Effects of reinforcer magnitude and alternative reinforcer delay on preference for alcohol during a multiple-choice procedure.

The Multiple-Choice Procedure [MCP; Griffiths, R.R., Troisi II, J.R., Silverman, K., Mumford, G.K., 1993. Multiple-choice procedure: an efficient approach for investigating drug reinforcement in humans. Behav. Pharmacol. 4, 3-13; Griffiths, R.R., Rush, C.R., Puhala, K.A., 1996. Validation of the multiple-choice procedure for investigating drug reinforcement in humans. Behav. Pharmacol. 4, 3-13] was developed to investigate the relationship between drug preferences and alternative reinforcers. The current study was designed to better characterize the relationships among reinforcer magnitude, delay associated with an alternative reinforcer, and preference for alcohol among a sample of undergraduate drinkers. Participants were 27 male undergraduates, over the age of 21, who reported engaging in at least three occasions of binge drinking over the previous month. All participants took part in a single laboratory session, during which six versions of the MCP questionnaire were administered. Across the versions, participants made a total of 180 discrete choices between three amounts of alcohol (12, 24, or 36 ounces of beer; deception was used to mask the fact that 36 ounces of beer would not actually be provided during the sessions) and escalating amounts of money ($0 to $20) delivered immediately or after a one-week delay. Response on the MCP varied as a function of the amount of alcohol available and the delay associated with the alternative monetary reinforcer, with the effect of the delay diminishing as the dose of alcohol increased. Results of the current study are consistent with previous laboratory studies of choice behavior and with behavioral economic theories of substance use.