Are there genes for personality

Twin and family studies have showed that personality traits are moderately heritable, and can predict various lifetime outcomes, including psychopathology. The Research Domain Criteria characterizes psychiatric diseases as extremes of normal tendencies, including specific personality traits.

This implies that heritable variation in personality traits, such as neuroticism, would share a common genetic basis with psychiatric diseases, such as major depressive disorder. First, Weiss and colleagues 59 found a global SWB-measure to be accounted for by unique genetic effects for neuroticism, extraversion and conscientiousness, and by a common genetic factor that influenced all five personality domains.

Environmental factors also contributed to the associations, but there were no genetic effects unique to SWB. In a similar vein, Hahn and colleagues 38 reported shared genetic effects for life satisfaction and the traits of neuroticism and extraversion, but not conscientiousness.

Both additive and non-additive genetic effects contributed to the relation between personality and life satisfaction, and again the entire heritability of life satisfaction was accounted for by personality-related genetic factors. Finally, a study examining personality traits and flourishing found substantial genetic effects on the associations, but also identified a unique genetic influence on wellbeing, unrelated to personality Thus, a few recent studies have reported exciting evidence of a substantial genetic contribution to the association between personality traits and wellbeing.

However, several important questions remain to be addressed. First, no studies to date have examined genetic and environmental contributions to the associations between personality facets and wellbeing. Given the findings for broad personality traits, we hypothesize considerable genetic effects also for their facets. Yet, the magnitude of such effects is unknown. Second, only one study 38 has examined life satisfaction specifically — rather than global measures of wellbeing.

Third, as previous studies have relied only on short-form measures of broader traits, there is a pressing need for examining both traits and facets in relation to life satisfaction by means of comprehensive, valid, well-established instruments. Fourth, findings from the few previous studies are divergent as to whether the entire genetic effect on wellbeing is due to personality-related genetic influences.

Fifth, whereas prior studies have examined samples with broad age ranges, we wanted to examine a specific period in life — middle to late adulthood — to assess how relatively stable personality characteristics contribute to life satisfaction in a life course perspective. Finally, as previous studies have been inconclusive regarding sex-differences in the underlying etiology of wellbeing 6 , 62 , we also wanted to test for such differences.

As shown in Table 1 , neuroticism, extraversion, and conscientiousness were all significantly correlated with life satisfaction, while agreeableness and openness were not.

The strongest correlation was found for neuroticism, yet with substantial associations also for extraversion and conscientiousness. In the multiple regression analysis including these three factors, only neuroticism and extraversion showed significant unique contributions. The effects remained when controlling for sex and age.

We next examined the associations for all the 30 personality facets. Table 2 shows the resulting correlations. A total of 23 facets were significantly associated with life satisfaction. Within extraversion, excitement seeking was virtually unrelated 0. In the openness domain, only one facet, ideas, showed a significant but very modest correlation 0. The agreeableness domain was notable for a combination of positive and negative associations.

Trust 0. Finally, in the conscientiousness domain, all factors showed significant and positive correlations, and in particular competence 0. Next, regression analyses were conducted in which all 30 facets were tested simultaneously. Ten facets showed significant and unique effects Table 2. Four facets yielded substantial betas, that is above 0. The remaining significant facets were found across all personality domains and included the openness facets of values and actions, the agreeableness facet of compliance, and the conscientiousness facets of order and deliberation.

However, these effects were relatively minor i. Thus, for the biometric analyses disentangling genetic and environmental effects we focused on these four facets with substantial and significant effects.

Summarizing the regression findings, the happy, or satisfied personality is given by the equation:. Twin-cotwin correlations across zygosity groups were calculated for the neuroticism and extraversion traits, the four major facets i.

Table 3 shows the correlations. In general, the monozygotic MZ correlations were substantial, and in all cases higher than the corresponding dizygotic DZ correlations, indicating additive genetic effects. Based on the findings from the regression analyses, we next tested a set of tri-variate Cholesky models including neuroticism, extraversion and life satisfaction.

