Running Head: MARIJUANA EFFETCS Article Summary of Marijuana effects on a modified Gambling Task Heather Frederick Psychology 2017 LAB Section 6 September 17th, 2010 Introduction: Previous studies on decision making abilities in people who are marijuana users on executive functioning has led researchers to believe that marijuana users have impaired decision making, but it is still not well understood. The experiment in this article aims at improving the current literature by observing direct effects of marijuana in double-blind controlled laboratory environment, while previous studies only had participants that had been abstinent from marijuana. The researchers’ hypothesis is that marijuana smokers will have a longer decision time, and would also do worse in card selection as the dosage of marijuana increases. There does not seem to be gaps in the logic of the hypothesis, since the previous research suggests this as well. Methods: There were 36 volunteer healthy adults from the ages of 21-36 years old. The inclusionary criterion for the experiment was that the participants were daily smokers, and had smoked marijuana between 2. 8-3. 8 years. The inclusionary criteria was reasonable, however the article does not state any exclusionary criteria. The researchers did give participants a urine analysis which confirmed that THC was the only drug present in the participants’ urine. The study was done in a controlled laboratory setting. The study was double-blind with 3 concentrations of marijuana cigarettes of 0. (control), 1. 8, and 3. 9% THC levels. The participants were assigned according to the Latin square design. The participants were told not to take an drugs or alcohol, and to confirm this they were given a urine analysis and breathe samples to confirm this. At the beginning of the experiment a baseline for participants was measured as well as heart-rate for the Gambling Task. After baseline measures were complete, participants smoked a marijuana cigarette controlled by number and duration of puff of the cigarettes. The I. V. is the marijuana cigarettes with 3 levels (0. . , 1. 8, and 3. 9% THC levels). The dependent variables was a. ) card selection, b. ) net earnings, and c. ) time needed to complete the task. The Gambling task was composed of 4 decks of cards. These decks were either advantageous, with a net gain of $25, or disadvantageous, with a net loss of $25. Results: Relative to baseline measurements participants in the experimental group did not show any significant differences in card selection. An ANOVA two-tailed analysis was performed to see the between-session effects on performance and planned comparison. The mean number of cards selected for the control group was 2. 5, while the experimental group with 1. 8% THC was 10, and the group with 3. 9% THC was 3. The mean amount of time required to complete the task for the control group was -22 seconds, while the experimental group with 1. 8% THC was -5 seconds, and the group with 3. 9% THC was -6 seconds. The mean amount of net earnings for control group was -$2, while the experimental group with 1. 8% THC was $2, and the group with 3. 9% THC was similar to that of the 1. % THC group. The data is not clearly represented in this article. The only data presented is a bar chart, and does not contain exact numbers which makes the findings difficult to understand. The results indicated that marijuana did not disrupt advantageous card selection or money earned on the modified Gambling task, but did have an effect on the time it took to complete the task. The sample size for the experimental was within reason for the experiment; however the study could be replicated to give more weight to the results. Discussion: The results of the experiment shows that advantageous card selection and amount of money earned on the modified Gambling task were not affected by marijuana intoxication, which is consistent with the previous findings showing similar concentrations of THC levels. The researchers discussed how the lack of marijuana-related affects on performance could have been linked to the fact that the task was completed several times which could produce practice effects on performance. Another flaw in the study was the concentration of the THC cigarettes which were only low to moderate concentrations. The researchers suggest that the larger dosing of THC could have a greater increase in performance on the gambling task. Also, the validity of the Gambling task on performance for substance abusers has not been established. I would be willing to extend the conclusion to most marijuana users, since the average concentration contained in street sample confiscated by the US DEA. The researchers concluded that naturalistic decision making needs to be accessed in future research.
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