“…This orientation anisotropy is evident at threshold, and also aVects perceived depth magnitude and the time required for depth to be perceived (Bradshaw & Rogers, 1999;Bradshaw, Hibbard, & Gillam, 2002;Hibbard, Bradshaw, Langley, & Rogers, 2002;Mitchison & McKee, 1990;Wallach & Bacon, 1976). Similarly, for a monocular observer making horizontal head movements while viewing a surface shape deWned by the motion parallax arising from these head movements, a similar orientation anisotropy exists which aVects threshold perception and perceived depth magnitude (Allison, Rogers, & Bradshaw, 1978;Cornilleau-Peres & Droulez, 1993;De Vries & Werkhoven, 1995;Rogers & Graham, 1983).…”