Social Cognitive Optimization (SCO) is a simple optimization model based on the obseravational learning in human social cognition. The foundational entity for simulating human cognition is social cognitive (SC) agent. Each SC agent includes a memory (MD) and a set of action rules. Specially, the agent acquires social sharing information (called I) not only from the MD of other agents, but also from the medium, called library (L), which stores NL points.