Object-based perceptual grouping affects negative priming

In 5 experiments the authors examine the role of object-based grouping on negative priming. The experiments used a letter-matching task with multiple letters presented in temporally separated prime and probe displays. On mismatch trials, distracter letters in primes were repeated as targets in probes, or distracter and target letters were completely different. Negative priming was shown by slowed responses when distracters were repeated as targets relative to when the stimuli differed. This occurred both when only letters were presented (Experiments 1 and 4) and when letters were surrounded by boxes (Experiment 5). Experiments 2, 3, and 4 showed that negative priming was affected by the grouping of target and distracter letters in prime displays. Negative priming was reduced when 1 of the distractor letters was placed in the target box and 1 was left outside the box; facilitatory priming was observed when both distracter letters appeared in the target box. The data were accounted for in terms of there being (a) object-based competition for visual selection, (b) inhibition of distracter objects that compete for selection with target objects, and (c) activation or inhibition of the identities of all component elements within target or distracter objects.