Using Motivation Manipulation to Evaluate Request Accuracy: Comparing Percent and Cumulative Graph

The Picture Exchange Communication System (PECS) represents one of the most effective procedural outlines for teaching broad based functional communication to individuals with autism and intellectual disability (Frost & Bondy, 2002). The PECS protocol includes explicit instruction on discrimination of symbols, however individuals with vision impairment may need adaptations to learn to discriminate. An alternative method for evaluating (and subsequently teaching) discrimination is by manipulating the motivation (establishing operation; EO) for certain reinforcers. Researchers used this EO manipulation method (Gutierrez et al., 2007) to determine if the request was discriminated or non-discriminated. The procedures included providing the individual with access to two reinforcers and not the third reinforcer. Researchers then evaluated the effects of the error correction procedure used within the PECS protocol on discrimination of requests for a 10-year-old individual with autism, intellectual disability, and visual impairment (VI) on a speech generating device (SGD). To guide decision making during the study researchers graphed as a cumulative graph, showing an increase in discrimination of requests across all three responses for the participant. Results indicated that the error correction procedure was effective at increasing discriminated responses for this participant. Researchers also graphed these data as a percentage, shared with six masked researchers, and asked them to rate the functional relation outcomes for both the cumulative graph and percentage graph. The preliminary results suggest that graphing the discriminated accuracy of requesting data as a cumulative graph was the more conservative estimate of the effectiveness of this intervention.