PLOTTING AND ANALYZING CUMULATIVE RESPONSE CURVES IN OPERANT CONDITIONING STUDIES1

Because the response and time scales used in plotting cumulative response curves are often poorly selected, ineffective displays often result. The visual cue of a response rate change is the difference, Δθ, between the angles, θ1 and θ2, representing the two rates, R1 and R2. These variables are related by: tan θ2 = R2/R1 tan θ1. For a given rate change, the value of θ1, namely, Mθ1, that yields the maximum value of Δθ, namely, Δθmax, is given by Mθ1 = arc sin. Ideally, the initial response rate should be represented by the Mθ1 appropriate for a given rate change. Because of practical considerations, however, some compromises with the ideal are allowable. Included in the discussion are (a) steps required to select appropriate response and time scales, with examples, and (b) guideposts for evaluating rate changes by means of angular changes.