The Wisdom of Herds: How Social Mood Moves the World

By John Casti from NewScientist 

"Put simply, the mood of a group - an institution, state, continent or even the world - is how that group, as a group, feels about the future. Is the group optimistic or pessimistic? Clearly, this question must be addressed on the timescale appropriate for the type of event we care about. For instance, in a short-timescale prediction such as the sort of films people will like next year, it would be useless to look at the shifting mood of the population over decades. But decades would be exactly right for a phenomenon like globalisation."

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