Key Study 1 (Agonist): Crockett et al. (2010)
Aim: To investigate the role of a serotonin agonist (SSRIs specifically) in prosocial behaviour (e.g. deciding that harmful behaviours towards others are unacceptable).
Participants: 24 males from Cambridge in 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 given either an SSRI (Citalopram), a drug used to treat ADHD or a placebo. The experiment used a double-blind design.
The first part of the procedure involved participants being asked to make moral judgements about a series of hypothetical scenarios, for example:
- Would you push someone in front of a train if it meant saving five other people? This was the emotionally salient ‘personal harm’ condition i.e. the idea involves actually physically pushing someone in front of a train
- Would you flick a switch so that a train hits one person instead of five? This was the less emotionally salient ‘impersonal harms’ condition i.e. the idea involves harming someone at a distance and is thus less personal
The responses were measured according to how many times each participant judged that an action (personal or impersonal harm) was ‘acceptable’.
Results: The emotionally salient personal harm condition (i.e. the idea of actually pushing someone in front of a train) produced the lowest number of ‘acceptable’ responses in both conditions i.e. participants were reluctant to imagine themselves physically harming another person even to save five other lives.
Participants in the SSRI condition (who had been taking Citalopram) made more prosocial responses i.e. by condemning harmful actions, compared to the ADHD drug group and the placebo group. The moral judgements made by the ADHD drug group and the placebo group were similar, showing no significant differences in prosocial responses.
Conclusion: Some SSRIs, such as Citalopram, may function as serotonin agonists, enhancing the effect of the serotonin in the brain which in turn may promote prosocial behaviour.
Evaluation of Crockett et al. (2010)
Strengths
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- The use of a double-blind procedure increases the internal validity of the findings
- Screening the participants for psychiatric and neurological disorders before the study also increases the validity of the findings as it helps to factor out any possible confounding variables linked to mental illness
Limitations
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- A sample of 24 participants is very small and reduces both the reliability (due to a lack of statistical power) and generalisability (again, due to the sample size) of the findings
- The study used an independent measures design so the differences in prosocial behaviour could simply be due to participant variables e.g. participants in the SSRI group may simply all have been naturally more prosocial than those in the other two groups
Key terms:
- SSRIs
- Serotonin
- Double-blind