| Abstract: | Ss were required to determine whether dot patterns were symmetric. Cuing the Ss in advance about the orientation of the axis of symmetry produced a substantial speedup in performance (Exps 1 and 3) and an increase in accuracy with brief displays (Exp 2). The effects appeared roughly additive, with an overall advantage for vertical symmetry; thus, the vertical axis effect is not due to a tendency to prepare for the vertical axis. The cuing advantage was found to depend upon the S's knowing in advance the spatial location as well as orientation of the frame of reference (Exp 4). Exp 5 provided evidence that the frame of reference responsible for these effects is the same as the one that determines shape perception: Ss viewed displays containing a letter (at an unpredictable orientation) and a dot pattern, rapidly naming the letter and then determining whether the dots were symmetric about a prespecific axis. When the top–bottom axis of the letter was oriented the same way as the axis of symmetry for the dots, symmetry judgments were significantly more accurate. Results suggest a single frame of reference for both types of judgment. A theory of visual symmetry is proposed to account for the phenomena and characterize their relation to "mental rotation" effects. (PsycINFO Database Record (c) 2010 APA, all rights reserved) |
