Bystander effect — MRCPsych Paper A MCQ

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ModeratePsychologyBystander effectMRCPsych Paper A

Several commuters see a man collapse on a train platform. They all recognise that he requires urgent assistance, but initially nobody calls the emergency services. When a member of staff directly asks one named commuter to make the call, that commuter acts immediately. Which social psychological process best explains the initial inaction?

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Correct answer: B — Diffusion of responsibility

B, diffusion of responsibility, is the reduction in an individual's perceived obligation to act when responsibility is shared among several potential helpers. The commuters recognise an emergency but fail to respond until responsibility is assigned to a named person, which is the key discriminator. Pluralistic ignorance involves interpreting others' apparent lack of concern as evidence that the situation is not an emergency; this is excluded because the commuters recognise the need for urgent help. Social loafing is reduced effort while performing a collective task, rather than failure to assume responsibility. Group polarisation concerns group discussion producing more extreme attitudes. Fundamental attribution error is the tendency to overemphasise dispositional explanations for another person's behaviour.

Reference: Oguni R, Tham YJ, Ishii C. Does gratitude moderate the bystander effect? A registered report. Cognition and Emotion. 2026. https://pubmed.ncbi.nlm.nih.gov/21534650/