Neurophysiological evidence against attentional suppression as the source of the same-location cost in spatial cueing

Spatial cues that mismatch the colour of a subsequent target have been shown to slow responses to targets that share their location. The source of this 'same location cost' (SLC) is currently unknown. Two potential sources are attentional signal suppression and object-file updating. Here, we tested a direct prediction of the suppression account using data from a spatial-cueing study in which we recorded brain activity using electroencephalography (EEG), and focusing on the event-related P_D component, which is thought to index attentional signal suppression. Correlating P_D amplitude with SLC magnitude, we tested the prediction that if attentional signal suppression is the source of the SLC, then the SLC should be positively correlated with P_D amplitude. Across 48 participants, SLC and P_D magnitudes were negatively correlated, in direct contradiction to a suppression account of the SLC. These results are compatible with an object-file updating account of the SLC in which updating is facilitated by reactive suppression of the to-be-updated stimulus information.