The internal structures and processes that are involved in the acquisition and use of knowledge, including sensation, perception, attention, learning, memory, language, thinking, and reasoning. These behaviors are studied by cognitive scientists, a group that includes, but is not limited to, researchers in the areas of cognitive psychology, philosophy, linguistics, computer science, and cognitive neuroscience. Cognitive scientists propose and test theories about the functional components of cognition based on observations of an organism's external behavior in specific situations.