Demarcated response sequences and generalised matching.

The generalised matching law was applied for the first time to sequences of responses. Pigeons responded on dependently arranged two-operandum concurrent schedules in which all four possible two-response sequences on these operanda were demarcated and reinforced. Reinforcer rates for the sequences were varied over a wide range, including extinction. Sequences of responses, rather than individual responses, followed the generalised matching law. We compared single-sensitivity and multiple-sensitivity versions of the generalised matching law. The multiple sensitivities were not significantly different from each other, so the single-sensitivity model provided the more efficient fit. As in previous research, responding was biased against the emission of sequences that required changeovers.