Aspartame demand in rhesus monkeys: Effects of volume and concentration manipulations

Tammy Wade-Galuska, Chad M. Galuska, Gail Winger, James H. Woods

Research output: Contribution to journalArticlepeer-review

2 Scopus citations


Three rhesus monkeys' lever presses produced aspartame-sweetened water according to a fixed-ratio schedule. The response requirement was increased across sessions and a demand-function analysis was used to assess the reinforcing effectiveness of different magnitudes of aspartame by manipulating reinforcer duration (1 and 3 s) in Phase 1 and concentration (0.3, 0.5, 0.7, and 1.0 mg/ml) in Phase 2. When duration was manipulated, the number of aspartame deliveries was mainly a function of the response requirement rather than unit price (responses/duration), suggesting that changes in duration did not significantly affect the reinforcing effectiveness of aspartame. When concentration was manipulated and the lowest concentration excluded, consumption was best described by unit price (responses/concentration) in two monkeys and by the response requirement in the third. Although results from the concentration manipulation provide some evidence that consumption was modulated by unit price, the results overall suggest that scalar equivalence does not exist between the components of unit price; specifically, the response requirement exerted a larger influence than duration or concentration on total consumption. Finally, a normalized demand analysis revealed that aspartame is a more elastic commodity than food and drug reinforcers.

Original languageEnglish (US)
Pages (from-to)71-78
Number of pages8
JournalBehavioural Processes
Issue number1
StatePublished - Jan 10 2007
Externally publishedYes


  • Aspartame
  • Behavioral economics
  • Demand function
  • Reinforcement
  • Rhesus monkey
  • Unit price

ASJC Scopus subject areas

  • Animal Science and Zoology
  • Behavioral Neuroscience


Dive into the research topics of 'Aspartame demand in rhesus monkeys: Effects of volume and concentration manipulations'. Together they form a unique fingerprint.

Cite this