8, SD = selleck compound 17.3; p < .05, Tukey's HSD). Physiological effects A significant brand �� bout �� time interaction, F(3, 87) = 7.7, p < .01, was observed for heart rate. Within each condition, heart rate increased significantly during each bout relative to presmoking (p < .05, Tukey's HSD). Collapsed across time, mean heart rate for Bout 1 was 77.4 bpm (SD = 9.0) for own brand and 75.2 bpm (SD = 9.4) for ultra-light. By Bout 4, heart rate for own brand (M = 76.7 bpm, SD = 9.6) remained elevated relative to ultra-light (M = 74.2 bpm, SD = 10.1). Additionally, own brand produced a greater magnitude of increase from presmoking to during smoking as compared with ultra-light, although only for Bout 1 (p < .05, Tukey's HSD). For expired-air CO, significant device �� brand, F(2, 58) = 4.1, p < .
05, brand �� bout, F(3, 87) = 250.3, p < .001, brand �� time, F(1, 29) = 13.5, p < .01, and bout �� time, F(3, 87) = 25.6, p < .001, interactions were observed. Within every condition, CO increased significantly at each timepoint relative to the presession value (i.e., Bout 1 pre-cigarette value; p < .05, Tukey's HSD), and scores at both pre- and postsmoking timepoints increased with successive bouts. Additionally, CO was significantly greater for own-brand cigarettes (M = 16.5 ppm, SD = 8.7) relative to ultra-light cigarettes (M = 14.8 ppm, SD = 6.9; p < .05, Tukey's HSD). These brand-induced changes were more pronounced for desktop (mean difference = 3.2 ppm, SD = 5.5) than for portable (mean difference = 1.0 ppm, SD = 5.3) and video (mean difference = 0.2 ppm, SD = 4.6; ns, Tukey's HSD).
Discussion Study results showed that measurement of smoking topography differed little between the computerized devices and video recordings. All three methods demonstrated brand- and bout-induced changes effectively, measured smoking topography reliably, and were correlated highly across all topography measures. Measurement of brand- and bout-induced effects Consistent with past work (e.g., Gust & Pickens, 1982; Zacny & Stitzer, 1985), characteristic brand- and bout-induced changes in smoking behavior were observed. Participants took significantly longer puff durations and larger average and total puff volumes for ultra-light than for own-brand cigarettes. Participants also took significantly more puffs from the first cigarette relative to subsequent cigarettes.
These findings were demonstrable with all three measurement methods, and the magnitude of these changes did not differ across methods (ns, Tukey’s HSD). Thus, all methods were sensitive to differences in GSK-3 cigarette brand and bout number. Comparison of computerized devices versus video recordings Topography data collected via mouthpiece-free video recordings did not differ from topography data collected via mouthpiece-based desktop or portable devices. We observed high and reliable correlations across cigarette brands and smoking bouts (all r’s �� .69, p < .01).