Four experiments assessed converging aspects of four-month-old infants' perceptions of visual patterns. Results together corroborate and extend previous findings that vertical symmetry has a special status in early perceptual development and that infants can perceive pattern wholes. (Author/AS)

Evaluates the efficacy of two training procedures for eliminating selective stimulus control observed with three trainable mentally retarded children. In another experiment, improvements in stimulus control were not a function of varying degrees of difficulty between stimulus sets or of a prior history of discrimination training with the less…