Reinforcer Accumulation in a Token‐reinforcement Context With Pigeons

Abstract

Four pigeons were exposed to a token-reinforcement procedure with stimulus lights serving as tokens. Responses on one key (the token-production key) produced tokens that could be exchanged for food during an exchange period. Exchange periods could be produced by satisfying a ratio requirement on a second key (the exchange-production key). The exchange-production key was available any time after one token had been produced, permitting up to 12 tokens to accumulate prior to exchange. Token accumulation, measured in terms of both frequency (percent cycles with accumulation) and magnitude (mean number of tokens accumulated), decreased as the token-production ratio increased from 1 to 10 across conditions (with exchange-production ratio held constant), and increased as the exchange-production ratio increased from 1 to 250 across conditions (with token-production ratio held constant). When tokens were removed, accumulation decreased markedly compared to conditions with tokens and the same schedules. These data show that token accumulation is an orderly function of token-production and exchange-production schedules, and they are broadly consistent with a unit-price model based on local and global responses per reinforcer.

Rats (Rattus norvegicus) and pigeons (Columbia livia) are sensitive to the distance to food, but only rats request more food when distance increases

“…These results were extended to pigeons by Yankelevitz, Bullock, and Hackenberg (2008) who reported very orderly increases in the accumulation of provisions in a token-economy. Tokens were accumulated, at costs of 1, 5 or 10 responses per token, with each exchangeable for 2 s access to food.…”

“…The research of Yankelevitz and associates (2008) suggests that the research with rats showing increased provisioning with increased physical distance should be easily replicated with pigeons. Against this is the fact that pigeons are not natural hoarders: Will pigeons, like rats, increase the number of responses per trip for food when the distance between food and the manipulandum is increased?…”

Pathological gamblers discount probabilistic rewards less steeply than matched controls.

“…Second, although animal research has the advantage of controlling extraneous factors that may affect probability discounting and gambling, at present animal preparations have yet to adequately capture the functional characteristics of human gambling. For example, human gamblers wager, win, and lose, token reinforcers whereas animal studies have thus far been unsuccessful in establishing a surplus of token reinforcers which an animal might wager unless exchanging tokens for food is restricted by requiring the subject complete a large work requirement before tokens may be exchanged (Yankelevitz, Bullock, & Hackenberg, 2008). This is important because gambling losses which mirror gambling wins cannot be arranged with food reinforcers which, once consumed, cannot be lost (see Madden, Ewan, & Lagorio, 2007).…”

Rats' choices with token stimuli in concurrent variable‐interval schedules

“…Their experiments used a variety of procedures, but many of them included token-production periods, in which pecking on response keys led to the illumination of the token lights, and tokenexchange periods, in which the pigeons could exchange each illuminated token light for one food delivery. Some of these studies used single schedules of token production and measured response rate as a dependent variable (e.g., Bullock & Hackenberg, 2006;Foster, Hackenberg, & Vaidya, 2001;Yankelevitz, Bullock, & Hackenberg, 2008), whereas others used choice procedures to compare the effects of different reinforcement schedules and temporal arrangements of tokens and food (e.g., Foster & Hackenberg, 2004;Jackson & Hackenberg, 1996;Hackenberg & Vaidya, 2003). One recurrent theme from the experiments with choice procedures was that choice behavior was mainly controlled by the delay to the primary reinforcer, food, not by the delay to the tokens.…”