736 vII. APPLICATIONS  AND  IMPLICATIONS
generally finds weak buffering effects (Anu -
sic et al., 2014a; Dyrdal & Lucas, 2013; Yap 
et al., 2012).
Associations with  Personality  Traits
The personality characteristics that have 
been studied most frequently in relation to 
SWB are extraversion and neuroticism (Die -
ner & Lucas, 1999). The focus on these two 
traits is often traced to a landmark study 
by Costa and McCrae (1980), who argued 
that the broad trait of extraversion influ -
ences feelings of positive affect, the trait of 
neuroticism influences negative affect, and 
together these two components of emotional 
well-being influence overall feelings of life 
satisfaction. In support of this hypothesis, 
Costa and McCrae found that extraversion 
was correlated with feelings of positive af -
fect, and neuroticism was correlated with 
negative affect. Although the correlations in 
their study were quite weak (e.g., r s around 
.20), the fact that they were stable over time 
led Costa and McCrae to suggest that stable 
individual differences were important for 
well-being.
This finding has been confirmed in a 
large meta-  analysis that focused on the as -
sociations between SWB and personality 
trait measures from three widely used per -
sonality inventories. Steel et al. (2008) found 
small to moderate correlations between 
SWB measures and most of the personality 
traits they examined, with especially high 
correlations with extraversion and neuroti -
cism. For instance, the correlations between 
extraversion and positive affect were .44 
for the NEO Personality Inventory (NEO-
PI; Costa & McCrae, 1992), .35 for the 
Eysenck Personality Questionnaire (EPQ; 
Eysenck & Eysenck, 1975), and .25 for the 
Eysenck Personality Inventory (EPI; Eysenck 
& Eysenck, 1968). The correlations between 
neuroticism and negative affect were .54 for 
the NEO, .53 for the EPQ, and .46 for the 
EPI. These results confirm the importance 
of extraversion and neuroticism as moder -
ately strong predictors of SWB (though most 
of these associations are from studies that 
assessed both constructs at the same time 
using the same methods, which can inflate 
correlations).
Steel et al.’s (2008) meta-  analysis also 
shows that extraversion and neuroticism are not the only traits that matter for SWB. 
For instance, Steel et al. showed that cor -
relations between agreeableness and SWB 
constructs were consistently significantly 
different from zero and ranged from .12 for 
positive affect to .30 for happiness. Simi -
larly, correlations with conscientiousness 
ranged from –.21 for negative affect to .40 
for overall quality of life. A separate meta- 
analysis by DeNeve and Cooper (1998), 
one that focused on a broader set of traits 
than that of Steel et al. (2008), found that 
repressiveness–  defensiveness, trust, hardi -
ness, and some forms of locus of control and 
self- esteem also exhibited relatively high 
correlations (though many of these correla -
tions were derived from a very small number 
of studies). Finally, personality traits such 
as optimism and self-  esteem reflect general 
positive views about the self and the world, 
and they too have been shown to correlate 
with well-being (e.g., Lucas et al., 1996; 
Schimmack & Diener, 2003).
Explanations for these associations gen -
erally take one of two forms. McCrae and 
Costa (1991) suggested that instrumental 
theories  posit an indirect link from person -
ality to SWB through choice of situations or 
the experience of life events. For example, 
extraverts may enjoy and participate in so -
cial activities, which may in turn affect the 
amounts of positive affect that they expe -
rience. These instrumental theories can 
be contrasted with temperament theories,  
which posit a direct link from the trait to 
the outcome in question. According to tem -
perament theories, the association does not 
flow through life choices, life events, or life 
experiences.
The most widely studied temperament 
theories link extraversion and neuroticism 
to affect through two basic motivational 
systems that have been proposed and inves -
tigated by Gray (1970, 1981, 1991; see also 
Elliot & Thrash, 2002; Tellegen, 1985). Ac -
cording to Gray, much of the variability in 
personality can be explained by three fun -
damental systems: the behavioral activation 
system (BAS), which regulates reactions to 
signals of conditioned reward and nonpun -
ishment; the behavioral inhibition system 
(BIS), which regulates reactions to signals 
of conditioned punishment and nonreward; 
and the fight–  flight system (FFS), which reg -
ulates reactions to signals of unconditioned 