Reducing overselective attention to compound visual cues with extended training in adolescents with severe mental retardation

Visual discrimination learning with an iPad-equipped apparatus

Visual discrimination tasks are commonly used to assess visual learning and memory in non-human animals. The current experiments explored the suitability of an iPad (Apple, Cupertino, California), as a low-cost alternative touchscreen for visual discrimination tasks. In Experiment 1, rats were trained with patterned black-and-white stimuli in a successive non-match to sample procedure. Rats successfully interacted with the iPad but failed to learn to withhold responding on trials in which the sample matched the comparison. Experiment 2 used the same patterned stimuli, but the procedure was simplified to a successive discrimination procedure and we explored the use of procedures known to facilitate discrimination learning. Rats that received training with differential outcomes and a differential reinforcement of other behavior schedule successfully acquired the task. In Experiment 3, the same rats were tested in a simultaneous discrimination task and we explored the use of a correction and non-correction method during acquisition. Rats that failed to learn the discrimination in the previous experiment, improved while trained with the correction method. These experiments support the use of the iPad in visual discrimination tasks and inform future studies investigating learning and memory within a touchscreen-equipped (iPad or other) apparatus.

Effects of schedule of reinforcement on over-selectivity

Stimulus over-selectivity refers to behavior being controlled by one element of the environment at the expense of other equally salient aspects of the environment. Four experiments trained and tested non-clinical participants on a two-component trial-and-error discrimination task to explore the effects of different training regimes on over-selectivity. Experiments 1 and 2 revealed no differentiation between partial reinforcement (PR) and continuous reinforcement (CRF) on over-selectivity. Experiments 3 and 4 both found that a change in reinforcement (from CRF to PR in Experiment 3, and from PR to CRF in Experiment 4) did not reduce levels of over-selectivity, but rather continuing training with the same contingency (either CRF or PR) did reduce over-selectivity. The results support assumptions made by the comparator hypothesis, extending the growing body of literature explaining over-selectivity as a post-acquisition, rather than attention, failure.

Touchscreen-enhanced visual learning in rats

The efficiency of traditional levers and of modern touchscreen technology for training rats on a computerized visual discrimination was studied in a series of observations. When compared with a lever-based discrimination procedure, the use of touchscreens supported the faster development of signal tracking behavior and acquisition of a two-stimulus simultaneous visual discrimination. It did not affect the final level of accuracy. Factors related to spatial proximity of the responses with the stimuli, sign-tracking, and increased ease of touchscreen motor responses were suggested as possible reasons for the touchscreen training advantage. This increased efficiency allows large numbers of animals to be tested quickly, a necessary requirement for studies involving genetic and physiological interventions.

Assessing visual attention in young children and adolescents with severe mental retardation utilizing conditional-discrimination tasks and multiple testing procedures

To effectively reduce overselective attention, a fine-grained analysis of the control exhibited by compound training cues is first needed. Computer software was developed in this study to administer two different stimulus control-testing procedures to assess how three young children of normal development and three adolescents with severe mental retardation attended to stimulus compounds when conditional-discrimination tasks were provided. One test assessed stimulus control by determining response accuracy for each component of the S+ compounds. The other testing procedure measured the response topographies of the compound stimuli using a touch screen attached to a computer monitor screen. After pretraining each stimulus component, all three children attended simultaneously to two elements in a conditional-discrimination task with few errors occurring. The adolescents with mental retardation eventually attended to both elements simultaneously but required more pretraining and exposure to the conditional-discrimination tasks before simultaneous attention occurred. Since the adolescents with severe mental retardation learned to simultaneously attend to multiple cues in the conditional-discrimination tasks, this demonstrated that restricted attention is not an unmodifiable perceptual characteristic among individuals with developmental disabilities. Recording response topographies with a touch screen was also discovered to be a sensitive measure of stimulus preferences for both groups. Utilizing touch-screen technology may prove to be critical for accurately identifying stimulus preferences and contribute to the understanding and treatment of overselective attention in students with attentional deficits.