Men and women who stare at goats…

…in attempts to determine the cause of their sexual behavior.

Estrous female goats use testosterone-dependent cues to assess mates The testosterone-dependent assessment cues are associated with scent marking or courtship behavior. In a subsequent study, these researchers looked only at the testosterone-dependent assessment cues that were associated with courtship behavior. That is, they looked only at associated visual cues.

Their results are not surprising:  Female goats use courtship display as an honest indicator of male quality. Testosterone dependent courtship display is important. But the design of the second study eliminates testosterone-dependent assessment cues associated with scent. Thus, secondary results are reported only on one of the two important variables that were initially reported. This selective reporting helps to ensure a false conclusion about what is responsible for mate assessment. Testosterone-dependent scent that was initially important is now not even considered to be important enough to compare it to the importance of visual cues seen by the female during courtship behavior.

Comparatively speaking, telling us visual cues are responsible for mate assessment is like telling us apples appeal to us because they look good. If true, there is no further need to determine the chemical or chemicals involved in establishing an apple’s odor appeal. But it’s not true.

Why does an apple look good? Certainly, good-looking apples do not “behave” differently than those that do not look as good, so why would we choose the best looking apple to eat? And why would a female goat chose the male that exhibits good-looking testosterone associated courtship behavior?

These authors seem to forget about any further investigation into the biological (e.g., chemical) basis for the either the apple’s, or the male goat’s appeal. Should we also forget that someone must have once been compelled to eat an apple, and find it appealing? How would the apple’s visual appeal compel anyone to initially eat an apple? How would an animal’s visual appeal compel another animal to initially see it as a potential mate? Suddenly, due to study design, the male’s appeal is due to visually perceived courtship behavior. And I say ‘suddenly’ also because adult behavior is examined in the absence of its development.

What troubles me is that these authors know male morphology is not used by female goats for mate choice (e.g., they cite their own initial study in this regard). They also cite works that show female mammals are able to distinguish between and show preference for particular males using chemical cues alone.

Chemical cues and pheromone activity in goats are testosterone dependent. Females are able to use chemical cues alone to distinguish among high and low quality males. Thus, the courtship cues provided by males are of no concern with regard to the proximate mechanisms involved in female assessment. As it is in all species that sexually reproduce, testosterone-dependent pheromones are responsible for the male’s appeal. That’s why, in our study, we used human pheromones to enhance the appeal of a man wearing them, as demonstrated by the observed increase in women’s flirtatious behaviors, and their self-reported increased attraction.