Lalchandani, R, Loula, F & Carrasco, M (2003). Temporal dynamics of negative priming. Vision Sciences Society. Sarasota, FL.

Abstract
Negative Priming refers to a slowed response to visual stimuli that is initially ignored and later presented as the target. This decrement in performance is due to the interference of the irrelevant stimulus on the processing of the relevant stimulus. It is unclear whether this interference in processing is of greater importance during the initial presentation of the irrelevant information in the prime display or during the later presentation of the relevant information in the probe display. In this experiment we used a mask to manipulate the processing time for the target following both the prime and the probe displays. Observers viewed a series of overlapping novel shapes (green target overlapping a red distracter) presented for 200 ms either to the left or right of fixation and determined whether the target was symmetrical or asymmetrical. Following a negative priming paradigm, in half of the trials (experimental condition) the red overlapping distractor reappeared as the green target (maintaining shape). In the remaining half of the trials (control condition) no shapes were repeated. A 100 ms mask interrupted processing at different time lags (0, 300, 500 ms). Reaction times and accuracy were recorded. We found that: (a) when the prime was masked either immediately or at 500 ms no negative priming emerged regardless of the time at which the mask followed the probe; (b) when the mask appeared 300 ms after the prime negative priming emerged for the probes that were masked either at 300 or 500 ms. These results suggest that the processing time of the prime is critical for negative priming to occur. When the mask appears immediately after the prime its representation may not be well established and thus need not be inhibited. In contrast, when the mask interrupts processing at 300 ms the representation is well established so that it needs to be inhibited for the probe to be processed efficiently.