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.
Social
Living organisms including humans are social when they live collectively in interacting populations, whether they are aware of it, and whether the interaction is voluntary or involuntary.
Social Science
Social science is a major category of academic disciplines, concerned with society and the relationships among individuals within a society. Social science as a whole has many branches, each of which is considered a social science. The social sciences include, but are not limited to: anthropology, archaeology, economics, history, human geography, jurisprudence, linguistics, political science, psychology, public health, and sociology. The term is also sometimes used to refer specifically to the field of sociology, the original "science of society", established in the 19th century. For a more detailed list of sub-disciplines within the social sciences see: Outline of social science.
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.