Biological Approach

• Maguire (2000) London Taxicab study:

  • IV: driving experience
  • DV: grey matter volume/distribution of hippocampus
  • Aim: investigate differences in the brains of London taxi drivers compared to the average brain
  • Method: quasi experiment, correlational study
  • Findings: taxi drivers had more gray matter in the posterior hippocampus, control group had more in the anterior hippocampus
• Milner (1966) HM localization of hippocampus:

  • Aim: investigate the effects of surgery on HM
  • Method: Case study
  • Findings: HM couldn't acquire new episodic or semantic information, but could remember his house and draw it, had working memory and procedural memories
• Draganski (2004) Juggling Study:

  • IV: learning
  • DV: grey matter growth of mid-temporal area
  • Aim: investigate if the brain can structurally reshape from environmental demands
  • Method: experiment, mixed design
  • Findings: juggling group showed more gray matter in the mid-temporal area after learning, correlation between juggling performance and brain changes
• Crockett (2010) Effect of serotonin on prosocial behavior:

  • Aim: investigate the effect of serotonin on positive social behavior
  • Method: experiment, repeated measures, double-blind
  • Findings: citalopram reduces acceptability of personal harm, promotes prosocial behavior
• Scheele (2012) Effect of oxytocin on fidelity:

  • Aim: investigate if oxytocin promotes fidelity
  • Method: experiment, independent measures, double-blind
  • Findings: oxytocin causes monogamous men to keep a greater distance from other attractive women, inhibits response to certain stimuli in men in stable relationships
• Kosfeld (2005) Effect of oxytocin on interpersonal trust:

  • Aim: investigate if oxytocin increases interpersonal trust
  • Method: experiment, independent measures
  • Findings: oxytocin group had higher levels of trust, reduced risk aversion, and increased interpersonal trust
• PET Freed (2001) Effect of dopamine on Parkinson's:

  • Aim: investigate the effects of dopamine on the behavioral symptoms of Parkinson’s disease
  • Method: experiment, independent measures
  • Findings: experimental group patients showed increased growth of dopamine-producing cells in the putamen
• Evaluation points for Scheele (2012) Effect of oxytocin on fidelity:

  • Low population validity, high ecological validity, high construct validity, high internal validity
• Oxytocin reduces risk aversion and increases interpersonal trust
• Evaluation of the study on AND and EST signaling gender and attractiveness:

  • Low population validity
  • Reductionist: environmental factors like life experience not considered
  • Higher internal validity: repeated 4 times
• Hare (2017) study on AND and EST:

  • Aim: investigate if AND and EST signal gender and affect mate perception
  • Method: experiment, repeated measures (counterbalanced)
  • Sample: 140 heterosexual adults
  • Findings: No difference in gender assigned or average attractiveness ratings between conditions
  • Conclusion: AND and EST do not act as signals of gender or attractiveness, do not qualify as human pheromones
• Counter-argument by Zhou (2014) found that AND and EST may influence how males and females perceive gender according to their sexual orientation
• Cutler, Friedmann, McCoy (1998) study on synthesized male pheromones:

  • Aim: investigate if synthesized male pheromones increase sociosexual behavior in men
  • Method: field experiment, independent measures
  • Sample: 38 heterosexual men, 25-42 years old
  • Results: Pheromone group showed a more significant increase in sociosexual behaviors compared to the placebo group
• Caspi (2003) study on 5-HTT allele gene and depression:

  • Aim: investigate the role of the 5-HTT gene in developing depression in response to stressful life events
  • Method: longitudinal study
  • Sample: 1037 children from New Zealand
  • Results: Participants with short allele [s/l or (especially) s/s] reacted to stressful life events with more depressive symptoms
  • Conclusion: The 5-HTT gene modulates an individual’s vulnerability to stress in response to environmental factors, impacting the likelihood of developing depression
• Bouchard and McGue (1981) study on the heritability of intelligence:

  • Aim: estimate heritability of IQ
  • Method: meta-analysis on twin studies
  • Sample: 111 twin studies
  • Results: Intelligence is 54% inherited based on the Falconer model
  • Conclusion: Intelligence is inherited to a considerable but not complete extent, environment also plays a role
• Scarr and Weinberg (1983) study on transracial adoption:

  • Aim: investigate environmental malleability of intelligence
  • Method: adoption study
  • Sample: 101 white families with a biological child and a different race adopted child
  • Results: Adopted black children had higher IQ when raised by white families compared to original black families
  • Conclusion: Genetics and environment both influence intelligence
• Curtis, Aunger, Rabie (2004) study on disgust and natural selection:

  • Aim: study disgust in relation to evolutionary psychology
  • Method: correlational study, online survey
  • Sample: 77,000 people across 165 countries
  • Results: Support for all hypotheses, disgust is a biologically based evolutionary response to disease-salient stimuli
• Fessler (2006) study on disgust in pregnant women:

  • Aim: investigate if disgust sensitivity acts as compensation for pregnant mothers’ compromised immune system
  • Sample: 496 healthy pregnant women
  • Results: Women in their first trimester scored higher in disgust sensitivity
  • Conclusion: Disgust acts as a protective mechanism against diseases during pregnancy