This chapter explores critiques of behaviourist theory, since many guidelines for educators that use this conceptual lens fail to declare their theoretical foundations, and so often disguise their limitations. The focus of the behaviourist approach is, as the name suggests, on overt, observable and measurable behaviour, rather than thoughts, feelings or internal processes of learning. The early 20th century saw an increase in research into learning as a behaviour, exploring how and where learning occurs and how it can be sustained. In the primary school yard, the stimulus of the bell causes the conditioned response in the children of lining up and moving towards the classroom. The teachers may have to intervene with a small number of children to keep them on track, but for the most part, behaviourist principles of associative learning ensure that behaviour remains positive, and the transition from yard to class is smooth.