Bidding for delayed rewards: Accumulation as delay discounting, delay discounting as regulation, demand functions as corollary

• Published in: Journal of the experimental analysis of behavior 2019-09, Vol.112 (2), p.111-127
• Main Author: Killeen, Peter R.
• Format: Article
• Language: English
• Subjects: accumulation; Animals; Compensation; compensation functions; Conditioning, Operant; cost–benefit ratio; Delay Discounting; demand; Demand curves; hyperbola; Models, Psychological; Rats; regulation; Reward; Time Factors; unit amount
• ISSN: 0022-5002; 1938-3711
• DOI: 10.1002/jeab.545

In the accumulation paradigm animals press one manipulandum to accumulate pellets or seconds of access to food, and then press another manipulandum, or run some distance, to collect it. The accumulation may be interpreted as delay discounting, with the animals adjusting the distal amount to compensate for its distance or delay. The amount accumulated before being collected is a linear function of the distance or time that the experimental paradigm stipulates for collecting it. That linear function follows from the Unit‐Price/Unit‐Amount axiom. The inverse of the linear compensation functions gives a delay‐discount hyperbola. The advantages of the accumulation paradigm and analytic framework for delay discounting studies are noted. Compensation functions are then derived from a behavioral regulation model, which generalizes them to contexts where the individual's budget for response cost becomes over‐taxed. In turn, such compensation/regulation models lead directly to representative demand functions. In sum, regulation models provide a theoretical grounding for demand functions, compensation functions, and delay discounting hyperbolas. The parameter that links them is the unit amount k, the slope of the compensation function and of the discount function, the setpoint for consumption in a regulation model, and the ideal quantity consumed at minimal price in a demand analysis.