Picture yourself scrolling through product reviews before buying a new pair of headphones. One review reads like a confident verdict, stating plainly what the product is and is not. Another sounds more personal, sharing what the writer felt and experienced. Which one nudges you toward a purchase, and which one quietly turns you off?
A study published in Marketing Letters examined a gap that turns out to matter for businesses that depend on customer reviews: the people who feel most sure their reviews will sway others may be writing the reviews that persuade the least.
A question about who judges a review
Most research on online reviews has asked what makes a review work from the reader’s side. Readers tend to find reviews persuasive when they are specific, detailed, include images, or come from someone who seems trustworthy. But Janina Steinmetz of Bayes Business School at City University of London and Emily Pronin of Princeton University wanted to add a perspective that earlier work mostly skipped: how the person writing the review judges it.
That perspective matters because reviewers decide whether to bother writing and sharing a review in the first place. If someone thinks their opinion will land with force, they are likely to post it. If they think it will fall flat, they may stay quiet. So a reviewer’s confidence shapes which reviews ever reach the public.
The authors built their investigation around a concept from psychology called the “objectivity illusion.” The idea is that some people strongly believe they see the world as it truly is, and they assume that anyone who disagrees with them must be biased or simply uninformed. People vary in how much they hold this belief, a trait the researchers call objectivism. Someone high in objectivism might agree with a statement like, “If somebody disagrees with me, it’s usually because they are mistaken or biased.”
Steinmetz and Pronin proposed that this trait would pull reviewers and readers in opposite directions. Reviewers high in objectivism, they reasoned, would assume that sharing their “correct” opinion would naturally convince others. Readers, on the other hand, might sense an air of superiority in those reviews and find the writer less likable, which in turn could make the review less persuasive.
How the studies worked
The team ran two main studies and one additional study, recruiting participants through Amazon Mechanical Turk, an online platform where people complete small tasks for pay. Across the studies, reviewers wrote a single review, while readers each evaluated ten reviews, mirroring how reviewing and reading typically happen in real life.
In the first study, 162 reviewers browsed posts from four Instagram accounts, picked the one they liked best, and wrote a recommendation for it. They then rated how persuasive they thought their own review was. Separately, every reviewer completed an 11-item questionnaire measuring objectivism. A second group of 200 readers then read ten randomly selected reviews and rated each one for persuasiveness, along with how likable and relatable the writer seemed.
The results split along the predicted line. The more objectivist a reviewer was, the more persuasive they believed their own review to be. Yet among readers, the pattern reversed: reviews written by more objectivist reviewers were rated as less persuasive. Readers also found those reviewers less likable, and the researchers’ analysis indicated that this drop in likability was the thread connecting objectivism to weaker persuasion. In plain terms, more objectivist reviewers came across as less likable, and that lower likability was linked to readers finding their reviews less convincing.
The authors checked whether something simpler might explain the finding. Maybe objectivist reviewers just enjoyed the task more, liked the account more, or wrote longer reviews. None of those explanations held up. Longer reviews did strike readers as more persuasive, consistent with earlier research, but review length did not account for the objectivism effect.
To get a sense of what set the reviews apart, the researchers used a large language model to compare reviews written by the most and least objectivist participants. Reviewers low in objectivism tended toward warm, enthusiastic, and humble language, with lines like “She’s my favorite!” Those high in objectivism leaned toward detached, ironic, or critical phrasing, such as “It’s hard to tell if she’s serious or satirical.” The authors suggest that warmth and humility generally read as more likable than distance and irony.
From confidence to sharing
The second study, with 191 participants, moved from a niche product to something familiar to nearly everyone: chocolate M&Ms. Participants wrote a review, rated how persuasive they thought it was, and then decided whether to let their review be shown to other people in future studies. The researchers stated clearly that this choice would not affect their pay.
Again, higher objectivism was linked to greater confidence in one’s own review. And that confidence carried into behavior. The analysis showed that more objectivist reviewers were more confident, and that greater confidence was associated with a higher willingness to share the review. Most participants chose to share, which the authors note as a limitation, but the link between perceived persuasiveness and the decision to share came through.
Because the first two studies relied on positive reviews, the team ran a supplemental study to see whether the pattern extended to criticism. This time, 196 participants picked a product they had recently bought and disliked, then wrote a negative review. The same relationship appeared: more objectivist reviewers believed their negative reviews were more persuasive. They also tended to see their reviews as more objective, and that belief was linked to thinking the reviews were more convincing.
What it might mean for businesses
Taken together, the studies point to a mismatch the authors find worth attention. The reviewers most eager to broadcast their opinions may be producing reviews that readers find less compelling. As the researchers put it, “especially those reviewers who write less persuasive reviews are willing to share them.”
Steinmetz and Pronin suggest a few practical responses for companies that solicit reviews. One is to guide reviewers toward a more personal framing. A follow-up email after a purchase might invite customers to describe their own experience and add a note like “there are no right or wrong opinions,” which could steer writers away from a stance that reads as superior. Another suggestion is to avoid leaning only on the customers who volunteer most readily, perhaps by offering targeted incentives that draw in a wider range of reviewers.
A few caveats are worth keeping in mind. The studies were run with online task-workers rather than actual shoppers on a retail site, and the products ranged from Instagram accounts to candy. The link between confidence and the willingness to share was statistically modest in the M&Ms study, and most participants chose to share regardless. The work also describes associations among traits and perceptions rather than proving that one directly causes another in every case. Still, the research offers evidence that the person behind a review, and how sure they are of their own objectivity, may shape which opinions ever reach the rest of us, and how well those opinions land.
