TripAdvisor and other review sites turn us into copycats by creating 'herd mentality' People who read positive reviews are more likely to leave positive remarks Online review websites such as TripAdvisor cannot be trusted because they create a "herd mentality," researchers say. People who read positive reviews on the world's largest travel website are far more likely to leave their own positive remarks. Negative votes or comments, on the other hand, are not nearly so persuasive, a team from America's Massachusetts Institute of Technology found. Online review websites such as TripAdvisor cannot be trusted because they create a 'herd mentality', researchers say Users who saw faked positive reviews on an unnamed website were 32 per cent more likely to write their own approving review. The faked positive reviews also had final ratings that were 25 per cent higher than average. Negative comments, among the 6,000 doctored reviews, were often quickly corrected by other users who had been influenced. The researchers behind the study called the phenomenon "positive herding" and warned consumers to be on their guard when looking at sites like Yelp or Amazon. The findings suggests that, when it comes to the Internet at least, the wisdom of the crowd is not what it used to be. They will also be welcomed by critics of Tripadvisor, which hoteliers claim has become a tool to threaten them with unless they get five star customer service. The US team collaborated with an unnamed website that has reader comments on news articles for its research. People who read positive reviews on the world's largest travel website are far more likely to leave their own positive remarks Readers can also give individual comments an up or down vote. The experiment involved using a small and random change on the ratings of the comments over a five month period. Reflecting the existing trend on the website towards positive reviews, some 4,049 comments were given fake positive feedback and 1,942 were given fake negative feedback. The findings showed that the first person reading the comment was 32 per cent more likely to approve of it than if it had not been tampered with. Subsequent ratings were not affected. Lead researcher Sinan Aral, a professor of information technology and marketing at the Massachusetts Institute of Technology, said this was a "significant change." He said that small signals of influence can create a "snowball effect" that demonstrated "hype can work and feed on itself as well." Professor Aral said: "It's a bit worrisome. If you think even beyond ratings, if this herding behavior, or the tendency toward bubbles is true, it has implications for housing prices, stock market prices, and we need future research in other settings. With the world migrating to the Internet, consumers are nowadays relying on online reviews ever more to decide what to buy. But they are problematic, not least because companies can pay for agencies to give them positive write-ups with fake names. Tripadvisor, which is worth £3billion and is the largest travel review website in the world, has attracted the most criticism because of the damage it supposedly does to the travel industry. Experts have gone so far as to claim that between 10 and 20 per cent of Tripadvisor reviews are fake. The most celebrated case against it was that of Richard Gollin, who owns a guest house on the Isle of Lewis in the Outer Hebrides. He sued Tripadvisor for £3,000 after customers confirmed they had cancelled bookings because of criticism they read on the site, but dropped the case over the legal bills. Eyebrows were also raised when a £35-a-night hotel in North Wales was rated the best in the world, according to Tripadvisor users at least. Christopher Chabris, an associate psychology professor at Union College who was not involved in the research, advised people using online review websites to use a bit of common sense. He said: "The case where the wisdom-of-the-crowd effects work well is where each person brings their own observation and knowledge, however imperfect and idiosyncratic. What this shows is when you don't have that independence and everyone sees the history of other people's opinions, you can get big biases in the outcome.