AbstractThis paper analyzes the effects of message strength on brand attitude when consumers simulate product usage. The relevant literature suggests that advertising message strength does not matter when consumers imagine product usage, but previous studies do not consider the potential moderating effects of involvement and product category knowledge. The results of this research demonstrate that among high‐involvement consumers who perceive their knowledge in the product category as limited, imagining product usage does not reduce the relevance of a strong advertising message. This paper also shows that overall, imagining product usage positively affects brand attitude – regardless of message strength, involvement, and self‐perceived knowledge. An important practical implication arises from the study. Marketers should encourage mental simulation in their advertisements, but be careful not to set a good argument aside if the product/service is highly relevant to potential customers and the potential customers do not perceive themselves as very knowledgeable about the product category. This finding is particularly relevant to complex or relatively new products, because here, the group of consumers who are highly involved but do not perceive themselves as very knowledgeable may be large. Copyright © 2010 John Wiley & Sons, Ltd.