The Fragrance of Pheromones
Pheromones are certain chemical substances that are produced by all animals that affect the behaviors and physiology of others within the same species. While most hormones work inside the body and affect only the individual producing them, pheromones are known as ectohormones and act outside of the host body to affect the behaviors or in some cases the physiology of others. Pheromones trigger many aspects of sexual behavior in animals and insects. Animal behaviors you many not be aware of that are influenced by the release of pheromones include mother-offspring recognition and bonding, leaving behind a food trail for others to follow, marking territory, and warning rivals to stay away.
While studies have been done to document the effects pheromones have on animals and insects, studies regarding pheromones in humans remain limited and inconclusive. The lack of evidence neither supports nor refutes the theory of human pheromones. Do humans have pheromones? If so, do these chemical substances affect our interaction with others? While some may consider human pheromones a myth, several theories and early studies seem to point towards the existence of human pheromones. A German scientist in the late 1800s identified the first human pheromones and called them anthropines. He believed human pheromones are associated with secretions of the skin and hair follicles. While there is still much that is not understood about pheromones and human behavior, research is ongoing in an attempt to understand the four main types of pheromones and discover how they are recognized in humans as well as in what ways these hormones may affect interaction between individuals of both genders.
These are the four main types of pheromones:
Often related to sexual attraction. Releaser pheromones provoke an immediate response.
Give out information by a genetic odor imprint. These enable some mothers to recognize babies by smell.
These have a slow response. Primer pheromones may alter physiology through hormone levels affecting development, menstrual cycles, and pregnancy.
Modulator pheromones may synchronize or alter body functions. In humans, they may alter a woman's menstrual cycle or elicit a relaxation response.
The study of human pheromones began to gain attention in 1971, when Martha McClintock published a study showing that the menstrual cycles of women living in close proximity often converged on the same schedule. She believed this was a result of the effect of human pheromones. Another study indicate that male pheromones have an influence on the female ovulation cycle although it was unclear what other factors may have also been influencing that result. While studies such as these open the door to further investigation, many researchers believe that such results should be observed within a context of influences that include psychological and social factors.
One theory investigating the influence of pheromones on human behavior is known as the Social Delusion Theory. This theory suggests that a certain pheromone is produced among individuals who feel like an accepted member of a group. When an individual feels like a part of a group, the theory is that this produces a pheromone that is sensed by the group and leads to true bonding and acceptance. An individual without the delusion of social acceptance from a group will not produce that particular pheromone, and the group then fails to easily accept that individual into the social group.
Do humans react or respond to odorants and pheromones subconsciously? One theory speculates that both odorants and pheromones are detected by way of specific receptors as well as by the typical sense of smell. One study tested female response to sweaty T-shirts; it may have been the news of this study that has led to pheromone parties, where singles sniff T-shirts in an effort to pick up on compatible pheromones and find their perfect match. A study conducted in 2002 and published online in the Neuroendocrinology Letters showed that when females were exposed unknowingly to male pheromones, their perception of male attractiveness was clearly influenced. However, it is not only the opposite sex that may be influenced by pheromones. One study indicates that the pheromone known as androstadienne increased cooperation between men making decisions.
With limited research suggesting possible connections between pheromones and human behavior, researchers continue to investigate new theories concerning how pheromones work in insects and other animals in the hopes of finding a key to the human pheromone puzzle. Researchers exploring ways that the pheromone signaling system has evolved among salamanders and honeybees are using their findings to make a connection to the evolution of pheromones among humans. This connection is possible because according to researchers, the neural pathways that link such things as the reaction to food odors and pheromones in the brain do not vary between insects and mammals (including humans). Early studies suggest that certain pheromones may signal fitness levels as well as work together with other indicators to influence sexual attraction. While current theories and research have yet to make a clear connection between human pheromones, sexual attraction, reactions, and behaviors among humans, there does appear to be initial evidence that our decisions about connecting with members of the opposite sex as well as the social groups to which we belong may somehow be influenced by pheromones. The goal of future research is to identify the missing key to specific neurological or pheromonal pathways in the human brain where this takes place. In time, we might begin to understand how and when pheromones are influential in human behavior.