

Team Perspective

From the early days of our discipline,theorists noted the importance of team perspec-tive to group interaction. Mead (1934) arguedthat only to the extent that individuals develop agroup concept does cooperative activity becomepossible. Asch (1952) claimed that group actionwas possible "only when each participant has arepresentation that includes the actions of othersand their relations" (p. 251). In more recentwork describing the knowledge, skills, andattitudes required for effective team perfor-mance, Cannon-Bowers, Tannenbaum, Salas,and Volpe (1995) noted the importance of groupmembers adopting a team concept, or collectiveorientation (Driskell & Salas, 1992), that placesteam considerations above individual concerns.Taking an information-processing perspective,Hinsz, Tindale, and Vollrath (1997) describedhow the attentional resources of group membersmay be directed internally (self-focused atten-tion) or externally. They further argued that themanner in which attention is allocated candetermine the nature and outcome of groupinteraction, noting that greater self-focus candivert attention from the task.

We define team perspective as a perception ofthe interrelations of actors and actions in a groupsystem. Team perspective consists of twoprimary components. The first component is acollective representation of the group, or groupidentity. Some argued that a critical element thatdefines a functioning group is the existence of acommon group identity. In Lewin's (1951)terms, a key component of group membership isthat individuals perceive the dynamic interdepen-dence of group members; this has also beentermed a mutual awareness (McGrath, 1984), ora common social identification (Reicher, 1982).Thus, one component of team perspective is a"we-ness," a sense of being part of a teamversus a more individualistic self-focus.

A second component of team perspective is acollective representation of the task or a teammental model of task activity. To coordinateactivity to pursue group goals, a group mustconstruct a common cognitive environment.That is, team members must develop a team-level perspective of the task and of the inter-

dependent roles that comprise the task. Cannon-Bowers, Salas, and Converse (1993) argued thata team mental model includes a model of taskinteraction—how team members must interactwith one another to perform the task. Otherresearch suggested that teams are more effectivewhen group members share a common perspec-tive on group resources, goals, and performancestrategies (Hackman, 1987). Group members'mental models of the task may range from ateam orientation (i.e., viewing the task as aninterdependent team effort) to a more individual-istic focus (i.e., viewing the task as an individualactivity).

Present Study

Our overall goal in this study was to examinethe extent to which stress degrades teamperformance and, more specifically, to examinewhether the effect of stress on team performanceis due to the more fundamental effect of stresson team perspective. We designed a study toexamine the relationship among stress, interde-pendence, team perspective, and performance.We first wished to examine the effects of stressand team interdependence on team perspective.To document the team perspective phenomenon,we wanted to observe whether greater interde-pendence among team members would lead to astronger team perspective. Further, we wished toexamine the effects of stress on narrowing ofteam perspective. Second, we wished to exam-ine the extent to which stress and teaminterdependence affected team performance.Finally, we wished to examine the role of teamperspective in mediating the effects of stress andinterdependence on performance.

We adopted the mediation model of Baronand Kenny (1986) as an analytic strategy to testthese relationships. According to this model,first, variation in the independent variable mustaccount for variation in the hypothesizedmediator. Second, variation in the independentvariable must account for variation in thedependent variable. Third, the hypothesizedmediator must affect the dependent variable.Finally, when the mediator is controlled, therelationship between the independent and de-pendent variable is substantially decreased.This strategy is formalized in the followinghypotheses.

294 DRISKELL, SALAS, AND JOHNSTON

Hypotheses

We reasoned that the greater the degree ofinterdependence among group members, themore likely group members are to develop astrong team perspective. That is, one factor thatdistinguishes an interdependent team from anaggregate of individuals is that the interdepen-dent team members develop a broad teamperspective. To examine this proposition, wedesigned an experimental task in which partici-pants performed either independently in acoacting team or as members of an interdepen-dent team. Those who comprised the coactingteams were introduced as members of a team(thus, they had a "nominal" team identity) andwere told that their team's performance wouldbe evaluated against that of other teams (thus,team members possessed a common fate).However, coacting team members performedthe task independently with no interaction withother group members (i.e., the coacting groupmembers were simultaneously engaged in asimilar activity).1 By contrast, in the interdepen-dent teams, group members were mutuallydependent and worked together to perform thetask. We predict that greater interdependenceamong group members should lead to a broaderteam perspective. Thus, we proposed thefollowing:

Hypothesis la: Greater interdependence among groupmembers will result in a broader team perspective.

