What are Pheromones? (HL IB Psychology)

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.