Dr. Nick Neave at Northumbria University talked at the annual convention of the British Psychological Society about how human behaviors are affected by sex pheromones.
In his experiment, 32 female participants were presented with portraits and photographs of several different male individuals and then asked to rate them in the order from “most attractive” to “least attractive.” Next, the participants were exposed to the pheromone secreted from the male armpit glands. After this exposure, they were asked to rate the same males again.
Two weeks later, the same female participants were gathered for the same experiment, but this time to see how the results would be different from the ones from the first part of the experiment when they are at a different stage of their menstrual cycles.
The results showed that all the female participants rated the males more positively after exposed to the male pheromone. Moreover, the man who was rated as the “least attractive” in the first part of the experiment was rated as the most attractive in the second part of the experiment. It was also found that the middle of the menstrual cycle , when females are ovulating, is the time when females are most affected by male pheromones.
"Chemical substances secreted from the human’s armpit are odorless, but like pheromones in animals, they affect others’ behaviors unknowingly,” said Dr. Neave, commenting on his experiment.
While the participants of this experiment were females, Australian researchers have already reported that female pheromones also affect behaviors in males, which shows that sex pheromones in both male and female humans have the same effect against the opposite sex.
(From Nikkei Health, May 26, 2000)
Where sexually-mature women are living together in close proximity, such as college dormitories, it is sometimes seen that their menstrual cycle onsets gradually become closer together in time than previously. This phenomenon is called the McClintock effect, and it is known that the male and female sex pheromones are involved in regulating female’s menstrual cycle.
This menstrual synchrony was brought to researchers’ attention in 1971, when a biopsychologist Martha McClintoc investigated and reported the phenomenon in Nature, advocating the existence of human pheromones. However, the menstrual synchorny itself did not prove the existence of human pheromones, although her research proved that the synchronization was certainly “not a coincidence.”
Therefore, it had to be demonstrated that human pheromones do exist and affect behaviors of other individuals. In the next experiment, sweat was extracted using ethanol from the armpit of a woman with a regular menstrual cycle who was kept secluded from the participants throughout the experiment. The sweat was applied under the nose of five female participants three times a week. After 4 months, the onset of the participants’ menstrual cycles became very closer.
A similar experiment was then conducted on male individuals, assuming the male sweat might have some effect. In this experiment, women who had irregular menstrual cycles experienced their cycles became regular after being exposed to the male pheromone. This is an experimental example which proved that pheromone exists in humans as well and they have some influence on other individuals.
American television network ABC News conducted an experiment to ascertain whether human pheromones really affect members of the opposite sex. An oil containing human pheromones was applied to one of the female twins who were alike, while hazelnut oil was applied to the other participant. The went into a shot bar, taking turns so that other customers would not realize they were twins, to see how male customers there would react to the two participants.
As a result, 11 male customers spoke to the participant wearing hazelnut oil were, while 30 male customers spoke to the woman wearing the oil containing the pheromone. Use of the pheromone tripled the participant’s attractiveness.
In this experiment, one of the four male participants was asked to wear pheromone substances to see if 10 female participants would find this male participant more attractive than the other male participants. The result showed that 7 out of the 10 female participants found the male participant with the pheromone substances the most attractive, even though they were all wearing a blindfold.
Next, in order to obtain fair results, all the male participants were asked to take a shower, and then a different male participant was chosen to wear the same pheromone substances for the same experiment. This process was repeated until all male participants got to wear the pheromone substances. The result showed that most female participants always found the male with the pheromone substances the most attractive. The pheromone substances used in this experiment were actually those extracted from a boar, but human pheromones also contain these substances.
This result proved that human beings also have an organ to sense pheromone substances, and these pheromone substances have some influence on those who sense them. According to the explanation by the scientist appeared in the show, the theory believed by many researchers that humans’ “pheromone substance-sensing organ" had been degenerated was proven erroneous, and we still have that organ in the nasal cavity.
(From the TV show “Takeshi's Genesis” aired on August 22, 2000)
The scientists of Karolinska Institute of Sweden conducted a research that they let subjects smell, they were 12 men who does healthy sexual behavior of the 20-30 years old, 12 women and 36 homosexuality men similarly, and they smelled air, vanilla, male pheromone compound and female pheromone compound.
