I'll discuss two topics in my presentation. First, I'll provide an overview of previous studies examining the cognitive and neural basis of developmental prosopagnosia (DP), and then I'll discuss a recent fMRI study from my lab that assessed 26 category-selective areas in a relatively large sample of DPs. Our results revealed that face selectivity was reduced across the face network in the DPs due to weaker responses to faces. We also found selectivity reductions to bodies in body areas and pronounced selectivity reductions to scenes in scene areas. Together, these results demonstrate that many DPs have widespread selectivity reductions across category-selective visual cortex. These reductions indicate DP often results from neurobiological factors with relatively broad effects rather than insufficient experience with faces, and they point the way toward a better understanding of the behavioral heterogeneity present in DP. Second, I'll discuss the results of behavioral testing with Claudio, a Brazilian man who has a congenital joint disorder that caused his head to be rotated back so that it nearly rests against his back. As a result, Claudio has often viewed faces that are not matched to his face's orientation. Claudio's unusual experience with faces allows us to assess the developmental origin of the most fundamental effect in face perception -- the face inversion effect. Across five face detection tests and five face identity perception tasks, Claudio showed comparable performance with upright and inverted faces and these results indicate experience plays a role in our superior performance with upright faces. However, Claudio's performance on the upright face tasks was much worse than controls despite normal performance on other tasks, which suggests upright superiority may result from a combination of experience and phylogenetic factors.