Two methods for teaching simple visual discriminations to learners with severe disabilities.
Tilting the stimulus 45 degrees inside a Wisconsin box and fading to upright can rescue visual discrimination training after flat-card methods fail.
01Research in Context
What this study did
Researchers worked with adults who have severe intellectual disability. None had learned simple visual discriminations with standard teaching.
The team tilted picture cards 45 degrees inside a small Wisconsin box. They slowly moved the cards upright while praising every correct choice.
What they found
After the angled shaping, accuracy jumped to 80-100 percent. The gains showed up in the very first session.
Once the learners hit the new setup, errors dropped and stays low across days.
How this fits with other research
Barnard et al. (1977) used the same Wisconsin box, but only to test vision, not to teach. Ganz et al. (2004) turned the assessment tool into a teaching machine by adding the tilt-and-fade method.
Whiting et al. (2015) also taught fine visual discriminations to severely disabled adults, yet they used flat cards and standard prompts. Both papers report success, but the 2004 tilt method works when flat-card training has already failed.
Saunders et al. (2016) shrank fading steps to five percent and added quick step-backs. Their lab data match the 2004 idea: tiny physical changes keep errors low and learning fast.
Why it matters
If your learner is stuck at 50 percent correct with regular flash cards, tilt the target picture 45 degrees and reinforce every hit. Slowly make the card upright across trials. One session may be all you need to see the jump.
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02At a glance
03Original abstract
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.
Research in developmental disabilities, 2004 · doi:10.1016/j.ridd.2003.08.002