Effects of orientation on the identification of simple visual patterns.

Two experiments, with 16 university students, revealed that errors of identification for alphanumeric characters increased approximately linearly with increased angular deviation from the standard upright orientation. Thus, pattern recognition does not seem to proceed via the extraction of "orientation-invariant features." It is argued that prior failures to discover systematic effects of orientation on the identification of simple patterns may have resulted from the use of RT as a dependent measure. Based on the data from Exp II, it was estimated that as little as 15 msec of processing time may have been sufficient to compensate fully for a 180° rotation of a simple pattern in the present experimental situation. Thus, RT experiments seeking effects of orientation must be designated to detect effects of smaller magnitude than may have been previously anticipated. (French abstract) (27 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)