Hormonal mechanisms for regulation of aggression in human coalitions.

Coalitions and alliances are core aspects of human behavior. All societies recognize alliances among communities, usually based in part on kinship and marriage. Aggression between groups is ubiquitous, often deadly, fueled by revenge, and can have devastating effects on general human welfare. Given its significance, it is surprising how little we know about the neurobiological and hormonal mechanisms that underpin human coalitionary behavior. Here we first briefly review a model of human coalitionary behavior based on a process of runaway social selection. We then present several exploratory analyses of neuroendocrine responses to coalitionary social events in a rural Dominican community, with the objective of understanding differences between in-group and out-group competition in adult and adolescent males. Our analyses indicate: (1) adult and adolescent males do not elevate testosterone when they defeat their friends, but they do elevate testosterone when they defeat outsiders; (2) pre-competition testosterone and cortisol levels are negatively associated with strength of coalitionary ties; and (3) adult males usually elevate testosterone when interacting with adult women who are potential mates, but in a striking reversal, they have lower testosterone if the woman is a conjugal partner of a close friend. These naturalistic studies hint that reciprocity, dampening of aggression, and competition among friends and allies may be biologically embedded in unique ways among humans.

Capuchin monkey tool use and Léon Croizat's ideas on the evolution of human behavior.

This note reviews Léon Croizat's ideas about the evolution of human behavior, based on his evaluation of the tool use capabilities of a capuchin monkey. Croizat theorized mainly on his orthogenetic view to explain such behavior. Interesting enough is the timeframe (1962) and context of his statement and the monkey's model used for such explanation. In this direction, some comments are provided considering the current knowledge of capuchin tool using and its potential implications for modeling hominid evolution.

Transport of tools and mental representation: is capuchin monkey tool behaviour a useful model of Plio-Pleistocene hominid technology?

Capuchin monkeys display greatly developed tool-using capacities, performing successfully a variety of tool-tasks. Impressed by their achievements in this respect, some investigators have suggested that capuchin tool-using behaviour could be used as a model of the tool behaviour of the first hominids. The transport of tools, a task requiring complex cognitive capabilities, is an essential ingredient in the technological behaviour of the first hominids. In this way, to qualify as another source for modelling hominid behavioural evolution, capuchins had to exhibit proficiency in the transport of tools. We investigated this problem through experiments designed to elicit the transport of objects. The results showed that the monkeys were able to transport food to be processed with the use of tools, but failed when the tools themselves had to be transported. Our hypothesis is that a limited capacity for abstract representation, together with the lack of a regulatory system ensuring that the food would not be lost and consumed by another individual during the search for and transport of the tools, were responsible for such a failure. We conclude that the tool-using behaviour of capuchins presents no functional analogy with the tool behaviour of the Plio-Pleistocene hominids, and that capuchin monkeys are a very inadequate source for modelling Plio-Pleistocene hominid's technological behaviour.

Um animal chamado homem / An animal named men

O artigo analisa a relação entre o homem e a animalidade, tanto internamente, como em sua relação com outros seres, fazendo-o à luz do instrumental psicanalítico, e servindo-se também das fábulas da literatura(AU)

O distanciamento e a proximidade / Distance and proximity

Neste final de milênio, as pessoas distanciam-se cada vez mais de si mesmas. Estranhos em corpos doentes que a moderna tecnologia científica, elaborada para as grandes massas urbanas, não consegue atingir. O câncer de mama ainda faz muitas vítimas, que são prisioneiras de sua doença, de seu estigma e da solidão social. O Centro de Estudos e Pesquisa em Psicanálise proporciona uma proximidade e uma escuta diferenciada à especificidade humana(AU)