title: Human visual search behaviour is far from ideal.
abstract: Evolutionary pressures have made foraging behaviours highly efficient in many species. Eye movements during search present a useful instance of foraging behaviour in humans. We tested the efficiency of eye movements during search using homogeneous and heterogeneous arrays of line segments. The search target is visible in the periphery on the homogeneous array, but requires central vision to be detected on the heterogeneous array. For a compound search array that is heterogeneous on one side and homogeneous on the other, eye movements should be directed only to the heterogeneous side. Instead, participants made many fixations on the homogeneous side. By comparing search of compound arrays to an estimate of search performance based on uniform arrays, we isolate two contributions to search inefficiency. First, participants make superfluous fixations, sacrificing speed for a perceived (but not actual) gain in response certainty. Second, participants fixate the homogeneous side even more frequently than predicted by inefficient search of uniform arrays, suggesting they also fail to direct fixations to locations that yield the most new information.
authors.affiliation: Department of Psychology, University of Aberdeen, Room T32, William Guild Building, King's College, Aberdeen, UK a.nowakowska@abdn.ac.uk.
authors.forename: Anna
authors.identifier: 0000-0002-0787-4726
authors.initials: A
authors.lastname: Nowakowska
authors.affiliation: Department of Psychology, University of Aberdeen, Room T32, William Guild Building, King's College, Aberdeen, UK.|Department of Psychology, University of Essex, Colchester, UK.
authors.forename: Alasdair D F
authors.initials: AD
authors.lastname: Clarke
authors.affiliation: Department of Psychology, University of Aberdeen, Room T32, William Guild Building, King's College, Aberdeen, UK.
authors.forename: Amelia R
authors.initials: AR
authors.lastname: Hunt
mesh_terms: D005075:Biological Evolution; D005133:Eye Movements; D005403:Fixation, Ocular; D006801:Humans; D010775:Photic Stimulation; D014785:Vision, Ocular
keywords: eye movements; optimal behaviour; visual search