Smells, Human Pheromones and Their Effects on Interpersonal Attraction
Progression of studies of pheromones and scents on human attraction are ongoing and have produced conflicting results. Further studies will continue to describe the interaction of conscious and subconscious olfactory cues and their effects on how attractive we think a person may be.
Advertisements subject us to an affirmative attitude that pheromones and good smells can lead to attraction of the opposite sex. This illusionary and non-valid conclusion is seen in advertisements for products such as deodorants, cologne, and perfume which claim to include pheromones that supposedly will make us more attractive to the opposite sex, however this is not necessarily so.
Recently, it has been shown that the human body still maintains a working a Vomeronasal organ, which is not simply a vestigial tag-along to one’s development [1]. This portion of the olfactory bulb is sensitive to gonadotropins, which are responsible for a variety of hormones that are released from both the hypothalamus and pituitary gland. The Vomeronasal organ binds the odorant and through synaptic activation solicits the hypothalamus to secrete hormones such as Luteinizing Hormone and Follicle Stimulating Hormone. In females, the release of these hormones are associated with stimulation of egg release during ovulation. In males, they increase spermatogenesis and testosterone levels [2]. People who are diagnosed with Kallmons syndrome have an underdeveloped olfactory bulb and concurrently underdeveloped gonads [3] The importance of this does not necessarily show causation, but there is a correlation between a normal olfactory bulb and properly developed gonads.
Another plausible causation of pheromones is the Vandenburgh effect [4]. This is the effect of adolescent girls in step-fathered homes reaching puberty faster than those who are still exposed to their genetic father in the typical nuclear family. Again, this has only been shown through correlation and does not directly imply that pheromones are responsible for reaching puberty earlier.
The aforementioned is indicative to humans subconsciously detecting signals put out from the opposite sex, but how does this lead to pheromones and smells actually altering the interpersonal attraction status of a person? Olfaction is the only sense that makes its neurological path through our limbic system. Our limbic system plays a large role in our emotional responses and memories. This is the reason that a distinct smell can quickly conjure up memories that have not been recalled for many years. Viewed through a classical conditioning lens; positive experiences that occur during the emittance of a certain scent can increases the likelihood to see a new person during the occurrence of that smell in a more positive light or even of them possessing a more favorable personality. Of course, the opposite is also true; conditioning to a smell that repeatedly occurred during unfavorable circumstances can lead to a near immediate repulsion to a person latter possessing, or emitting it.
The specifics of pheromones and interpersonal attraction revolves around Major Histocompatibility Complexes (MHCs). These polymorphic genes play a role in our immune system and its development of new antibodies which are able to target and destroy foreign particles, and invasive diseases. The polymorphic genes allow antibodies to be produced in a random pattern which can eventually lead to increased attraction of immune cells to antigens present on the foreign body, and increased survival chances. Matings between two people with different MHCs leads to a more comprehensive immune system for the child and increased chances for survival.
Although further elucidation is needed, it is known that MHCs are tied to odorants of androgen based pheromones which are released from apocrine glands, which themselves are concentrated in the armpits [5]. In one study, females rated strips of material laced with MHCs that were dissimilar to their own as being more pleasant. However the opposite is true for pregnant females, whom rate strips of material laced with MHCs that are more similar to their own as being more pleasant [6].
This can be explained evolutionarily as women may be more attracted to men outside of their own lineage for copulation and fertilization. Later on, the same woman,now pregnant, may be more attracted to her family so that she is nearest to those who have the greatest genetic interest in the positive outcome of her birthing a child.
Overall, more studies are needed to further clarify the role of smells and pheromones on attraction. Humans are primarily a visual animal and smells and pheromones may play secondary or tertiary roles to more salient stimuli. Also, many of the studies conducted lacked mundane realism as they were conducted in lab settings, or were confounded by using different people, which inherently have different visual appeal to the opposite sex. The symptoms of current studies make them less generalizable and only provide correlational data.
- ^ Wysocki CJ, Lepri JJ. Consequences of removing the vomeronasal organ.J Steroid Biochem Mol Biol 1991;39:661–9.
- ^ Monti-Bloch L, Jennings-White C, Berliner DL. The human vomeronasal system: a review. Ann N Y Acad Sci Nov 30 1998;855:373–89.
- ^ Kohl JV, Atzmueller M, Fink B, Grammer K. Human pheromones: integrating neuroendocrinology and ethology. Neuroendocrinol Lett 2001;22:309–21.
- ^ Ellis BJ, Garber J. Psychosocial antecedents in variation in girls’ pubertal timing: maternal depression, stepfather presence, and marital and family stress. Child Dev 2000;71:485–501.
- ^ Jordan WC, Bruford MW. New perspectives on mate choice and the MHC. Heredity 1998;81:239–45.
- ^ Wedekind C, Seebeck T, Bettens F, Paepke AJ. MHC-dependent mate preferences in humans. Proc R Soc Lond B 1995;260:245–9.