influential for later consumers. While the aggregated ratings transfer overall evaluation towards products, they might also bring biases to potential consumers. In this study, we hypothesize the collective rating presence induces a confirmation bias in product review perception. We also propose that the level of expectation moderates the effect of confirmation bias. Using online reviews of multiple product categories from Amazon.com, our results support the hypotheses and help understand the direct and indirect roles of collective rating presence in affecting people’s perception of review information: not only people are more likely to perceive reviews that confirm their expectation as more helpful, but they are more prone to the confirmation bias as their prior expectations towards the products are higher. Our research contributes to the current understanding of collective rating presence, reconciles the inconsistent findings in prior research on online review helpfulness and provides insights to consumer behaviours on information seeking and interpretation.