A progressive category-specific semantic deficit for non-living things.

We report a longitudinal study of a patient, ES, with a progressive degenerative disorder resulting from generalised cerebral atrophy. Across a range of tasks, ES showed a greater difficulty in recognising and naming artifacts than living things. This deficit for artifacts emerged over time, as she became more severely impaired. In one task, picture naming, there was a crossover from an initial deficit for living things to the later artifact deficit. All materials were carefully controlled to rule out potential confounding factors such as concept familiarity or age of acquisition. There was no evidence that ES's deficit for artifacts was associated with a greater loss of functional than visual information. The pattern of results are consistent with a recently proposed distributed connectionist model, in which a deficit for artifact concepts can emerge as the result of severe, general damage to semantic memory.