Human time-based schedule performance: Exploring interactions between instructions and response-reinforcer contiguity.

Abstract

Spontaneous regulation of human behavior on a simple time-based mixed schedule of reinforcement was studied as a function of instructions and response-reinforcer contiguity. Seventeen subjects were exposed to a mixed fixed-interval (FI) 10 s schedule (Condition A) and a conjunctive fixed-time 10 s fixed ratio 1 (Condition B) schedule of reinforcement using either an ABAB or a BABA design across 5 sessions. One of three instructional categories were employed (normal, ratio, and interval instructions) on a simple button pressing task. Subjects either produced a high rate of responding with short postreinforcement pauses (PRPs), a high rate of responding decreasing to a low rate with long PRPs, or a low rate of responding with long PRPs. Evidence of spontaneous regulation in terms of consistent differential responding across components was displayed only under interval instructions. These results highlight the interaction of instructions with the role of response-reinforcer contiguity in controlling spontaneous regulation of human performance on simple time-based schedules of reinforcement. ********** Typical human performance on a fixed-interval (FI) schedule of reinforcement is commonly described as either a high rate performance with a small postreinforcement pause (PRP), or a low rate performance with a long PRP (e.g., Leander, Lippman & Meyer, 1968; Lippman & Meyer, 1967; Weiner, 1969). These findings differ from nonhuman performance on the FI where a scallop or break-and-run is the typical pattern (Baron & Leinenweber, 1994; Hyten & Madden, 1993; Perone, Galizio & Baron, 1988). Attempts to explain the discrepant findings between human and nonhumans, and the differences in findings between humans, have lead to the development of a number of research areas. These include studies concerned with the effect of the experimental setting (Barnes & Keenan, 1989; Orne, 1962), the effect of conditioning histories (e.g., Weiner, 1969, 1972), and the determinants of choice (e.g., Belke, Pierce, & Powell, 1989; Darcheville, River6re, & Wearden, 1993). One of the defining features of human behavior, the complexity of the verbal repertoire, also has drawn special attention in the study of schedules of reinforcement. Many studies have investigated verbal behavior by focusing on the role of either experimenter-generated or self-generated instructions on schedules of reinforcement (e.g., Baron & Galizio, 1983; Galizio, 1979; Hayes, Brownstein, Zettle, Rosenfarb, & Korn, 1986; LeFrangois, Chase, & Joyce, 1988; Matthews, Shirnoff, Catania, & Sagvolden, 1977). Conclusions to date highlight the power of instructions in generating responding which may be insensitive to the programmed contingencies (Baron & Galizio; for a more recent analysis see Madden, Chase & Joyce, 1998). Some researchers have also pointed to the role of self-generated instructions in determining behavior (Bentall & Lowe, 1987; Lowe, 1979). Before we can fully understand the role played by verbal behavior in human schedule performance we must have a clear understanding of how the formal structure of a schedule of reinforcement critically determines the dynamics involved in behavioral adaptation. To date most research investigating the interaction between instructions and programmed contingencies have employed schedules simply as tools for generating behavior. The problem with this is that we do not fully understand how the tools themselves function. That is, we are limited in the extent to which we understand schedules as contexts for controlling dynamic processes in the multiple determination of behavior (Keenan & Toal, 1991). If we are limited in our understanding of these fundamental issues, the addition of an another layer of complexity (verbal behavior) makes our task more difficult. A detailed analysis of the workings of simple schedules of reinforcement is therefore necessary. …