Washington: People are heavily influenced by the positive opinions others express online but are much less swayed by negative opinions posted in the same venues, a new study has found.
The study co-authored by a researcher from Massachusetts Institute of Technology (MIT) detailed a five-month experiment conducted on a major news-aggregation web site.
The research group systematically altered the favourability ratings given to certain comments on the site, to see how perceptions of favourability affected people`s judgement about those comments.
They found that comments whose ratings were manipulated in a favourable direction saw their popularity snowball, receiving a 25 per cent higher average rating from other site users.
"This herding behaviour happens systematically on positive signals of quality and ratings," said Sinan Aral, an associate professor at the MIT Sloan School of Management, and one of three authors of the study.
At the same time, Aral noted, the results "were asymmetric between positive and negative herding."
Comments given negative ratings attracted more negative judgements, but that increase was drowned out by what the researchers call a "correction effect" of additional positive responses.
"People are more skeptical of negative social influence. They`re more likely to `correct` a negative vote and give it a positive vote," Aral said.
While this phenomenon of social positivity sounds pleasant enough on the surface, Aral warned that there are pitfalls to it, such as the manipulation of online ratings by some political operatives, marketers or anyone who stands to profit by creating an exaggerated appearance of popularity.
The experiment also revealed topical limitations in herding: Stories under the rubrics of "politics," "culture and society" and "business" generated positive herding, but stories posted under the topics of "economics," "IT," "fun" and "general news" did not.
The researchers also found that comments manipulated to have positive ratings were 32 per cent more likely than untreated comments to receive a favourable rating from the very next viewer of those comments, and 30 per cent more likely than untreated comments to obtain a very high favourable rating.
The other study authors include Lev Muchnik of the Hebrew University of Jerusalem and Sean Taylor of New York University.
The results were published in the journal Science.