The target effect: Visual memory for unnamed search targets

Abstract

Search targets are typically remembered much better than other objects even when they are viewed for less time. However, targets have two advantages that other objects in search displays do not have: They are identified categorically before the search, and finding them represents the goal of the search task. The current research investigated the contributions of both of these types of information to the long-term visual memory representations of search targets. Participants completed either a predefined search or a unique-object search in which targets were not defined with specific categorical labels before searching. Subsequent memory results indicated that search target memory was better than distractor memory even following ambiguously defined searches and when the distractors were viewed significantly longer. Superior target memory appears to result from a qualitatively different representation from those of distractor objects, indicating that decision processes influence visual memory.

Keywords:

• Visual search
• Visual memory
• Target memory
• Eye movements

Mark D. Thomas is now at the University of Wisconsin–Whitewater.

Notes

¹Although our primary concern was target memory, we also examined distractor memory differences between PT and UO searches. For all distractor types, memory for the UO distractors exceeded that of the PT distractors [all Fs(1, 60) ≥ 4.13, .065 ≤ η²_p ≤ .099, ps ≤ .042]. The distractor memory differences between the two conditions can probably be attributed to search time differences. Overall, UO searches averaged more than twice as long as PT searches. The greater search time probably allowed for more fixation time on the UO distractor objects improving distractor memory accuracy (see Williams, 2010b, for discussion of predictions of memory given additional distractor viewing).