Visual expertise with pictures of cars correlates with RT magnitude of the car inversion effect.

In their seminal study Diamond and Carey (1986, Journal of Experimental Psychology: General 115 107-117) found a larger inversion effect for dog pictures in dog experts than novices, supporting a role of visual expertise in the observation of particularly large inversion effects for faces. However, subsequent studies have provided mixed results, and very few have compared the inversion effects for faces and familiar non-face object categories. Here we tested the effect of inversion on faces and cars in car experts and novices, using a delayed matching task across viewpoint changes. Inversion affected accuracy much more for pictures of faces than of cars for both groups, with no interaction between expertise and category. However, for car experts only there was a significant correlation between the magnitude of the inversion cost in RT for car pictures and the level of expertise as measured in an independent task. These observations support the view that the particularly large inversion effect found for faces is related to expert visual processes which can be at least partially recruited to process other non-face object categories.