Table 4 upper part, block I shows the fit of the different models. Model 1 included additive genetic A , common environmental C and non-shared environmental E factors, and allowed estimates to vary across sex. Model 2, which included only A and E effects, did not fit significantly worse i. Further, models 3 and 4, involving scalar sex-limitation, yielded additional improvements in fit, that is, increasingly lower AIC values, no significant reduction in fit, and more parsimony.

Finally, models 5 and 6, where parameters were constrained to be equal across sex, resulted in higher AIC and worse fit. Thus, model 4 yielded overall best fit, and included only A and E effects with standardized parameters similar for men and women. Figure 1 shows the Cholesky parameters of the model. Biometric Cholesky model of neuroticism, extraversion and life satisfaction.

Based on the Cholesky model we also calculated the genetic and environmental correlations between the two personality traits and life satisfaction. Moving from the big five factors to the personality facets, again we tested a set of models including the four facets found to be most strongly predictive of life satisfaction. Table 4 lower part, block II, models 7—12 shows the results. Again, the best fitting model included only A and E effects model 10 , and standardized estimates did not differ across sex.

Figure 2 shows the parameter estimates of the best model. Biometric Cholesky model of four personality facets anxiety, depression, activity and positive emotions and life satisfaction. In this best-fitting model, heritabilities were estimated to 0. As can be seen in Fig. However, after the effect of latent factor A1 reflecting the genetic variance in anxiety was accounted for, there was no additional genetic effect from the unique genetic factor of depression A2. Likewise, the genetic variance in activity A3 influenced life satisfaction, but there was no additional genetic effect from positive emotions E4.

Thus, the genetic variance in each of the two personality domains, which influenced life satisfaction, appeared to be shared by the facets within their respective domain neuroticism or extraversion , and the facet-specific influences on life satisfaction appeared to be driven by environmental effects.

Notable is also the unique genetic factor A5 influencing life satisfaction after all the genetic effects of the facets were accounted for. Figure 3 shows the decomposed sources of variance for life satisfaction, along the corresponding variance components of the four facets. Life satisfaction: Sources of origin decomposed. Genetic and non-shared environmental components, divided into personality-based and non-personality sources. For facets, additive genetic A and non-shared environmental variance E shown.

Based on the best-fitting model, we also calculated genetic and environmental correlations for the variables, shown in Fig. Generally, the genetic correlations within personality domains were high, and the genetic correlations between facets and life satisfaction were moderate to high. The corresponding environmental correlations were generally lower, but suggested also important associations due to environmental factors. We set out to delineate etiological factors involved in the associations between personality and life satisfaction.

Personality traits are well-established predictors of wellbeing in general and life satisfaction in particular 3 , The issue of why personality traits influence life satisfaction was addressed along two paths: First, we examined the broad personality traits and the specific personality facets that drive the effects from traits. Second, we examined the role of genetic and environmental factors in the link between personality and life satisfaction.

At the level of broad traits, neuroticism and extraversion were uniquely predictive of life satisfaction, in line with previous studies 3 , 4. Further, four facets of unique importance for life satisfaction were identified, namely anxiety and depression from the neuroticism domain, and positive emotions and activity from the extraversion domain.

The happy, or satisfied personality thus seems to have low levels of anxiety and depression, and high levels of positive emotions and activity. The highly emotional nature of these facets is noteworthy.

That is, three out of the four facets explicitly refer to affective tendencies, whereas the fourth facet activity adds vigor, energy and liveliness Thus, the cognitive evaluation of life satisfaction is partly based on emotional tendencies inherent in the big five model. Our findings accord with previous studies in identifying depression, and partly positive emotions, as central predictors of life satisfaction 52 , However, whereas prior studies have found facets such as vulnerability, excitement-seeking 52 , and achievement striving 54 to be significant, in this population based sample covering middle to late adulthood, we found anxiety and activity to be important.

Although a high number of facets were correlated with life satisfaction at the zero-order level, most facets did not show unique effects on life satisfaction in the multivariate analyses. There were no unique effects from interpersonal facets such as warmth, assertiveness, gregariousness, trust or straightforwardness.

Neither did we find effects from accomplishment-related facets such as competence, self-discipline or dutifulness. This does not imply that having warm and trustful relations, or high levels of competence, are inconsequential for wellbeing.

