Effects of delta 9-THC on marijuana smoking, dose choice, and verbal report of drug liking.
Choice data reveal drug potency effects that consumption counts and liking scales miss.
01Research in Context
What this study did
Brown et al. (1994) let adults with marijuana use choose between puffs that had different THC strengths. The team also asked, "How much do you like the drug?" after each sample.
Each person worked alone in a quiet lab room. Sessions ran like a vending-machine test: press one button for dose A, another for dose B, and the machine gave the matching puff.
What they found
Higher THC puffs were chosen more often, even when people did not smoke more total puffs. The choice data picked up potency differences that puff counts and liking scores missed.
In plain words, watching what people pick showed the drug effect better than asking them or counting smoke.
How this fits with other research
Chandler et al. (1992) ran a near-copy design with caffeine. People also chose between low and super-low doses. Both studies prove that choice procedures catch tiny drug differences that surveys overlook.
Sarber et al. (1983) trained pigeons to peck one key after PCP and another after salt water. Birds, like humans, shifted pecks when drug strength changed. Same method, different species, same clean result.
Cohen (1986) seems to disagree at first glance. That paper says drugs do NOT always weaken behavior the way extinction or pre-feeding does. H et al. show the opposite: THC clearly strengthened choosing. The gap is about what you measure. L looked at how long responding survives disruption; H looked at whether the drug itself becomes a reinforcer. Both can be true.
Why it matters
If you need to know whether a treatment, med, or edible is acting as a reinforcer, skip the rating scale. Set up a simple choice: left button for item A, right for B. Count the picks. This lab trick now has 30 years of drug studies behind it and works in any setting where clients can make repeated selections. Try it next time you assess preference for leisure items, snacks, or even therapy tasks.
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02At a glance
03Original abstract
The effects of delta 9-tetrahydrocannabinol content of marijuana on cigarette smoking, dose choice, and verbal report of drug "liking" by adult males living in a residential laboratory were investigated. Marijuana cigarettes were available during programmed intervals while subjects were engaged in recreational activities. The tetrahydrocannabinol content of the cigarettes remained constant each day, but was changed across days. Subjects provided written ratings of drug liking at the end of each day. In the first study, placebo or active (2.3% delta 9-tetrahydrocannabinol) marijuana cigarettes were available for 1-, 2-, or 3-day intervals at varying times of day. The number of cigarettes smoked was unrelated to tetrahydrocannabinol content, although verbal reports of drug liking were consistently higher when marijuana cigarettes containing tetrahydrocannabinol were smoked. In a second study, a choice procedure, consisting of four 3-day blocks of 2 sample days and 1 choice day, was used. On sampling days, subjects smoked cigarettes varying in tetrahydrocannabinol content (0.0, 2.0, and 3.5%, w/w); on choice days they were allowed to choose between the two previously sampled doses. The number of cigarettes was not consistently related to tetrahydrocannabinol content. Ratings of drug liking were increased when marijuana cigarettes contained tetrahydrocannabinol, but ratings of marijuana containing 2.0% and 3.5% of the compound were similar. In contrast, subjects consistently chose the 3.5% dose over either the 0.0% or 2.0% dose. Dose choice was more sensitive to tetrahydrocannabinol content than either reports of drug liking or numbers of cigarettes smoked.
Journal of the experimental analysis of behavior, 1994 · doi:10.1901/jeab.1994.61-203