Harassment of Mature Female Chimpanzees by Young Males in the Mahale Mountains

Juvenile and adolescent male chimpanzees sometimes threaten older, apparently stronger individuals such as mature females. I label the behavior harassment. Harassment comprises 25 behaviors, 14 of which are accompanied by the use of objects such as branches: Clubbing, flailing and throwing are the most common. Females respond to harassment with 10 behaviors, including scream, avoid, ignore, and retaliate. Females tend to respond to harassment by juvenile males by ignoring them. However, they are more likely to retaliate, scream or avoid in response to harassment by adolescent males. I propose the rank improvement hypothesis that harassment initiates the process of male domination of females, and compare the predictions derived from it with those of the exploratory aggression hypothesis. Males stopped harassing females significantly earlier when females ignored them versus when they did not ignore them. This is not consistent with the exploratory aggression hypothesis. Males harassed adult females significantly longer when females retaliated than when they did not, which is consistent with the rank improvement hypothesis. Although the observations are congruent with my hypothesis, we need more data to test it.     

The Unknown Vygotsky: On the Experience of a Literary Translation from Hebrew

Following is the first publication of a previously unknown translation by L.S. Vygotsky from Hebrew of a fictional short story by M.J. Berdyczewski, a Jewish writer popular at the beginning of the twentieth century. The commentary by the authors of this article reconstructs the context of Vygotsky’s life situation during the prerevolutionary period. Particular attention is focused on the questions of ethnic and cultural self-determination that were confronting him. The cultural contexts essential for an understanding and interpretation of the artistic and world-view features of the text of the short story are explored. A comparison is drawn to show the connection between the themes addressed in the story and the substantive problems that Vygotsky would subsequently deal with as a professional psychology: the artistic inner experience, moral choice, and cultural mediation.     

Differences in Subadult Behaviors of Chimpanzees Living in Peer Groups and in a Family Group

In several primate species, peer-group rearing conditions affect the development of social behavior. We compared the social behavior of adolescent chimpanzees reared in peer groups and in a family group to see whether chimpanzees raised under different regimes show differences in sexual behavior, teasing behavior, and grooming behavior and in their ability to cope with support strategies. Surprisingly, the lack of opportunity to practice or to watch in peer groups had no measurable effect on the development of normal sexual behavior in adolescence and adulthood. Peer-group individuals groomed each other as much as peers did in the zoo. Sex differentiation in reaction to teasing and in conflict initiatives may indicate only an earlier sex differentiation in the zoo than in the peer group. This result may be attributed to the difference in demographic composition of the groups instead of some inherent difference in skill. Peer-group chimpanzees simply cannot find adult partners with which they may preferably test their position. However, there was a lack of sex differentiation in the reaction to teasing and in the number of conflicts started; both are indications of lesser sex-role development in the peer-group adolescents. Furthermore, the frequency of giving support to peers in conflicts differed, which suggests a greater ability in zoo adolescents to cope with support strategies. Accordingly, providing more natural conditions than is usual in laboratories may still add considerably to chimpanzee well-being.