Two normal and two mentally retarded children were trained to earn pennies by pressing a key according to a multiple variable-interval extinction schedule of reinforcement. Retarded children differed from normal children by producing more positive than negative discriminative stimuli. (Author/DB)

Objective: To examine the ability of the flicker task to demonstrate greater utility in discriminating performance in young adults with and without ADHD compared to the Conners' CPT (CCPT). Method: Flicker task and CCPT performance were compared between an ADHD (n = 28) and control (n = 30) group of college students. Results: This study replicated…

Compared tendencies of adults and rhesus monkeys to escape adaptively when uncertain. In a visual discrimination task using a threshold paradigm, humans and monkeys escaped trials in which they were uncertain of the stimulus. In a similar task with constant stimuli, some humans escaped adaptively, but one escaped infrequently and non-optimally,…

Visual persistence was investigated in adults with and without dyslexia in order to determine whether dyslexic adults demonstrate problems similar to those found in childhood dyslexia. Results showed that sensitivity of dyslexic adults was impaired when parts of a test stimulus were presented to adjacent retinal areas, suggesting that under…

This study explored whether visual discrimination problems impair achievement in children with and without learning disabilities. Children (N=66) with learning disabilities were tested for visual discrimination problems, tracked throughout elementary school, and compared to a normally achieving sample. Results indicated lower reading and general…

Methods to automatically convert graphics into tactile representations have been recently investigated, creating either raised-line or relief images. In particular, we briefly review one raised-line method where important features are emphasized. This paper focuses primarily on the effects of such emphasis and on comparing both raised-line and…

Attention-deficit/hyperactivity disorder (ADHD) is associated with unexplained impairments on speeded naming of coloured stimuli. These deficits may reflect hypofunctioning retinal dopaminergic mechanisms impairing particularly blue-yellow colour discrimination. Colour perception and rapid colour naming ability were investigated in 14 children…

This report summarizes the results of more than 10,000 individual judgments, carried out in five related studies, all concerned with perceived reading efforts of text on visual displays and printouts. Students and personnel in the Department of Computer Science at the University of Stockholm served as study subjects. In experiments in which…

Thirty subjects were presented with a visual form discrimination task requiring them to match Roman letters when a variety of transformations were held constant. They were given massed practice across four blocks of eight stimuli. Results of a repeated measures analysis of variance showed support for the distinctive features hypothesis. (JC)

The efficiency of several visual and auditory predictors of the Metropolitan Readiness Test was examined utilizing 106 grade 1 subjects considered by their teachers to show learning difficulties. (Author/JC)

Meaningful visual experience requires computations that identify objects as the same persisting individuals over time, motion, occlusion, and featural change. This article explores these computations in the tunnel effect: When an object moves behind an occluder, and then an object later emerges following a consistent trajectory, observers…

Reports on three experiments that investigated why young children's perceptions of bimodal speech are less influenced by the visual component of speech than adults' perceptions are. Results argue in favor of the explanation that children are poorer lipreaders than adults. (HOD)

Verbal self-instruction was employed in training impulsive first-grade children to perform visual discrimination matching tasks. Posttests, following the four training conditions, showed that while strategy training increased latency, self verbalization both increased latency and reduced errors. (Author/DEP)

Self-recognition abilities were measured using an optical system and a psychological scaling procedure that results in a recognition threshold. Subjects were 30 mentally retarded adolescents and 30 normal college freshmen. (Author/CM)