Assessing Discrimination Skills of Individuals with Developmental and Physical Disabilities Using Microswitches

The Assessment of Basic Learning Abilities (ABLA) measures the ability of a person with developmental disabilities to learn basic discrimination tasks. Its ease of use and strong psychometric properties make the ABLA a valuable tool for research and training. However, the ABLA requires a person to respond on each trial by grasping and placing an object into a container, which may not be possible for persons with limited hand function or arm movements. We modified the procedure by replacing the original response with switch-pressing to assess individuals who were not testable previously due to physical difficulties. Three females with developmental and physical disabilities participated. In Phase 1, all three participants demonstrated that their switch-pressing response was sensitive to positive reinforcement in an ABAB design. In Phase 2, baseline assessments showed that participants were unable to perform the ABLA 2-choice discrimination tasks. Switch pressing was introduced in a multiple-baseline design across four tasks and participants responded consistently on nearly all trials. Moreover, all participants performed the visual-position discrimination task at high accuracy using the switch-pressing response.