title: Winding one's ps and qs: mental rotation and mirror-image discrimination.
abstract: Subjects were timed as they made judgments about ps and qs (also interpretable as ds and bs) in different angular orientations. Whether these judgments were left-right mirror-image discriminations (b vs. d or p vs. q) or up-down mirror-image discriminations (b vs. p or d vs. q), the subjects' reaction times increased sharply with the angular departure of each letter from its designated normal upright orientation, a fact implying mental rotation. This was so whether the subjects responded with the letter labels themselves (e.g., b vs. d) or with the labels left versus right or top versus bottom. It was again the case when the letters were replaced by nonletter forms, in which event there was also a left visual-field advantage in reaction time. This study is therefore the first to demonstrate a mental-rotation strategy when the canonical forms to be discriminated are up-down mirror images as well as when they are left-right mirror images. In both cases, however, the task requires the ability to tell left from right, and we suggest that this is the critical ingredient that induces mental rotation.
mesh_terms: D000328:Adult; D004292:Dominance, Cerebral; D005260:Female; D005556:Form Perception / Q000502:physiology*; D006801:Humans; D008297:Male; D009949:Orientation; D010364:Pattern Recognition, Visual / Q000502:physiology*; D011930:Reaction Time; D012399:Rotation; D014794:Visual Fields