The several roles of stimuli in token reinforcement

Abstract

Three experiments were conducted with pigeons to identify the stimulus functions of tokens in second-order token-reinforcement schedules. All experiments employed two-component multiple schedules with a token-reinforcement schedule in one component and a schedule with equivalent response requirements and/or reinforcer density in the other. In Experiment 1, response rates were lower under a token-reinforcement schedule than under a tandem schedule with the same response requirements, suggesting a discriminative role for the tokens. In Experiment 2, response rates varied systematically with signaling functions of the tokens in a series of conditions designed to explore other aspects of the temporal-correlative relations between tokens and food. In Experiment 3, response rates were reduced but not eliminated by presenting tokens independent of responding, yoked to their temporal occurrence in a preceding token component, suggesting both a reinforcing function and eliciting/evocative functions based on stimulus-food relations. Only when tokens were removed entirely was responding eliminated. On the whole, the results suggest that tokens, as stimuli temporally correlated with food, may serve multiple stimulus functions in token-reinforcement procedures--reinforcing, discriminative, or eliciting--depending on the precise arrangement of the contingencies in which they are embedded.

Token reinforcement: Translational research and application

“…A laboratory study by Bullock and Hackenberg () attempted to disentangle these multiple stimulus functions of tokens. The tokens were lights arranged in a horizontal row above the response keys and the subjects were pigeons, well experienced with token economies.…”

“…In addition to token‐production schedules, several studies have shown that rates and patterns of token‐reinforced behavior are systematically related to exchange‐production schedules. In laboratory studies, for example, when token‐production schedules are held constant, pausing increases and response rate decreases with increases in FR exchange‐production ratio (Bullock & Hackenberg, , ; Foster, Hackenberg, & Vaidya, ), similar to that seen under simple FR schedules (Felton & Lyon, ; Ferster & Skinner, ; Powell, ).…”

“…Token‐production response rates across token‐production segments for three pigeons in token (filled symbols) and tandem (open symbols) schedules (from Bullock & Hackenberg, ). The different columns represent different exchange‐production schedules: FR2, FR4, and FR8.…”

Substitution effects in a generalized token economy with pigeons

“…Thus, in the present case, (1) pecking the white token production key on the water panel produced a white token and yellow exchange‐production key on both panels; (2) pecking the yellow exchange‐production key, in turn, produced a flashing white generalized token, signaling an exchange period; and (3) pecking this flashing key, in turn, produced the terminal reinforcer (water or food, depending on the panel on which the exchange response occurred). As stimuli correlated with different links in the chain, the tokens and other correlated stimuli undoubtedly contributed to the coordinated sequences of behavior comprising the token reinforcement performance, as previous research has shown (Bullock & Hackenberg, , ; Foster & Hackenberg, ; Lagorio & Hackenberg, ; Yankelevitz, Bullock, & Hackenberg, ).…”

“…Second, the small exchangeproduction requirement (FR 1) does not promote strong reinforcing or discriminative functions of the tokens. Such functions stand out more clearly under extended exchangeproduction schedules (Bullock & Hackenberg, 2015;Yankelevitz et al, 2008). And finally, these conditions were studied in the context of an open economy, in which the value of food (and food-correlated stimuli) was low.…”