easily discerned because deep processing, than other-race faces are. This hypothesis, however, is controversial because of its inability to be replicated within studies. Challenges for social cognition models There are two challenges to the social cognition models (a) mixed evidence dealing with race accessibility, face perception, and memory and (b) the effects of development and training on the cross-race effect. Regarding the mixed evidence, the popular belief is that the more someone is exposed to people of different races the less likely they will be affected by the cross-race effect. There have been studies that support this theory, but other research has shown mixed results. For example, the results of studies done where the accessibility, as in how easy or not it is for a person to be around people of difference races, to different races is manipulated, showed that this does not always affect face memory. Second regarding the development and training effects, just because someone shows improvement with dealing with the cross-race effect due to exposure to cross race training or experience, it is not a direct prediction of a good social cognitive model. For the social cognitive model to start explaining such effects there would have to be evidence that ingroup and outgroup distinctions occur developmentally at the exact time the cross-race effect emerges in a child. There is some evidence showing when the cross-race effect first emerges, but there is little research directly testing the onset of ingroup and outgroup recognition biases in young children. While social cognition models indicate a lack of effort to individuate other-race faces explains the cross-race effect, some research has challenged this by arguing that individuals do not spend less effort looking at other-race faces than same-race ones. Perceptual expertise hypothesis The perceptual expertise theory also suggest that if we identify the perceptual learning mechanisms that control perceptual expertise with face and non-face stimuli we will understand the cross-race effect. There are many models that deal with perceptual expertise, but all of these models share the idea that a human's face processing ability does not generalize equally to all faces. Hence, these theories propose that racial segregation results in people developing better expertise in distinguishing between faces of our own race or of a different race. Research around these theories also suggests that the more a child is exposed to cross-race face processing the lower the cross-race effect. However, if the