Here is an interesting introduction to evolutionary psychology. The idea is that “human behavior is a product both of our innate human nature and of our individual experience and environment”. The “innate human nature” is the product of millions of years of evolution and has a serious impact on our behavior.

The results of this kind of analysis can often seem ‘ugly’ to us. They are not polite, they are not meant to be. They are however very interesting and their clear logic appeals to me.

There are ten examples in the article (not all of which I agree with), but some are interesting. An interesting introduction to the field so I have included a few quick summaries below:

2. Humans are naturally polygamous

• “Polygyny (the marriage of one man to many women) is widely practiced in human societies”
• We know that humans have been polygynous over our history because men are generally bigger than women. In other species (specifically other primates), bigger males indicate polygyny

3. Most women benefit from polygyny, while most men benefit from monogamy

• Contrary to popular belief, polygyny actually benefits women! In a highly unequal society a woman is better off sharing half of a wealthy man than all of a poor one. In a polygenous society poor men lose out and the average women gain. So our monogamous society actually benefits men.
• “Men in monogamous societies imagine they would be better off under polygyny. What they don’t realize is that, for most men who are not extremely desirable, polygyny means no wife at all”

The Trivers-Willard hypothesis is also discussed

• The hypothesis states roughly that the sex of a child is slightly skewed depending on the parents’ circumstances to maximize reproductive payoff
• Sons of wealthy and high status parents will inherit that wealth and status. These sons could go on to have many “wives, mistresses and concubines, and produce dozens or hundreds of children, whereas their equally wealthy sisters can have only so many children”
• “So natural selection designs parents to have biased sex ratio at birth depending upon their economic circumstances—more boys if they are wealthy, more girls if they are poor.”
• “This hypothesis has been documented around the globe. American presidents, vice presidents, and cabinet secretaries have more sons than daughters. Poor Mukogodo herders in East Africa have more daughters than sons. Church parish records from the 17th and 18th centuries show that wealthy landowners in Leezen, Germany, had more sons than daughters, while farm laborers and tradesmen without property had more daughters than sons. In a survey of respondents from 46 nations, wealthy individuals are more likely to indicate a preference for sons if they could only have one child, whereas less wealthy individuals are more likely to indicate a preference for daughters.”

A lot of people don’t “get” or won’t accept that evolution is real because of the immense time scales required. National Geographic reports on a case when evolution was witnessed over a few years.

A bacteria had been killing almost all male larvae of a species of butterfly found on two Somoan islands. A 2001 study found that 99% of the butterflies were female. As recently as 2005 when an informal count was done no males were found at all. The bacteria was really hammering the males of the species and was in danger of wiping the butterfly out completely.

However, all of a sudden (OK, it took a few years but on evolutionary time scales that is all of a sudden) scientists noticed the male butterflies making a comeback. It seems that a single male evolved a mutation which allowed it to escape the bacteria’s attacks. Because this was such a huge advantage the genes spread extremely rapidly. It seems that the whole recovery took only a few generations.

Evolution in action baby. Don’t deny it. Don’t come with your micro-evolution rubbish. Love it.