Attention

5. The ‘pre-motor’ theory

It is generally agreed that there were conceptual mistakes built into the debate about early versus late selection that Broadbent’s theory of attention launched. That theory nonetheless remains hugely influential, and opinions continue to be divided on the question of where the mistakes lay (see Driver 2001). Broadbent’s claim that attention serves the function of managing a bottleneck in ‘central’ processing capacity, related to the limited capacity of consciousness, continues to be regarded by many researchers as axiomatic and discussions of attention often introduce their subject matter in these terms. There have, however, always been rivals to the idea that attention is a matter of allocating limited central-processing resources. This idea has recently been thrown into renewed contention by a resurgence of interest in ‘pre-motor theories of attention’, which see attention as concerned, not with the direction of central processing resources, but with the direction of sense organs (see Moore et al. 2003). As in most recent work on attention, this proposal has been worked out in most detail for the case of attention to visual stimuli. For visual stimuli the pre-motor theorist’s claim is that the processes responsible for bringing about eye movements play a role in attention, even in those cases of attention in which the eyes are not moved. Cases where attention is given to an item without the eyes being directed towards that item (identified by Posner 1980) are, according to this theory, cases in which eye movements are planned but never executed.

There are empirical debates around this ‘pre-motor theory of attention’, and questions remaining to be explored about how the theory might account for attention to items outside the visual field, but even in its current state the theory is a matter of some philosophical interest. The pre-motor theory of attention is, for example, a natural accompaniment to the sensori-motor accounts of perception, recently popularized in the works of Alva Noë (see Noë 2004), Susan Hurley (1998) and others. Incorporating the pre-motor theory may be the most plausible way for such accounts to accommodate the facts about attention.

The pre-motor theory is also philosophically interesting because the processes of preparing for eye-movements have a relatively small part to play in our cognitive lives. The identification of these processes with attention therefore poses a challenge to the idea that the tradition of research on attention initiated by Broadbent succeeded in bringing ‘higher-order’ mental phenomena into the explanatory domain of science.

The nature of this challenge can be seen by contrasting two attitudes to Broadbent’s achievement that one might take in the light of the pre-motor theory of attention. The (alleged) discovery that the facilitative effects usually credited to attention are owing to truncated versions of the processes by which we target eye movements can be taken as showing that our attempts to bring cognitive phenomena into the explanatory domain of science have failed: from this point of view the pre-motor theory shows that our research on attention did not really give us a grip on complex mental functioning at all – all it really told us about was the mundane matter of gaze direction. The contrasting attitude sees the pre-motor theory of attention as showing that our best attempt to bring the mental under the remit of science is not a failure but a better-than-expected success: what had appeared to be a mysterious mental faculty is shown to be unmysteriously explicable as nothing more than a truncated version of the process by which we target eye-movements.

The disagreement between these two attitudes to the pre-motor theory, with their very different consequences for how one views the prospects for scientific understanding of the mind, is not a disagreement about whether the pre-motor theory is true, or supported by the evidence. It is a disagreement about how that theory should be taken. This is an unavoidably philosophical matter and so, whether or not the psychologist can succeed in accounting for attention with the resources of cognitive science, the attempt to do so cannot leave philosophy behind.