Neuroticism and Self-Discipline as Predictors of Happiness: a Mediation Model

Running head: NEUROTICISM, SELF-DISCIPLINE AND HAPPINESS

Neuroticism and Self-Discipline as Predictors

of Happiness: a Mediation Model

201132

9 May 2011

Boston University

Psychology Department

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NEUROTICISM, SELF-DISCIPLINE AND HAPPINESS

Abstract

Previous research has revealed negative correlations between neuroticism and both self-

discipline and happiness, and a positive correlation between self-discipline and happiness. The

present research sought to replicate these findings and further explore the relationships between

neuroticism, self-discipline and happiness. Of particular interest was the conscientiousness facet

of self-discipline, and how this variable might affect happiness in neurotic individuals. One

hundred and seventy-two participants completed an Internet survey including measures of

neuroticism, self-discipline and happiness. Negative correlations were observed between

neuroticism and both self-discipline and happiness, and a positive correlation was obtained

between self-discipline and happiness, as prior research has indicated. Self-discipline was found

to have a mediating effect on the inverse relationship between neuroticism and happiness;

neurotic individuals who are more self-disciplined are happier. This finding has implications for

increasing happiness in neurotic individuals through learned, controllable behaviors and

cognitions related to self-discipline. Of interest may be training in time management and study

skills, or therapy designed to reduce antecedents of procrastination such as task aversion and fear

of failure. Future research should consider a longitudinal approach to explore how changing

environmental task demands may affect the relationships between neuroticism, self-discipline

and happiness.

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Neuroticism and Self-Discipline as Predictors

of Happiness: a Mediation Model

Previous studies have revealed negative correlations between neuroticism and both self-

discipline and happiness, and a positive correlation between self-discipline and happiness. The

present research further explored these relationships in an attempt to understand how these three

constructs may be interrelated. For instance, although neuroticism and self-discipline tend to be

negatively correlated, it is possible for an individual to possess both characteristics. In such a

case, does self-discipline serve to protect the neurotic individual from unhappiness?

Understanding the answer to this question may have implications for increasing happiness in

neurotic individuals through learned, controllable behaviors and cognitions related to self-

discipline. Of interest may be training in time management and study skills, or therapy designed

to reduce antecedents of procrastination such as task aversion and fear of failure.

Neuroticism, a Big Five personality factor, refers to an individual’s degree of emotional

instability. Neurotic individuals are psychologically troubled, have unrealistic ideas, extreme

cravings or impulses, and poor coping responses. Other characteristics of neuroticism include

worrying, nervousness, emotionality, and feelings of inadequacy (Costa & McCrae, 1985).

Neuroticism has been negatively associated with self-discipline (Pearman & Storandt, 2005).

Self-discipline, a facet of the Big Five factor of conscientiousness, is described as “the

ability to begin tasks and carry them through to completion despite boredom and other

distractions” (Costa & McCrae, 1998, p. 127). Self-discipline is most generally referred to in a

work-oriented context, and is related to productivity. Those who lack self-discipline are

sometimes described as self-defeating and have a tendency to procrastinate (Costa & McCrae,

1998).

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Johnson and Bloom (1995) conducted a correlational study to examine the relationships

between procrastination and various personality constructs. Two hundred undergraduate

psychology students with a mean age of 19.28 years completed self-report measures of

procrastination and the Big Five personality factors with subscales for different facets. Self-

discipline was negatively correlated with procrastination, and was the strongest predictor of

procrastination for this sample. There was a significant positive association between neuroticism

and procrastination. The latter finding is in line with the inverse relationship between

neuroticism and self-discipline found by Pearman and Storandt (2005) because of the strong

negative correlation between self-discipline and procrastination.

Watson (2001) further explored the correlations between procrastination and the Big Five

factors of personality. In Watson’s study, 349 university students with a mean age of 21.98 years

completed self-report measures of personality factors and procrastination. As previous research

by Johnson and Bloom (1995) indicated, self-discipline was found to have a strong negative

correlation with procrastination. However, Watson found a stronger positive correlation between

neuroticism and procrastination than did the Johnson and Bloom study. This disparity suggests a

need for additional research to further explore the relationship between neuroticism and

procrastination. The present study looks at self-discipline rather than procrastination, but the

strong negative association between the two constructs indicates that the findings may have

implications for procrastination as well.

