Clark, H. J. (1968). Random shape recognition at brief exposure durations. Psychonomic Science, 12(6), 245-246.

Two groups of Ss were tested in forced-choice recognition test for memory of 20 random shapes having two levels of complexity and two levels of association value (A). One group viewed each shape for 0.25 sec. and the other group viewed each shape for 0.50 sec. Shapes of high A were recognized more accurately (p < .01) than shapes of low A while the effects of complexity and exposure duration were statistically insignificant. Consideration of the characteristics of the distractor shapes paired with the observed shapes during the forced-choice recognition test suggested that they may also have influenced recognition accuracy. If simple and complex distractor shapes are not equated for amounts of stimulus confusion introduced into the recognition test, that test may be biased agains simple shapes.