Manipulating color and other visual information influences picture naming at different levels of processing: evidence from Alzheimer subjects and normal controls

There is now a large body of evidence suggesting that color and photographic detail exert an effect on recognition of visually presented familiar objects. However, an unresolved issue is whether these factors act at the visual, the semantic or lexical level of the recognition process. In the present study, we investigated this issue by having Alzheimer's patients and normal controls name figures in four presentation displays (PDs): black and white and colored line drawings, and black and white and color photographs. We also collected image agreement (IA) values (a measure of the extent to which the presented figure matches the stored structural description of the depicted object) for the same stimuli and compared the effects of PD on IA and naming accuracy. Our results suggest that color acts on naming by assisting semantic processing of the stimuli to be recognized; by contrast, photographic detail seems to benefit visual processing by increasing IA.