 The variety among the deflationary explanatory approaches that characterized the theories of attention offered in the nineteenth century gave way in the early twentieth century to a period in which one such explanatory tactic was dominant: the tactic of behaviourism. Behaviourists tended to neglect attention, but did not ignore it entirely. John Dashiell’s 1928 Fundamentals of Objective Psychology, for example, is a behaviourist work that attempts to account for attention “as a form of posturing” (Ch. 10, §3). The project of identifying a behaviour with which to explain attention was, nonetheless, an understandably unpopular one. As Gilbert Ryle notes, it is not only attention, but also ‘heed concepts’ more generally, that resist simple behaviourist analysis: