Adult criticism and vigilance diminish free riding by children in a social dilemma.

In cooperative situations, individual interests can be in conflict with those of the group, creating a social dilemma in which one must choose whether to cooperate or not. Sensitivity to social stimuli is an important factor influencing cooperative behavior in such dilemmas. The current study investigated the influence of verbal feedback and vigilance by adults on children's donating behavior in a public goods game. The participants were 739 public school children, between 5 and 12 years of age, who were divided into 34 groups. Each group was assigned to one of four experimental conditions: control, positive feedback (praise), negative feedback (criticism), or vigilance. Participants then played eight rounds of the game. The children's donations were greater in the feedback and vigilance conditions, but the effects were mediated by age and rounds. The results are most likely related to concerns about reputation, which tend to become stronger with age. Older children are better at self-presentation and understanding social norms. Thus, compared with younger children, they seemed more concerned with appearing to be generous, but only when they could get credit for it. Nevertheless, children's donations still decreased across the rounds. Although adult vigilance and feedback influence children's cooperation among peers, other mechanisms are necessary to stabilize their behavior over time.

Estilos de dominancia e comportamento em femeas de Callithrix jacchus

O sagui comum(Callithrix jacchus) possui uma organizacao social baseada em dominancia que se evidencia pelos niveis de agonismo entre os animais do grupo. Clarke et al(1986) sugerem dois tipos de dominancia em primatas: clara, quando um animal sempre domina o outro em todas as disputas, e contestada ou reversivel, quando ha uma inconsistencia nos resultados das disputas. O objetivo deste trabalho foi o de comparar as diferencas comportamentais entre grupos de C. jacchus apresentando dominancia clara (G1) e contestada ou reversivel (G2). Para isto utilizamos cinco pares de femeas e cinco machos adultos do Nucleo de Primatologia da UFRN. Os animais foram observados por 20 semanas consecutivas. Foram registradas os comportamentos agonisticos, os afiliativos com o parceiro e as interacoes sexuais. Em relacao ao agonismo foram encontradas diferencas significativas entre femeas dominantes e subordinadas, mas com as femeas subordinadas do G2 apresentando niveis significativamente maiores que as do G1. Para o comportamento afiliativo observamos uma tendencia do macho em interagir preferencialmente com a femea dominante no G1; no G2 os niveis foram comparaveis para as femeas dominante e subordinada. Nao houve diferencas entre os grupos quanto aos comportamentos sexuais. Os resultados sugerem que a diferenca entre os grupos se deveu aqueles encontradas nos indices de agonismos das femeas subordinadas: as que se submetem (G1) e as que resistem a dominacao (G2).