| More than four decades ago, Stanley Milgram and his collaborators performed a series of original experiments to test the small-world hypothesis: whether any random pair of individuals can be connected through short chains of acquaintances. They found support for the hypothesis and their results are currently known as the "six degrees of separation." Closer examinations, however, revealed that Milgram's experiments actually confirmed two related but distinct hypotheses: topological and algorithmic small-world hypotheses. Topological small-world hypothesis posits that there are short paths connecting two individuals. Algorithmic small-world hypothesis asserts that individuals with limited information can actually find these short paths by actively searching social networks. The goals of this dissertation are two-fold: (1) to test the algorithmic small-world hypothesis, and (2) to understand the mechanisms that make the algorithmic small-world possible. To achieve the first goal, we used data from our global internet-based search experiment and, using a novel statistical method, estimated algorithmic distance distributions. Then we used computational models to understand search processes and identified search strategies, individual characteristics, and structural conditions that increase the probability of success in search processes. |
