This chapter describes how the question of how animals perceive their world led to developments in discrimination training. These studies included ones that, for example, tested whether a dog, cat, or rat could learn to discriminate between two stimuli that differed only in color. Developments in the study of discrimination learning became increasingly theoretical. For example, one important issue had to do with the possible role of attention in discrimination learning. Rejection of this possibility by the highly influential behaviorist, Kenneth Spence, led to his important continuity theory. In turn, studies of phenomena such as transfer-along-a continuum and the overtraining-reversal-effect in the 1950s and 1960s by a series of researchers, including Stuart Sutherland and Nick Mackintosh in the UK, led to a revival of interest in selective attention in discrimination learning. The final section describes studies of stimulus generalization and behavioral contrast.

All the conspirators could read, and most could write, more or less. Radical newspapers and tavern trade clubs and societies provided their political education. ’Low’ radicals in regency London were as deeply influenced by the agrarian socialist Thomas Spence as by Tom Paine, but, either way, their values drew on Enlightenment. They believed in the people’s right to resist oppression, and some hoped for the redistribution of landed property throughout the kingdom.Spence propagated his ideas through slogans, songs, graffiti, and tokens as well as pamphlets and books; and after his death in 1814 they were propagated through the Society of Spencean Philanthropists and Wedderburn’s ‘chapel’ in Soho, to both of which key conspirators belonged.