Abstract
When the Necker cube was presented at 109 exposures/min. and 46 exposures/min. the median reversal rates were 41.0 and 0.0, respectively. A variety of figures consisting of parts of the Necker cube were interpolated between successive exposures of the test Necker cube. Some of these figures proved to be effective interpolators, i.e., they shifted the reversal rate toward 14.0, the median for continuous viewing. These figures had in common a minimum linear length. Dispensable characteristics of the effective interpolated figure included intersecting lines, oblique lines, and the feature of reversibility.