In 2004 , James Surowiecki ( an American Journalist ) published a book called “ The Wisdom of Crowds “ which talked about the aggregation of information in group , resulting in decisions that often better than it could have been made by any single member of the group. The Wisdom of Crowds is generally traced back to an observation by Charles Darwin’s cousin Francis Galton in 1907. Galton pointed out that the average of all the entries in a ‘guess the weight of the ox’ competition at a country fair was amazingly accurate – beating not only most of the individual guesses but also those of alleged cattle experts. This is the essence of the wisdom of crowds: their average judgement converges on the right solution. On contrary , this book “ Extraordinary Popular Delusion and Madness of Crowds “ by Charles MacKay wrote about the crowd psychology that drive ......