Happiness, another construct that has been studied in relation to neuroticism and self-

discipline, encompasses overall well-being, subjective quality of life, and “positive

psychological functioning” (Ryff, 1989, p. 1077). According to Ryff, happiness is related to self-

acceptance, mastery of one’s environment, affect stability, positive relations with others,

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autonomy, and having a purpose in life. Research has associated happiness with high

conscientiousness, the personality factor that consists of dutifulness, competence, achievement

striving, order and self-discipline (Costa & McCrae, 1998).

The relationships between happiness and the Big Five personality factors were

demonstrated in a correlational study by Hayes (2003). In Hayes’ study, 129 adults living in

England, with a mean age of 37.77, completed three different self-report measures of happiness,

as well as a self-report measure of personality factors. Across the three happiness measures,

increased happiness was associated with decreased neuroticism and increased conscientiousness.

Hayes acknowledged the negative correlation between conscientiousness and neuroticism, and

the possibility that there may be a unique association between happiness and conscientiousness,

in addition to the correlations found among the other personality factors. The study did not

include a facet-level analysis of the Big Five factors of personality, which would have revealed

more specific correlates of happiness (e.g., self-discipline).

A correlational study by Bienvenu et al. (2004) added to previous research on the Big

Five factors by conducting a more detailed facet-level analysis. The study examined how anxiety

and depression is related to different personality constructs. A population-based sample of 731

adults with a mean age of 45 completed a self-report measure of personality traits, and

psychiatrists diagnosed those individuals in the sample with anxiety and depressive disorders. On

the factor level, all of the chronic anxiety and depressive disorders identified in the study were

associated with high neuroticism. The conscientiousness facet that was most often low when

associated with the disorders of interest was self-discipline. Since happiness and depression are

divergent constructs, these results complement earlier findings indicating a negative association

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between happiness and neuroticism, and a positive association between happiness and self-

discipline.

The present study sought to replicate previous findings indicating negative associations

between neuroticism and both self-discipline and happiness, as well as a positive association

between self-discipline and happiness. Of particular interest was the correlation between

neuroticism and self-discipline, as the literature reviewed did not examine this relationship in

depth. Recent research has highlighted the usefulness of analyzing personality constructs in

terms of lower-order facets, which are more specific than the Big Five factors of personality. To

build on previous findings, the present study looked at the conscientiousness facet of self-

discipline to see how this variable affects happiness in neurotic individuals. Are neurotics who

are self-disciplined happier than those who are not?

Methods

Participants

172 participants were recruited to complete this study. The sample consisted of 102

females (59%) and 70 males (41%) ranging in age from 18 to 61 (M = 25.1, SD = 10). Table 1

summarizes the demographic characteristics of the sample. As can be seen, the average

respondent was Caucasian and self-reported as middle or upper middle class. The data set was

generated by college students completing a psychology research methods course at a large

private urban university in the Northeastern United States for class research projects. Students

were required to recruit a minimum of five volunteers, at least two of whom had to be male, to

complete a set of self-report measures assessing personality constructs and interpersonal attitudes

and behaviors via an online survey presented through SurveyMonkeyTM. Participants were

provided with a digital informed consent form prior to starting the survey. They were debriefed

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at the end of the survey with a page describing the types of studies being conducted, and whom

to contact for results and other relevant information. American Psychological Association ethical

guidelines were followed throughout this process.

Measures

For the purposes of the present study, data from three of the measures included in the

Internet survey was analyzed—specifically—Mini-IPIP, IPIP Self-Discipline Subscale and

Oxford Happiness Questionnaire Short-Form. The Mini-IPIP (Donnellan et al., 2006) is a 20-

item measure designed to assess The Big Five factors of personality: extraversion, agreeableness,

conscientiousness, neuroticism, and openness. For this study, only the four neuroticism items

were relevant. Participants responded to the five-point Likert scale by selecting from choices

ranging from “very inaccurate” to “very accurate.” Items are either positively or negatively

associated with the personality factor in question; responses to items with negative associations

are reverse coded. Scores for the present sample ranged from 3 to 18, with higher scores

indicating higher levels of neuroticism. Donnellan et al. (2006) have demonstrated that the

neuroticism subscale of the Mini-IPIP is internally consistent, with alphas of at least .60 across

five different studies conducted in the same year. Test-retest reliability was established over both

a few weeks (r = .80) and several months (r = .82). The Mini-IPIP has shown convergent and

criterion-related validity comparable to other Big Five measures. Cronbach’s alpha for the Mini-

IPIP neuroticism measure for the present sample was .738 (.753 for females and .702 for males).

