title: Spatial frequency discrimination at different orientations.
abstract: Hirsch and Hylton (1984) have reported a meridional anisotropy for spatial frequency discrimination with a periodicity containing both square and hexagonal components. We measured the difference limen for spatial frequency for sine-wave gratings whose orientations varied over a 180 deg range and whose nominal spatial frequency varied between 2.5 and 10.0 c.deg.-1. Although some periodicity was evident at the lowest spatial frequency, it was not consistent between observers and it did not contain a hexagonal component. At the higher spatial frequencies there was no evidence for any meridional anisotropy.
authors.affiliation: Department of Psychology, University of St Andrews, Fife, Scotland, U.K.
authors.forename: D W
authors.initials: DW
authors.lastname: Heeley
authors.forename: B
authors.initials: B
authors.lastname: Timney
mesh_terms: D000328:Adult; D015350:Contrast Sensitivity / Q000502:physiology; D004192:Discrimination, Psychological / Q000502:physiology; D005260:Female; D005556:Form Perception / Q000502:physiology*; D006801:Humans; D010364:Pattern Recognition, Visual / Q000502:physiology*; D012399:Rotation; D012684:Sensory Thresholds / Q000502:physiology