Do categorical representations modulate early perceptual or later cognitive visual processing? An ERP study.

Encoding of perceptual categorical information has been observed in later cognitive processing like memory encoding and maintenance, starting around 300 ms after stimulus onset (P300). However, it remains open whether categorical information is also encoded in early perceptual processing steps (reflected in the mismatch negativity component; vMMN). The main goal of this study was to assess the influence of categorical information on both early perceptual (i.e., vMMN component) and later cognitive (i.e., P300 component) processing within one paradigm. Hence, we combined an oddball paradigm with a delayed memory task. We used five-dot patterns belonging to different categories even though categorical information is not mirrored in their physical characteristics. Distinct vMMNs were observed for patterns belonging to the same as compared to different categories, suggesting that abstract categorical information was encoded during early perceptual processing. However, inconsistent with prior studies, we observed no effect of categories on the P300, indicating no additional encoding of categorical information in later cognitive stages of processing. Our findings emphasize that the encoding of categorical information depends on specific task demands and hence is more flexible and dynamic than previously suggested.