As we noted earlier, research indicates thatindividuals respond to stress with a narrowing ofattention and increased self-focus. Extendingthis proposition to the group level, we predictedthat increased stress would result in a restrictionof social cues and a narrowing of teamperspective. To examine this proposition, wehad half of the teams perform under high-stressconditions (increased auditory distraction, taskload, and time pressure) and half of the teamsperform under low-stress conditions withoutthese distractions. We predicted that, understress, group members would shift from abroader team perspective to a more narrow,individualistic perspective. Thus, we proposedthe following:

Hypothesis lb: Increased stress will result in anarrowing of team perspective.

We predicted that stress and team interdepen-

dence would affect team performance. Stresshas been shown to degrade performance in anumber of studies (Driskell & Salas, 1991;Johnston, Driskell, & Salas, 1997), and wepredicted that high-stress conditions would leadto poorer performance on the present task thanlower stress conditions. Furthermore, given thatthe task used in this study is a team-level task,we expected that greater interdependence amonggroup members would lead to more effectiveperformance. Thus, we proposed the following:

Hypothesis 2a: Greater interdependence among groupmembers will lead to more effective performance.

Hypothesis 2b: Increased stress will lead to degradedtask performance.

However, the more interesting issue is therole of team perspective in mediating the effectsof interdependence and stress on performance,that is, the extent to which the effects of stressand team interdependence on performance aredue to the more fundamental effects of stressand team interdependence on team perspective.We propose that one way stress degrades teamperformance is by narrowing team perspective.If this is the case, then the effects of stress onperformance should weaken when variability asa result of team perspective is partialed out.Similarly, if we argue that one way in whichinterdependence enhances team performance isby strengthening team perspective, then theeffects of interdependence on performanceshould weaken when the variability as a result ofteam perspective is partialed out. Thus, weproposed the following:

Hypothesis 3: When team perspective is controlled, theeffects of stress and interdependence on performancewill be substantially reduced.

Method

Participants

Participants in this study were 95 U.S. Navytechnical school personnel who volunteered totake part in a study of decision making. Thestudy was a 2 (type of group: coacting vs.

1 Many hold that a coacting group is not a task group atall. However, others fsuch as Shaw (1981) noted that grouptasks differ in the degree of cooperation required, frominstances in which group members must coordinate theiractions to instances in which group members workindependently.

TEAM PERSPECTIVE 295

interdependent) X 2 (stress: high vs. low) de-sign. Participants were randomly assigned toone of four experimental conditions.

Procedure

The participants arrived at the experimentallaboratory to take part in a study of teamperformance and were assigned to a three-person group. Participants were seated atindividual work stations in an open room andinteracted over a computer network. For the firsthalf hour of the session, participants werebriefed on the nature of the experimental task,first listening to a video training tape and thenreceiving individualized instruction and prac-tice. The task was a computer simulation of anaval decision-making task. The task requiredthat participants monitor a radar screen thatcontained their own ship at the center andnumerous unidentified contacts positioned atconcentric rings away from the ship. Theobjective was to identify and label each contactaccording to three classifications: type of craft(aircraft, surface craft, or subsurface), its status(civilian or military), and intentions of the craft(hostile or peaceful). To make each classifica-tion, the participant would access one of threeinformation fields or menus: A, B, and C,corresponding to these headings. For example,Menu A contained five items of informationused to help identify the type of craft. WithinMenu A, the participant could access the altitudeitem to ascertain whether the contact was abovethe surface, on the surface, or below the surfaceof the water. After the participant determined thetype of craft, he or she then proceeded to gatheridentifying information from Menu B and MenuC. Once the contact had been labeled as to thetype of craft, its status, and its intentions, thecontact would then be either cleared from thescreen if it was determined not to be a threat orengaged (targeted) if it was determined to behostile. Participants were told to work as quicklyand as accurately as possible to identify eachcontact before it reached their ship.

