title: Spatial-interval discrimination in two-dimensions.
abstract: This study is concerned with the precision of spatial-interval discrimination when the stimulus is varied in two-dimensions rather than one-dimension. For the two-dimensional task, observers were required to judge the centrality of a dot within a circle. Similar measurements were made in a one-dimensional task, i.e. the test dot was displaced only along one meridian, and the results were compared. This study shows that thresholds for the two-dimensional task are approx. square root of 2 times the threshold of the one-dimensional task when the observer's task is to simply detect an offset in both one- and two-dimensional conditions. However, thresholds are about a factor of two higher for the two-dimensional task if the observer is required to label the direction of offset.
authors.affiliation: University of Houston, College of Optometry, TX 77204-6052.
authors.forename: B C
authors.initials: BC
authors.lastname: Jiang
authors.forename: D M
authors.initials: DM
authors.lastname: Levi
mesh_terms: D004192:Discrimination, Psychological / Q000502:physiology*; D006801:Humans; D011601:Psychophysics; D012684:Sensory Thresholds / Q000502:physiology; D013028:Space Perception / Q000502:physiology*; D014792:Visual Acuity / Q000502:physiology