The brain scan was performed after the subjects smelled these for 1 minute. Each did not have a particularly outstanding smell. The subjects have reported that it was especially general to all the smells. However, when a woman smelled a male pheromone compound, a male smelled a female pheromone compound, and when the male of homosexuality smelled not a female pheromone compound but a male pheromone compound, it turned out that the cerebral hypothalamus which manages sex behavior had reacted.
As for a woman, the increase in heart rate was limited, the body temperature rose, and relaxation sense was brought with rise of the body temperature, and it was not same in a man, but it was confirmed the similar condition could be caused. It is supposed that it is the release from a healthy feeling and strain that are a part in man's sexual reaction.
On the contrary, the brain of the man showed no reaction to a male pheromone compound, the brain of the woman showed no reaction for the female sex hormone compound and the male of homosexuality showed no reaction at all for a woman pheromone compound in the same way.
Moreover, it is said that the brain domain which smells and participates in a sexual desire was not activated in any group. It turns out that the operation of the sexual function with a smell is not necessarily brought about from this, and human pheromone caught by hypothalamus has caused these.
(Report by Shankar VEDANTAMU, journalist August 28, 2001)
The men and women with whom they completely have no acquaintance were collected the same number of people respectively, and an experiment was performed. Firstly-- man and woman -- they were separated in the different room and had them write in the questionnaire about feeling. Then, the sense-of-smell test to a male pheromone compound was done on the women subjects. Every one of seven 30-ml medicine bottles containing test paper was handed in turn to the subjects, we had them judge whether the smell existed, what kind of fragrance and whether it is comfortable or unpleasant one.
【7 medicine bottles】
1.Nothing is on ×2
2.Male pheromone compound ×2
5.Ambrox (a kind of fragrance)
Next, in order to see a change in behavior, after taking one pair of a man and a woman to a separated room, we applied any one of the above mentioned to the both sexes. And we had the subjects imagine that they were staffs of the TV program, and the subjects were given an assignment that "a program was actually recorded on videotape for 10 minutes." We had them return to the same room in 10 minutes respectively, and had them fill in a questionnaire about feeling again. Before going out of the laboratory, one of reagents above-mentioned we had the objects apply were flushed.
As for the test on the mood such as “anger,” “unpleasantness,” and “joy” of three main categories, of feeding behavior, a different inspector respectively conducted the test 3 times to the subjects. As a result, as for the woman who has sensed the male pheromone compound, the rise of the courtship display (the state of having a favorable impression of a male and accepting approach) to a male was seen. On the other hand, when a male pheromone compound was applied to a male, since these changes were not seen, it is presumed that this female situation was influenced by the male pheromone compound.
Furthermore, it also turns out that the female negative mood decreased with the male pheromone compound. This change is regarded as the influence that had on the hypothalamus which expresses a reaction of nerve and endocrine system in a male pheromone compound. And it is thought that this function is just the mediator of courtship behavior.
Moreover, the rise of feeling is reported from the man who is together by the reason the woman who attached the male pheromone compound becomes attractive.
(From collaborative investigation carried out in IFF research institute and Philadelphia City, Pennsylvania Moner chemical sense center, April, 2002.)
For the woman with people’s normal sense-of-smell and physiological cycle, the sense-of-smell test of a crystalline male pheromone compound, a female pheromone compound and air (odor-free) were carried out. After doing 3 patterns and 3 times, after reading the change by a machine, the degree of irritation, tension and a sense of nostalgia, etc. were investigated. It was mostly odor-less in the air and nothing that activates hypothalamus was contained.
While a nerve and the hypothalamus showed a reaction of the endocrine system were activated by a male pheromone compound and aerial mixture. The result wasn't judged by conspicuous activation for only aerial mixture and air as a female pheromone compound. Without activation of an olfactory cortex, the male pheromone compound has the same work as a male pheromone, and this result of having activated only female hypothalamus can be presumed that influence may be brought to a brain.
(From the research result announced at Neuro Image Human Brain Mapping 2000, in 2000.)