The mammalian record thus confirms our statement that any animal which is not too strongly conditioned by some special sort of experience is capable of responding to any adequate stimulus. This is what we find in the more uninhibited segments of our human species, and this is what we find among young children who are not too rigorously restrained in their early sex play. Exclusive preferences and patterns of behavior, heterosexual or homosexual, come only with experience, or as a result of social pressures which tend to force an individual into an exclusive pattern of one or the other sort. Psychologists and psychiatrists, reflecting the mores of the culture in which they have been raised, have spent a good deal of time trying explain the origins of homosexual activity; but considering the physiology of sexual response and the mammalian backgrounds of human behavior, it is not so difficult to explain why a human animal does a particular thing sexually. It is more difficult to explain why each and every individual is not involved in every type of sexual activity.