Implicit alternatives to a stimulus, difficulty of encoding, and schema-plus-correction representation.

Garner has hypothesized that a S exposed to a stimulus infers alternatives to it. Data are reviewed which establish a close correlation between the number of implicit alternatives to a stimulus and the difficulty of encoding that stimulus. This correlation provides a datum to be explained and suggests that the identification of specific implicit alternatives may provide clues to the encoding process. For dot patterns of a certain kind, it has been suggested that the rotations and reflections of a stimulus are its only alternatives, but a close examination of certain data indicates that, for many of these patterns, the alternatives also include one or more other patterns which differ from the stimulus only in the position of a single dot and which locate that dot in a position where it is more predictable from the other dots. It is suggested that the one-dot-different alternatives represent schemas used in schema-plus-correction encoding.