Hormone + behaviour

• Study for hormone + Pheromones?

  Ditzen - Oxytocin

  Wedekind - MHC
• What is oxytocin and trust?

  'love/trust hormone'. Linked to the bonding between mothers and child.

  
  

  Produced in the hypothalamus and secreted by the pituitary gland. Hormone important for social bonding seen in trust, affection and communication in animals and humans. Hugs increase oxytocin.

  
  

  Trust - essential for forming relationships + maintaining them. No oxytocin = no trust.
• Ditzen 2009


  Aim - investigate role of oxytocin in how couples communicates when in a contentious issue. Hypothesised that participants receiving oxytocin would have more positive communication.

  
  

  Procedure - double-blind, 47 heterosexual couples given either a placebo or oxytocin intranasally. Then videotaped while engaging in a topic which would lead to conflict, coded for verbal and non-verbal behaviour. Also measured cortisol levels (stress hormone).

  
  

  Findings - oxytocin improved positive communication and low cortisol levels compared to the placebo.

  
  

  Conclusion - Oxytocin has a role in relationships with oxytocin being linked to pair bonding and positive communication. As positive behaviour strengthen relationships.

  
  

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  High control - IV groups.

  Temporal validity 2009.

  Double blind - demand characteristics.

  
  

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  Only heterosexual - cannot pro-create naturally.

  Only 47 couples - small.

  Lab - artificial.
• What are pheromones?

  Substances secreted from an individual to another member of their species.

  
  

  Are known in animals however are uncertain in adults due to no working VNO (vomeronasal) organ which is known to receive pheromones in animals.

  
  

  Grammer 2005 - pheromones exist in humans but found in our armpits. The gland in our armpit occur at sexual maturity (pubity).
• Wedekind 1995


  Background - MHC gene enables immune system to recognise pathogens. The more diver MHC the better immune system. Smell MHC.

  
  

  Aim - Investigate if MHC would affect mate choices.

  
  

  Sample - 49 females + 44 males from Uni. All types for MHC.

  
  

  Procedure - men asked to wear t-shirt for 2 nights and left in an open bag in the day. Perfume-free detergent and soap. No deodorant/perfume, no smoking/drinking, eating spicy food and no sex.

  
  

  - Women ranked 7 t-shirts for smell. Happened 2 weeks after menstruation and used a nose spray.

  
  

  - 3 similar MHC, 3 different and 1 control (unworn). Scored for intensity and pleasantness.

  
  

  Results - scored more pleasant for dissimilar MHC genes = MHC influences mate choice.

  
  

  Conc - Prefer men with different immune system due to better health of potential babies. Evo explanation of mate selection.

  
  

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  Double-blind experiment.

  High controls.

  
  

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  Unrepresentative - same age.

  small sample size.

  Cannot explain same-sex relationships, cant procreate naturally.
• Critical thinking points for pheromones?

  Bio = determinism + reductionist.

  
  

  Unable to explain same-sex partners. Complexity of human attraction and human scent.