The isolation of stimulus-reinforcer associations established with multiple schedules

Abstract

Multiple schedules established stimulus-reinforcer IS-SR) associations on baselines in which equal response rates and patterning were maintained in all components. Subsequently, stimuli associated with an increase in reinforcement but no change in ongoing response rate were compounded. For one experimental group, free-operant avoidance WOA) was programmed in tone and in light while variable-Interval (VI) food reinforcement was effective in their simultaneous absence irr + L). The opposite stirnulus-schedule combinations were programmed for the other. Both groups remained in their VI components 85% of the session on schedule preference tests, and on a stimulus compounding test emitted approximately 1.5 times as many responses to tone-plus-light (T + L) as to tone or light alone. This is the first report of additive summation to combined discriminative stimuli associated with only an increase in reinforcement, Nondifferentially trained controls who had the same contingency effective in tone, light, and T + L-VI or FOA-showed neither preference among schedule components or summation during stimulus compounding, indicating that nonassociative stimulus factors made no contribution to either resultant in the experimental animals. Evidence supporting an algebraic combination of response and reinforcement associations is presented, and functional similarities between transfer-of-control studies and the stimulus compounding tests of the experimental groups in the present experiment are discussed.When an organism's operant response rate is under discriminative stimulus (SO) control a stirnulusresponse-reinforcer (S-R-SR) sequence is usually established. Within this framework, two types of association to the SO may be identified, the stimulusresponse (S-R) association established through the response-reinforcer contingency and the stimulusreinforcer (S-SR) association. The contribution of each type of association to stimulus control is often ambiguous, because on most multicomponent freeoperant baselines response rate and reinforcement rate are highly correlated. As an example, consider a three-component multiple schedule where responding is maintained to a tone and a light by rein forcement while in the absence of both tone and light (T + I") responding is eliminated through nonreinforcement. Here, the tone and the light (I) will come to be discriminative for an increase in response rate, the S-R association, and (2) will signal an increase in reinforcement frequency, the S-SR asociation. This confounding of S-R and S-SR associations complicates causal analysis when behaviors may be ex-

Conditioning history and inhibitory instrumental stimulus control: Independent-groups and within-subjects measures

“…The significant test differences between control and transfer groups of this experiment, systematically replicated in Experiment 2, reveal the power of the manipulated variables, and stand on their merits. Weiss (1977) did report some results potentially relevant to a concern about the unconditioned disruptive powers of the compound. He gave rats extensive training in which FOA operated in tone, light and 'F +L.…”

Generalization Peak Shift for Autoshaped and Operant Key Pecks

“…Spence's theory made no distinction between gradients resulting from operant or respondent contingencies. Therefore, because excitatory and inhibitory gradients for autoshaped pecks following interdimensional discrimination training have been reported (Tomie et al, 1976;Wessells, 1973) Although Spence (1937) made no distinction between operant and respondent control here, Weiss' (1971Weiss' ( , 1977Weiss' ( , 1978 two-factor model of stimulus control deals with the contribution of these different contingencies to the likelihood, and robustness, of peak shift. He observed that in the large majority of operant discrimination studies, the presence of S+ is correlated with an increase in both response and reinforcement frequency and argued that this covariation obscures the contributions of each contingency to the resulting stimulus control.…”

Some determinants of response summation

“…109-114). Using appetitive operant conditioning, summation has been found with rats (Hamm, Porter, & Oster, 1978;Strub & Barske, 1977;Weiss, 1977) and pigeons (Long & Allen, 1974;Meltzer & Hamm, 1976). Summation has also been reported with avoidance responding using dogs (LoLordo & Hart, 1972)and rats (Emurian & Weiss, 1972;Van Houten & Rudolph, 1971;Weiss, 1976Weiss, , 1977.…”