Academic journal article Mankind Quarterly

The Pheromone Androstenol: Evolutionary Considerations

Academic journal article Mankind Quarterly

The Pheromone Androstenol: Evolutionary Considerations

Article excerpt

Cowley & Brooksbank have shown that female exposure to androstenol increases the number and depth of female interactions with males. However, in nature, the only females customarily close enough to males to be affected by male-emitted androstenol would be sleeping and cuddling partners, i.e. mates or potential mates. Thus, the observed behavioral response is probably a mechanism for promoting bonding with mates and the evaluation of potential mates. Recognizing an evolutionary purpose for the female reaction to androstenol makes one feel more confident that the observed effects are real.

Key Words: Pheromones, androstenol, bonding, mate selection

Human females exposed to Sa-16-androsten-3a-ol (androstenol) overnight interact more with males than unexposed females do. The experimental procedure (Cowley & Brooksbank, 1991) involved having students wear overnight a necklace designed to release androstenol. Next morning the subjects filled in a questionnaire regarding who they had interacted with (i.e. who they had spoken with, including greetings), who initiated the interaction, and the depth of the interaction ("i.e. the extent to which he/she felt the exchange encompassed personal involvement."). No effect was found for males, or for female interaction with females, but the females reported a significant increase in interactions with males. For instance, the control females reported 3.08 interactions that morning with males, while those females exposed to androstenol overnight reported 5.42 interactions with males, a difference that had probability of occurring by chance of .024. The measure of depth rose from 34.2 to 97.4, significant at .011. The measure of duration rose from 6.09 to 26.7, significant at .001.

The authors of the article offer very little explanation for what function the rather strong effects of androstenol serve, saying at the end merely that "it appears that exposure to androstenol induces 'approach' response in females." Earlier (p. 657), the authors had stated "clearly from a sociobiological point of view the benefit would be to the male signaler as the source of the pheromone." From an evolutionary theory viewpoint this is a weak argument, since if it was not in the female interest to receive a message they would have evolved not to receive it, or not to let it affect their behavior. A signaling system must be in the interests of both parties. The purpose of this paper is to provide a plausible reason for the emergence and continuation of female sensitivity to androstenol, and for the male ability to emit it.

It does appear that human males are designed to emit androstenol, or closely related pheromones (Kohl & Francoeur, 1995; Stoddart, 1990). It is produced in apocrine glands that are typically at the follicles from whence hair grows, especially under the arm and in the public regions. They appear designed to wick up the odors from the apocrine glands and distribute them to the atmosphere. This is shown by the axillary hairs being associated with more apocrine glands than hairs in other parts of the body. The musky odor produced from the axillae is caused by the presence there of androstene and Sa-androstenol. Androstenol is known to be a sexual pheromone in the pig which causes the sow to assume the position required for mating. Men produce much more androstenol than do women in their urine (Brooksbank, 1962) and more androstenone in their axillae (Bird, & Gower, 1982, as cited by Stoddart, 1990, p. 66).

While some human hairs can be argued to serve various purposes, such as protecting the head from the sun, or sexual signaling, the underarm hairs are not located to keep us warm, nor to protect us from the sun, or even to be visible at a distance. The only plausible purpose appears to be facilitating emitting odors or pheromones. They do this efficiently. Only one in ten shaved armpits are described as odorous 24 hours after washing, while nine out of ten unshaved armpits are described as odorous (Shelley, Hurley & Nicols, 1953, as cited in Stoddart, 1990, pp. …

Search by... Author
Show... All Results Primary Sources Peer-reviewed

Oops!

An unknown error has occurred. Please click the button below to reload the page. If the problem persists, please try again in a little while.