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, SELF-DISCIPLINE AND HAPPINESS
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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NEUROTICISM, SELF-DISCIPLINE AND HAPPINESS
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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NEUROTICISM, SELF-DISCIPLINE AND HAPPINESS
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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NEUROTICISM, SELF-DISCIPLINE AND HAPPINESS
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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NEUROTICISM, SELF-DISCIPLINE AND HAPPINESS
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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NEUROTICISM, SELF-DISCIPLINE AND HAPPINESS
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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NEUROTICISM, SELF-DISCIPLINE AND HAPPINESS
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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NEUROTICISM, SELF-DISCIPLINE AND HAPPINESS
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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NEUROTICISM, SELF-DISCIPLINE AND HAPPINESS
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
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NEUROTICISM, SELF-DISCIPLINE AND HAPPINESS
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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NEUROTICISM, SELF-DISCIPLINE AND HAPPINESS
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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NEUROTICISM, SELF-DISCIPLINE AND HAPPINESS
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, SELF-DISCIPLINE AND HAPPINESS
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