"Imagery played a central role in theories of the mind for centuries. For example, the British Associationists conceptualizes thought itself as sequences of images. And, Wilhelm Wundt, the founder of scientific psychology, emphasized the analysis of images. However, the central role of imagery in theories of mental activity was undermined when Kulpe, in 1904, pointed out that some thoughts are not accompanied by imagery (e.g., one is not aware of the processes that allow one to decide which of two objects is heavier)."