The effect of task on object processing revealed by EEG decoding

Recent studies showed that task demand affects object representations in higher-level visual areas and beyond but not so much in earlier areas. There are, however, limitations in those studies including the relatively weak manipulation of task due to the use of familiar real-life objects, the low temporal resolution in functional magnetic resonance imaging (fMRI) and the emphasis on the amount and not the source of information carried by brain activations. In the current study, observers categorised images of artificial objects in one of two orthogonal dimensions, shape and texture, while their brain activity was recorded with electroencephalogram (EEG). Results showed that object processing along the texture dimension was affected by task demand starting from a relatively late time (320- to 370-ms time window) after image onset. The findings are consistent with the view that task exerts an effect on the later phases of object processing.