What regulates the surface color effect in object recognition: Color diagnosticity or category?

The effect of surface color on object recognition has been controversial. Tanaka and Presnell (1999) claimed that the degree to which an object is associated with a specific color, or color diagnosticity is crucial: Surface color plays a major role in recognition of high color diagnostic (HCD) objects (e.g., banana), but not in that of low color diagnostic (LCD) objects (e.g., sports car). On the other hand, past results also suggest that color is beneficial in recognition of natural objects (e.g., fruit and vegetables) more than man-made objects (e.g., tools and furniture). The present study examined the relation between the surface color effect, color diagnosticity, and object category. In a classification experiment, the surface color effect was observed only in HCD objects regardless of their category, supporting the color diagnosticity hypothesis of Tanaka and Presnell (1999). Moreover, there was no difference in response time between HCD and LCD man-made objects, whereas HCD natural objects were classified faster than LCD natural objects. The interaction between category and color diagnosticity requires future examination.