The current research systematically investigates the role of social identity framing in consumer choice and its underlying mechanism.We propose that compared with a narrow identity framing,a broad identity framing can activate a broader category of self-knowledge and enhance subjective knowledge,which will in turn leads people to behave more optimistically in subsequent tasks.Across three empirical experiments,our findings suggest that participants who are more accessible to a broad identity (vs.a narrow identity) will predict better performance in cognitive test (experiment l) and be more likely to choose professional model of products (experiment 2-3).