Choice in Transition: A Comparison of Melioration and the Kinetic Model

Abstract

Transition-state choice behavior of pigeons was examined in two experiments designed to test predictions of melioration and the kinetic model. Both experiments began with an initial training condition during which subjects were maintained on concurrent variable-interval schedules. In Experiment 1, subjects were then exposed to concurrent variable-ratio schedules, whereas in Experiment 2, subjects were then exposed to concurrent extinction. Contrary to the predictions of melioration, but consistent with the kinetic model, acquisition of preference on concurrent variable-ratio schedules followed a negatively accelerated logistic trajectory, and preference remained stable in concurrent extinction. Predictions made by the kinetic model concerning rates of switching between alternatives were also supported.Key words: kinetic model, melioration, matching law, choice, transition-state behavior, concurrent schedules, key peck, pigeonsThe behavior of organisms on probabilistic concurrent schedules of reinforcement is well described by the matching law (Herrnstein, 1970; for a review see de Villiers, 1977). For time allocation, the matching law may be written as(1) (Baum & Rachlin, 1969), where T1 and T2 are the cumulative durations of two behaviors and R1 and R2 are the obtained rates of reinforcement for those behaviors. The purpose of the present endeavor is to compare two theories of the process that gives rise to matching. One theory, melioration, describes a process whereby the organism adjusts its preference so as to equalize local rates of reinforcement (Herrnstein, 1982;Herrnstein & Vaughan, 1980;Vaughan, 1981;Vaughan & Herrnstein, 1987). The other theory, the kinetic model, describes an equilibration process formally similar to the kinetics of chemical reactions (Myerson & Miezin, 1980;Staddon, 1977 According to the melioration theory, organisms allocate behavior based on the difference, D, between local reinforcement rates: (2) where P is preference for the alternative whose current local reinforcement rate is N1/T1, and f(D) is any increasing function such that f(0) = 0. At equilibrium, NI/T -N2/T2 = 0, and rearranging yields T1/T2 = N1/N2. Dividing both the numerator and denominator of the right-hand fraction by T1 + T2 converts this fraction to the ratio of the overall reinforcement rates which equals (matches) the time ratio (Equation 1).According to the kinetic model, each reinforcement on one schedule decreases the rate of switching to the alternative by some proportion, k, and the sum of the local rates of switching back and forth is a constant, c. This may be expressed as dX/dt = k*R2*(c -X) -k*R1*X, (3) where X is the local rate of switching from the alternative reinforced at rate R, to the alternative reinforced at rate R2, and c -X is the local rate of switching back again. Local switching rate is defined as the number of switches from a schedule divided by the time spent on that schedule. Thus the local switching rates X and c -X equal n/Tj and n/T2, respectively, where n is the number of switches 2...

Dynamics of time matching: Arousal makes better seem worse

“…A number of results, beginning with Heyman (1979) and extending through some recent work of the Myerson group (Buckner, Green, & Myerson, 1993;Myerson & Hale, 1988;Real, 1983;Real & Dreyfus, 1985), confirm the exponential character of the DTs. Our analysis may be seen to encompass this result as follows: Assuming that the intersampling times, t f J' are themselves exponentially distributed, a pleasing result from stochastic process analysis (cf.…”

Choice behavior in transition: Development of preference in a free-operant procedure

“…For free-operant choice, however, the kinetic model makes the same prediction as does the original version of melioration theory-acquisition rates should be identical for all conditions with the same difference between reinforcement probabilities (4)1-4>2)' Therefore, if the results of the present experiment were similar to those of Bailey and Mazur, they would 00 inconsistent with the predictions of the kinetic model. In addition, such results would tend to contradict the view that free-operant choice and discrete-trial choice are governed by different principles (Myerson & Hale, 1988).…”

“…Myerson has anaIyzed the results of studies that supported some predictions of his kinetic model (Catania, 1969;Killeen, 1972;Myerson & Hale, 1988). Kacelnik et al (1987) reported an experiment that failed to support the predictions of some optimal-foraging This research was supported by Grant MH 38357 from the National Institute of Mental Health.…”

“…The kinetic model makes no predictions for the Baileyand Mazur experiment because that experiment used a discrete-trial procedure, with al-sec intertrial interval (lTI) after each trial. Myerson and Hale (1988) suggested that the factors that control choice in discrete-trial situations are substantially different from those in free-operant procedures, and the predictions of the kinetic model are limited to the latter. For free-operant choice, however, the kinetic model makes the same prediction as does the original version of melioration theory-acquisition rates should be identical for all conditions with the same difference between reinforcement probabilities (4)1-4>2)' Therefore, if the results of the present experiment were similar to those of Bailey and Mazur, they would 00 inconsistent with the predictions of the kinetic model.…”

Stability and variability in extinction.

“…Myerson and Hale (1988) showed that reinforced distributions of choices were also maintained during extinction. Under a concurrent variableinterval schedule, pigeons' choices approximately matched relative frequencies of reinforcement.…”