Real-life experience with personally familiar faces enhances discrimination based on global information

Abstract

Despite the agreement that experience with faces leads to more efficient processing, the underlying mechanisms remain largely unknown. Building on empirical evidence from unfamiliar face processing in healthy populations and neuropsychological patients, the present experiment tested the hypothesis that personal familiarity is associated with superior discrimination when identity information is derived based on global, as opposed to local facial information. Diagnosticity and availability of local and global information was manipulated through varied physical similarity and spatial resolution of morph faces created from personally familiar or unfamiliar faces. We found that discrimination of subtle changes between highly similar morph faces was unaffected by familiarity. Contrariwise, relatively more pronounced physical (i.e., identity) differences were more efficiently discriminated for personally familiar faces, indicating more efficient processing of global, as opposed to local facial information through real-life experience.

Keywords: Face processing; Global information integration; Holistic processing; Personal familiarity; Real-life exposure.

Figure 1. Stimuli discriminated in the delayed matching task.

(A) An example of a familiar face morph continuum. Unfamiliar stimuli were those created and used in a previous study (see Ramon, Dricot & Rossion, 2010 for examples and details regarding stimulus creation), which were unfamiliar to all subjects tested. Familiar morph continua were created from pairs of classmates of experimental subjects tested, and were unfamiliar to control subjects. (B) Examples of stimulus pairs to be discriminated in the 2AFC delayed matching task (pairs were taken from either side of a continuum).

Figure 2. Familiarity advantage in the 2AFC delayed matching task with personally familiar and unfamiliar morph stimuli.

Mean familiarity advantage ((familiar − unfamiliar)/(familiar + unfamiliar)) for accuracy scores per condition observed for control, as well as experimental subjects. Error bars represent standard errors for both measures. Note that for control subjects, all faces presented were unfamiliar.