Cochran’s Q Test of Stimulus Overselectivity within the Verbal Repertoire of Children with Autism
Run Cochran’s Q on verbal data to get a yes-or-no verdict on overselectivity instead of trusting your gut.
01Research in Context
What this study did
Mason and colleagues built a simple recipe for spotting stimulus overselectivity in kids with autism. They show how to run Cochran’s Q test on single-subject verbal data. The paper walks you through the math and gives a clear yes-or-no answer about whether the child is really glued to only one cue.
What they found
The authors did not collect new kid data. Instead they proved the test works on sample charts. Cochran’s Q flagged when a child echoed only the first word of a phrase and ignored the rest. The test gives a p-value so you can tell real overselectivity from random noise.
How this fits with other research
Miranda et al. (2023) use a different metric to catch a different artifact: positional bias in MSWO. Both papers give you a quick number to check if stimulus control is real or just a layout trick.
Wanchisen et al. (1989) also hand clinicians a fast pre-session tool, but theirs measures reinforcer value instead of overselectivity. Together the three papers form a toolkit: pick the right quick check for the right problem.
Charman (2004) warns that language matching in preschool autism research is messy. Mason’s test answers part of that mess by giving an objective cutoff for one common language quirk.
Why it matters
You can now add Cochran’s Q to your Excel sheet after a verbal session. If the p-value is low, you know the child is stuck on one cue and you need to broaden stimulus control. No guesswork, no eyeballing. One formula, one answer, next target.
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Join Free →After the next verbal session, plug correct/incorrect by cue into Cochran’s Q in Excel; p < .05 means plan stimulus fading.
02At a glance
03Original abstract
Stimulus overselectivity remains an ill-defined concept within behavior analysis, because it can be difficult to distinguish truly restrictive stimulus control from random variation. Quantitative models of bias are useful, though perhaps limited in application. Over the last 50 years, research on stimulus overselectivity has developed a pattern of assessment and intervention repeatedly marred by methodological flaws. Here we argue that a molecular view of overselectivity, under which restricted stimulus control has heretofore been examined, is fundamentally insufficient for analyzing this phenomenon. Instead, we propose the use of the term “overselectivity” to define temporally extended patterns of restrictive stimulus control that have resulted in disproportionate populations of responding that cannot be attributed to chance alone, and highlight examples of overselectivity within the verbal behavior of children with autism spectrum disorder. Viewed as such, stimulus overselectivity lends itself to direct observation and measurement through the statistical analysis of single-subject data. In particular, we demonstrate the use of the Cochran Q test as a means of precisely quantifying stimulus overselectivity. We provide a tutorial on calculation, a model for interpretation, and a discussion of the implications for the use of Cochran’s Q by clinicians and researchers.
Perspectives on Behavior Science, 2022 · doi:10.1007/s40614-021-00315-w