问答题 Like many concepts in social psychology, aggression has many definitions, even many evaluations. {{U}}(1)Some think of aggression as a great virtue(e, g. "the aggressive businessperson"), while others see aggression.{{/U}} The fact they we do keep the same word anyway suggests that there is a commonality: Both positive and negative aggression serve to enhance the self. {{U}}(2)The positive version, which we could call assertiveness, is acting in a way that enhances the self, without the implication that we are hurting someone else. The negative version, which we might call violence, focuses more on the" disenchantment of others as a means to the same end.{{/U}} Although the life of animals often seems rather bloody, we must take care not to confuse predation--the hunting and killing of other animals for food-with aggression. {{U}}(3)Predation in carnivorous species has more in common with grazing in vegetarian species than with aggression between members of the same species. Take a good look at your neighborhood cat hunting a mouse: He is cool, composed, not hot and crazed. In human terms, there is not the usual emotional correlate of aggression: anger. He is simply taking care of business.{{/U}} That taken care of, there remains remarkably little aggression in the animal world. But it does remain. We find it most often in circumstances of competition over a resource.{{U}}(4)This resource must be important for" fitness," that is, relevant to one's individual or reproductive success. Further, it must be restricted in abundance: Animals do not, for example, compete for air, but may for water, food, nesting areas, and mates.{{/U}} It is the last item-mates-that accounts for most aggression in mammals. And it is males that are most noted for this aggression. {{U}}(5) As we mentioned earlier, females have so much at stake in any act of copulation (求偶结合)-so many months gestation, the increased energy requirement, susceptibility to attack, the dangers of birth, the responsibility of lactation-that it serves their fitness to be" picky" when looking for a partner.{{/U}} If females are picky, males must be show-offs: The male must demonstrate that he has the qualities that serve the female's fitness, in order to serve his own fitness. Deer are a good example. Mind you, this need not be conscious or learned; in all likelihood, it is all quite instinctual in most mammals. It may possibly have some instinctual bases in us as well.