Sequences of Spaced Responses: Behavioral Units and the Role of Contiguity

Abstract

Sequences of temporally spaced responses were reinforced to investigate the effects of delay of reinforcement on the formation of functional behavioral units. In Experiment 1, rats' two- and three-response demarcated sequences of left and right lever presses were reinforced such that different response distributions would occur depending on whether the sequences themselves or individual responses were functional units. The matching law could thus be obeyed either by individual responses or by sequences, but not by both; intermediate results were possible. Both regular (nonretractable) and retractable levers were used; the retractable levers precluded the occurrence of insufficiently spaced responses. At a minimum interresponse time of 5 s for regular levers and 7 s for retractable ones, matching results were intermediate, with greater evidence of sequence conditionability in the two-response sequences than in the three-response sequences. In Experiment 2, the required minimum interresponse spacing for two-response retractable-lever sequences was varied in an attempt to locate the sequence matching threshold. This attempt was unsuccessful, but the sequences (instead of individual responses) more closely obeyed the matching law. In the shortest spaced condition, conditional probability data on Lag 1 sequence emission order showed marked, highly similar patterning for all rats, indicating sequential control of the sequences. Post hoc definition of the behavioral unit in these studies is ambiguous. Although reinforcement contiguity was important, aspects of the results could support both molar- and molecular-level interpretations.

The copyist model of response emission

“…Generally speaking, procedures structured to demonstrate the shaping of behavioral patterns do not provide evidence that behavioral patterning is a defining characteristic of behavioral output in experiments not so structured. In particular, a common characteristic of studies demonstrating the occurrence of behavioral patterning is that reinforcement of the pattern does not occur for successive responses and they tend to make use of a fixed number of behaviors to define the sequence (e.g., Pisacreta, 1982;Reid, Chadwick, Dunham, & Miller, 2001;S. M. Schneider & Morris, 1992;Schwartz, 1982).…”

Resurgence of Integrated Behavioral Units

“…Several different terms have been used to represent the concept of theoretical response units, beginning with Skinner's (1935Skinner's ( , 1938 functional response units that may change over time (see also Arbuckle & Lattal, 1988;Reid et al, 2001;Schneider & Morris, 1992). Shimp (1976) used the term functional units of analysis.…”

“…3. Several researchers have concluded that sequences of two or three lever presses or key pecks had become organized into integrated (theoretical) behavioral units by demonstrating that the generalized matching law was better described by sequence matching than by matching of individual responses (Fetterman & Stubbs, 1982;Reid et al, 2001;Schneider & Davison, 2005;Schneider & Morris, 1992;Schwartz, 1986;Stubbs, Fetterman, & Dreyfus, 1987 Baum, 2002). A behavioral unit that has been reinforced frequently should have substantial strength as a whole, allowing it to resist disruption by a change in contingency (Schwartz, 1981(Schwartz, , 1982.…”

The Development of Functional Response Units: The Role of Demarcating Stimuli

“…With extended training, adaptive patterns of behavior sometimes become integrated into functional response units (Fetterman & Stubbs, 1982;Schneider & Morris, 1992;Schwartz, 1981Schwartz, , 1982Schwartz, , 1986Shimp, 1982;Stubbs, Fetterman, & Dreyfus, 1987;Thompson & Zeiler, 1986). In an intriguing examination of functional response units, Fetterman and Stubbs reinforced sequences of two responses in a reinforcement schedule in which matching of response sequences was pitted against matching of individual key pecks.…”