Expressions of doubt and trust in online user reviews

How do expressions of doubt affect trust in online reviews? Previous research leads to conflicting predictions: some studies find that people trust confident advisors more than doubtful advisors, whereas others find doubtful advisors are trusted more, especially when advisors have salient conflicts-of-interest. We tested the effects of doubt in the Yelp Open Dataset (N = 5.9 million user reviews). Reviews were coded using the Linguistic Inquiry Word Count (LIWC) software, which contains two dictionaries related to doubt, tentativeness and (lack of) certainty. Doubtful reviews were more likely to be seen as useful, and this result was robust when controlling for other psychological variables, as well as review length and linguistic complexity. The beneficial consequences of expressing doubt were strongest for positive (5-star) reviews, suggesting that doubt may mitigate concerns about the veracity of overly positive reviews. The present study emphasizes the advantages of expressing doubt.