The International Personality Item Pool (IPIP; Goldberg et al., 2006) contains over 2000

items to assess various aspects of personality. For the present study, only the self-discipline

subscale was used. Due to an error, only nine of the ten self-discipline items were included in the

online survey. Participants responded to the five-point Likert scale by selecting from choices

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ranging from “very inaccurate” to “very accurate.” Items are either positively or negatively

keyed to self-discipline; responses to those with negative associations are reverse coded. Scores

for the present sample range from 8 to 40, with higher scores indicating higher levels of self-

discipline. The IPIP scales are derived from external parent scales with demonstrated reliability

and validity. The IPIP scales correlate highly with their parent scales, and the alpha coefficients

of the IPIP scales are comparable to those of the original scales. Exact values of the alpha

coefficients for individual subscales are not currently available on the IPIP website, nor are there

any published norms (Goldberg et al., 2006). Cronbach’s alpha for the IPIP self-discipline

measure for the present sample was .877 (.875 for females and .880 for males).

The Oxford Happiness Questionnaire Short-Form (OHQ-SF; Cruise & Lewis, 2006) is an

eight-item measure designed to assess personal happiness. Participants responded to the six-point

Likert scale by selecting from choices ranging from “strongly disagree” to “strongly agree.”

Reverse coding is used for three items, and scores range from 8 to 48, with higher scores

indicating more happiness. Cruise and Lewis (2006) demonstrated that the OHQ-SF has short-

term test-retest reliability over two weeks (r = .69) and has acceptable internal consistency

reliability (Time 1: = .62; Time 2: = .58). Cronbach’s alpha for the OHQ-SF for the present

sample was .719 (.739 for females and .698 for males).

Results

Descriptive statistics for measures of neuroticism, self-discipline and happiness are

shown in Table 2. An independent samples t-test was conducted between males and females for

all three variables to assess differences in means. Females scored significantly higher than males

in neuroticism (Mf = 12.0, SDf = 3.3, Mm = 11.0, SDm = 3.5, t = 2.021, p = .045, Cohen’s d = .310,

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Carl W. Kantner, 05/08/11,

This phrase is needed for the above descriptions.


mean difference = 1.06). No significant differences were observed between males and females

for self-discipline or happiness.

Pearson bivariate correlations were computed between neuroticism, self-discipline and

happiness. Significant negative correlations were observed between neuroticism and self-

discipline (r = -.296, p < .001, r2 = .088) and neuroticism and happiness (r = -.567, p < .001, r2

= .321). A significant positive correlation was obtained between self-discipline and happiness (r

= .306, p < .001, r2 = .094). A Fisher r-to-z transformation revealed no significant differences

between the correlation coefficients for males and females.

Happiness was regressed onto neuroticism and self-discipline using a hierarchical linear

regression model to determine if self-discipline had a mediating effect on the relationship

between neuroticism and happiness. The combination of neuroticism and self-discipline

significantly predicted happiness better than neuroticism or self-discipline alone, indicating a

significant mediation effect (R = .585, R2 = .343, F2,169 = 44.047, p < .001). According to the

model, if neuroticism is held constant, a one-unit increase in self-discipline predicts a .128

increase in happiness (mpneuros = -.921, t = -7.995, p < .001; self_discipline = .128, t = 2.326, p

= .021).

Discussion

The negative correlations observed between neuroticism and both self-discipline and

happiness are consistent with previous findings, as is the positive correlation found between self-

discipline and happiness. A post-hoc Fisher r-to-z transformation revealed a marginally

significant difference between the correlation coefficients for the present sample and the

Pearman and Storandt (2005) sample for the relationship between neuroticism and self-

discipline. The correlation found in the present study was weaker than the relationship reported

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by Pearman and Storandt (2005), which may be due to the much higher mean age of their elderly

sample (73.2 years).

