Problems with the measurement of illusory correlation

Authors

  • S. Alexander Haslam,

    Corresponding author
    1. Department of Psychology, The Australian National University
    • Department of Psychology, The Australian National Universtty, GPO Box 4, Canberra, ACT2601, Australia
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  • Craig McGarty

    Corresponding author
    1. Department of Psychology, The Australian National University
    • Department of Psychology, The Australian National Universtty, GPO Box 4, Canberra, ACT2601, Australia
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Abstract

The illusory correlation eflect (ICE) refers to a tendency for people to over-represent rare behaviours performed by members of an infrequently encountered (minority) group. On the basis of an empirtcal study ( N = 245) this paper examines three procedural features that are common to studies in this field: (a) excluding subjects who assign too many behaviours to the minority group, (b) asking subjects to estimate the incidence of distinctive behaviours, and (c) submitting phi coefficients to Z transformation. Results show that the ICE is significantly lower amongst subjects who (a) are excluded and (b) estimate non-distinctive behaviours and (c) that Z transformation applied to phi coefficients renders the distribution of responses non-normal and does not provide a more linear index of efect strength. Implications for future research are discussed.

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