Response bias with prototypic faces

RESPONSE BIAS WITH PROTOTYPIC FACES Kenneth R. Laughery and Dean G. Jensen Department of Psychology, Rice University Houston , Texas, U.S.A. Michael S. Wogalter Department of Psychology, University of Richmond Richmond, Virginia, U.S.A. Three experiments employed a facial recognition task where target faces did not appear in a five or six-item test set . The test set consisted of a prototype face that differed by one feature from each of the distractors, which in turn differed by two features from each other . Subjects ranked the faces on the likelihood they were a target face. Results showed the prototype was ranked significantly above chance, indicating the procedure resulted in a response bias. The findings have implications for lineup and photospread construction. This paper presents the results of three experiments that addressed the issue of response bias in a facial recognition task. This issue concerns the situation in which the recognition test set contains a face that is a prototype of the others in the set . For example, suppose the set is made up of faces each of which is a variation on one particular face, the prototype, that is also included in the set . One might expect that such a set would result in a response bias favoring the identification of the prototype face. There is some support for this prototype notion in a study by Solso and McCarthy (1981), Using a recognition memory paradigm, they constructed distractor faces from the features of faces that had been presented. Their subjects were more confident in recognizing (incorrectly) the distractor faces than the faces they had seen . Additionally, Wogalter and Jensen (1986) have demonstrated a bias towards a prototype in a recognition task using nonfacial stimuli. The practical issue with which this work is concerned is fairness, or its opposite -- bias, in law enforcement lineups and photospreads . A biased lineup is one where persons who were not witnesses to a crime are more likely than chance to pick the suspect. Malpass and Devine (1983) and Wells (1978) have discussed lineup bias and have noted that the suspect must not be distinctive in comparison with other members ( the distractors) . Malpass and Devine (1983) reported an experiment in which similarity between a suspect photograph and the other photospread members was manipulated. Their results showed an increase in fairness with increasing suspect-distractor similarity. Hence, in constructing lineups or photospreads, law enforcement agencies would be advised Practical Aspects of Memory: Current Research and Issues , Vol. 1 ; pp. 157-162, 1988. In M. M. Gruneberg, R. Sykes, & P. Morris (Eds.), Chichester: John C. Wiley. 158 K.R. LAUGHERY ET AL. to select lineup or photospread distractors who are similar to the suspect. But such an approach creates the possibility of bias due to the suspect being a prototype of the lineup or photospread faces. That is, the suspect may have more features in common with the distractors than the distractors share with each other. In this regard the suspect may be distinctive, and in situations where the suspect is not the target person (criminal), the lineup or photospread may fail a crucial criterion in that the likelihood of the suspect being chose ,n is greater than chance, The present experiments employ a recognition paradigm . In Experiment 1 subjects saw a single target face before examining a group of photographs -- a photospread.