Pheromones

Pheromones - what

are chemical substances produced and released by an animal that affect the behavior of other members of the same species. 

Initial research focused on bugs like silkmoths, termites, ants and bees

pheromones and behavior

Pheromones have also been shown to play a role in the behavior of mammals, mainly in mating behavior

• If a male rhesus monkey cannot sense the pheromones signalling fertility, he will ignore the romantic attention of a female

pheromones and processing

Although many pheromones have a smell, it is not processed in the brains of animals in the regions as ordinary smells. 

pheromones and processing - structures

Mammals have a separate structure called the vomeronasal organ (VNO) which is located in the anterior nasal cavity. 

• Nerves from the VNO in animal brains connect to a special region called the accessory olfactory bulb.  

pheromones and processing - humans

Human fetuses do have the accessory olfactory bulb, but it regresses and disappears after birth. 

• Some people do have a VNO and some do not.  

• Even in those who have a VNO, it appears to be non-functional: there is no connection to the central nervous system.

  • If pheromonal information is processed in the human brain, it must be processed somewhere else. 

If human pheromones exist, can they really influence the formation of personal relationships?  

1. Complexity of human attraction

2. Complexity of human scent.

If human pheromones exist, can they really influence the formation of personal relationships?  

1. Complexity of human attraction

• Why we feel attracted to one person - and not someone else - is complex. 

• It encompasses all five of ours senses, not to mention our culture, memories, and personality. 

• This makes it very difficult to isolate and measure the effect of just one factor - such as human pheromones - on attraction. 

If human pheromones exist, can they really influence the formation of personal relationships?  

1. Complexity of human scent.

• Your "odorprint" - the unique smell you give off - is made up of hundreds of unidentified chemicals, including bacteria (ex. in the armpits) that mixes with your bodily chemicals. 

• Furthermore, humans have over 400 odor receptors - and each odor receptor has genetic variants, meaning that each person processes odours differently. 

• Given this complexity, it is very difficult to test how just one chemical - such as a pheromone - could make a significant difference in attraction.  

Studies on pheromones

1. Saxton et al.

2. Cutler et al.

Saxton et al

Aim

The study aimed to investigate if exposure to androstadienone (a male pheromone secreted under the armpits), could influence women's perceptions of male attractiveness during speed dating interactions. 

• The researchers sought to determine if androstadienone could affect attraction in real life. 

Saxton et al

Method

25 women participated in a speed-dating event in a double-blind, placebo-controlled experiment. 

• The women were exposed to either androstadienone (the pheromone) or a placebo (control condition) during the speed-dating event.

  • Androstadienone/the placebo were applied to a facial tissue and rubbed under the nose. 

• Participants engaged in a series of short encounters with multiple men.

• After each interaction, the women rated the attractiveness of the men they met.

Saxton et al

Results

Women who were exposed to androstadienone rated men as more attractive compared to those who were exposed to the placebo.

Saxton et al

Conclusion

Androstadienone may influence women's perceptions of men during brief social interactions, such as speed dating.

• Androstadienone, could play a role in romantic attraction. The effects were small, indicating that while pheromones can have an impact, they are only one factor among many in social and romantic attraction

Saxton et al

Evaluation

Confounding variables influencing attraction ratings, double blind, field experiment (ecological validity) 

Cutler et. al

Aim

investigated whether synthesized male pheromones increase sociosexual behaviour of men.

• aim to “test whether a male pheromone added to aftershave lotion would increase the romance in their lives”

Cutler et al.

Method

Participants (38 men) were recruited through local press releases that invited volunteers

• Participants were randomly divided into two groups (in a double-blind manner).

• Each participant brought his aftershave lotion (which was examined by the researchers) and was asked to use it after every shave and at least three times a week throughout the study period.

• Participants were also given a behavioural calendar including: kissing, sleeping next to a romantic partner, sexual intercourse, mastrubation

Cutler et al.

Results

there were significantly more men in the pheromone group (as compared to the placebo group) who had an increase over the baseline in the first four behaviours

• increase over the baseline in the first four behaviours (petting, affection and/or kissing; sleeping next to a partner; sexual intercourse; and informal dates).

• Differences were not observed for the last two behaviours (formal dates and masturbation).

Cutler et al.

Conclusion

that applying the synthetic pheromone resulted in an increase of sociosexual behaviours “in which the willingness of a female partner plays the major role”

• In contrast, behaviours like masturbation did not increase.

• The researchers took it as evidence that the synthetic human pheromone did not just increase libido but actually increased the attractiveness of men to women.

Cutler et al.

Evaluation

• a lot of confounding variables

• Cutler owns a buisness selling pheremone products