Rather, we interpret the findings to suggest that the predominantly emotional facets are underlying tendencies accounting for some of the zero-order associations between other facets and life satisfaction.

Why and how do depression, anxiety, positive emotions and activity play such important roles in generating a good — or not so good — life? We believe that a dual set of mechanisms are involved. First, from a top-down perspective 64 , 65 , life satisfaction is influenced by a general way of seeing life, the glasses through which we perceive the world.

Therefore, negative and positive affective tendencies might color our ongoing evaluations of what life has been like. Second, and in accordance with a bottom-up perspective 64 , positive and negative affective tendencies over time contribute to life experiences that are taken into account when performing a current evaluation. These basic emotions are seen as evolutionary adaptive and functional responses to environmental exposures.

Although we are all equipped with the potential to experience such emotions, from a personality perspective there are individual differences in our tendency to activate them, and as such they are encompassed as facets in the five-factor personality model.

Adding the facet of activity energy to the equation we have four basic building blocks, inherent in our personality, that contribute uniquely to a good life. In the wellbeing-illbeing structural model WISM , wellbeing is conceptualized as comprising both well-staying and well-moving, and illbeing is correspondingly divided into ill-staying and ill-moving 15 , The model posits that humans have various goal states, and we may experience the presence of an obtained goal state well-staying , we may be in a process towards a desired goal well-moving , we may experience threats implying a risk of losing goals ill-moving , and finally we may realize that a goal state is lost ill-staying.

The current findings are noteworthy in identifying personality facets that have certain connections to these four goal-state conditions. Positive emotions can be seen as indicative of well-staying, activity is potentially important for well-moving, anxiety is a core feature of ill-moving and depression is a characteristic of loss and ill-staying.

Thus, our findings lend support to the notion of well-staying, well-moving, ill-staying and ill-moving as fundamental human scenarios that all are important for generating or obstructing good lives.

The estimated heritability for life satisfaction was 0. This is in the lower range of previous estimates for general wellbeing 24 , 35 , and below a meta-analysis estimate of 0. However, although findings are divergent, several studies have reported heritability estimates for life satisfaction that are moderately lower than for other wellbeing constructs 32 , 70 , 71 , and the meta-analysis by Bartels 6 reported a heritability of 0. Our study is one of the first to examine life satisfaction beyond midlife specifically, with a well-established instrument.

The findings point to both genetic and environmental influences — yet with the latter clearly being the most important. As such, life satisfaction appears to be more about the environmentally influenced life course, events and relationships, than about a genetically driven tendency.

Such an interpretation also implies potentials for change in life satisfaction, and possibly substantial benefits of wellbeing interventions 35 , We tested models examining sex-differences in the genetic and environmental sources of wellbeing.

In line with several studies 6 , 21 , 70 , but in contrast to some others 62 , 73 , we found the heritability, and the environmental component, to be of similar magnitude for females and males. Although the total variance might vary, our findings provide evidence that the relative contribution of genetic factors is similar across sex. While genetic factors seem to play only a moderate role for the total variability in life satisfaction, genetic factors appear to have a major role in the association between personality and life satisfaction.

Both at the levels of broad traits and more specific facets, genetic factors were highly important in explaining the effect of personality on life satisfaction. That is, there are genetic factors influencing personality that also influence life satisfaction, whereas environmental factors play a more limited role in this relationship.

More specifically, the genetic dispositions to experience a low degree of depression and anxiety, and a high degree of positive emotions and activity contribute to a life experienced as good and satisfactory.

To our knowledge this study is the very first to examine genetic factors in the association between personality facets and life satisfaction. In general, our finding of genetic factors playing a key role accord with the few previous studies examining broad personality traits and wellbeing in genetically informative samples 38 , 59 , However, whereas two of these previous studies found the entire heritability of wellbeing to be due to personality-related genetic factors 38 , 59 , in line with Keyes et al.

We can only speculate on the genetic mechanisms involved. Theoretically, there could be a specific, genetically driven, tendency to having a positive outlook on life that is not captured within the five-factor model.

Alternatively, there could be influences from conditions such as mental abilities or somatic disorders — both of which have substantial genetic influences 19 — that also are outside the personality domain. Further studies are required both to address this aspect of life satisfaction, and generally to delineate the complex processes starting with DNA-molecules and ending up with a person evaluating her life as good — or not.

