A Contextual Model of Concurrent‐chains Choice

Abstract

An extension of the generalized matching law incorporating context effects on terminal-link sensitivity is proposed as a quantitative model of behavior under concurrent chains. The contextual choice model makes many of the same qualitative predictions as the delay-reduction hypothesis, and assumes that the crucial contextual variable in concurrent chains is the ratio of average times spent, per reinforcement, in the terminal and initial links; this ratio controls differential effectiveness of terminal-link stimuli as conditioned reinforcers. Ninety-two concurrent-chains data sets from 19 published studies were fitted to the model. Averaged across all studies, the model accounted for 90% of the variance in pigeons' relative initial-link responding. The model therefore demonstrates that a matching law analysis of concurrent chains-the assumption that relative initial-link responding equals relative terminal-link value-remains quantitatively viable. Because the model reduces to the generalized matching law when terminal-link duration is zero, it provides a quantitative integration of concurrent schedules and concurrent chains.

Operant Conditioning

“…It fits the basic presuppositions of the field: that choice is about response strength, that response strength is equivalent to response probability, and that response rate is a valid proxy for probability (e.g., Skinner 1938Skinner , 1966Skinner , 1986Killeen & Hall 2001). (For typical studies in this tradition see, e.g., Fantino 1981;Grace 1994;Herrnstein 1961Herrnstein , 1964Herrnstein , 1970Rachlin et al 1976; see also Shimp 1969Shimp , 2001 We can also look at concurrent schedules in terms of linear waiting. Although published evidence is skimpy, recent unpublished data (Cerutti & Staddon 2002) show that even on variable-interval schedules (which necessarily always contain a few very short interfood intervals), postfood wait time and changeover time covary with mean interfood time.…”

Economic context and pigeons’ risk-taking: an integrative approach

“…It should be noted that other interpretations of these approaches are no doubt possible. Additionally, Grace's (1994) contextual choice theory would make predictions comparable to delay reduction in these experiments. The hope was that the results of these experiments would give some sense of the strengths and weaknesses of the three general approaches to risky choice as a function of budget.…”

“…7 DRT loses its quantitative accuracy when applied to schedules other than variableintervals, or to situations in which reinforcer magnitude differs between the two alternatives (but see Grace, 1994). Choice is more extreme than DRT would predict when fixed schedules are used (Duncan & Fantino 1970), and little work has been done examining choice in concurrent chains using ratio schedules (as the studies reported here have done).…”

Adaptive Behavior and Learning

“…Rachlin (1973) has proposed a non-quantitative theory of contrast similar to the dynamic model sketched out at the end of this chapter. In recent years, Nevin and his associated have elaborated a theory of behavioral "momentum" that can accommodate a wide range of contrast and choice phenomena (e.g., Grace, 1994;Nevin, 1974;Nevin, Tota, Torquato, & Shull, 1990) 12. Use of the term controlled to refer to the effect of a stimulus on a response is conventional, but it is not quite accurate.…”