The proactive brain: memory for predictions

Abstract

It is proposed that the human brain is proactive in that it continuously generates predictions that anticipate the relevant future. In this proposal, analogies are derived from elementary information that is extracted rapidly from the input, to link that input with the representations that exist in memory. Finding an analogical link results in the generation of focused predictions via associative activation of representations that are relevant to this analogy, in the given context. Predictions in complex circumstances, such as social interactions, combine multiple analogies. Such predictions need not be created afresh in new situations, but rather rely on existing scripts in memory, which are the result of real as well as of previously imagined experiences. This cognitive neuroscience framework provides a new hypothesis with which to consider the purpose of memory, and can help explain a variety of phenomena, ranging from recognition to first impressions, and from the brain's 'default mode' to a host of mental disorders.

Figure 1

Combining object and context information to find a quick and reliable analogy. In parallel to the bottom–up systematic progression of the image details along the visual pathways, there are quick projections of low spatial frequency (LSF) information, possibly via the magnocellular pathway. This coarse but rapid information is sufficient for generating an ‘initial guess’ about the context and about objects in it. These context-based predictions are validated and refined with the gradual arrival of higher spatial frequencies (HSFs) (Bar 2004). (MPFC, medial prefrontal cortex; OFC, orbital frontal cortex; RSC, retrosplenial complex; PHC, parahippocampal cortex; IT, inferior temporal cortex.) The arrows are unidirectional in the figure to emphasize the flow during the proposed analysis, but all these connections are bidirectional in nature. Adapted from Bar (2004).

Figure 2

When seeing a novel image of a scene, its LSF version rapidly activates a prototypical context frame (a) in memory (i.e. an analogy). The relatively slower and gradual arrival of detail in the HSFs (b) results in a more episodic context frame (c), with scene-specific information. Image in (a) courtesy of A. Torralba.)

Figure 3

Medial view of the left hemisphere, demonstrating the overlap between the default network (defined, for example, using the contrast between activation at ‘rest’ baseline versus activation in an n-back working memory task) and the associative predictions network (defined, for example, using the contrast between recognition of highly associative objects versus recognition of only weakly associative objects). Brown area, contextual associations network; yellow area, default network; red area, overlap. MTL, medial temporal lobe; MPC, medial parietal cortex; MPFC, medial prefrontal cortex.