Pheromones

Question 1

Define pheromones

Answer 1

Pheromones are chemicals released externally to the body that effect other members of the same species

Question 2

Do pheromones exist in humans?

Answer 2

Exist and function in animals, however there is no compelling evidence of existence or functioning in humans

evolutionary basis - animals have them so so should we (problematic as to massive evolutionary changes)

Question 3

Explain the problems with pheromone research

Answer 3

• too difficult to isolate a specific molecule, however this is what is needed
• nobody has systematically gone through all odours humans have produced to work out which molecules are actually pheromones (BIOASSAY)
• humans are taught what smells good or bad, changing our response to pheromones
• cleanse a lot more then other animals, removing substances containing pheromones
• each human smells differently
  
  • 400 receptors, humans can have variants in each
• apocrine secretions not secreted by 20% of the population (china, japan, korea)

Question 4

Zhou et al

Answer 4

Aim: to determine if androstadienone and estratetraenol influence human sexual behaviour

• Androstadienone: found in male semen and sweat
• Estratetraenol: found in female urine

Participants:

• 24 gay males
• 24 lesbian females
• 24 straight males
• 24 straight females

Procedure:

1. Participants were asked to determine the sexual orientation of a stick figure walking on a screen
2. Participants did this in 3 conditions, just the smell of cloves, the smell of cloves with androstadienone, and the smell of cloves with estratetraenol

Results
Researchers found that smelling the androstadienone condition biased gay males and straight females towards perceiving the figures as more masculine, and that smelling the estratetraenol condition biased gay females and straight males towards perceiving the figures as more feminine.

Conclusion
Pheromones influence communication of gender information in a sex-specific manner

Evaluation

• too high levels of substances to be ecologically viable
• why would humans need a pheromone to tell what sex a person is?
• not a study of sexual attraction but rather whether a person’s walk was feminine or masculine
  
  • not reliable measure of sexual behaviour
• small sample

Question 5

Doucet et al

Answer 5

Aim: to investigate the role of areolar gland excretions in suckling behaviour of infants

• repeated measures design
• lab experiment
• double blind procedure

Participants were 19 3-day old infants (obtained informed consent)

Procedure:

1. Researchers administrated seven different secretions nasally to infants on a sterile glass rod, as well as using a control rod with no secretions
2. They then monitored the infants breathing rate and behaviour
3. The seven different secretions were areolar secretions, sebum, human milk, cow milk, formula milk, and vanilla

Results:
The researchers found that the infants only began suckling when being nasally administrated areolar secretions, but did not respond to any other secretions. Additionally, infants breathing rate increased significantly

Conclusions
Researchers concluded that molecules specific to areolar gland secretions cause infants to start suckling, and could perhaps be due to a pheromone molecule however more research is needed.