P2-2: Effects of Color Preview History on Inter-Trial Inhibition of Selective Attention

The distractor previewing effect (DPE) refers to the phenomenon that search times for target colors that were previewed (target preview or TP) in a preceding target-absent display (TAD) are slower than for distractor colors that were previewed (distractor preview, DP) in the TAD. The DPE is explained as attentional inhibition for the features associated with TADs. We investigated history effects of this inter-trial inhibition by manipulating color preview history and examined the DPE using RT and the N2pc (an electrophysiological index of attention allocation). The TAD, ranging from 0 to 2, was followed by a target-present display in which participants responded to the shape of a color-oddball. For the 2TADs, a single color (red or green) was repeated twice or the two colors were alternated, resulting in TTP, DDP, TDP, and DTP conditions depending on which color (target or distractor) in the search display was previewed. The 1TADs resulted in the TP and the DP, and the 0TADs comprised immediate search trials. RTs showed: (a) the TP was slower than the DP; (b) the TTP and DDP were slowest and fastest, respectively, and between these the DTP was slower than the TDP; (c) the TTP-DDP difference doubled the TP-DP difference due to the RT increase in the TTP. The conditions with slower RTs corresponded with late onsets and smaller amplitudes in the N2pc. These results suggest that effects of color preview history are cumulative with weight on more recent events and support the idea of inter-trial inhibition of target selection