Cognitive Science
Cognitive science is the interdisciplinary, scientific study of the mind and its processes. It examines the nature, the tasks, and the functions of cognition (in a broad sense). Cognitive scientists study intelligence and behavior, with a focus on how nervous systems represent, process, and transform information. Mental faculties of concern to cognitive scientists include language, perception, memory, attention, reasoning, and emotion; to understand these faculties, cognitive scientists borrow from fields such as linguistics, psychology, artificial intelligence, philosophy, neuroscience, and anthropology. The typical analysis of cognitive science spans many levels of organization, from learning and decision to logic and planning; from neural circuitry to modular brain organization. The fundamental concept of cognitive science is that "thinking can best be understood in terms of representational structures in the mind and computational procedures that operate on those structures."
Psychology
Psychology is the science of behavior and mind, including conscious and unconscious phenomena, as well as feeling and thought. It is an academic discipline of immense scope and diverse interests that, when taken together, seek an understanding of the emergent properties of brains, and all the variety of epiphenomena they manifest. As a social science it aims to understand individuals and groups by establishing general principles and researching specific cases.
Science
Too often, this concern for the big picture is simply obscurantist and is put forward by people who prefer vagueness and mystery to (partial) answers. Vagueness is at times necessary and mystery is never in short supply, but I don’t think they’re anything to worship. Genuine science and mathematical precision are more intriguing than are the “facts” published in supermarket tabloids or a romantic innumeracy which fosters credulity, stunts skepticism, and dulls one to real imponderables.
John Allen Paulos, Innumeracy: Mathematical Illiteracy and its Consequences (1988), pp. 126-127
Science
Alas! A scientific man ought to have no wishes, no affections — a mere heart of stone.
Charles Darwin, in a letter to T.H. Huxley, 9 July 1857, More Letters of Charles Darwin, Francis Darwin and A.C. Seward, editors (1903) volume I, chapter II: "Evolution, 1844-1858", page 98.
Psychology
We cannot describe how the mind is made without having good ways to describe complicated processes. Before computers, no languages were good for that. Piaget tried algebra and Freud tried diagrams; other psychologists used Markov Chains and matrices, but none came to much. Behaviorists, quite properly, had ceased to speak at all. Linguists flocked to formal syntax, and made progress for a time but reached a limit: transformational grammar shows the contents of the registers (so to speak), but has no way to describe what controls them. This makes it hard to say how surface speech relates to underlying designation and intent–a baby-and-bath-water situation. I prefer ideas from AI research because there we tend to seek procedural description first, which seems more appropriate for mental matters.
Marvin Minsky, in "Music, Mind, and Meaning" (1981)