Exploring levels of face familiarity by using an indirect face-matching measure

An experiment is reported in which participants matched complete images of unfamiliar, moderately familiar, and highly familiar faces with simultaneously presented images of internal and external features. Participants had to decide if the two images depicted same or different individuals. Matches to internal features were made faster to highly familiar faces than both to moderately familiar and to unfamiliar faces, and matches to moderately familiar faces were made faster than to unfamiliar faces. For external feature matches, this advantage was only found for "different" decision matches to highly familiar faces compared to unfamiliar faces. The results indicate that the differences in familiar and unfamiliar face processing are not the result of all-or-none effects, but seem to have a graded impact on matching performance. These findings extend the earlier work of Young et al (1985 Perception 14 737-746), and we discuss the possibility of using the matching task as an indirect measure of face familiarity.