When is it time to move to the next raspberry bush? Foraging rules in human visual search

• Published in: Journal of vision (Charlottesville, Va.) Vol. 13; no. 3; p. 10
• Main Author: Wolfe, Jeremy M
• Format: Journal Article
• Language: English
• Published: United States The Association for Research in Vision and Ophthalmology 01-01-2013
• Subjects: Attention; Humans; Memory, Short-Term - physiology; Pattern Recognition, Visual - physiology; Task Performance and Analysis; visual attention; foraging; marginal value theorem; visual search; decision rules
• ISSN: 1534-7362; 1534-7362
• DOI: 10.1167/13.3.10

Animals, including humans, engage in many forms of foraging behavior in which resources are collected from the world. This paper examines human foraging in a visual search context. A real-world analog would be berry picking. The selection of individual berries is not the most interesting problem in such a task. Of more interest is when does a forager leave one patch or berry bush for the next one? Marginal Value Theorem (MVT; Charnov, 1976) predicts that observers will leave a patch when the instantaneous yield from that patch drops below the average yield from the entire "field." Experiments 1, 2, 3, and 4 show that MVT gives a good description of human behavior for roughly uniform collections of patches. Experiments 5 and 6 show strong departures from MVT when patch quality varies and when visual information is degraded.