Facial distinctiveness: its measurement, distribution and influence on immediate and delayed recognition.

It is conventionally assumed that many faces are relatively typical and few are distinctive (e.g. Valentine, 1991), producing a highly skewed distribution. However, Burton and Vokey (1998) argue that the distribution will be normal, and our review of previous research suggested this is true. In three studies we explored the distributions using different techniques to estimate distinctiveness. Both traditional ratings and pairwise selection produced normal distributions. However, ratings emphasizing the degree of deviation from a typical face were skewed towards the distinctive end of the scale. The instructions given when distinctiveness is rated may not necessarily oppose typicality with distinctiveness: a face that is relatively typical might also stand out in a crowd because of some particular feature, familiarity or a host of other reasons. In our fourth study, recognition memory was predicted by all of the distinctiveness measures, with the relationship being stronger after a 5-week delay than in the immediate test.