title: Selective scanpath repetition during memory-guided visual search.
abstract: Visual search efficiency improves with repetition of a search display, yet the mechanisms behind these processing gains remain unclear. According to Scanpath Theory, memory retrieval is mediated by repetition of the pattern of eye movements or "scanpath" elicited during stimulus encoding. Using this framework, we tested the prediction that scanpath recapitulation reflects relational memory guidance during repeated search events. Younger and older subjects were instructed to find changing targets within flickering naturalistic scenes. Search efficiency (search time, number of fixations, fixation duration) and scanpath similarity (repetition) were compared across age groups for novel (V1) and repeated (V2) search events. Younger adults outperformed older adults on all efficiency measures at both V1 and V2, while the search time benefit for repeated viewing (V1-V2) did not differ by age. Fixation-binned scanpath similarity analyses revealed repetition of initial and final (but not middle) V1 fixations at V2, with older adults repeating more initial V1 fixations than young adults. In young adults only, early scanpath similarity correlated negatively with search time at test, indicating increased efficiency, whereas the similarity of V2 fixations to middle V1 fixations predicted poor search performance. We conclude that scanpath compression mediates increased search efficiency by selectively recapitulating encoding fixations that provide goal-relevant input. Extending Scanpath Theory, results suggest that scanpath repetition varies as a function of time and memory integrity.
authors: Department of Psychology, University of Toronto, Toronto, ON, CanadaM5S 3G3; Rotman Research Institute, Baycrest Health Sciences, Toronto, ON, CanadaM6A 2E1.
authors: Jordana S
authors: JS
authors: Wynn
authors: Department of Psychology, University of Toronto, Toronto, ON, CanadaM5S 3G3; Rotman Research Institute, Baycrest Health Sciences, Toronto, ON, CanadaM6A 2E1.
authors: Michael B
authors: MB
authors: Bone
authors: Department of Biology, York University , Toronto , ON , Canada M3J 1P3.
authors: Michelle C
authors: MC
authors: Dragan
authors: Department of Biology, York University, Toronto, ON, CanadaM3J 1P3; Department of Psychology, York University, Toronto, ON, CanadaM3J 1P3; Centre for Vision Research, York University, Toronto, ON, CanadaM3J 1P3.
authors: Kari L
authors: KL
authors: Hoffman
authors: Department of Psychology, University of Toronto, Toronto, ON, CanadaM5S 3G3; Rotman Research Institute, Baycrest Health Sciences, Toronto, ON, CanadaM6A 2E1.
authors: Bradley R
authors: BR
authors: Buchsbaum
authors: Department of Psychology, University of Toronto, Toronto, ON, CanadaM5S 3G3; Rotman Research Institute, Baycrest Health Sciences, Toronto, ON, CanadaM6A 2E1.
authors: Jennifer D
authors: JD
authors: Ryan
keywords: Eyetracking; relational memory; scanpath; visual search