Birds, Bees: Choices, Costly Signals, and Genetic Adjustments

Intelligence and mate choice: Intelligent men are always appealing

Mark Prokosch, Richard Coss, Joanna Scheib & Shelley A. Blozis
Evolution and Human Behavior, January 2009, Pages 11-20

Abstract:
What role does a man's intelligence play in women's mate preferences? Selecting a more intelligent mate often provides women with better access to resources and parental investment for offspring. But this preference may also provide indirect genetic benefits in the form of having offspring who are in better physical condition, regardless of parental provisioning. Intelligence then may serve as both a cue of a mate's provisioning abilities and his overall heritable phenotypic quality. In the current study, we examined the role of a man's intelligence in women's long- and short-term mate preferences. We used a rigorous psychometric measure (men's WAIS scores) to assess intelligence (the first study to our knowledge), in addition to women's subjective ratings to predict mate appeal. We also examined the related trait of creativity, using women's ratings as a first step, to assess whether creativity could predict mate appeal, above and beyond intelligence. Finally, we examined whether preferences for intelligent and creative short-term mates shifted according to a woman's conception risk. Multilevel modeling was used to identify predictors of mate appeal. Study participants (204 women) assessed the long- and short-term
mate appeal of videos of 15 men with known measures of intelligence performing verbal and physical tasks. Findings indicate that both intelligence and creativity independently predicted mate appeal across mating contexts, but no conception-risk effects were detected. We discuss implications of these findings for the role of intelligence and creativity in women's mate choices.

--------------------

Duration of courtship effort as a costly signal

Robert Seymour & Peter Sozou
Journal of Theoretical Biology, 7 January 2009, Pages 1-13

Abstract:
We consider a male and a female in a courtship encounter over continuous time. Both parties pay participation costs per unit time. The game ends when either one or other of the parties quits or the female accepts the male as a mate. We assume that there is a binary variable which determines whether the male is a “good” or “bad” type from the female's point of view, according to either his condition or his willingness to care for the young after mating. This variable is not directly observable by the female, but has fitness consequences for her: she gets a positive fitness payoff from mating with a “good” male but a negative fitness payoff from mating with a “bad” male. We assume also that a “good” male has a higher ratio of fitness benefit from mating to fitness cost per unit time of courtship than a “bad” male. We show that, under suitable assumptions, there are evolutionarily stable equilibrium behaviours in which time-extended courtship takes place. A “good” male is willing to court for longer than a “bad” male; in this way the duration of a male's courtship signals his type, and acts as a costly handicap. By not being willing to mate immediately the female achieves a degree of screening because the posterior probability that the male is “good”, conditional on his not having quit the game, increases with the duration of courtship.

--------------------

"A UK researcher has a new explanation for how the human race manages to keep a fairly even balance of males and females, despite massive deaths of young males in war and selective abortion of female fetuses in certain parts of the world. Corry Gellatly, a research scientist at Newcastle University, proposes that there's a gene that determines whether a man will father more sons, more daughters, or equal numbers of each. When females are in short supply, they have a better chance of snagging a mate, and are thus more likely to pass the gene for fathering daughters on to their offspring. And when men are scarce, they have a better chance of mating and passing along the gene for having sons...The ratio of male to female births jumped significantly at the end of each of the world wars in countries involved in the fighting. A number of hypotheses have been floated to explain why. One idea is that returning soldiers have extra-frequent sex with their partners, which could lead to fertilization earlier in the menstrual cycle, possibly making male births more likely. Another hypothesis holds that larger males are more likely to survive wars and more likely to father boys. After sorting through 927 family trees from North America and Europe, including 556,387 people in all, Gellatly proposes another explanation. In an article published online in the journal Evolutionary Biology, the researcher suggests that men carry a gene that controls their ratio of X to Y sperm, and thus the likelihood of their fathering sons or daughters. Women carry the gene as well and pass it along, but do not express it." [Source: Reuters]

Questions: How in the world did I ever get married? Fraud, perhaps? Is it really true that "good" men will court longer? Why? And having a gene that "controls" the ratio of X to Y....how? In response to what stimulus?

(Nod to KL)