After receiving detailed task instructions andpractice, participants performed the task. After15 min, action was stopped and participantscompleted a task questionnaire. At this point,they were asked to complete several items:measures of their perception of the group, taskfocus, and collective orientation (these measures

are described later). We chose to administerthese items during task performance rather thanat completion of the task to enhance theimmediacy of their responses. Participants thencontinued the task for an additional 15 min, afterwhich play was stopped and participants re-ceived a postexperimental questionnaire. Afterthe questionnaire was completed, participantswere interviewed individually, received a fullexplanation of the study, and were thanked fortheir participation.

Experimental Manipulations

Type of Group

The task was configured so that participantsperformed as part of a three-person coactingteam or an interdependent team. In the coactinggroup condition, participants were introduced toone another as team members Alpha, Bravo, andCharlie. They were told that they would beworking as a team on a computer-based task andtheir team's performance would be comparedwith that of other teams. However, the task wasstructured so that each group member performedthe task independently. That is, Alpha's task wasto select an unidentified contact, gather informa-tion from Menu A, Menu B, and Menu C, andthen clear or engage the contact. Bravo andCharlie did the same. Thus, in the coactinggroup condition, group members worked on thetask independently, with no interdependencerequired.

In the interdependent team condition, the taskwas structured so that Alpha, Bravo, and Charlieworked interdependently. Menu A was onlyavailable to Alpha, Menu B was only availableto Bravo, and Menu C was only available toCharlie. Furthermore, the information itemswithin each menu were shared across partici-pants. For example, Alpha was responsible forascertaining the five items of information thatwould allow him or her to determine the type ofcraft in Menu A; however, two of these pieces ofinformation were held by the other teammembers. That is, Alpha would have to get oneitem of information from Bravo and one itemfrom Charlie to combine with the information inMenu A to determine the type of craft. Thus, toprocess a contact, each team member had torequest needed information from others andprovide required information to others. There-

296 DRISKELL, SALAS, AND JOHNSTON

fore, in the interdependent team condition, thetask was configured so that participants had towork interdependently to perform the task.

Stress

Participants performed the task in either anormal-stress or a high-stress environment. Toinduce high stress, we manipulated three fac-tors: auditory distraction, task load, and timepressure. Auditory distraction was implementedby playing a multitrack audio recording oftask-related chatter over the participants' head-phones during the task. Task load was imple-mented by increasing the rate at which contactswere presented on the screen. Thus, in thehigh-stress conditions, participants were pre-sented with a greater number of potentiallythreatening contacts. Finally, time pressure wasinduced by the experimenters telling the partici-pants to "hurry up" and "work harder" at 5-minintervals during the task. We implementedmultiple stressors rather than a single stressor toprovide a more robust manipulation of taskstress.

Measures

We defined team perspective as consisting oftwo primary components: (a) a collectiverepresentation of the group, or group identity,and (b) a collective representation of the task.

Collective Representation of the Group

This component of team perspective repre-sents the extent to which group membersperceive themselves as belonging to a distinctsocial unit or team. We assessed this componentof team perspective using two measures: (a)group members' perception of the group and (b)the extent to which group members evaluatedthe outcome of performance in egocentricversus group terms.

Perception of the group. We adapted anitem previously used by Gaertner, Mann,Murrell, and Dovidio (1989) to assess the extentto which participants perceived themselves as agroup. This item was designed to assess par-ticipants' conceptual representations of thegroup by asking them to rate the extent to whichthey perceived themselves as a team or as threeseparate individuals. This measure has been

successfully used in previous research to dif-ferentiate groups_of varying salience (Gaertner,Mann, Dovidio, Murrell, & Pomare, 1990;Gaertner et al., 1989). This item ("To whatextent do you feel like a team, or do you feelmore like three individuals?") was presented ona scale ranging from 1 (team) to 7 (individuals).We administered this item immediately whenplay was paused after the first 15 min of taskperformance.

