Evolutionary Psychology

What dating adverts tell us

Age differentials by gender

What first attracted you to the multi-millionaire……..?  On the 28th September 2000, a judge in the United States awarded a former Playboy model, 26 year old Anna Nicole Smith, $449m after she was left out of the will of her 90-year-old husband.  Ms Smith was 26 when she married J Howard Marshall a Texan oil tycoon who died 14 months after they married.  A lawyer in the case commented: "He's given her cars, a company. He had given incredible things that were intended to help her get ahead and survive and make money".

Females and males have a particular interest in selecting partners that will enhance their reproductive success and inclusive fitness. Evolutionary psychology calls these sexual strategies. One hypothesis is that:  Females have evolved mechanisms that enable them to detect men that will transfer resources to their offspring (i.e. health and paternal investment ). These are sometimes referred to as 'good provider' and 'good genes' attributes in the male

Males have evolved mechanisms that enable them to detect females that promise rapid production of offspring, and a disinclination to mate with other men (i.e. health, fertility and faithfulness )

Waist to hip ratio

To see whether estrus was really “lost” during human evolution (as researchers often claim), we examined ovulatory cycle effects on tip earnings by professional lap dancers working in gentlemen's clubs. Eighteen dancers recorded their menstrual periods, work shifts, and tip earnings for 60 days on a study web site. A mixed-model analysis of 296 work shifts (representing about 5300 lap dances) showed an interaction between cycle phase and hormonal contraception use. Normally cycling participants earned about US$335 per 5-h shift during estrus, US$260 per shift during the luteal phase, and US$185 per shift during menstruation. By contrast, participants using contraceptive pills showed no estrous earnings peak. These results constitute the first direct economic evidence for the existence and importance of estrus in contemporary human females, in a real-world work setting. These results have clear implications for human evolution, sexuality, and economics. Ovulatory cycle effects on tip earnings by lap dancers: economic evidence for human estrus? ☆ Geoffrey Miller, Joshua M. Tybur, Brent D. Jordan

When a baby is born, relatives and friends invariably comment on how the child resembles other members of the family - the 'he has his father's chin' syndrome. Christenfield and Hill (1995) report that strangers presented with a picture of a one year old and photographs of the child's mother, father and unrelated adults, spotted the child's father at above chance levels, but were unable to identify its mother. An evolutionary explanation of this result would be that a child's facial characteristics inherited from the father are preferentially expressed to reassure daddy that the child is his. Christenfield and Hill Mummies babies daddies maybes: the effect of paternity certainty on mate retention behaviour.

Paternity certainty Male paternal investment and female faithfulness have costs and benefits to both sexes that must be reconciled to maximize individual inclusive fitness. Fertility in the human female is 'silent' - there are no clear-cut external cues that a woman is ovulating. In terms of inclusive fitness it may be beneficial for a woman to marry a 'good- provider', but mate with a man with 'good-genes'. Thus a woman's husband and mate may be different males. It is very difficult to obtain data on the rate at which this occurs in humans - for obvious reasons! But Mace (2000) suggests that about 10% of children are the result of extramarital mating.