I will introduce a series of interesting phenomena in social networks: (a) opinion diffusion (b) social influence and (c) social relation change. Within each agent's situation, local changes in state are characterized both by an automaton and by a dynamic operator in a certain logical language. These two ways of modeling lead to different research questions which I will explain and show some results. Constraints are introduced when we combine the local situations to obtain a global one. My focus will be the logic of the agent's reasoning, in particular, higher-order reasoning. I will also show a few simulations of the dynamics in NetLogo.This is a joint project with Jeremy Seligman.