Goals and challenges pertaining to infant sensory and perceptual development are discussed. It is suggested that the inability of researchers to think and talk wisely about "partial accomplishments" in development creates a barrier in developmental research. Conceptual schemes are needed to accommodate these partial accomplishments. Three major…

Discrepant effects of drugs on behavior maintained by temporal-discrimination procedures make conclusive statements about the neuropharmacological bases of timing difficult. The current experiment examined the possible contribution of a general, drug-induced disruption of stimulus control. Four pigeons responded on a three-component multiple…

To measure how the complexity of a television image affects the viewer's ability to identify or recognize visual details within the image, two coders rated the form complexity of 30 public service announcements, basing their evaluation on the familiarity of the images in the announcements, the rate at which they presented new information, and the…

Two techniques were used to modify an impulsive conceptual tempo on a visual discrimination task. The subjects were 42 first grade white children who had previously been classified as impulsive or near-impulsive on the Matching Familiar Figures Test given to 82 children. These subjects, who had scored above the median on errors and below the…

Two experiments examined pigeons' generalization to intermediate forms following training of concept discriminations. In Experiment 1, the training stimuli were sets of images of dogs and cats, and the transfer stimuli were head/body chimeras, which humans tend to categorize more readily in terms of the head part rather than the body part. In…