- Radical behaviourism
- Skinner's philosophical position that all behaviour — including thinking, feeling, and verbal behaviour — can and should be explained in terms of environmental contingencies without reference to mental causes. Unlike methodological behaviourism (Watson's position, which simply excluded mental states from scientific study), radical behaviourism acknowledges that private events like thoughts and feelings exist — but treats them as behaviours caused by the environment, not as causes of other behaviours. Radical behaviourism was both a scientific programme and a philosophical stance on the nature of mind.
- The operant chamber (Skinner box)
- An apparatus designed to study the relationship between an organism's behaviour and its consequences under controlled conditions. The basic version contained a lever (or key for pigeons), a food dispenser, a light, and a speaker — allowing precise measurement and control of stimulus-response-consequence relationships. The chamber made it possible to study behaviour quantitatively over extended periods, producing the cumulative response records that revealed the characteristic patterns of different reinforcement schedules.
- Verbal behaviour
- Skinner's 1957 analysis of language as a category of operant behaviour — shaped by reinforcement like any other behaviour. He distinguished different types of verbal operants: mands (requests, controlled by states of deprivation), tacts (naming, controlled by the stimulus named), intraverbals (responses to other verbal stimuli), and echoics (imitation). Noam Chomsky's 1959 review of Verbal Behaviour became one of the most cited papers in linguistics, arguing that Skinner's account could not explain language acquisition — a critique widely credited with accelerating the cognitive revolution.
- Behaviour modification
- The systematic application of operant principles to change behaviour in applied settings. Techniques include reinforcement of target behaviours, extinction of unwanted behaviours, shaping, and chaining. Behaviour modification has been applied in clinical psychology, education (programmed instruction), management, sports coaching, and parenting — with a particularly strong evidence base in applied behaviour analysis for autism spectrum conditions.
- Walden Two and the designed society
- Skinner's 1948 utopian novel depicted a community governed by behaviourist principles — in which positive reinforcement replaced punishment, work was structured to maximise reinforcement, and child-rearing followed conditioning principles. The novel sparked intense debate about free will, social control, and the ethics of applying behavioural science to social design. Skinner saw it as a hopeful vision; critics read it as a chilling portrait of engineered conformity.
- Beyond Freedom and Dignity (1971)
- Skinner's most controversial book argued that the concepts of autonomous agency, free will, and personal moral responsibility are prescientific fictions that obscure the environmental determinants of behaviour. Acknowledging these determinants, he argued, is not dehumanising — it is the prerequisite for designing environments that reliably produce human flourishing rather than leaving behaviour to unplanned contingencies. The book was widely misread as a call for authoritarian control and was fiercely attacked by humanist psychologists, philosophers, and the general press.