Abstract
We are extremely good at recognizing the faces of people we know even from highly impoverished stimuli, such as pictures that are highly distorted or blurred. However, when we are unfamiliar with someone, our recognition of their face is much slower and more prone to error. Research has shown that when we are only briefly exposed to unfamiliar faces, we often fail to recognize them and that we can even fail to accurately match two pictures of the same person that are simultaneously presented (e.g. Bruce et al., 1999; Burton et al., 1999). Our aim is to study the changes in behavioral performance as we become familiar with faces. We trained participants to recognize the faces of eight unfamiliar individuals. Participants were trained on three separate days. In one of the tasks, participants had to match two faces across different views and lighting conditions. In another task, participants selected one of the studied faces among two distractors. Participants' performance improved gradually across the three training sessions. At the end of the training, participants performed 20% to 30% better on both tasks compared to their performance in the initial session. Crucially, when they were tested with eight new faces, participants' performance was significantly worse than with the learned faces, demonstrating that most of the training effect is specific to the faces that were learned. We suggest that this change in performance reflects a change in the representations of the faces that were learned. We believe that this change depends only minimally on semantic information but instead reflects modifications of the visual representations of the faces that were learned. In follow-up fMRI studies, we will examine neural changes that accompany this face learning effect.