Abstract
When searching for two or more targets, people are more likely to miss a second target after having found a first one (a subsequent search miss). This may be due to a depletion of cognitive resources from tracking the location of the first target. Given that tracking moving objects is resource-demanding, would finding a moving target further increase our chances of missing a subsequent one? This is an important question, as many real-world scenarios involve searching for moving objects (e.g., police searching for suspects in a crowd). Participants searched displays containing one or more targets hidden among a number of distractors and clicked on any targets they found. For some participants, targets and distractors moved randomly throughout the display. For others, targets and distractors always remained stationary. Critically, the probability of missing a second target increased by 50% in moving compared to non-moving displays. In a second experiment, we assessed whether this effect was due to participants allocating resources to tracking the first target. Participants searched the same moving or non-moving displays, but for some participants, any found targets were highlighted in a different color to facilitate tracking them. When found targets were not highlighted, the probability of missing a second target increased by 31% in moving compared to non-moving displays. However, when found targets were highlighted, the probability of missing a second target only increased by 3%. Together, these results suggest that our likelihood of missing a second target after finding a first one increases in dynamic search environments. This is likely due to the increased difficulty that comes from tracking the location of the first found target. More broadly, these results suggest that searching for multiple targets is demanding in terms of cognitive resources, and that subsequent search misses occur when these resources are depleted.
Meeting abstract presented at VSS 2017