The paper gives a geometry based explanation for organization ecology's resource partitioning theory. The original theory explains market histories of generalist and specialist organizations with scale economies. We show that the main predictions can be restated in terms of certain structural properties of the n-dimensional Euclidean resource space. We… (More)
Network diversity yields context-dependent benefits that are not yet fully-understood. I elaborate on a recently introduced  distinction between tie strength diversity and information source diversity, and explain when, how, and why they matter. The issue whether there are benefits to specialization is the key.
Resource partitioning theory claims that " Increasing concentration enhances the life chances of specialist organizations. " We systematically think through this theory, specify implicit background assumptions, sharpen concepts, and rigorously check the theory's logic. As a result, we increase the theory's explanatory power, and claim— contrary to received… (More)
Diffuse competition due to niche overlap between actors without (direct) ties with each other, constrains their structural autonomy. This is not dealt with in Burt's mathematical model of his well-known structural holes theory. We fix his model by introducing a network measure of niche overlap. In structural holes, the social structure of competition, Burt… (More)
Humans often coordinate their social lives through norms. When a large majority of people are dissatisfied with an existing norm, it seems obvious that they will change it. Often, however, this does not occur. We investigate how a time lag between individual support of a norm change and the change itself hinders such change, related to the critical mass of… (More)
For people to act collectively in actual situations—in contrast to public goods experiments—goal ambiguity, diversity of interests, and uncertain costs and benefits stand in their way. Under such conditions, people seem to have few reasons to cooperate, yet the Arab revolutions , as conspicuous examples, show that collective action can take place despite… (More)
Collective violence in direct confrontations happens in short bursts wherein small subgroups briefly attack small numbers of opponents, while the majority of participants forms a supportive audience. These bursts can be explained by Kuramoto's synchronization model.
One of the big questions about social life is how people manage to cooperate for public goods. Current answers rely on individuals' relations and reputations, but have difficulty explaining the onset, when relations are sparse and reputations largely unknown. The challenge rises when realizing that actual situations are often characterized by uncertainties… (More)