The mediating effect of self-discipline on the relationship between neuroticism and

happiness observed in the present study suggests that self-discipline serves to protect neurotic

individuals from unhappiness. In other words, neurotic individuals who are also self-disciplined

are happier than those who are not. This mediating effect has implications for methods of

increasing happiness in neurotic individuals through behavioral and cognitive interventions in

the realm of self-discipline. A behavioral approach may involve teaching self-discipline through

time management and study skills. Treatment concerning procrastination may be useful as well,

since neuroticism is associated with increased procrastination, and procrastination is negatively

associated with self-discipline. Methodical efforts to increase organization and efficiency may

include “active external structuring” via making prioritized to-do lists or following a daily

routine (Johnson & Bloom, 1995, p.132). Cognitive interventions may focus on reducing

antecedents of procrastination such as task aversion, fear of failure, risk taking, lack of assertion,

difficulty making decisions, and lack of independence (Watson, 2001). Rothblum (1990) has

suggested using behavioral techniques similar to those used in the treatment of phobias in order

to reduce academic procrastination. This approach seems particularly applicable given the

educational circumstances of the majority of the present sample.

A potential limitation of the present study is that approximately half of the participants

were college students, as is often the result when recruiting a convenience sample for academic

purposes. The unique environmental and situational factors that college students experience (e.g.,

frequent exams and pressure to get good grades) may have an impact on the inverse relationship

between self-discipline and neuroticism. A student low in self-discipline and other

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conscientiousness facets may experience increased anxiety and neuroticism when presented with

academic tasks, as they often lack the skills necessary for efficient and successful performance.

Future research should consider a longitudinal approach to explore how changing environmental

task demands may affect the relationships between neuroticism, self-discipline and happiness

(Johnson & Bloom, 1995).

Another potential limitation of the present study is the fact that one of the ten IPIP self-

discipline items was omitted from the online survey due to human error. Although the nine IPIP

self-discipline items included in the survey still indicated excellent internal consistency

reliability, a replication of this study using all ten of the IPIP self-discipline subscale items would

be beneficial to assess the validity of the present findings.

The current study sought to replicate previous findings indicating negative associations

between neuroticism and both self-discipline and happiness, as well as a positive association

between self-discipline and happiness. Of particular interest was the conscientiousness facet of

self-discipline, and how this variable might affect happiness in neurotic individuals. Negative

correlations were observed between neuroticism and both self-discipline and happiness, and a

positive correlation was obtained between self-discipline and happiness, as prior research has

indicated. Self-discipline was found to have a mediating effect on the inverse relationship

between neuroticism and happiness; neurotic individuals who are more self-disciplined are

happier. This finding has implications for increasing happiness in neurotic individuals through

learned, controllable behaviors and cognitions related to self-discipline. Of interest may be

training in time management and study skills, or therapy designed to reduce antecedents of

procrastination such as task aversion and fear of failure. These types of interventions have the

potential to decrease stress and improve life-satisfaction in individuals with uncontrollable

11


neurotic tendencies. Future research should consider a longitudinal approach to explore how

changing environmental task demands may affect the relationships between neuroticism, self-

discipline and happiness.

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Table 1

Frequencies and Percentages of Demographic Characteristics of the Sample by Gender

Demographic Females Males Total Characteristics N % N % N %

Social Class Lower Working Middle Upper Middle/Upper Ethnic Background Caucasian Asian or Asian-American Latino/Hispanic Other

______________________________________________________________________________

2 2 3 4.3 5 2.9

12 11.8 12 17.1 24 14

40 39.2 26 37.1 66 38.4

48 47.1 29 41.4 77 44.7

64 62.7 44 62.9 108 62.8

14 13.7 8 11.4 22 12.8

10 9.8 6 8.6 16 9.3

14 13.7 12 17.1 26 15.1

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Table 2

Descriptive Statistics for Neuroticism, Self-Discipline and Happiness by Gender_____________________________________________________________________________

Females Males Total _____________ _____________ _____________

Variable M SD M SD M SD ______________________________________________________________________________

Neuroticism

Self-discipline

Happiness

______________________________________________________________________________

12.0 3.3 11.0 3.5 11.6 3.4

25.0 6.1 24.0 6.4 24.6 6.2

34.5 6.1 35.6 5.9 34.9 6.0

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Neuroticism and Self-Discipline as Predictors of Happiness: a Mediation Model