We examined the causal effect of external quality cues on brand image of cigarettes, in the absence of any internal cue, among Iranian adults. The experimental research employed a 3*2*2 factorial design with three levels of graphic quality, two levels of price and two levels of product variety signs. Results suggested that all three factors had an impact on brand image, though the effects varied noticeably among smokers and non-smokers. The effect of moderating variables was also studied and results indicated that a respondent's profile and status, particularly his age, education, marital status and number of cigarette-consuming companions could influence the way he interprets the quality cues. Moderating factors were formulated as a new variable we called it permeability.