Under this assumption, which requires an epistemological shift from empiricism, situativity theorists suggest a model of knowledge and learning that requires thinking on the fly rather than the storage and retrieval of conceptual knowledge. In essence, cognition cannot be separated from the context. Instead knowing exists, "in situ", inseparable from context, activity, people, culture, and language. Therefore, learning is seen in terms of an individual's increasingly effective performance across situations rather than in terms of an accumulation of knowledge, since what is known is co-determined by the agent and the context. This perspective rejects mind–body dualism, being conceptually similar to functional contextualism, and B. F. Skinner's behavior analysis.