The complex behaviour of our society emerges from decisions made by many individuals. In certain combinations, these numerous decisions can lead to sudden catastrophe, as demonstrated during crowd disasters and financial crises. Here, we investigate whether analyses of queries to the search engine Google may be able to give us insight into the early information gathering stages of collective decision making in financial markets. Results of the implementation of a profitable hypothetical trading strategy are consistent with the proposal that changes in the volume of online searches for information about a company may be detected before large stock market moves. These results suggest that big data capturing our everyday interactions with the Internet may be able to provide new evidence for the science of collective decision making.
IntroductionThe increasing volumes of "big data" reflecting various aspects of our everyday activities represent a vital new opportunity for scientists to address fundamental questions about the complex social world we inhabit [1][2][3][4][5][6][7][8][9][10][11][12][13]. Studies in this area have demonstrated promising links between aggregate online behaviour and collective real world behaviour across a range of data sources such as the search engine Google [14][15][16][17][18][19][20][21], the search engine Yahoo! [22,23], the online encyclopedia Wikipedia [24][25][26][27][28], the microblogging platform Twitter [29][30][31][32][33][34] and the photosharing website Flickr [35,36]. For example, a recent study has demonstrated that Internet users from countries with a higher per capita GDP are more likely to search for information about years in the future than years in the past [37,38].Such studies have generally interpreted changes in search volume as changes in interest and attention to a subject. This permits compelling explanations of relationships between online and real life behaviour in areas where increases in search activity can be linked to increases in real life activity in a straightforward T. Preis ( ) • H.S. Moat