Experimental design and timeline.
During the initial assessment and test sessions 1, 2 and 3, a novel smoking-related video was shown to participants. Physiological measures (heart rate (HR) and skin conductance (SC)) were collected prior to and during the last minute of each video presentation. During these same visits, blood pressure (BP) and self-reported cigarette craving and urge to smoke scores were collected pre- and post-video. On the day of the behavioral intervention, baseline physiological measures (HR, SC, and BP) and self-report data were gathered, followed by one of four conditions (phase 1): stress task and smoking cue, stress task and neutral cue, non-stressful task and smoking cue, or non-stressful task and neutral cue. Physiological and craving measures were collected and followed by a 10-minute break. All participants then went through the extinction protocol (phase 2) consisting of additional smoking videos, smoking images, and the manipulation of smoking-related paraphernalia. Immediately after phase 2, physiological and craving measures were gathered again.