Two Key Studies of Biological Theories of Altruism (DP IB Psychology)

Revision Note

Claire Neeson

Last updated

Key study one: Simmons et al. (1977)

Aim: To test kin selection theory by investigating the extent to which close relatives of a kidney patient would be willing to offer themselves as kidney donors

Participants:

  • An opportunity sample of potential kidney donors

  • These donors were the relatives of existing kidney patients

  • The sample was obtained from the records of University of Minnesota hospitals

Procedure:

  • The participants were given questionnaires which asked them whether they would be willing to donate one of their kidneys to their close relative

  • The close relative was an existing patient receiving treatment for a kidney condition

  • The potential kidney recipients (the kidney patients) were asked to rate how emotionally close they felt to all of their possible donors (before the choice of a donor had been made)

Results:

The following table shows the results for agreeing to donate a kidney and the degree of closeness to potential donors/non-donors felt by the kidney patients:

 

Agree to donate kidney

Level of closeness felt by kidney patient

Parent

86%

 

Sibling

47%

 

Donor

 

63%

Non-donor

 

42%

Conclusion:

  • Kin selection theory goes some way towards explaining prosocial behaviour from a biological/evolutionary perspective:

    • Those closest genetically to the patient were more willing to donate a kidney (86% agreement from the parents of kidney patients)

    • The drop to 47% for siblings also agrees with the theory as siblings are not as genetically close as parent and child  

Evaluation of Simmons et al. (1977)

Strengths

  • The study used actual kidney patients who were awaiting kidney donation, which makes the ecological validity of the study high

  • The results support the idea of altruism as an evolutionary mechanism as it makes evolutionary sense for a parent to sacrifice their own fitness to ensure that their offspring survives 

Limitations

  • 14% of the parents in the sample did not agree to donate a kidney to their son/daughter:

    • this finding casts some doubt on the validity of the theory

    • if kin selection theory held true then 100% of parents should automatically agree to donate a kidney to their child

  • There may be other factors determining the decision to donate a kidney, for example:

    • the siblings who agreed to donate were generally the same sex as the recipient, closer in age

    • the above finding means that these siblings probably had more in common with the recipient than with those who did not agree to donate

    • some potential donors who did not agree to donate may have had underlying health issues which precluded them from donating a kidney

    • some potential donors may have had a phobia of hospitals or surgery which is not a biological explanation of behaviour

    • some potential donors may simply not have felt very close or even liked the recipient which is not a biological explanation of behaviour

Key study two: Crockett et al. (2010)

Aim:

  • To investigate if serotonin directly affects moral judgement by increasing the motivation of participants to help others and their aversion to personally harming others

  • In tandem with the above aim: to investigate the role of serotonin in prosocial behaviour

Participants:

  • 24 males from the Cambridge area of the UK with a mean age of 25.6 years

  • The participants were screened for psychiatric and neurological disorders before the study began

Procedure:

  • The participants were randomly assigned to one of the following three groups/conditions:

    • SSRI group: the participants were given the antidepressant citalopram, which works as a selective serotonin reuptake inhibitor and is regularly prescribed to treat depression

    • ADHD and OCD drug group: the participants were given a drug used to treat ADHD and OCD 

    • Placebo group: the participants were not given any sort of drug

  • The drugs were administered using a double-blind procedure:

    • neither the participants nor the researchers knew which group each participant had been assigned to

  • The first part of the procedure involved participants being asked to make moral judgements about a series of hypothetical scenarios, each of which was linked to one of the two conditions of the independent variable:

    • The emotionally salient ‘personal harm’ condition: 

      • Would you push someone in front of a train if it meant saving five other people? 

    • The emotionally salient ‘impersonal harms’ condition:

      • Would you flick a switch so that a train hit one person instead of five? This was the less  

  • There was no time limit on how long the participants spent thinking about each scenario and making their decisions

  • The responses were measured according to how many times each participant judged that an action was ‘acceptable

Results:

  • The emotionally salient personal harm condition (i.e. which involved participants imagining themselves harming someone else directly) produced the lowest number of ‘acceptable’ responses from all participants

    • in other words, participants could not agree to intervene personally to harm another person, even if it meant saving others

  • Participants in the SSRI group were far more likely to say that harmful actions were unacceptable compared to the other two groups

  • The moral judgements made by the ADHD/OCD drug group and the placebo group were roughly similar, showing no great differences

Conclusion: Serotonin may induce prosocial behaviour and reduce acts of harm towards others

Evaluation of Crockett et al. (2010)

Strengths

  • The procedure involved a double-blind allocation of drugs and placebo, which increases the validity of the findings

    • it means that both researchers and participants did not know what drug was being taken, which should eliminate any bias

    • neither participants nor researchers could act in accordance with any expectations they might have had as to the effects of a drug

  • The study used objective methods and a replicable, standardised procedure which increases the reliability of the findings

Limitations

  • The small sample size of 24 males from Cambridge presents several issues:

    • 24 participants divided between 3 conditions, means that the results are not statistically robust

    • the results cannot easily be generalised to males outside of Cambridge

    • an all-male sample brings with it gender bias 

  • There may be alternative explanations for the moral judgements made by the participants:

    • some of the participants may have held religious principles which would mean that they were predisposed to be prosocial 

    • some of the participants may have been in a better mood than others which would increase their inclination to be prosocial

    • some of the participants may have been presented with the same or similar moral dilemmas before which would bias their response to the scenarios

Worked Example

ERQ (EXTENDED RESPONSE QUESTION) 22 MARKS

The question is, ‘To what extent can biological theories explain prosocial behaviour?’ [22]

This essay is asking you to judge the extent to which biological theories alone can account for prosocial behaviour. Here are two paragraph for guidance:

Simmons et al.’s results revealed that 86% of the parents of the kidney patients said that they would be willing to donate one of their kidneys whereas 47% of the siblings in the study agreed to donate a kidney. The kidney recipients reported feeling emotionally close to 63% of the potential kidney donors but this dropped to 42% for non-donors. These results show some support for Kin Selectiontheory, however, the fact that 14% of the parents did not agree to donate a kidney to their son/daughter casts some doubt on the validity of the theory as if it held true then 100% of parents should automatically agree to donation. The drop to 47% for siblings also agrees with Kin Selection theory to some extent as siblings are not as genetically close as parent and child.  There may, however, be other factors determining the decision to donate or not as the siblings who agreed to donate were more likely to be the same sex as the recipient, closer in age and with more in common with their sibling than the siblings who refused to donate. This finding therefore uses other explanations for prosocial behaviour which are not biological e.g. individual differences, upbringing, personality.

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Claire Neeson

Author: Claire Neeson

Expertise: Psychology Content Creator

Claire has been teaching for 34 years, in the UK and overseas. She has taught GCSE, A-level and IB Psychology which has been a lot of fun and extremely exhausting! Claire is now a freelance Psychology teacher and content creator, producing textbooks, revision notes and (hopefully) exciting and interactive teaching materials for use in the classroom and for exam prep. Her passion (apart from Psychology of course) is roller skating and when she is not working (or watching 'Coronation Street') she can be found busting some impressive moves on her local roller rink.