As outlined in Chapter 7 , psychology began in the late nineteenth century as the study of mental processes, but the dominance of the behavioural perspective in the fi rst half of the twentieth century saw the virtual abandonment of cognition as a topic of psychological investigation. By the end of the 1950s, however, many researchers were becoming increasingly dissatisfi ed with what they saw as the limitations of radical behaviourism. The behavioural paradigm, it was argued, failed to account for the complexity and creativity of human behaviour. More particularly, it did not capture the very quality that makes us human, namely our capacity to think.