What are Pheromones? (HL IB Psychology)
Revision Note
What are Pheromones?
What is a pheromone?
A pheromone is a chemical that is secreted by glands to act outside of the body, unlike hormones which are secreted internally from the endocrine glands into the bloodstream
The first research on pheromones was conducted on animals and there is compelling evidence to show that animals use pheromones for the purposes of mate selection and territoriality
Pheromones communicate their signals to members of the same species i.e. they are conspecific
Do pheromones exist in humans?
Mammals use the vomeronasal sensory organ (VNO) to detect pheromones
The VNO is a collection of neurons deep within the nose that transmit signals via the accessory olfactory bulb to the hypothalamus
To date there is no real evidence to show that the VNO or the accessory olfactory bulb exist in humans though both of these are present in the developing foetus up to 18 weeks of gestation
There may be some validity that a ‘pheromone nerve’ exists in humans: this is known as cranial nerve 0 (CN0) or the terminal nerve
Cranial nerve 0 is a pair of nerves that run from the nose directly into the brain in front of cranial nerve 1, the olfactory nerve (‘olfactory’ relates to the sense of smell)
Research into human pheromones have investigated the effect of androstadienone (AND) which signals maleness and estratetraenol (EST) which signals femaleness: both of these substances are steroidal hormones
Males and homosexual women should be attracted by EST; women and homosexual men should be attracted by AND
Could her lack of interest be due to his pheromones?
Which studies investigate the effect of pheromones on behaviour?
Zhou et al. (2014) – a lab experiment in which AND and EST were used to investigate the influence of potential human pheromones on gender perception
Hare et al. (2017) – a lab experiment which investigated the effect of AND and EST on gender perception
The studies by Zhou et al. (2014) and Hare et al. (2017) can be found in 'Two Key Studies of Pheromones' on this site: just navigate the Hormones & Pheromones topic to find it.
Exam Tip
Read the wording of the question carefully – if the question asks for the effect of pheromones on human behaviour then don’t write about animal research as this is not answering the question and will not gain you any marks
Worked Example
ERQ (Extended Response Question) - 22 marks
Discuss the effect of hormones or pheromones on human behaviour. [22]
The following two paragraphs are part of a discussion on the procedure used in Zhou et al.’s (2014) study.
Zhou et al. controlled for the potentially confounding variable of sexual preference in their research on the effect of pheromones as the sample included both heterosexual and homosexual participants. As the study looked at gender recognition linked to AND or EST, it depended on the sexual orientation of the sample (e.g. gay men and straight women should be stimulated by AND) so the inclusion of both straight and gay participants helps to ensure the validity of the responses.
However, appraising gender via the analysis of a light-point figure is an ambiguous task which may have resulted in participants guessing or making arbitrary decisions. Some of the light-point figures may have looked neither male nor female to the participants so it would then be down to personal preference as to which gender was selected. If this happened, then the decision as to gender would have nothing to do with AND or EST which would mean that the study lacked internal validity i.e. it was not measuring what it set out to measure.
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