genetics and aggressionto what exte

genetics and aggression
to what extent is human agression rooted in our genetic heritage? agression is certainly a trait that can be selectively bred in animals, as evidenced by the breeding if fighting bulls in spain or pit bulls for dog fighting. Mice (Lagerspetz & Lagerspetz,1983) and fruit flies (diereck & greenspan,2006) can also be bred selectively for aggressiveness,allowing researchers to bein identifying particular genes that might be involved. Human twin studies indicate significant genetic influence on aggressiveness (Rushton, Fulker, Neale, Nias, & Eysenck, 1986). The heritability of impulsive aggressiveness is particularly high, between 44and 72 percent (coccaro, Bergeman,Kavoussi, & Seroczynski, 1997;Seroczynski, Bergeman, & Coccaro, 1999).
most within-species aggression is confined to the establishment of dominance,and it is unusual for one animal to kill another. typically,the "loser" need only withdraw to end the aggressive engagement. The only species in which groups of males systematically hunt and kill members of their own species are chimpanzees and humans (wrangham & peterson,1996;wright,1994)