The findings also accord with a recent molecular genetic study of the association between wellbeing and neuroticism. Okbay, et al. It is also noteworthy that there was a common genetic factor for anxiety and depression that contributed to life satisfaction, and there was no unique genetic variance in depression that predicted life satisfaction beyond that shared with anxiety.

The facet-specific influences appear to be driven by environmental effects. Corresponding findings were seen for extraversion; a common genetic factor for activity and positive emotions contributed to the genetic variance in life satisfaction.

Strengths of the current study include a population based sample, a fairly high response rate, and well-established extensive measurements. Nevertheless, some limitations should be noted. First, as with any twin study, heritabilities and genetic correlations are not fixed figures, but are estimated for a certain population, and only future studies can validate the findings across other societies and age groups.

Measure content performance. Develop and improve products. List of Partners vendors. Psychologists often talk about personality traits , but what exactly is a trait? How do mental health professionals define this term? It is our personalities that help make us unique individuals, but not everyone agrees on exactly how many different traits exist.

Some break personality down into very narrow and specific traits, while others prefer to look at traits much more broadly. Traits are typically defined as the different characteristics that make up an individual's personality. In the Handbook of Personality: Theory and Research , authors Roberts, Wood, and Caspi define personality traits as "the relatively enduring patterns of thoughts, feelings, and behaviors that distinguish individuals from one another.

Trait theory suggests that our personalities are made up of a number of different broad traits. For example, extroversion often known as extraversion is a personality dimension that describes how people interact with the world. Some people are very extroverted or extraverted and outgoing, for example, while others are more introverted and reserved. Until fairly recently, it was believed that personality traits changed very little over the course of a lifetime.

Some newer longitudinal studies have revealed that traits are a bit more nuanced than previously believed and that some personality changes can and do occur over time.

What would you say if someone asked you to list the personality traits that best describe you? You might rattle off a variety of traits such as kind, aggressive, polite, shy, outgoing, or ambitious. If you were to make a list of every personality trait, it would probably include hundreds or even thousands of different terms used to describe different aspects of personality. Psychologist Gordon Allport once created a list of personality traits that included more than 4, terms.

The question of just how many personality traits there is has been the subject of debate throughout much of psychology's history, but many psychologists today rely on what is known as the big five model of personality. According to the big five model , personality is composed of five broad dimensions. Individual personalities may be either high, low, or somewhere in between on each of the five core traits.

The five traits that make up personality are:. It seems ridiculous now, but that was the orthodoxy back then. And to mention genetics was just beyond the pale. Within the world of science and psychology, he says, there is no longer any problem. While there has always been widespread acceptance that genes determine our physiology for good and bad, much greater controversy has surrounded the subject of our psychology — our behaviour and personality traits.

We prefer to think of such traits as social constructions, brought about by the familial and social environments into which we happen to be born. After all, if one child is subject to parental love and attention in comfortable, secure surroundings with plenty of intellectual stimulation, while another grows up in conditions of neglect and social deprivation, we expect the former to perform better at school and in life in general.

And, by and large, they do, though Plomin believes that has less to do with social factors than biological ones. This is a difficult concept to absorb for several reasons. The first is that we can all come up with examples in which environment would have a profound effect on outcome. For example, if you locked a child in a room and never taught that child to read or allowed it access to a book, then, released, that child at age 13, would, to say the least, display distinct learning difficulties.

Another problem that Plomin encounters with explaining his findings is that people often confuse group and individual differences — or, to put it another way, the distinction between means and variances. Thus, the average height of northern European males has increased by more than 15cm in the past two centuries. That is obviously due to changes in environment.

However, the variation in height between northern European males is down to genetics. The same applies to psychological traits. The confusion between means and variances is a fundamental misunderstanding.

For much of the relatively brief history of genetic science, there has been an even greater misunderstanding — the notion that the presence or absence of single genes is the determining factor that accounts for illnesses, abnormalities, dysfunctions, etc.

Hence, some environmentalists have demanded to be shown the gene for various complaints and, when it is not produced, declare that there is no genetic explanation.