Egocentricity. This measure of group iden-tity was designed to assess the extent to whichparticipants evaluated task performance inindividual versus team terms. Beck (1993) notedthat one aspect of egocentricity is the tendencyto interpret the meaning of events in terms ofwhat they mean to the individual rather than themeaning of the event to the group as a whole.Therefore, we devised an item to measure theextent to which participants interpreted taskperformance in terms of how they performedversus how well the team performed. At the endof the task, each participant was given a printoutshowing purported individual and team scores.The experimenter described the chart, whichindicated that the individual's score was in thehigher range (80—90th percentile) comparedwith how others had performed on the task.However, the team score was shown to be in thelower performance range (20-30th percentile).After participants were left for several minutesto review their score sheets, they were given apostexperimental questionnaire, which askedthem to rate how well the task was performed ona scale ranging from 0 (extremely poor) to 100(extremely well). Note that this question wasintentionally broad in that it asked participantshow well "the task" was performed, thusleaving the participants to interpret this questionin terms of their individual performance or theirteam's performance. Group members providinga higher evaluation of performance were per-ceived as interpreting the task according to howwell they themselves did. Group membersproviding a lower evaluation of performancewere perceived as interpreting the task accord-ing to how well the group did.

Collective Representation of the Task

The second component of team perspective isa collective representation of the task, or ateam-level model of task activity. To assess this

TEAM PERSPECTIVE 297

aspect of team perspective, we used measures of(a) task focus, (b) collective orientation, and (c)the elaboration of a team task model.

Task focus. The extent to which individualswere focused on individual versus team activi-ties was assessed by three items. The first itemasked participants to rate where their attentionhad been focused on a scale ranging from 1{interacting with the team) to 7 (doing indi-vidual tasks). The remaining two items askedparticipants whether they felt more responsiblefor their own efforts rather than how others weredoing and whether they felt they concentratedmore on their own tasks rather than interactingwith others. This three-item scale rendered analpha of .93.

Collective orientation. Collective orienta-tion refers to the mutual interdependence ofteam members (Driskell & Salas, 1992). Groupmembers who are collectively oriented perceivethemselves as working together as a group tosolve the task. Group members who are lesscollectively oriented view their actions in amore autonomous manner. We assessed theextent of collective orientation in the followingmanner. After participants had performed thetask for 15 min, we paused the action andadministered a task questionnaire. We askedparticipants to describe the events that hadoccurred during the task. Participants wereasked, "If you were asked to explain to someonewhat has been going on the last 10 to 15minutes, what would you say?" Participantswere given 5 min to write down their responseon a blank form.

The measure of collective orientation usedwas the proportion of first person plural pronounusage (e.g., we, us, our, ours, ourselves) in thewritten transcripts. This approach is an adapta-tion of a technique used by Wegner and Giuliano(1980) and Mullen, Chapman, and Peaugh(1989) to assess the self-focus of individuals.We expected that participants with a morecollective or group focus would respond with agreater proportional usage of first person pluralpronouns (i.e., We identify targets close to ourship"). For each subject, we calculated the totalnumber of first person plural pronouns used indescribing task activities divided by the totalword count.

Team task model. We assessed the extent towhich group members elaborated a team-levelmodel of the task by having three independent

judges who were unaware of the conditions rateeach written transcript according to the extent towhich it illustrated a team perspective of thetask versus an individual perspective. A teamtask perspective was defined as emphasizing theinterdependency of group members (i.e., "Al-pha, Bravo, and Charlie must exchange informa-tion to identify targets"). An individual taskperspective was defined as emphasizing indi-vidual actions or perceptions (i.e., "I have todetermine whether a target is peaceful orhostile"). Transcripts were rated on a 5-pointscale, ranging from 1 (emphasis on individualperceptions, feelings, and actions) to 5 (empha-sis on group perceptions and activities of othergroup members or the group as a whole). Thethree judges' ratings were reliable, yielding amean interrater correlation of .86 and Spearman-Brown effective reliability of .95.

Performance. During the 30-min perfor-mance period, group members were required todetermine three classifications for each contact:type of craft, its status, and its intentions. Groupmember performance was assessed by theproportion of classifications that were correctlyidentified.

