The concept of strength in the analysis of verbal behavior.

Gillberg (1993) read every page of Skinner’s Verbal Behavior. The goal was to see when Skinner actually uses the word ‘strength.’

The paper is a textual analysis, not an experiment. It counts and sorts each time ‘strength’ appears.

Skinner almost never says ‘strength’ for single, easy-to-see responses. He saves the word for two messy cases.

Case one: many variables push on the same word at once. Case two: the verbal act is private, so you can’t watch it.

Bottom line: ‘strength’ is a last-resort label. Use it only when you can’t point to a clear, single cause.

Stemmer (1992) came just before and showed how generic extensions help listeners ‘get it’ even when words are fuzzy. Gillberg (1993) adds: if the fuzz comes from many controllers, call it ‘strength’ and move on.

Guerin (1994) next year says attitudes are just verbal operants under social control. That view keeps all causes outside the skin, so ‘strength’ is rarely needed—exactly what Gillberg (1993) advises.

Sponheim (1996) later extends the same careful language rule to measurement itself. Data are verbal stimuli; call their power ‘intraverbal control,’ not ‘strength,’ unless many mixed cues are in play.

Together the four papers form a chain: pick exact terms first, and reserve ‘strength’ for the leftover tangles.

In your session notes, swap ‘mand strength is low’ for ‘no EO present, no reinforcement history observed.’ The crisper wording tells the next therapist exactly what to test. Save ‘strength’ for moments like a child who echoes, mands, and tacts the same word all at once—then label it ‘high strength under multiple control’ and probe which variables you can separate.