Abstract

What happens when an expectation of a certain perceptible event is fulfilled? Traditional empiricist theories about intentionality, as well as several recent theories about mental imagery, emphasise the concrete similarity between expectations and perceptions. For example, one can almost "hear in one's head" a melody which one is anticipating. This has been the starting point for many theories which postulate some kind of similarity matching between the expectation and its fulfilment. According to such theories, an analogue mental representation of the expected fact is "held up" against the incoming percept, and their similarity or non-similarity determines whether the expectation is or is not fulfilled. If such theories are taken as descriptions of phenomenologically accessible facts, they are difficult to defend. First, analogical expectations - when they do occur - usually do not persist into the fulfilment phase. And how could they be matched for similarity, if they are not available at the same time? Second, many cases of expectation do not involve any imagery at all but only reveal themselves as a feeling of surprise if they are not fulfilled. The philosophical literature abounds with arguments against the thesis that concrete similarity to a certain percept is essential for an expectation to have that percept as its object. But of course these are not arguments against cognitive and/or neural-network theories which entail that simultaneous matchings are performed below the introspectively accessible level; such an assumption is often used in explanations of perceptual learning. I here suggest a simple alternative theory of the nature of matching in such learning. Suppose that thought and perception alternate using the same representational medium, and that the contents of this medium are being continuously fed into the cognitive system which produces thought. Such a common feedback/input mechanism will, in itself, give rise to learning because at each alternation from expectation to perception, the system will perform an implicit matching. If the percept is sufficiently dissimilar to what would have occurred in the common medium without perception, the cognitive system will tend to switch to another region of its state-space, in which other kinds of expectations are produced.