Detection of Motion-defined Forms by Individuals with Mental Retardation and Autism: Evidence of Modifiability

Eight individuals with mental retardation and autism and 16 individuals without mental retardation or autism were studied with regard to their ability to detect the presence or absence of a form in a random-dot kinematogram (RDK). Those individuals that failed to demonstrate criterion performance (i.e., 85% correct) with the initial assessment (i.e., 50% density, 100% temporal correlation of target elements) were provided with a novel binary training procedure. The procedure involved response-based training in conjunction with a procedure in which the density of the surround in the visual array was incrementally increased. Subsequent to training, all subjects with mental retardation and autism successfully met criterion with the initial stimulus and proceeded to demonstrate performance comparable to individuals without mental retardation. The presence and generalization of training effects suggests that initial failures on such “preattentional” detection tasks may be due, at least in part, to post-perceptual factors.