Mate choice and friendship in twins: evidence for genetic similarity

This study examined the genetic and environmental contribution to people's preference for spouses and friends to be similar to themselves. In their responses to 130 personality, attitude, and demographic questions, 174 pairs of monozygotic (MZ) twins resembled each other (r= .53) more than did 148 pairs of dizygotic (DZ) twins (r= .32), 322 pairs of spouses (r= .32), and 563 pairs of best friends (r= .20). It was not previously recognized that spouses and friends are as similar as DZ twins. MZ twins also chose spouses and best friends more similar to their co-twins' friends and spouses than did DZ twins (mean rs = .22 vs. .14). The twins' preference for spouses and friends similar to themselves was about 34% due to the twins' genes, 12% due to the twins' common environment, and 54% due to the twins' unique (nonshared) environment. Similarity to partners was more pronounced on the more heritable items than the less heritable items. It is concluded that people are genetically inclined to choose as social partners those who resemble themselves at a genetic level.     

Personality similarity in twins reared apart and together

We administered the Multidimensional Personality Questionnaire (MPQ) to 217 monozygotic and 114 dizygotic reared-together adult twin pairs and 44 monozygotic and 27 dizygotic reared-apart adult twin pairs. A four-parameter biometric model (incorporating genetic, additive versus nonadditive, shared family-environment, and unshared environment components) and five reduced models were fitted through maximum-likelihood techniques to data obtained with the 11 primary MPQ scales and its 3 higher order scales. Solely environmental models did not fit any of the scales. Although the other reduced models, including the simple additive model, did fit many of the scales, only the full model provided a satisfactory fit for all scales. Heritabilities estimated by the full model ranged from .39 to .58. Consistent with previous reports, but contrary to widely held beliefs, the overall contribution of a common family-environment component was small and negligible for all but 2 of the 14 personality measures. Evidence of significant nonadditive genetic effects, possibly emergenic (epistatic) in nature, was obtained for 3 of the measures.     

Associations between online friendship and Internet addiction among adolescents and emerging adults

The past decades have witnessed a dramatic increase in the number of youths using the Internet, especially for communicating with peers. Online activity can widen and strengthen the social networks of adolescents and emerging adults (Subrahmanyam & Smahel, 2011), but it also increases the risk of Internet addiction. Using a framework derived from Griffiths (2000a), this study examined associations between online friendship and Internet addiction in a representative sample (n = 394) of Czech youths ages 12-26 years (M = 18.58). Three different approaches to friendship were identified: exclusively offline, face-to-face oriented, Internet oriented, on the basis of the relative percentages of online and offline associates in participants' friendship networks. The rate of Internet addiction did not differ by age or gender but was associated with communication styles, hours spent online, and friendship approaches. The study revealed that effects between Internet addiction and approaches to friendship may be reciprocal: Being oriented toward having more online friends, preferring online communication, and spending more time online were related to increased risk of Internet addiction; on the other hand, there is an alternative causal explanation that Internet addiction and preference for online communication conditions young people's tendency to seek friendship from people met online.     

Personality,husband-wife similarity,and Holland's occupational types

The present investigation had two purposes. The first was to investigate the generalizability of the theorized personality characteristics of men within Holland's occupational types to groups of men typed by their actual vocations instead of their vocational interests. The second purpose was to investigate the extent to which the wives of men in each of the occupational groups were similar to their husbands in terms of personality characteristics. Multiple discriminant analysis of the groups' 16PF scores resulted in significant overall groups differentiation and in two significant discriminant functions labeled tender-mindedness and self-confidence. The second finding was that Social and Enterprising men were significantly similar to their wives on personality dimensions consistent with the defining characteristics of the respective Holland groups. Implications of the present results and suggestions for future research are presented.     

Personality trait similarity between spouses in four cultures

We examined patterns of trait similarity (assortative mating) in married couples in four cultures, using both self-reports and spouse ratings on versions of the Revised NEO Personality Inventory. There was evidence of a subtle but pervasive perceived contrast bias in the spouse-rating data. However, there was strong agreement across methods of assessment and moderate agreement across cultures in the pattern of results. Most assortment effects were small, but correlations exceeding .40 were seen for a subset of traits, chiefly from the Openness and Agreeableness domains. Except in Russia, where more positive assortment was seen for younger couples, comparisons of younger and older cohorts showed little systematic difference. This suggested that mate selection, rather than convergence over time, accounted for similarity. Future research on personality similarity in dyads can utilize different designs but should assess personality at both domain and the facet levels.     

