Linking biology to behavior

Many people buy into the idea that we shouldn’t have the bright line between biology and psychology that we do. That said it is challenging to try and link biology and consumer behavior. (Not least because we have few scholars who have enough knowledge of both domains).

Marcelo Nepomuceno and his colleague attempt to do this by linking hormones to ‘behavior’. I am sympathetic to the idea but I’m not convinced they get there.

One problem relates entirely to my ignorance. The paper hinges on digit ratios which are associated with prenatal testosterone exposure. The argument is more prenatal testosterone is associated with more masculinized digit ratios. I will happily admit that I don’t really understand what exactly I should take from this. The paper could be clearer but I’m happy to accept I’m the problem. Of course the best thing about this strain of research is that it induces the almost automatic human reaction to start staring at your fingers to work out how much prenatal testosterone you were exposed to.

More pertinently the study looks at how people with more masculinized/feminized digit ratios say they behave. I must confess to not being a huge fan of this type of research. They are some methodological challenges — for example, they have to throw out a vast amount of responses. Critically we don’t get to behavior, we get to whether students say they engage in more what are described as courtship related behaviors. (With men this is a lot of gym related stuff; most of it wasn’t “consumption” per se. With women it was choice of clothes, make up, and keeping oneself “clean and groomed” which seemed an odd choice of phrase).

Looking at links between digit ratios and self reported behavior is a little simple so the authors add a complicating factor, “mating confidence”. This seemed a little random and I had a worry about the theory. “H2. In men, the association between digit ratios and courtship related consumption to acquire mates will be strongest among those with high mating confidence.” (Nepomuceno et al. 2016, page 234). I wasn’t sure why the most masculinized males with the most confidence were making the most effort. (It seems to happen less with women). I guess the men’s result is plausible but so is the opposite — the less confident make most effort. The results also don’t hold for people looking to retain mates. Why not?

Overall I was left hoping that theory would be stronger, (and the methods too). At least looking at our hands and puzzling about digit ratios created more fun than most research.

Read: Marcelo Vinhal Nepomuceno, Gad Saad, Eric Stenstrom, Zack Mendenhall and Fabio Iglesias (2016) Testosterone at your fingertips: Digit ratios (2D:4D and rel2) as predictors of courtship-related consumption intended to acquire and retain mates, Journal of Consumer Psychology 26, 2 (2016) 231–244