Preconscious attentional bias in cigarette smokers: a probe into awareness modulation on attentional bias

It has been frequently reported that smokers showed attentional bias toward smoking-related stimuli. The current study aimed to examine whether such bias was also present when subjects were unaware of the presented stimuli and the possible role of awareness modulation on attentional bias. With a psychophysical approach (interocular suppression), we suppressed subjects' awareness to the cigarette pictures presented to one of their eyes. The visual dot probe task was modified to increase the perceptual load and to control the physical features between two rivaling images. Twenty-eight male smokers and 25 male non-smokers participated in the experiment. We found a significant interaction between experiment conditions and subject groups, with only the smoker group showed attentional bias toward cigarette pictures in unaware condition. Moreover, smokers' attentional bias in unaware condition was negatively correlated with their scores on Cigarette Dependence Scale while their attentional bias in aware condition was positively correlated with scores on Questionnaires of Smoking Urges. Such dissociation indicates the possibility of awareness modulation on attentional bias: it is possible that in aware condition, the attentional bias was modulated by smoking urge in awareness, thus concealed the effect of dependence degree. Further studies indicated that awareness modulated attentional bias through many factors, such as craving, quit attempt, attitude and disgust. Interestingly, non-smokers also showed attentional bias in aware condition, which further suggested that due to awareness modulation, attentional bias could even be addiction-unrelated.