Evolutionary Perspective on Relationships and Child-rearing

We tend to think of relationships as social affairs dictated by our desire for love and companionship. While that is true, there is also a version of the thought that is less romantic and more instrumental in its approach. This approach is primarily biological in nature and is known as the evolutionary approach to relationships.

So what exactly is the evolutionary approach? In other words, what does it say? Well, the evolutionary approach states that all animals (including human beings) are motivated to select a mate with the best possible genes, who will be best able to ensure their offspring’s future health and survival. To this end, animals (and humans) engage in several mate selection strategies.

Mate Selection Strategies

When it comes to selecting a mate, it appears that males and females confirm the popular notion of being fundamentally different. Although both no doubt come from Earth (as opposed to Mars or Venus), men popularly engage mostly in what is called intrasexual mate selection and women in what is known as intersexual mate selection. Both the types of mate selection strategies are as discussed in the following paragraphs:

• Intrasexual Mate Selection: This is the type of selection in which the competitive sex, in this case, males, fight amongst themselves. What ensures reproductive success is either directly winning a physical fight, or through a more subtle strategy of claiming control over scarce resources. This is demonstrated by all primates as well as most mammals, the males of which species engage in fierce combats for access to females. This generally leads to a polygamous society rather a monogamous one, as society is structured in the form of an alpha male maintaining a harem of females. There is, however, a strong exception to this rule, as we will see in a moment.
• Intersexual Mate Selection: This is the type of selection in which the competitive sex, once again males, show off or display physical features or abilities to get the attention of the other sex, that is, females. However, the choice of whether to mate with the male or not rests ultimately upon the female. Birds often show this kind of mate selection strategy, as is evidenced by the exquisite show of plumage by the peacock to attract a peahen.

So which model of sexual selection do humans follow? As in most primate species, human males too adopt an intrasexual approach more often, although an intersexual approach isn’t uncommon. Results from a 2018 study (Kordsmeyer et. al., 2018) show that physical dominance, but not sexual attractiveness, predicted mating success. Metrics such as upper body size, physical strength and vocal and facial dominance are more associated with mating success than female choice. Humans, however, are different from other similar species in that intrasexual competition doesn’t generally result in polygamous societies. This shows that social norms and taboos play a major role in human society, and genetic influences are partly suppressed. A similar effect is seen in another area of human behaviour. That is the area of parental investment.

Parental Investment. What is it?

In evolutionary psychology, parental investment is any expenditure made by a parent in terms of time, energy or resources that benefit the offspring at the cost of the parent’s own fitness or well-being. Robert Trivers proposed the Theory of Parental Investment, whereby he said that the sex making the greatest contribution or investment in the well-being of the offspring in terms of lactation, nurture or protection, will be more discriminating while choosing a partner. On the other hand, the sex that invests less in offspring will compete for access to the higher investing sex. This is in accordance with Bateman’s Principle which says that the greater-investing sex is the limiting resource over the the sex that competes and invests less. This is clearly evident in our society and our media where men are the pursuers and women are the choosers (in general). In this regard, there are fundamental, complex differences between maternal and paternal investment in offspring. When it comes to humans, the differences, like everything else, become even more complex.

In simple evolutionary terms, offspring have a deeper bond with their mothers than with their fathers. Women are typically seen as caregivers for offspring whereas men are generally seen as the providers of material resources. However, men also have a meaningful role to play in the lives of children by taking part in decision-making in the family.

However, according to the parental investment theory, mothers tend to invest more in their offspring because of the certainty that the offspring is genetically related to her. Fathers, on the other hand, typically have less investment in potential offspring because of an innate uncertainty involving their genetic relationship with the offspring. This phenomenon is called paternal insecurity. Humans, however, are exceptional in this regard. Human males invest quite heavily in offspring, as opposed to our primate kin. Studies on the father-child relationship have had some surprising results, such as demonstrating a decrease in testosterone in men following a child’s birth, making men less likely to be abusive, commit adultery or seek divorce.

Conclusion

Long-term monogamous relationships are absolutely crucial to a child’s healthy physical, social and emotional development. The evolutionary perspective on parenting shows that fathers have a strong incentive to invest in children because it increases the chances of the propagation of their own genes into the next generation through the reproduction of their children. In this way, the father’s genes may be carried forward. Thus, humans have been shaped by evolutionary and social pressures to be involved in the upbringing of their children and ensure that their genes pass on down the generations through time.