In "patchwork" families, full siblings, maternal and paternal half-siblings, and non-related children are raised together, and sometimes, genetically related children are separated. As their number is steadily growing, the investigation of the factors that influence withinfamily relations is becoming more important. Our aim was to explore whether people differentiate between half-and full-siblings in their social relations as implied by the theory of inclusive fitness, and to test whether co-residence or genetic relatedness improves sibling relations to a larger extent. We administered the Sibling Relationship Questionnaire to 196 individuals who were in contact with full-, half-, or step-siblings in their childhood. We built Generalized Linear Mixed Models models to test for the effects of relatedness and co-residence on sibling relations. In general, a higher degree of relatedness was associated with better sibling relations, but only among those who did not live together during childhood. Co-resident siblings' overall pattern of relation quality was not influenced by the actual level of genetic relatedness. In contrast to this, full siblings reported having experienced more conflicts during childhood than halfsiblings, possibly resulting from enhanced competition for the same parental resources. The results suggest that inclusive fitness drives siblings' relations even in recent industrial societies. However, among individuals who live together, the effect of relatedness might be obscured by fitness interdependence and the subjective feeling of kinship.

Currently our understanding of environmental factors that influence the development of dark personality traits (DT) is limited. Therefore, we conducted three studies using online questionnaires, each examining a different aspect of the relation between dark personality traits and family environment. In Study 1, 117 adults (mean age: 30.36 years, SD = 10.19) filled out questionnaires regarding their childhood relationship with siblings and their own DT traits. We found that the amount of conflicts with siblings during adolescence correlated positively with Machiavellianism and psychopathy. The feeling of closeness towards the siblings showed negative correlation with Machiavellianism. Parental partiality towards the other sibling was positively correlated with narcissism. In Study 2, 111 adolescents (mean age: 15.92, SD = 1.24) reported their perceptions of the rearing style of their parents, in addition to their sibling relationships and DT traits. Perceived parental emotional warmth was negatively associated, whereas both rejection and overprotection were positively correlated with psychopathy. Parental warmth was positively, while rejection negatively associated with narcissism. Machiavellianism was positively associated with the amount of conflicts with siblings, but negatively with closeness to siblings. In Study 3, 110 adults (mean age: 32.62 years, SD = 12.25) reported their levels of the Vulnerable Dark Triad that included measures of primary and secondary psychopathy, maladaptive covert narcissism, and borderline personality organization. Results indicated that sibling relation quality had a significant effect on primary psychopathy and borderline traits. Parental rejection and overprotection correlated with borderline traits and vulnerable narcissism. The results of these studies shed some light on how environmental impulses, particularly the quality of relationships between family members, affect the development of personality.

Background Studies on person perception showed that stereotypes can be activated by presenting either characteristic traits of group members, or labels associated to these groups. However, it is not clear whether these pieces of semantic information activate negative and positive stereotypes directly, or via an indirect cognitive pathway leading through brain regions responsible for affective responses. Our main objective with this study was to disentangle the effects of semantic and affective contents. To this end, we intended to scrutinize whether the representation of occupational labels is independent of the emotions they evoke. Methods Participants (N = 73, M = 27.0, SD = 9.1, 31 men 42 women,) were asked to complete two tasks presented online. In the first task they had to arrange 20 occupational labels—randomly chosen from a pool of 60 items—in a two-dimensional space, moving the mouse pointer along two undefined axes. In a second task the axes’ names were defined a priori. Subjects were asked to arrange the labels according to valence, the extent to which the word evoked pleasant or unpleasant feelings, and arousal, the extent to which the word evoked excitement or calmness. Results Based on the final coordinates of the labels, two cluster analyses were carried out separately in the two tasks. The two clusters were compared with Fisher’s exact test, which revealed that the cluster structures overlap significantly. Conclusions The results suggest that the spontaneous categorization and the semantic representation of occupations rely largely on the affective state they evoke. We propose that affective content might have a primacy over detailed semantic information in many aspects of person perception, including social categorization.

Háttér és célkitűzések A csoporton belüli, illetve csoportközi együttműködés témáját már régóta intenzív érdeklődés övezi mind az evolúciós, mind a szociálpszichológia képviselői körében. Napjainkra hasonlóan kiterjedt szakirodalommal rendelkezik a Sötét Triád személyiségjegyekkel rendelkező emberek társas dilemma helyzetben jellemző viselkedésének elemzése. Kutatásunkban egy újfajta kísérleti játék kétféle változatával kívánjuk górcső alá venni a csoporthoz tartozás élményének, valamint a sötét személyiségjegyeknek a csoportközi együttműködésre gyakorolt hatását. Módszer A kutatás résztvevői egy saját fejlesztésű, innovatív csoportközi társas dilemmát szimuláló kísérleti játékban vettek részt, melyben két eltérő (1. vizsgálat, n = 236), illetve két azonos színű (2. vizsgálat, n = 147) falu lakói készülődtek az árvízi védekezésre. A résztvevőknek a játék mindkét fordulójában el kellett dönteniük, hogy milyen (önző, saját csoportot preferáló, vagy közös együttműködést támogató) stratégia szerint osztják szét homokzsákjaikat. A vizsgálat végén a résztvevőket az SD3 kérdőív kitöltésére is megkértük. Eredmények Kutatásunk fő eredménye, hogy az azonos színű házakat bemutató kondíció második fordulójában – a különböző színű házakat látó résztvevőkhöz képest – szignifikánsan magasabb csoportközi együttműködést mértünk. A sötét személyiségvonások befolyásolták a résztvevők allokációit, ugyanakkor a várakozásainkkal ellentétben a magas sötét személyiségvonások nem mindig az önző választásokkal jártak együtt. Következtetések Kutatásunk igazolta, hogy már a másik csoportról kapott minimális információk – a házak színei – is képesek befolyásolni a csoportközi együttműködés mértékét egy társas dilemma helyzetben. Eredményeinket a törzsi ösztön hipotézis, valamint a minimális csoport paradigma elméleti keretében tárgyaljuk.

Background: Studies on person perception showed that stereotypes can be activated by presenting either characteristic traits of group members, or labels associated to these groups. However, it is not clear whether these pieces of semantic information activate negative and positive stereotypes directly, or via an indirect cognitive pathway leading through brain regions responsible for affective responses. To disentangle the effects of semantic and affective contents, first we intended to scrutinize whether the representation of occupational labels is independent of the emotions they evoke.Methods: Participants (N = 71, M=27.0, SD=9.1, 31 men 42 women,) were asked to complete two tasks presented online. In the first task they had to arrange 20 occupational labels—randomly chosen from a pool of 60 items— in a two-dimensional space, moving the mouse pointer along two undefined axes. In a second task the axes’ names were defined a priori. Subjects were asked to arrange the labels according to valence, the extent to which the word evoked pleasant or unpleasant feelings, and arousal, the extent to which the word evoked excitement or calmness. Results: Based on the final coordinates of the labels, two cluster analyses were carried out separately in the two tasks. The two clusters were compared with Fisher’s exact test, which revealed that the cluster structures overlap significantly.Conclusions: The results suggest that the semantic representation of occupations relies largely on the affective state they evoke. We propose that affective content might have a primacy over detailed semantic information in many aspects of person perception, including categorization and face recognition.