Foundations Of Cognitive Science

Imagery Debate

The imagery debate centres around the problem of what can be viewed as the primitives of cognition. Primitives serve as the foundation of the algorithmic level of the computational hierarchy. Presumably, it is these primitives which are implemented in the physical substrate of the brain.

The central question related to the imagery debate then is: Do images form the basis of all our higher cognition? If not, what does? Could propositions serve that function? Or both images and propositions? Or something altogether different?

Historically, the imagery debate was conducted between two camps: the depictive camp, which argued that the pictorial properties of images were primitive (Kosslyen et al., 1979) and the propositional camp, which argued that these properties were derived from other primitives, such as propositional logic (Pylyshyn, 1981). By the 1980s, the debate had faded from the literature, largely because many believed Anderson's (1978) argument that it could never be resolved with available evidence. However, the debate has re-emerged recently as some have argued that the depictive properties of images are grounded in the brain (Kosslyn, 1994; Kosslyn et al., 2003). Unsurprisingly, the propositional camp has replied to these more recent depictive arguments (Pylyshyn, 2003a, 2003b).


  1. Anderson, J. R. (1978). Arguments concerning representations for mental imagery. Psychological Review, 85, 249-277.
  2. Kosslyn, S. M. (1994). Image and Brain. Cambridge, MA: MIT Press.
  3. Kosslyn, S. M., Ganis, G., & Thompson, W. L. (2003). Mental imagery: against the nihilistic hypothesis. Trends in Cognitive Sciences, 7(3), 109-111.
  4. Kosslyn, S. M., Pinker, S., Smith, G., & Shwartz, S. P. (1979). On the demystification of mental imagery. The Behavioral and Brain Sciences, 2, 535-581.
  5. Pylyshyn, Z. W. (1981). The imagery debate: Analogue media versus tacit knowledge. Psychological Review, 88, 16-45.
  6. Pylyshyn, Z. (2003a). Return of the mental image: are there really pictures in the brain? Trends in Cognitive Sciences, 7(3), 113-118.
  7. Pylyshyn, Z. W. (2003b). Explaining mental imagery: now you see it, now you don't - Reply to Kosslyn et al. Trends in Cognitive Sciences, 7(3), 111-112.

(Revised February, 2010)