Essential value of cocaine and food in rats: Tests of the exponential model of demand

Chesley J. Christensen, Alan Silberberg, Steven R. Hursh, Mary E. Huntsberry, Anthony L. Riley

Research output: Contribution to journalArticlepeer-review

60 Scopus citations


Rationale: To provide a prospective test of the predictive adequacy of the exponential model of demand (Hursh and Silberberg, Psych Rev 115(1):186-198, 2008). Objectives: In Experiment 1, to measure the 'essential value' (the propensity to defend consumption with changes in price) of cocaine and food in a demand analysis (functional relation between price and consumption) by means of the exponential model; in Experiment 2, to test whether the model's systematic underestimation of cocaine consumption in Experiment 1 was due to weight loss; and in Experiment 3, to evaluate the effects of cocaine on the essential value of food. Materials and methods: In Experiment 1, demand curves for food and cocaine were determined by measuring consumption of these goods in a multiple schedule over a range of fixed ratios; in Experiment 2, a demand curve for only cocaine was determined; and in Experiment 3, demand for food was determined in the absence of cocaine. Results: In Experiment 1, the exponential equation accommodated high portions of variance for both curves, but systematically underestimated cocaine demand; in Experiment 2, this predictive underestimation of the equation was eliminated; and in Experiment 3, the essential value of food was greater than in Experiment 1. Conclusions: The exponential model of demand accommodated the data variance for all cocaine and food demand curves. Compared to food, cocaine is a good of lower essential value.

Original languageEnglish (US)
Pages (from-to)221-229
Number of pages9
Issue number2
StatePublished - Jun 2008


  • Behavioral economics
  • Cocaine
  • Demand
  • Exponential model of demand
  • Food
  • Lever press
  • Rats

ASJC Scopus subject areas

  • Pharmacology


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