ABSTRACT
Indirect aggression includes behaviours such as criticizing a competitor's appearance, spreading rumours about a person's sexual behaviour and social exclusion. Human females have a particular proclivity for using indirect aggression, which is typically directed at other females, especially attractive and sexually available females, in the context of intrasexual competition for mates. Indirect aggression is an effective intrasexual competition strategy. It is associated with a diminished willingness to compete on the part of victims and with greater dating and sexual behaviour among those who perpetrate the aggression.
1. INTRODUCTION
The study of sexual selection among human females has primarily focused on two competition strategies used to attract mates: (i) self-promotion and (ii) the derogation of rivals. Self-promotion involves epigamic displays of physical attractiveness such as wearing make-up or sexy clothing to attract the attention of a potential partner. The derogation of competitors involves making a rival seem less attractive or less appealing to members of the opposite sex, which is typically achieved by disparaging the competitor's appearance or by spreading rumours that question the fidelity or level of promiscuity of a rival.
2. WHO USES INDIRECT AGGRESSION?
When comparing mean levels of direct forms of aggression, which includes physical aggression, there is a clear and pronounced sex difference favouring males across the lifespan. When comparing sex differences in mean levels of indirect aggression, there is a slightly higher rate found among females during childhood, adolescence and adulthood. Importantly however, when examining the proportion of engagement in this type of aggression, research demonstrates that females preferentially use indirect aggression (e.g. 52% for girls versus 20% for boys in 15-year olds; over all other forms of aggression. When girls and women aggress against others, they almost invariably use indirect aggression.