Do persons with intellectual and developmental disabilities prefer to save the best for last in an MSWO? A preliminary investigation
The last item picked in an MSWO is not always the weakest reinforcer—verify with a brief reinforcer test.
01Research in Context
What this study did
Castillo et al. (2022) watched four adults with intellectual or developmental disabilities do an MSWO. The tray held both edible and leisure items. After each pick, the team ran a short progressive-ratio test to see how hard the person would work for that same item.
They wanted to know if the last item touched was truly the least wanted. Maybe some folks were saving the best for last.
What they found
Only one of the four adults showed a clear save-the-best-for-last pattern. For the other three, the final item was not their weakest reinforcer. Pick order did not predict how hard they would work for the item.
How this fits with other research
Borrero et al. (2022) asked the same question with food-selective children. They also found just one in four kids saved the best bite for last. The mixed result repeats across two groups and two tasks.
Fritz et al. (2020) already warned that MSWO misses the true top item for about one in four clients. Castillo’s data give one reason why: last pick does not equal low value.
Conine et al. (2019) showed leisure items can rank high in MSWO. Castillo agrees—leisure sometimes outranked edibles, even when picked late.
Why it matters
Stop tossing the last-selected item into the discard pile. One in four clients may be circling back to their favorite. Run a quick reinforcer check before you label anything low preference. A two-minute progressive-ratio test saves you from weak reinforcement and wasted sessions.
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02At a glance
03Original abstract
AbstractThe multiple stimulus without replacement (MSWO) preference assessment is commonly used to identify potential reinforcers. In this arrangement, individuals can choose the order in which they consume edibles or activities. The item selected first is often designated the highest preferred, and the item selected last is often designated the least preferred. Scattered reports suggest that some individuals may save the best for last in an MSWO. Despite these reports, few systematic evaluations of “saving the best for last” in the MSWO have been conducted. We examined this phenomenon using an MSWO and progressive‐ratio‐reinforcer assessment. Evidence of “saving the best for last” was obtained for one of four individuals across assessments involving edibles and leisure activities, respectively.
Behavioral Interventions, 2022 · doi:10.1002/bin.1883