Category-specific naming errors in normal subjects: the influence of evolution and experience

The importance of "artifactual" variables (such as conceptual familiarity) have been highlighted in current accounts of category-specific disorders for living things (e.g., Funnell & Sheridan, 1992). The difficulties experienced by patients are essentially viewed as an exaggeration of normal processes and the implication is that normal subjects should also have greater difficulty naming living items (because they have lower conceptual familiarity than nonliving things). The current study examined normal subjects' ability to name pictures of artifact-matched sets of living and nonliving things in a naming-to-deadline paradigm. Contrary to the prediction, normal subjects made more nonliving naming errors. Furthermore, female subjects made more nonliving-thing errors than male subjects. These findings could not be reduced to differences in either category-based or gender-based familiarity ratings. Rather, it is proposed that an elaborated domain-specific evolutionary model parsimoniously explains both the greater incidence of living thing deficits in patients and the better performance of normal subjects with living things.