17. Human Sexual Behavior III & Aggression I | Summary and Q&A

February 1, 2011
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17. Human Sexual Behavior III & Aggression I

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This video discusses various topics related to sexual behavior and the evolution of attraction in different species. It covers concepts such as the role of symmetry and secondary sexual characteristics in mate selection, the handicap principle, and the importance of homogamy in human relationships.

Questions & Answers

Q: What information does symmetry convey in terms of attractiveness?

Symmetry is considered attractive because it is seen as a marker of health. It indicates that an individual has good genes and is free from developmental complications or health issues. The preference for symmetrical faces is observed in humans, as well as in various animal species.

Q: How do secondary sexual characteristics play a role in mate selection?

Secondary sexual characteristics, such as large antlers or colorful feathers, are often exaggerated in males and are seen as attractive by females. These characteristics serve as signals of good health and reproductive fitness. They indicate that the male has enough energy and resources to invest in these characteristics, making him an attractive mate.

Q: What is the handicap principle?

The handicap principle, proposed by Israeli zoologist Zahavi, suggests that exaggerated secondary sexual characteristics serve as indicators of good genes and overall health. According to this principle, the larger and more extreme the characteristic, the more it signals the individual's ability to survive and thrive despite the energy cost. This principle is based on the idea that only genetically superior individuals can afford to invest in costly traits and still have enough resources to reproduce successfully.

Q: What are some explanations for the evolution of homosexuality?

There are three theories that have been proposed to explain the evolution of homosexuality. The first is the heterozygotic-vigor argument, which suggests that individuals with a mix of certain genes may have advantages in some aspects of survival and reproduction. The second is the gender-dependent genetic argument, where a trait may be maladaptive in one gender but highly adaptive in the other. The third is the "helper at the nest" model, which suggests that individuals who do not pass on their own genes directly may help their siblings in raising offspring, contributing to overall genetic success. However, the genetic component of sexual orientation is still not well understood, and further research is needed.

Q: What are some characteristics that are universally attractive in mate selection?

In addition to symmetry and secondary sexual characteristics, there are certain characteristics that are universally attractive in mate selection. These include facial features associated with health, such as clear skin and good muscle tone. Waist-hip ratio, where a ratio skewed towards larger hips is seen as attractive in females, is also considered universally attractive. Furthermore, individuals tend to be attracted to others who are similar to them in terms of religion, age, race, socioeconomic status, and political views.


This video highlights the various factors that play a role in mate selection across different species, including humans. It emphasizes the importance of physical traits such as symmetry and secondary sexual characteristics in attracting mates. The handicap principle explains the role of exaggerated characteristics as indicators of good health and genetic fitness. Additionally, mate selection often involves a preference for partners who are similar to oneself in terms of various personal traits. Understanding these factors can provide insights into the evolution of sexual behavior and attraction.

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