Psychology is the practice of studying, teaching or applying an understanding of the mind, thought and behaviour. It is largely concerned with psychology of humans, although the behaviour and thought of non-human animals is also studied; either as a subject in its own right (see animal cognition), or more controversially, as a way of gaining an insight into human psychology by means of comparison (see comparative psychology).

Psychology is conducted both scientifically and non-scientifically. Mainstream psychology is based largely on positivism, using quantitative studies and the scientific method to test and disprove hypotheses, often in an experimental context. Psychology tends to be eclectic, drawing on scientific knowledge from other fields to help explain and understand behaviour. However, not all psychological research methods are scientific, and some may involve qualitative or interpretive techniques more allied to the humanities. Some psychologists, particularly adherents to humanistic psychology, may go as far as completely rejecting a scientific approach. However, mainstream psychology has a bias towards the scientific method, which is reflected in the dominance of cognitivism as the guiding theoretical framework used by most psychologists to understand thought and behaviour.

Psychology does not necessarily refer to the brain or nervous system and can be framed purely in terms of phenomenological or information processing theories of mind. Increasingly though, an understanding of brain function is being included in psychological theory and practice, particularly in areas such as artificial intelligence, neuropsychology and cognitive neuroscience.

Psychology differs from sociology, anthropology, economics, and political science, in part, by studying the behaviour of individuals (alone or in groups) rather than the behaviour of the groups or aggregates themselves. While psychological questions were asked in antiquity (c.f., Aristotle's De Memoria et Reminiscentia or "On Memory and Recollection"), psychology emerged as a separate discipline only recently. The first person to call himself a "psychologist", Wilhelm Wundt, opened the first psychological laboratory in 1879. Please continue.