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Numerosity estimates for attended and unattended items in visual search
Troy D Kelley1, Daniel N Cassenti2, Laura R Marusich2
1US Army Research Laboratory, Human Research and Engineering Directorate, Adelphi, MD, 20783, USA. troy.d.kelley6@mail.mil.
Attention, Perception & Psychophysics
|March 22, 2017
Summary
Participants often underestimate item counts in visual search tasks. This memory underestimation is more severe in easier searches, suggesting less attention is paid to item numbers when the search is efficient.
Area of Science:
- Cognitive Psychology
- Visual Perception
- Memory Studies
Background:
- Visual search tasks are common for studying attention and perception.
- Understanding how people remember quantities, or numerosity, is crucial for cognitive science.
Purpose of the Study:
- To investigate memory for the number of items during visual search.
- To determine how search efficiency impacts numerosity memory.
Main Methods:
- Participants performed visual search tasks with varying difficulty (feature, conjunction, spatial configuration).
- Recall of item counts and direct numerosity estimation were measured.
- Follow-up studies isolated the estimation task and examined single-recall effects.
Main Results:
- Participants consistently underestimated item counts in visual search tasks.
- Underestimation severity correlated with search efficiency, being greater in easier searches.
- Direct numerosity estimation showed underestimation, but less than in search tasks and independent of stimuli type.
Conclusions:
- Visual search efficiency influences memory encoding of item quantities.
- Lower attentional demands in efficient searches may lead to reduced encoding of distractor set numerosity.
- Underestimation is a robust phenomenon not solely due to task knowledge.