Results

Manipulation Check

As a check on the success of the stressmanipulation, participants were asked to rate theextent to which they felt distracted and pres-sured during die task. Participants performingunder high-stress conditions reported feelingmore distracted (M = 2.29, SD = 1.06) thanthose in the no-stress conditions (M = 1.50,SD = .86), t(93) = 4.00, p < .01, and reportedfeeling more pressured (M = 2.11, SD = 1.06)than those in the no-stress conditions (M = 1.86,SD = 1.00), r(92) = 4.02, p < .01. There wereno significant effects of team interdependenceon the distraction or pressure measures (ps > .1).

Team Perspective

To gauge th^ effects of stress and teaminterdependence on team perspective, we exam-ined the various indicators of team perspectiveand found that they were highly intercorrelated

298 DRISKELL, SALAS, AND JOHNSTON

(mean r = .70).2 Therefore, these various in-dicators were standardized into Z scores andaggregated into a composite measure of teamperspective (for which a higher score indicatesgreater team perspective). Then this compositeindicator of team perspective was subjected to a2 (type of group: coacting vs. interdependent) X2 (stress: low stress vs. high stress) analysis ofvariance (ANOVA). Means and standard devia-tions for team perspective scores are presentedin Table 1. The expected main effect of stresswas significant, F(l , 91) = 11.99, p < .001.Group members performing under high-stressconditions exhibited lower team perspective(M = -.010) than those operating under lowstress (M = .086). Similarly, the expected maineffect of type of group was significant, F(l,91) = 396.84,/? < .001. Participants operatingin interdependent teams exhibited higher levelsof team perspective (M = .766) than thoseoperating in mere coaction (M = —.783).

The interaction between stress and type ofgroup was also significant, F(l , 91) = 8.91,/? =.004. In the interdependent teams, there was asignificant loss of team perspective from lowstress (M = 1.016) to high stress (M = .515),r(91) = 4.60, p < .001. In the coacting teams,there was no loss of team perspective from lowstress (M = -.766) to high stress (M = -.803),t(9l) = 0.34, p = . 369.

Performance

To gauge the effects of stress and teaminterdependence on performance, a 2 (type ofgroup: coacting vs. interdependent) X 2 (stress:low stress vs. high stress) ANOVA was con-ducted on performance scores. Means andstandard deviations for performance scores are

Table 1Means and Standard Deviations for TeamPerspective and Performance as a Functionof Stress and Type of Group

Low stress High stress

Measure M SD M SD

Team perspectiveInterdependent 1.016 0.393 24 0.515 0.492 24Coacting -0.766 0.319 26 -0.803 0.260 21

PerformanceInterdependent 0.950 0.112 24 0.888 0.156 24Coacting 0.892 0.145 23 0.859 0.160 20

also presented in Table 1. The expected maineffect of stress was marginally significant, F(l ,87) = 2.47, p = .059. Participants operatingunder conditions of low stress performed better(M = .922) than those operating under condi-tions of high stress (M = .875). Similarly, theexpected main effect of type of group wasmarginally significant, F(l , 87) = 2.09, p =.076. Participants operating in interdependentteams performed better (M = .919) than thoseoperating in mere coaction (M = .877). Theinteraction between stress and type of group wasnot significant, F(l , 87) = 0.22, p = .639.

Mediating Role of Team Perspective

The foregoing analyses reveal that stress andteam interdependence exert predictable effectson team perspective and performance. However,the critical issue that drives this research effort isthe extent to which the effects of stress andinterdependence on performance are due to themore fundamental effects of stress and interde-pendence on team perspective. The most directway to test the proposed relationship is to testfor mediation.

