🧬 Pheromones and Behaviour

📘 Key Concepts

Term	Definition
Pheromone	A chemical substance produced and released by an organism affecting behaviour or physiology of others of the same species.
Olfactory system	Neural system responsible for detecting chemical signals.
Vomeronasal organ (VNO)	Accessory olfactory structure proposed to detect pheromones in mammals.
Primer pheromones	Cause long-term physiological changes.
Signalling pheromones	Trigger immediate behavioural responses.

📖 Key Studies

1. Wedekind et al. (1995) — The “Sweaty T-Shirt” Study

• Aim: To determine if body odour influences mate preference through genetic compatibility.
  
• Method: Men wore shirts for two days; women rated odours.
  
• Results: Women preferred scents of men with dissimilar MHC genes.
  
• Conclusion: Olfactory cues may influence attraction for genetic diversity.
  
• Evaluation:
  
  • ✅ Controlled odour conditions
    
  • ❌ Artificial setting
    
  • ✅ Supported evolutionary mate selection
    
    

2. Zhou et al. (2014) — Sex Pheromones and Gender Perception

• Aim: To see if AND (male pheromone) and EST (female pheromone) affect perception of gender.
  
• Method: Participants watched point-light displays of walking figures while exposed to AND or EST.
  
• Results: AND made participants perceive figures as more masculine; EST as more feminine.
  
• Conclusion: Pheromones may influence gender perception in humans.
  
• Evaluation:
  
  • ✅ Controlled exposure
    
  • ❌ Small sample size
    
  • ✅ Suggests subtle human chemosensory communication
    

3. Cutler, Friedmann, & McCoy (1998) — Synthetic Pheromones and Sociosexual Behaviour

• Aim: To test if synthetic male pheromones increased sociosexual behaviour.
  
• Results: Men who added synthetic pheromones to aftershave reported more sexual activity.
  
• Conclusion: Pheromones may play a role in human sexual behaviour.
  
• Evaluation:
  
  • ✅ Field-based data
    
  • ❌ Self-reported behaviour (bias)
    
  • ❌ Correlational, not causal
    

💡 TOK Links Are human behaviours like attraction biologically determined or socially constructed? Can pheromones be considered a valid “way of knowing” in humans when evidence is inconclusive?

🌍 Real-World Connections Pheromone research informs fragrance design, relationship therapy, and marketing psychology. Genetic compatibility studies help understand mate selection and fertility treatment.

❤️ CAS Links Community projects on gender bias, relationships, or attraction science awareness. Creativity projects: designing “Myth vs Science” presentations on pheromones.

🧪 IA Guidance Potential IA replications: gender perception or scent preference under controlled conditions. Ethics: informed consent, avoidance of deception about sexual stimuli.

🧠 Examiner Tips State whether pheromones in humans are hypothesised or empirically established. Always discuss biological mechanisms (MHC, olfactory cues). Evaluate evidence — it remains correlational and inconclusive in humans.