Evaluating the Number of Sessions in Multiple Stimulus Without Replacement Preference Assessments for Social Interaction

The multiple stimulus without replacement preference assessment (MSWO) has frequently been evaluated or used in research. Some researchers have evaluated how the number of MSWO sessions used to obtain a hierarchy of preference can impact the assessment's outcomes. To date, no researchers have conducted such evaluations with MSWOs for social stimuli or with a reinforcer assessment including all of the same stimuli as a point of comparison. In the current study, we used previously published data from MSWOs for social stimuli to compare one-, two-, and three-session MSWOs with four-session MSWOs and a progressive-ratio reinforcer assessment. Results indicated that MSWOs consisting of one, two, three, and four sessions produced hierarchies that were positively correlated with reinforcer assessment hierarchies and identified highly preferred stimuli that functioned as reinforcers. Including more sessions did not improve median correlation coefficients or the likelihood of identifying reinforcers. Results generated by comparing the one-, two-, and three-session MSWO hierarchies with the four-session hierarchy did not correspond with results generated by comparison with the reinforcer assessment hierarchy. Implications for clinical use of, and future research on, MSWOs are discussed.