To test the mediating role of team perspective,we conducted an analysis of covariance(ANCOVA), wherein a 2 (type of group: co-acting vs. interdependent) X 2 (stress: low stressvs. high stress) analysis was conducted on per-formance scores, with team perspective scoresserving as a covariate. If the effects of stress andteam interdependence on performance are pri-marily a result of their effects on team per-spective, then the effects of stress and teaminterdependence on performance should bereduced when variability resulting from teamperspective is partialed out. Indeed, this isprecisely what happened: In this ANCOVA, theexpected main effect of stress was now reducedto negligible magnitude, F(l , 86) = 0.93, p =.169. Similarly, the expected main effect of typeof group was now reduced to negligiblemagnitude, F(l , 86) = 0.62, p = .216. Onceagain, the interaction between stress and type ofgroup was not significant, F(l, 86) = 0.0002,

2 The egocentricity measure did not show the overallpattern of results that was consistently shown by the othermeasures of team perspective and failed to correlate highlywith the other measures of team perspective (averager = .31). Therefore, this measure was not included in thecomposite measure of team perspective.

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p = .987. The results of this ANCOVA areillustrated in Figure 1. It can be seen that themain effect and interactive effects of stress andinterdependence on performance are reducedwhen the effects of stress and interdependenceon team perspective are first partialed out.

Discussion

Teams have become a critical means toaccomplish complex tasks from the companyboardroom to the commercial airliner. Teams areoften called on to respond effectively undercrisis or emergency conditions. Sometimes theyare able to coordinate their resources andactivities to land an immobilized airliner, andsometimes team performance deteriorates to apoint at which team members barely acknowl-edge one another.

The idea that stress narrows the scope ofattentional focus is well documented in theresearch literature. There has been some sugges-tion that stress may affect how group membersattend to social information as well. In an earlyexamination of small group behavior understress, Torrance (1954) wrote, "Under stress . . .

linkages between members may become con-fused and thus_people do not have a clearperception of what they can expect from oneanother, with whom they can relate, [and] howthey can relate to one another" (p. 754).

Although the effects of stress on disruptingteam performance have been well documentedin the research literature, reviewers oftenbemoan the fact that we lack a clear understand-ing of the processes by which this occurs (cf.Littlepage & Karau, 1997). The results of thisstudy provide one explanation for the tendencyfor groups to function less effectively understress: Stress leads to a loss of team perspective.

The results of this study demonstrate thatinterdependence leads to a broader team perspec-tive and that stress results in a narrowing of teamperspective. The results further indicate that thenarrowing of perspective that occurred understress led to impaired team performance. This isnot altogether surprising; however, what isstriking is the central role played by teamperspective. After partialing out the effects ofteam perspective, both group interdependenceand stress became insignificant predictors ofperformance. These results suggest that team

b = -.165(p = .O59)

Stress

Stress X b = -.Interdependence

Interdependence

b = -.019(p = .860)

Figure 1. Path analysis illustrating the interrelations of stress, interdependence, teamperspective, and performance. Values above lines represent direct effects; values below linesrepresent indirect effects (after the mediating role of team perspective is partialed out).

300 DRISKELL, SALAS, AND JOHNSTON

perspective is a critical factor in group perfor-mance and that one way in which stress andgroup interdependence impact performance isthrough their influence on team perspective.

We now examine the theoretical rationale forwhy stress narrows team perspective. Theclassic arousal perspective argues that stressresults in heightened arousal and that arousalleads to a narrowing of attention (see Broadbent,1971; Easterbrook, 1959). As attention narrows,peripheral (less relevant) task cues are firstignored, followed by further restriction ofcentral or task-relevant cues. To the extent thattask-relevant cues are neglected, performancesuffers. Accordingly, tasks that demand atten-tion to a wide range of cues are more susceptibleto degradation under stress. Team tasks requireattention to both direct task-related activitiesand interpersonal or teamwork activities such acoordination and communication. To the extentthat these social or team cues are marginalizedas attention is narrowed under stress, teamperspective is weakened and performance maysuffer.

Cohen (1980) presented a related argument,noting that stress leads to increased demand asthe individual must attend to novel and distract-ing stimuli. This information overload results ina narrowing of attentional capacity. To reducethis informational overload, attention is re-stricted to those cues most relevant to the task.Cohen proposed that this restriction may affectboth social and nonsocial cues. As importantsocial cues (such as attention to others' requestsor actions) are neglected, individuals becomeless socially cognizant. Accordingly, a team-level perspective is likely to become weakenedin task groups under stress as these social orinterpersonal cues are disregarded. In summary,both the arousal and the information overloadpositions maintain that stress leads to a narrow-ing of perspective as attention is focused on themost central or salient task cues. The results ofthe present research provide evidence that thistheoretical approach can be extended to thegroup level as well and that the narrowing ofattentional focus under stress may include aweakening of team perspective.

