واکنش پذیری نشانه در واقعیت مجازی: نقش زمینه ای

Abstract Cigarette smokers in laboratory experiments readily respond to smoking stimuli with increased craving. An alternative to traditional cue-reactivity methods (e.g., exposure to cigarette photos), virtual reality (VR) has been shown to be a viable cue presentation method to elicit and assess cigarette craving within complex virtual environments. However, it remains poorly understood whether contextual cues from the environment contribute to craving increases in addition to specific cues, like cigarettes. This study examined the role of contextual cues in a VR environment to evoke craving. Smokers were exposed to a virtual convenience store devoid of any specific cigarette cues followed by exposure to the same convenience store with specific cigarette cues added. Smokers reported increased craving following exposure to the virtual convenience store without specific cues, and significantly greater craving following the convenience store with cigarette cues added. However, increased craving recorded after the second convenience store may have been due to the pre-exposure to the first convenience store. This study offers evidence that an environmental context where cigarette cues are normally present (but are not), elicits significant craving in the absence of specific cigarette cues. This finding suggests that VR may have stronger ecological validity over traditional cue reactivity exposure methods by exposing smokers to the full range of cigarette-related environmental stimuli, in addition to specific cigarette cues, that smokers typically experience in their daily lives.

Introduction Numerous laboratory cue-reactivity studies have demonstrated that smokers report higher levels of craving when exposed to smoking cues compared to neutral cues (Carter & Tiffany, 1999). More recently, virtual reality (VR), an immersive experience that presents life-like smoking environments along with specific cues, has been used to elicit and assess cue reactivity among smokers (Bordnick et al., 2005 and Traylor et al., 2008). However, in these studies, given the complex multi-sensory presentation of VR scenarios, it remains unclear whether explicit cues (e.g., lit cigarettes) are the primary stimuli for increased craving during VR exposure. Although the power of explicit cues to evoke craving in laboratory experiments is well established, less is known about the power of other stimuli (e.g., smoking-related environments) to evoke craving in the VR world. Conklin, Robin, Perkins, Salkeld, and McClernon (2008) investigated explicit cues alone and contextual stimuli alone (e.g., a bar scene without explicit cigarette cues) to explore craving responses in smokers. Using photographs for cue exposure, they found a significant increase in craving following exposure to the contextual stimuli which were devoid of specific cigarette cues. They also obtained smokers' reactivity to photographs of explicit cues (e.g., cigarette in an ashtray) and found significantly higher craving compared to the contextual cues. Given the complex sensory world of the smoker's natural environment, it seems likely that other stimuli, more distally associated with smoking, can induce a craving response. The findings of Conklin et al. (2008) also suggest that a VR immersion in a context tacitly associated with smoking can produce strong craving. For the purposes of this study, we refer to “context” as the complex, interrelated stimuli (e.g., a room where smoking is allowed) as separate from the discrete (explicit) cues such as cigarettes or other smokers. This study examined the influence of environmental context on smokers' craving to smoke in VR. We explored smokers' craving reactivity after exposure to a context related to smoking but devoid of explicit cigarette cues. We then exposed the same smokers to the same context with explicit cigarette cues included. This comparison was designed to replicate the context findings of Conklin et al. (2008), but in a VR setting, and test whether explicit cues added to the context-only environment elicit additional increases in craving.

3. Results 3.1. Sample Participants were 62.5% male, 37.5% female, 70.8% White, 20.8% Black, 8.3% Hispanic, had an average age of 33.l, smoked 18.6 cigarettes per day, began smoking at age 15.7, and had baseline levels of expired CO of 26.2 ppm. 3.2. Craving Craving was indexed as the mean craving response immediately following each VR environment (first neutral, store without cues, second neutral, and store with cues). Dependent samples t-tests were conducted on four planned comparisons: each of the two store environments versus its preceding neutral environment, store without cues versus store with cues, and the first neutral versus the second neutral. Results are accompanied by effect size estimates using Cohen's d ( Cohen, 1988). Craving means and standard errors for each VR environment are displayed in Fig. 2. Self reported craving after each VR environment. Error bars are standard errors ... Fig. 2. Self reported craving after each VR environment. Error bars are standard errors of the mean. Figure options There was a significant increase in craving between the first neutral and the store without cues, t(23) = 5.03, p < .0001, d = 0.95, indicating that an environmental context related to smoking, but devoid of explicit cigarette cues, also elicits craving in smokers. There was also a significant increase in craving between the second neutral and the store with cues, t(23) = 4.44, p < .0001, d = 0.74, which replicates our previous findings indicating an environmental context associated with smoking, with explicit cigarette cues included, elicits craving ( Bordnick et al., 2005 and Traylor et al., 2008). There was also a significant increase in craving between the first neutral and the second neutral, t(23) = 3.18, p < .01, d = 0.64, indicating that, despite a 5-min rest period following the store without cues, craving remained higher than the craving reported after the first neutral environment. Furthermore, a significant increase in craving between store without cues and store with cues, t(23) = 3.20, p < .01, d = 0.58, indicated that the highest level of craving was evoked by the store that combined both contextual and explicit cigarette cues. 3.3. Presence questionnaire The PQ demonstrated good overall internal consistency and reliability with a Cronbach's alpha coefficient of .85. Participants reported a strong overall feeling of presence in the virtual environments (M = 118, SD = 19.4), which is similar to previous VR cue-reactivity research (Bordnick et al., 2008; Bordnick et al., 2005).