第46回心理学研究室セミナー(土井隆弘先生) 2020年1月8日開催


文学部心理学研究室では、第46回心理学研究室セミナーとして以下のような講演会を開催しますので、ふるってご参加下さい。なお、講演内容は大学院生以上を想定しております。


第46回心理学研究室セミナー

日時:2020年1月8日(水) 午後5時から

場所:法文1号館2階 214教室

【講師】 土井隆弘先生 (ペンシルベニア大学)


【演題】 「Suboptimal visual averaging reveals compulsory, nonlinear mechanisms in human vision」

【要旨】

How humans integrate ambiguous and conflicting signals has been a focus of perception and decision-making research for decades. Identifying the source of suboptimality can reveal the information integration strategy used by the nervous system to solve ecologically relevant tasks in natural environments. In this study, we examined visual spatial averaging, a fundamental process underlying the transformation of noisy local signals into a more stable global estimate. A novel paradigm was used to measure the degree of human suboptimality against the ideal observer. In this talk, first I will establish that human visual averaging is suboptimal in both luminance and stereoscopic domains: the visual system does not faithfully compute the average of a spatially varied stimulus, especially when spatial variability is large. Then, I will present a series of experiments designed to identify the source of suboptimality. Our results indicate two kinds of nonlinear mechanisms at work: one is related to the down-weighting of outlier samples and the other is the spatial interaction among nearby signals within a stimulus. These compulsory nonlinear mechanisms, while suboptimal in our laboratory task, may reflect an information integration strategy that improves performance in more natural contexts cluttered with object boundaries and illumination variation.