Cognitive: The earliest entries for the word “cognitive” in the OED take it to mean roughly pertaining “to the action or process of knowing”.
Cognitive science: the term :
The term “cognitive” in “cognitive science” is “used for any kind of mental operation; cognitive process, or structure that can be studied in precise terms” (Lakoff and Johnson, 1999).
The term “cognitive science” was coined by Christopher Longuet-Higgins in his 1973 commentary on the Light hill report, which concerned the then-current state of Artificial Intelligence research.
Cognitive Psychology:
Cognitive psychology is concerned with information processing, and includes a variety of processes such as attention, perception, learning, and memory. It is also concerned with the structures and representations involved in cognition. Cognitive psychology is one of the more recent additions to psychological research, having only developed as a separate area within the discipline since the late 1950s and early 1960s following the “cognitive revolution” initiated by Noam Chomsky’s 1959 critique of behaviorism and empiricism more generally.
The core focus of cognitive psychology is on how people acquire, process and store information. There are numerous practical applications for cognitive research, such as ways to improve memory, how to increase decision-making accuracy, and how to structure educational curricula to enhance learning.
Cognitive science:
Cognitive science can be defined as the study of mind or the study of thought. We can also define it as the interdisciplinary study of cognition. Cognition includes mental states and processes such as thinking, remembering, language understanding and generation, visual and auditory perception, learning, consciousness, emotions, etc. It embraces multiple research disciplines, including psychology, artificial intelligence, philosophy, neuroscience, linguistics, anthropology, sociology, and biology. It relies on varying scientific methodology (e.g. behavioral experimentation, computational simulations, neuro-imaging, statistical analyses), and spans many levels of analysis of the mind (from low-level learning and decision mechanisms to high-level logic and planning, from neural circuitry to modular brain organization, etc.).
Some cognitive scientists limit their study to human cognition; other consider cognition independently of its implementation in humans or computers.