It is further worthwhile to consider thepractical implications of this research. Theresults indicate that teams are indeed vulnerableto stress, and one mechanism through which

stress affects team performance is by narrowingteam perspective._Both the arousal and informa-tion overload theories contend that stress resultsin a narrowing of attention. As external demandsincrease, teamwork behaviors, such as attendingto others, may be neglected to the benefit ofmore central task cues, such as those involved inperforming one's own immediate task. If weassume that the narrowing of attention is anadaptive response to the stress environment, anattempt to simplify an increasing complex anddemanding task environment, then one approachto maintaining effective performance is tosimplify the task environment. For those set-tings in which effective teamwork is critical, itmay be necessary to structure the task to make itless demanding (i.e., by delegating subtasks), sothat attention can be maintained on essentialtask and teamwork cues. In brief, if stressrestricts attentional resources, the task environ-ment may need to be restructured so that groupmembers are not forced to sacrifice attention toteamwork matters to maintain performance.Unfortunately, for many real-world tasks, reduc-ing the complexity of the task environment is adifficult undertaking.

A second approach to counter the effect ofstress on narrowing team perspective is theattempt to enhance or strengthen team perspec-tive. Wickens (1996) noted that the attentionalnarrowing resulting from stress is, at least tosome degree, determined by subjective impor-tance. That is, attention is maintained onhigh-priority items to the exclusion of informa-tion that is perceived to be of lower importance.It is possible that, for many team tasks, theimportance of teamwork behaviors such ascoordination and communication may be per-ceived as secondary to other basic, individualtask demands. Anecdotally, highly interdepen-dent sports such as soccer seem to illustrate thisphenomenon: When teams get behind, teammembers often ignore team play and eachperson tries to win the game on his or her own,with predictable results. (Interestingly, thisseems to occur more on inexperienced vs. moreexperienced teams.) Interventions that attemptto enhance team perspective, such as teambuilding (see Satas, Rozell, Driskell, & Mullen,1999), or the use of preparatory information toreinforce the interrelations of actors and theinterdependent nature of the task (Inzana,

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Driskell, Salas, & Johnston, 1996) may beeffective approaches to counter stress effects.

We should also note several limitations of thepresent study. First, although we conducted thisresearch in an applied setting with real-worldparticipants, the teams that were formed wereshort-lived, and the nature of the experimentaltask did not allow the observation of otherfactors that may be important in more naturalsettings. Whether these results hold for groupsthat have been together for longer periods oftime or that juggle multiple tasks is unknown.

Second, the primary objective of this studywas to examine the extent to which teamperspective mediates the relationship betweenstress and team performance. A variable such asteam perspective functions as a mediator if itmeets several conditions: (a) Variations in levelsof the independent variable (stress) account forvariations in the level of the mediator, (b)variations in the mediator account for variationsin the dependent variable (team performance),and (c) when the mediator is controlled, therelationship between the independent variableand the dependent variable is substantiallyweakened (Baron & Kenny, 1986). Theseconditions were all upheld. Although the media-tion analysis was the most direct way to test thehypothesized relations, mediation is best donewhen there is a strong relation between theindependent variable and the dependent vari-able, and in the present case this effect wasmodest. For example, the main effect of stresson team performance translates into a smalleffect size of .17 (p = .059). Future researchersshould be advised to test these relationships witha larger sample size, rendering greater statisticalpower.

Finally, the present research has revealed anovel effect of stress on team perspective thathas not been previously demonstrated. We haveidentified one mechanism through which stressimpacts team performance: by narrowing teamperspective. If we adopt Hinsz et al.'s (1997)model of groups as information processors, it islikely that, in addition to affecting attentionalprocesses, stress may disrupt other aspects ofgroup functioning, such as memory, retrieval,processing, and response. Further researchshould be directed toward gaining a morecomplete understanding of the processes bywhich stress impacts team performance.

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