Biomedical subjects

Richard B Graff

Publications and source records attributed to Richard B Graff.

4 recordsLinked to original sources

PubMed2006

The impact of high- and low-preference stimuli on vocational and academic performances of youths with severe disabilities.

Pictorial and tangible paired-stimulus preference assessments were compared with 4 adolescents with developmental disabilities. In the tangible assessment, two stimuli were placed in front of the participant on each trial; in the pictorial assessment, two line drawings were placed in front of the participant on each trial. Approach responses were recorded for each assessment. The assessments generated similar preference hierarchies for all participants. Reinforcer assessments confirmed that response rates were higher when access to high-preference items was available than when low-preference items were available. Implications for assessing preferences and selecting items to be used in training programs are discussed.

Achievement↗

PubMed2005

Assessing object-to-picture and picture-to-object matching as prerequisite skills for pictorial preference assessments.

Tangible and pictorial paired-stimulus (PPS) preference assessments were compared for 6 individuals with developmental disabilities. During tangible and PPS assessments, two edible items or photographs were presented on each trial, respectively, and approach responses were recorded. Both assessments yielded similar preference hierarchies for 3 participants who could match pictures and objects but different hierarchies for 3 participants who could not. Reinforcer assessments verified that items identified as high preference on PPS assessments functioned as reinforcers only for participants with matching skills.

Adolescent↗

PubMed2003

Using pictures to assess reinforcers in individuals with developmental disabilities.

Tangible preference assessments were compared with pictorial preference assessments for 4 individuals with developmental disabilities. In the tangible assessment, on each trial two stimuli were selected and placed in front of the participant, who approached one. In the pictorial assessment, on each trial two line drawings were placed in front of the participant, who pointed to one. For both assessments, the percentage of opportunities each stimulus was approached or touched was calculated, and hierarchies of preferred items were developed. The two assessments yielded similar preference hierarchies for 3 of 4 participants. Reinforcer assessments using a simple free operant response confirmed that items identified as highly preferred on tangible and pictorial assessments functioned as reinforcers.

Adolescent↗

PubMedDate not supplied

Two methods for teaching simple visual discriminations to learners with severe disabilities.

Simple discriminations are involved in many functional skills; additionally, they are components of conditional discriminations (identity and arbitrary matching-to-sample), which are involved in a wide array of other important performances. Many individuals with severe disabilities have difficulty acquiring simple discriminations with standard training procedures, such as differential reinforcement. Errorless training methods may be more effective with this population. We used multiple-probe designs to compare two potentially errorless procedures for teaching simple discriminations among three pairs of photos of preferred items (S+) and colored rectangles (S-) to three youths with severe disabilities. In Experiment 1, baseline trials conducted with differential reinforcement yielded near-chance performances on all stimulus sets. A progressive delayed prompt training procedure was then implemented, with stimuli presented flat on the tabletop for one participant and at a 45 degrees angle to the tabletop for the other participants. After 120 teaching trials, accuracy remained near chance. Next, a stimulus control shaping procedure was implemented using an adapted Wisconsin General Test Apparatus (WGTA), with stimuli at a 45 degrees angle to the tabletop. Accuracy increased when this procedure was implemented with each stimulus pair in succession. In Experiment 2, for the participant whose stimuli were presented flat on the tabletop during the progressive delayed prompt training procedure, baseline trials were presented on the WGTA as at the end of Experiment 1, with differential reinforcement; accuracy remained high. On probe trials with stimuli placed flat on the tabletop, accuracy decreased to near-chance levels, indicating that the orientation of the stimulus array was a controlling variable.

Adult↗