Sex, competitiveness, and intimacy in same-sex friendship in Hong Kong adolescents

One of the alleged reasons that males report lower intimacy in same-sex friendships than females is that males tend to be more competitive than females, but this assumption has not been empirically tested. In the current study, 121 Hong Kong adolescents filled out Chinese versions of the Intimate Friendship Scale and the Competitiveness Index. As predicted, females reported having more intimate same-sex relationships than males, and they scored lower on competitiveness than males. However, the correlations between scores on the Competitiveness Index and the Intimate Friendship subscales were small and nonsignificant, suggesting that the sex difference in intimacy was not a function of competitiveness.     

Accuracy in perceptions of interpersonal interactions: effects of dysphoria, friendship, and similarity.

Conflicting views of depressives' interpersonal accuracy were addressed in an investigation of the accuracy of mild depressives (dysphorics) across differing social contexts. Women who were either friends or strangers and who were either similar or dissimilar in level of dysphoria conversed about 3 topics: a neutral topic, their own disclosure of a personal problem, and their partner's disclosure. Dysphorics were not more accurate in general than nondysphorics. After self-disclosure, all women more accurately detected sympathy from a similar stranger. After the partner's disclosure, women also better detected the mood of a similar partner. When interacting with nondysphoric strangers, however, dysphorics underestimated their partner's sympathy toward them. Implications for cognitive and interpersonal theories of depression and for depressives' relationships are discussed.     

Personality types and behavioural activation and inhibition in adolescents

A hypothesis relating personality types to activity of the Behavioural Approach System (BAS) and the Behavioural Inhibition System (BIS) was tested in a sample of 1015 10–18-year-old adolescents. According to this hypothesis, Undercontrollers could be characterized as individuals with overactive BAS, Overcontrollers as individuals with overactive BIS, and Resilients as individuals with low activity of both systems. These predictions were generally confirmed. Psychometrically measured BAS and BIS appeared to be the strongest predictors of Undercontrolled and Overcontrolled prototypes, respectively. Resilients were characterized by low scores on both dimensions.     

Perceptions of fear in other Children and adolescents: The role of gender and friendship status

Gender differences in fear were examined in 693 Chinese children and adolescents. Subjects were asked to rate their own fears, the fears of their best friends, and the fears of other classmates using the Fear Survey Schedule for Children — Revised (Ollendick, 1983). Consistent with previous investigations in Western and Eastern countries, girls rated themselves as more fearful than boys. In addition, both girls and boys rated their best friends as similar in number, content, and intensity of fears. However, girls rated their classmates as less fearful than themselves or their best friends, while boys rated their classmates as more fearful than themselves or their best friends. Findings are discussed in terms of gender role expectations and similarity-attraction hypotheses.     

The Millon Adolescent Personality Inventory profiles of depressed adolescents

The evidence indicates that adolescent depression may be more difficult to recognize than its adult counterpart, although the reasons for this difficulty remain unclear. The research in this area is in part impeded by the lack of adolescent-specific measures of personality functioning. In this study the personality styles, expressed concerns, and behavioral tendencies of depressed adolescents were investigated by means of the Millon Adolescent Personality Inventory (MAPI), a relatively new personality inventory designed specifically for this age group. Three hundred sixty-six high school students completed the Beck Depression Inventory (BDI) and the MAPI, resulting in 332 valid and reliable MAPI profiles. The data were reduced to two factors, accounting for 65.1% of the total variance, by means of a principal components analysis. The two factors were interpreted as two dimensions of personality functioning associated with depression in adolescents. The first dimension suggested a socially withdrawn, overtly recognizable depression, whereas the second presents acting-out tendencies that may overshadow depressive symptomatology. The findings are integrated with the theoretical positions represented in the literature. Theoretical and practical implications for the use of the MAPI with depressed adolescents are discussed.     

