New York Times Syndicate (November 9, 1995)
Pheromone Increased Sexual Activity |
(Medical Tribune Obstetrician and Gynecologist Edition)
Pheromones have been known to exist for quite some time. Pheromones play a significant role in the mother-infant connection through breast milk, in women developing menstrual synchrony, and in communication between animals (Cutler, 2000). The debate, however, concerns the way pheromones contribute to sexual attraction between men and women. There is speculation that pheromones are somewhat gender-specific, having distinct effects in men and women. In the past twenty-five years, there has been a considerable increase in the number of studies that address human pheromones, which I will explore in examining the role of male pheromones in sexual attraction.
Pheromones are odorless, invisible molecules that are secreted by organisms and are received by another individual of the same species that causes some behavior change and is involved in reproduction (Cutler, 1999).
In males, pheromones are heavily concentrated in the urine and in sweat on the surface of the skin. There is difficulty, however, in isolating male pheromones and measuring their subsequent effect. Earlier research focused on androstenol, a human steroid that acts as a pheromone in animals, to see if effects could be found in human attraction. Virtually no pheromonal effect was found (Black & Biron, 1982; Filsinger, Braun, & Monte, 1985). It could be that androstenol simply does not function as a human pheromone. It is difficult to draw conclusions, however, because earlier studies often used subjects rating attractiveness of slides and pictures and not human-to-human contact. Although using human-to-human contact decreases the experimenter¡¯s control over the environment, human pheromone functioning could become more apparent with this approach. This is exactly the direction that research began to take.
Many began suspecting androstenone and androstadienone as other potential human pheromones. In 1993, a study was done to connect olfaction with androstenone in attraction because these pheromones are often secreted through sweat. Female subjects that initially rated androstenone as an unpleasant odor changed to a neutral response during the menstrual cycle. This point in the menstrual cycle happens to be when conception is most likely. These findings support that androstenone may facilitate female mate choice (Grammer, 1993). Further studies on females using androstadienone found psychological and mood effects with positive increases in mood and a decrease in female discomfort and tension. Although this substance may not serve as a direct causal factor, it could allow for an increase in factors necessary for sexual attraction (Grosser, Monti-Bloch, Jennings-White, & Berliner, 2000; Jacob & McClintock, 2000).
In 1994, a study by Cutler, Friedmann and McCoy significantly contributed to the debate of the effect of male pheromones. Using synthetic pheromones in men¡¯s aftershave, subjects kept a diary of any sexual activity over a six-week period. The results were then compared to a two-week baseline and revealed that pheromone users experienced a significantly higher increase in sexual intercourse and sleeping next to a romantic partner. There were also increases in petting, kissing, and informal dates. Because there were no significant differences above baseline for masturbation and formal dates (which require planning), it appears that human pheromones influence initial sexual attraction for males more significantly than once thought (Cutler, Friedmann, & McCoy, 1998). Exactly how human pheromones are received and perceived remains controversial.
There has been an established link between animal pheromones and a vomeronasal organ (VNO) where sensory information is conveyed and processed. Many suspected, therefore, that this organ was involved in the functioning of human pheromones (Cutler, 1999). Previously, this organ was thought to stop growing after birth; however, it has recently been confirmed that the human VNO continues growing after birth. A study by Grosser et al. (2000), demonstrates the effects of androstadienone directly on the VNO structure. Androstadienone was directly applied to female VNO¡¯s without contaminating other nasal chemoreceptors and was found to significantly decrease female discomfort, tension, and changes in autonomic activity, thus demonstrating that the structure is functional in adult female perception of male pheromones (Grosser et al., 2000).
The most recent developments in pheromone research come from scientists who believe they have located a human gene, labeled V1RL1, that is responsible for creating a pheromone receptor. They found this gene in all the subjects they randomly chose for study (WebMD Medical News Staff, 2000). This gene may be connected to the functioning of the VNO structure, but only future research will tell.
Sexual attraction in humans is not as directly affected by pheromones as it is in animals. Humans rely much more on other sensory information, such as vision, in choosing a mate. Considering the numerous developments in pheromone research, however, it seems that male pheromones, such as androstadienone, do play a more significant role in female sexual attraction than once thought. Identifying and tracking the function of the VNO structure and possible gene links make finding more primary contributions of pheromones increasingly likely. Future research and studies that use more realistic social and environmental factors in human activity will allow for a better understanding of the exact significance of pheromones in human sexual attraction.
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