Cognition refers to the process of coming to know the world and our place within it. Cognitive neuroscience is the field of inquiry devoted to understanding how the brain enables cognition. Work in this field focuses on defining the neural processes that permit us to perceive and attend to events, determine their meaning and relevance, and respond appropriately. A key discovery in this field was that the higher mental functions, such as attention, memory, emotion, decision-making and language arise through the activation of dedicated neural circuits localized in discrete areas of the brain. Notably, cognitive neuroscience actively probes subjective states such as emotion, imagery and awareness, which were considered inappropriate for scientific study by behaviourist psychologists of the early and middle twentieth century.