ABSTRACT
This chapter provides an outline of the transition from traditional animal learning to modern comparative cognition. It considers the advantages and disadvantages of advancing to complex and extended stimuli in studies of stimulus control. The chapter presents experimental results concerning the role of exposure to real-world locations on discrimination and generalization of complex natural scenes depicted in slide photographs. The chapter discusses the advances in our understanding of the nonhuman mind and cognitive abilities brought about by the shift from stimulus control by few simple artificial stimuli to stimulus control by many complex natural stimuli. Discrimination training consists of at least two discriminable stimuli: responses directed at one (S+) are reinforced and responses directed at the other (S-) are not reinforced. The notion that the discrimination was based on a concept, rather than on rote memorization of meaningless blobs, marks a turning point in the history of research on stimulus control in nonhumans.
