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Bias in the use of base rates: Racial prejudice in decision‐making
Author(s) -
Hewstone Miles,
Benn William,
Wilson Andrew
Publication year - 1988
Publication title -
european journal of social psychology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.609
H-Index - 111
eISSN - 1099-0992
pISSN - 0046-2772
DOI - 10.1002/ejsp.2420180207
Subject(s) - psychology , social psychology , prejudice (legal term) , white (mutation) , normative , ethnic group , witness , base (topology) , sociology , law , chemistry , gene , mathematical analysis , biochemistry , mathematics , political science , anthropology
Two studies investigated biases in the use of base rate information when assessing the probability of a witness' accurate identification of a white or West Indian as a burglar. An adapted version of the Kahneman‐Tversky cab problem was used, to provide a social decision in which biases could be measured against some normative standard. Ethnicity of youth (white/West Indian) and nature of base rate (incidental/causal) were manipulated in a 2 × 2 between‐subjects design. A significant interaction effect revealed that subjects took no account of the base rate for a West Indian subject, but used the base rate only when it was causal and the youth was white. This ‘prejudice effect’ against a West Indian youth and ‘exoneration effect’ for a white youth were replicated in a second study, using a microcomputer and chronometric analyses. Results are discussed in terms of heuristic decision‐making, social schemata, and the cognitive versus motivational bases of bias in the use of base rates.