Motivation levels and the marihuana high.

Abstract

A total of 112 volunteer males, aged 18-30 years, were randomly assigned to eight groups, with 14 subjects per group. For each of two drug conditions (no drug and marihuana), there were four motivation conditions. In the first motivation group, the subjects were merely given instructions concerning how to perform on each dependent measure. The second motivation group was given the additional instructions to "try as hard as possible" on each measure. The third motivation group could earn a small amount of money, contingent on the performance of the dependent measures. The fourth group could earn a substantial amount of money contingent upon task performance. Time perception, choice reaction time, and a paired-associate memory task were used as dependent measures. The results indicated a significant, detrimental drug effect on all measures and a significant motivation effect on the reaction time measure. Close examination of the data suggests that the drug effect occurred because of the ineffectiveness of the motivation manipulation with the marihuana subjects.Much diversity of opinion surrounds the phenomenon of marihuana intoxication. There is presently little agreement among researchers on the effect of marihuana on behavior. For example, whereas some authors have found that marihuana impairs various coordination and cognitive skills (reviewed in LeDain, Campbell, Lehmann, Stein, & Bertrand, 1972) others have suggested that attentional factors and boredom might be producing these deficits (e.g., Manno, Kiplinger, Scholz, & Forney, 1971). Indeed, there is an increasing body of evidence to support the notion that extrapharmacological factors may play at least as great a role in marihuana intoxication as the drug itself.

Marijuana Effects on Sensitivity to Reinforcement in Humans

“…: (713) 500-2620, Fax: (713) NO . 4 Marijuana and Sensitivity to Reinforcement 521 reinforcement or "motivational" processes (Foltin et al 1989;Haney et al 1997, Kagel et al 1980Miles et al 1974;Pihl and Sigal 1978). While the present study was not intended to address specific mechanisms, activity at the biochemical level provides a plausible rationale for disruptive effects of ⌬ 9 THC on reinforcement processes.…”

“…At the behavioral level, acute administration of ⌬ 9 THC has repeatedly been shown to impair performance on learning tasks shaped and maintained by reinforcement Balster 1980, Kelly et al 1993;Kamien et al 1994;Schulze et al 1989). Furthermore, on simulated tasks in which subjects could work to earn money, acute marijuana smoking decreased rates of working (and earnings)-an effect presumably mediated by changes in reinforcement or "motivational" processes (Foltin et al 1989;Haney et al 1997, Kagel et al 1980Miles et al 1974;Pihl and Sigal 1978).…”

The Effects of Low Doses of Δ-9 Tetrahydrocannabinol on Reinforcement Processing in the Risky Decision-Making of Young Healthy Adults

“…In comparison, studies with flying simulations have demonstrated more consistent deficits following cannabis intake (Janowsky et al, 1976). Second, THC can alter choices on operant tasks sustained by reinforcement (Brady and Balster, 1980;Kelly et al, 1993;Kamien et al, 1994;Schulze et al, 1989) while other studies with humans show that THC can produce motivational deficits when working for monetary reward (Foltin et al, 1989;Haney et al, 1997;Miles et al, 1974;Pihl and Sigal, 1978).…”

“…The highest two doses of THC (1.77 and 3.58%) induced a tendency to maintain responding on the schedule with a decreasing density of reward, suggesting that cannabinoid activity reduced participants' sensitivity to reinforcement. Against this background, and evidence of motivational changes following marijuana intake (Foltin et al, 1989;Kagel et al, 1980;Pihl and Sigal, 1978), one might hypothesize that sublingual THC will reduce discrimination between response options with zero and those with varying expected value.…”

Acute Marijuana Effects on Human Risk Taking

“…-THC may alter sensitivity to reinforcing consequences (Galbicka et al, 1980;Foltin et al, 1989;Lane and Cherek, 2002;Pihl and Sigal, 1978;Schulze et al, 1989). This phenomenon may be related to the action of D…”