Well, The Naked Ape was written in 1967, for context. Here’s are a few of Morris’s other (discredited) theories:
• The female orgasm developed, in part, because of the female’s need to stay horizontal after the sexual act. If she were to get up and walk away, like other apes do, the seminal fluid would leak out of her vertically aligned vaginal passage and she would never conceive. The violent response of the female orgasm, leaving her sexually satiated and exhausted, has the effect of keeping her horizontal for the appropriate amount of time for insemination to occur.
• Weak and effeminate fathers raise lesbian daughters and strong and masculine mothers raise gay sons. Children or either gender, exposed to a behaviorally “inappropriate” parent, will seek those behaviors in a mate when they come of age, and may only find them in people of their same gender.
• Humans intentionally imbue commercial products and brands with a resemblance to our “threat-faces.” Car designers arrange headlights, metal grilles, and hoods so that they take on the appearance of an aggressive human face because roads have become increasingly crowded and driving has become an increasingly belligerent activity.
• The corporal punishment used in some schools, especially the spanking and paddling, are a cultural holdover from our evolutionary predisposition for male sexual dominance over females. The schoolboy assumes a classic submissive feminine posture of rump-presentation, and the teacher has replaced the repetitive pelvic thrusts of the dominant male with the rhythmic whipping of the switch.
• Girls think spiders are icky because their long legs remind them of the hair that sprouts on their bodies during puberty, and body hair is essentially a male characteristic, and therefore grotesque from a young girl’s point of view.
• Morris’s pair-bonding argument. He was trying to suggest that human females are generally faithful to their mates. This is indeed a good question (if you believe they are, that is). For high fidelity would place women in a distinct minority within the animal kingdom. Though female animals are generally less licentious than males, the females of many species are far from prudes, and this is particularly true of our nearest ape relatives. Female chimpanzees and bonobos are, at times, veritable sex machines. In explaining how women came to be so virtuous, Morris referred to the sexual division of labor in an early hunter-gatherer economy.
“To begin with,” he wrote, “the males had to be sure that their females were going to be faithful to them when they left them alone to go hunting. So the females had to develop a pairing tendency.”
Stop right there. It was in the reproductive interests of the males for the females to develop a tendency toward fidelity? So natural selection obliged the males by making the necessary changes in the females? Morris never got around to explaining how, exactly, natural selection would perform this generous feat."