Trends or fashions are spontaneous collective decisions made by large portions of a community, often without an apparent good reason. Trend formation provides a well documented mechanism for the creation of culture, the spread of information and the self-regulation of social behavior.
This applies not only to trivial matters of popular culture but also to aspects of social organization (e.g. crime, political decision making), in economics and indeed in setting directions for scientific research. In this talk I introduce an agent-based dynamical model that captures the essence of trend formation and collapse.
I will show that it leads to complex global dynamics, alternating states of great variety (large information entropy) with others where large trends spontaneously emerge.
This behavior bears interesting analogies with physical systems undergoing critical phenomena. I will also discuss the robustness of trends under external influences, such as population growth and information biases. Finally I will analyze the influence of social networks. I will concentrate on the effects of community structure within a larger populations and on the influence of community leaders as public opinion bellwethers.