Delay discounting of saccharin in rhesus monkeys

Behav Processes. 2009 Oct;82(2):214-8. doi: 10.1016/j.beproc.2009.06.002. Epub 2009 Jun 18.

Abstract

The value of a reinforcer decreases as the time until its receipt increases, a phenomenon referred to as delay discounting. Although delay discounting of non-drug reinforcers has been studied extensively in a number of species, our knowledge of discounting in non-human primates is limited. In the present study, rhesus monkeys were allowed to choose in discrete trials between 0.05% saccharin delivered in different amounts and with different delays. Indifference points were calculated and discounting functions were established. Discounting functions for saccharin were well described by a hyperbolic function. Moreover, the discounting rates for saccharin in all six monkeys were comparable to those of other non-human animals responding for non-drug reinforcers. Also consistent with other studies of non-human animals, changing the amount of a saccharin reinforcer available after a 10-s delay did not affect its relative subjective value. Discounting functions for saccharin were steeper than we found in a previous study with cocaine, raising the possibility that drugs such as cocaine may be discounted less steeply than non-drug reinforcers.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Choice Behavior*
  • Macaca mulatta / psychology*
  • Male
  • Reinforcement Schedule
  • Reinforcement, Psychology
  • Saccharin / administration & dosage*
  • Sweetening Agents / administration & dosage*
  • Time Perception*

Substances

  • Sweetening Agents
  • Saccharin