Date of Award




Faculty Advisor

Gilbert, David G.


The current study tested the hypothesis that the effects of THC on affect are mediated by the ability of THC to alter attentional bias to positive and negative stimuli. The study was completed by 16 participants, all of whom were consistent marijuana users. During sessions, participants used a machine called a Quantified Smoke Delivery System, which delivers a controlled amount of smoke to the user, to smoke either a cigarette that contained THC or a placebo cigarette. After smoking, participants would complete a task. During tasks, participants were placed in an eye tracking apparatus in order to record the movement of their eye gaze using an eye tracking program while they looked at a computer monitor. Participants were presented with sets of two pictures depicting faces showing varying degrees of different emotions and instructed to look freely between the pictures. Participant eye-gaze was then analyzed. A clear interaction between time and drug type was found, such that the eye-gaze of participants was biased more toward the negative emotional picture during the first .667ms of gaze time. A greater bias for positive relative to negative and negative relative to neutral stimuli was also found in the placebo condition, and was not observed in the THC condition.