I found this amusing paper, Adaptation to Sperm Competition in Humans, via google scholar. The topic itself isn't necessarily amusing, but the description of how a human penis is engineered to scoop out the sperm from another male can't help but induce some smirks. In any case, most of the time we've discussed sperm competition it has been in an explicitly physiological & anatomical context. How viscous is the sperm? How quickly does it dry up and serve as a "plug"? How large are the testicles of various primate species? This paper examines possible "psychological adaptations," and tries to offer an explanatory model for proximate phenomena. For example, why do males tend to ejaculate larger volumes after viewing pornography which involves group sex between two males and one female than between three females? Of course, being evolutionary psychology in the classic mode there really isn't examination or entertainment of human differences, which might open up the possibility of a multiplicity of conditional strategies varying in terms of utilization across individuals.

Related: Our sperm competition posts.

Labels: Psychology