What is psychology?

Definition

Psychology investigates how minds work and how organisms behave, spanning processes from sensation and perception to learning, memory, motivation, emotion, language, and social interaction. It is defined by its method as much as its subject matter: psychologists frame questions as testable hypotheses and gather evidence through controlled experiments, observation, surveys, and measurement. This commitment to systematic, replicable enquiry is what distinguishes psychology as a science from informal everyday reasoning about people.

Major perspectives

Psychology contains several theoretical perspectives that emphasise different causes of behaviour. The behavioural perspective focuses on observable responses and learning; the cognitive perspective on internal mental processes such as attention and memory; the biological perspective on the brain, genetics, and physiology; and the social and developmental perspectives on context and change over time.

Other influential approaches include the psychodynamic tradition associated with Freud and the humanistic perspective. Modern psychology is typically integrative, drawing on whichever perspectives best explain a given phenomenon rather than committing to a single school.

Sub-disciplines

The field is broad, encompassing cognitive psychology, developmental psychology, social psychology, biological and neuropsychology, personality psychology, and many applied areas such as educational, organisational, and health psychology. Quantitative and methodological specialisms — including psychometrics and statistics — support the whole discipline by developing the tools used to measure psychological constructs and analyse data. This breadth reflects the wide range of questions that fall under the study of mind and behaviour.

Psychology as an empirical science

Because its subject matter is often abstract and not directly observable, psychology depends heavily on careful measurement and research design. Constructs such as intelligence, attitude, or anxiety must be operationalised — defined in terms of measurable indicators — and assessed with attention to reliability and validity. Standards of evidence, replication, and transparent reporting are central to the discipline's credibility and link it closely to the wider methods and integrity standards of empirical research.