Abstract
The current study examined long-term incidental memory for both targets and distractors in a visual search task. Participants counted the number (0–3) of targets (identified by a color and category, e.g. yellow car) present in an array containing 12 real-world objects. Search targets were changed on each search trial. In addition to the targets, the array contained color distractors, category distractors, and unrelated distractors (objects that were neither the same category nor color as the search target). Every object presented was a unique token (384 objects/participant) and appeared in only one search array. Participants were shown each of the 32 arrays twice, but the arrangement of the objects and the number of targets in the arrays was different in the two presentations. Following presentation of all of the search arrays and a filled interval of approximately 10 minutes, participants' memory was tested using a surprise token discrimination task. A target, and one color distractor, category distractor, and unrelated distractor were tested from each search array. Memory for targets was reliably better than distractors. Of most interest for this study, however, was memory for the distractor items. Color and category distractors were discriminated from foils at similar levels and both were discriminated reliably better than the unrelated distractors. We also examined the eye movements that were made during the search task and will relate these to the memory results. We conclude that visual search for real-world objects leaves a lingering memory trace of both targets and attended distractors. This trace is incidentally generated, is relatively long-lasting, and contains enough visual detail to support discrimination of a presented object from a visually similar memory foil.