Mentor
Dr. Edward Wasserman
Participation year
2009
Project title

Is a specialized face-processing system necessary for the other-race effect to occur?

Abstract

It has been proposed that face recognition in primates depends on a specialized mechanism, different from the system used to recognize other objects, physically located in the fusiform gyrus of the right medial temporal lobe (the fusiform face area). One interesting aspect of human face recognition is the other-race effect; the finding that people are more accurate in recognizing faces of their own race than faces of other races. The effect has traditionally been explained as the result of general learning mechanisms working over differential experience with several races, but recent evidence indicates a higher engagement of specialized face processing mechanisms for faces of the own race than faces of other races, which opens the question as to whether these specialized mechanisms are necessary for the effect to occur. The goal of the present study was to explore this problem by looking at the possibility of an experience-based other-race effect in a non-primate animal: the pigeon. We tested the other race effect in four pigeons without experience in the recognition of African and Asian faces. The experimental task consisted in the presentation of a pair of faces in a computer screen; pigeons were reinforced with food for pecking at only one of the two faces. During a first training phase, the pigeons were trained with an incrementally larger number of discriminations involving faces of only one race, starting with one discrimination between two faces and ending with eight. At this moment, we only have partial results from this first experimental phase. These results show differences in the way pigeons are learning discriminations involving different races. Pigeons trained with Asian faces show a significant rise in accuracy across training stages, indicating positive transfer of learning from old discriminations to new discriminations. Pigeons trained with African faces do not show the same trend. However, these results are based on only part of the data to be gathered during Phase 1 and it is still too early to draw any definitive conclusion. Furthermore, the most critical data from Phase 2 have not yet been gathered. Our short-term goal involves completing training for both phases and gathering the necessary data to draw firmer conclusions about the possibility of an experienced-based other-race effect in pigeons.

Veronica  Bonilla Pacheco
Education
Pontifical Catholic University