On Response Strength and the Concept of Response Classes
Keep response strength in your language, but always map the full response class and competing contingencies.
01Research in Context
What this study did
Palmer (2021) wrote a theory paper. He asked: should we still talk about response strength?
He said yes, but only if we define it clearly. He also tightened the definition of response class and functional class.
What they found
The paper keeps response strength in our toolbox. It warns us to include competing behaviors. It says strength is more than nerve firing.
How this fits with other research
Cudré-Mauroux (2010) seemed to disagree. That review said conditioned reinforcers might not strengthen behavior at all. Palmer (2021) answers: strength is still useful, just broader than reinforcer count.
Roth et al. (2025) shows the idea in action. They treated vomiting and other attention behaviors as one response class. Their case study proves the refined definition works in clinic.
Abrahamsen et al. (1990) gave early lab data. They showed that ratio size and reinforcement rate change how hard a rat presses. Palmer uses these facts to ground his new definition.
Why it matters
You can keep saying response strength when you write reports. Just check what other behaviors compete for the same reinforcer. Use Roth’s tip: list the whole response class before you treat one topography.
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02At a glance
03Original abstract
Simon et al. (2020) argue that the concept of response strength is unnecessary and potentially harmful in that it misdirects behavior analysts away from more fruitful molar analyses. I defend the term as a useful summary of the effects of reinforcement and point particularly to its utility as an interpretive tool in making sense of complex human behavior under multiple control. Physiological data suggest that the concept is not an explanatory fiction, but strength cannot be simply equated with neural conductivity; interaction with competing behaviors must be considered as well. Decisions about appropriate scales of analysis require a clarification of terms. I suggest defining behavior solely in terms of its sensitivity to behavioral principles, irrespective of locus, magnitude, or observability. Furthermore, I suggest that the term response class be restricted to units that vary together in probability in part because of overlapping topography. In contrast, functional classes are united by common consequences; they vary together with respect to motivational variables but need not share formal properties and need not covary with acquisition and extinction contingencies.
Perspectives on Behavior Science, 2021 · doi:10.1007/s40614-021-00305-y