Personality disorders associated with substance use among American and Greek adolescents

A study was conducted to investigate the association between personality disorder (PD) symptomatology and substance use among adolescents in community settings in the United States and Greece. The Structured Clinical Interview for DSM-IV Personality Disorders and the Adolescent Health Behavior Survey were completed by 37 male and 84 female adolescents, ages 15 to 18, who were recruited from an adolescent medical clinic and schools in and near New York City (n = 71) and Heraklion, Greece (n = 50). Results indicated that: (1) adolescents with PDs reported more frequent alcohol consumption during the past year than did those without PDs; (2) adolescents with borderline PD reported more cigarette smoking and heavy alcohol consumption than did those without borderline PD; (3) adolescents with antisocial PD symptomatology reported greater alcohol, cigarette, and illicit drug use than did those without antisocial PD symptomatology; and (4) although more American (30%) than Greek (4%) adolescents reported illicit substance use, differences were not observed in the prevalence of alcohol use, cigarette use, or personality disorders as a function of nationality.     

Personality profile for adolescents at risk for internalizing and externalizing problems

To estimate the personality profile for adolescents at psychopathological risk, a community sample of 762 adolescents, ages 12 to 16 years (M = 13.8, SD = 1.3), 53% boys and 47% girls, from the city of Barcelona, Spain, were tested with the Youth Self-Report and the High School Personality Questionnaire. Among this group, 140 adolescents were identified as showing symptoms of psychopathological risk for internalizing or externalizing syndromes as defined by Achenbach's theory. Analysis indicated that adolescents who scored high for internalizing and externalizing symptoms showed differing personality profiles, which also differed by sex. Boys scoring high on internalizing tended to adopt an inhibited, shy, and apprehensive behavior, while girls showed a tendency to display a more distant and cold affect and changeable emotionality. The personality pattern of boys and girls who scored high on externalizing symptoms showed both similar and different aspects. Both sexes displayed characteristics such as dominance, poor rule conformity, and low self-discipline. However, girls who scored high on externalizing symptoms also tended to show impulsiveness, social boldness, and low sensitivity.     

Personality judgment at zero acquaintance: agreement, assumed similarity, and implicit simplicity

Previously unacquainted participants (N = 218) were assessed in small-group sessions in which they rated themselves and each other on (a) the Big Five (e.g., Costa & McCrae, 1992) and (b) an instrument assessing various traits not traditionally measured in the Big Five taxonomy as well as sociopolitical attitudes. Replicating earlier research, we obtained a significant self-stranger correlation on Extraversion; in addition, we found significant agreement on ratings of thriftiness, athleticism, traditionalism, conservatism, and attractiveness. Assumed similarity correlations were substantial for Neuroticism, Agreeableness, and Conscientiousness; furthermore, consistent with previous findings, there was a strong inverse relation between agreement and assumed similarity across the assessed characteristics. Finally, the correlations between Neuroticism, Openness, Agreeableness, and Conscientiousness were significantly greater in the strangers' ratings than in the self-ratings, indicating that these peer judgments are less complex. We also compared our Big Five findings with those from previous samples of varying acquaintanceship; these analyses indicated that the strangers' ratings were characterized by lower levels of self-other agreement (for all traits except Extraversion) and somewhat higher levels of assumed similarity (for ratings of Neuroticism and Agreeableness).     

Personality similarity in unrelated look-alike pairs: Addressing a twin study challenge

Numerous twin studies have demonstrated genetic influence on personality traits, yet twin methods continue to be challenged. A common misconception is that monozygotic co-twins’ personality resemblance results from similar treatment by others, due to their matched physical appearance. The present study brings unique evidence to this question by assessing the similarities in personality and self-esteem of 23 pairs of unrelated look-alike individuals. Intraclass correlations for the Big Five personality traits (r_is = −.27 to .29) and the Rosenberg Self-Esteem Scale (r_i = −. 03) demonstrated little within-pair resemblance. It is concluded that (1) MZ co-twins’ personality similarity mostly reflects their shared genes, and (2) reactive gene-environment correlation best explains MZ co-twins’ similar treatment by others.     

Personality, career decision self-efficacy and commitment to the career choices process among Chinese graduate students

This study examined the mediating effect of career decision self-efficacy on the relationship between the Five-Factor Model of personality and the career commitment process (i.e., vocational commitment and the tendency to foreclose) in a sample of 785 Chinese graduate students. The multiple regression analyses showed that neuroticism and conscientiousness related significantly to progress in vocational commitment both directly and indirectly through career decision self-efficacy. High agreeableness related to less premature foreclosure. In addition, career decision self-efficacy associated with greater progress in vocational commitment but also a strong tendency to foreclose. The implications for career development theory and practice are discussed.