Perceptual Experience and Attention

I'm drafting an entry for Sage Press's forthcoming Encyclopedia of Perception. Since Sage seems to want a fairly relaxed, conversational style and the draft isn't much longer than a blog post, I thought I'd make it today's post.

Perceptual Experience and Attention

Do you have constant tactile experience of the shirt on your back? Constant auditory experience of the background rumble of traffic? Constant visual experience of the tip of your nose? Or, when you aren’t paying attention to such things, do they drop out of consciousness entirely, so that they form no part of your stream of experience – not even vaguely, peripherally, amorphously – no part of your phenomenology, no part of what it’s like to be you?

There is, of course, perceptual processing without attention. A gentle tug on the shirt or an unexpected movement in the visual periphery will generally call your attention, even if you are fully absorbed in other things. To call attention such events must register, first, pre-attentively. While your attention centers on one or a few things, you monitor many others inattentively, ready to redirect attention when an inattentional processes detects a large or important change. The interesting question is not whether there is perception without attention, but whether experience accompanies our inattentional perceptual processing or whether that processing is entirely nonconscious. We might think of consciousness as like a soup. Is it a rich soup, replete with experience across broad regions of several modalities simultaneously? Or is it a thin soup, limited to one or a few regions or objects or modalities at a time?

Ordinary people’s intuitions diverge considerably here. So also do the views of philosophers and psychologists. On intuitive or introspective grounds, William James and John Searle (among others) endorse the rich view, Julian Jaynes and David Armstrong the thin view. One widely discussed case is the absent-minded driver: You’ve driven to work a thousand times. Today you drive habitually, utterly absorbed in other thoughts. You arrive and seem suddenly to wake up: Ah, I’m here already! Now, did you actually visually experience the road – at all? very much? – on your way to work?

One might think the question easily settled. Simply introspect now. How much is going on in your consciousness? Unfortunately, the “refrigerator light phenomenon” frustrates any such straightforward test: The fact that you hear (or auditorially experience) the hum of traffic when you’re thinking about whether you hear the hum of traffic provides no evidence on the question of whether you hear the hum of traffic when you’re not considering the matter. Just as the act of checking the refrigerator light turns it on, so also might the act of checking for tactile experience of one’s shirt or visual experience of one’s nose produce those very experiences.

Often we fail to parse, respond to, or remember what might seem to be salient stimuli – a stream of speech we’ve decided to ignore, a woman in a gorilla suit walking through a fast-paced ballgame, substantial changes in a flickering picture, a geometric figure briefly presented in an unattended part of a visual display. Daniel Dennett and Arien Mack, among others, have interpreted such phenomena as evidence for the thin view. However, the conclusion does not follow. We may not parse unattended stimuli much or remember them well, but they may still be experienced in an inchoate or immemorable way, or the general gist may be remembered if not the details.

Ned Block has emphasized that it seems introspectively that we visually experience more of a visual display than we focally attend to. On the face of it, this fact (if it is a fact) seems to suggest that perceptual experience outruns attention. But might it, instead, be a matter of diffuse attention spreading more broadly than focal attention, perhaps along a gradient? Even if you visually experience this whole page while focally attending only to a few words at a time, it doesn’t follow that you also visually experience the wall in the far periphery when you’re not thinking about it, or the pressure of the shoes on your feet.

The issue of whether perceptual experience is, in general, rich or thin may also be addressed by gathering introspective or immediately retrospective reports about randomly sampled moments of experience. Eric Schwitzgebel, giving people beepers to wear during ordinary activities and asking them to reflect on the last undisturbed moment before each beep, found a majority of participants to report visual experience in 100% of sampled moments, tactile experience and peripheral visual experience somewhat less. However, as Schwitzgebel admits, it’s unclear how much credence to give such reports.

The rich and thin views draw radically different pictures of our experience. If the rich view is right, consciousness contains much more than adherents of the thin view suppose. Although there is room here for merely terminological confusion, it appears that there is also room for major substantive disagreement. Strange that this question, concerning an absolutely fundamental and pervasive aspect of human experience, is so poorly studied!

Suggested further readings:

Armstrong, D.M. (1981), The nature of mind. Ithaca, NY: Cornell.

Block, N. (forthcoming), Consciousness, accessibility, and the mesh between psychology and neuroscience. Behavioral and Brain Sciences.

Dennett, D.C. (1991), Consciousness explained. Boston: Little, Brown & Co.

James, W. (1980/1981), The principles of psychology. Cambridge, MA: Harvard.

Jaynes, J. (1976), The origin of consciousness in the breakdown of the bicameral mind. Boston: Houghton Mifflin.

Mack, A., & Rock, I. (1998), Inattentional blindness. Cambridge, MA: MIT.

Reddy, L., Reddy, L., & Koch, C. (2006), Face identification in the near-absence of focal attention. Vision Research, 46, 2336-2343.

Rensink, R.A. (2000), When good observers go bad: Change blindness, inattentional blindness, and visual experience. Psyche, 6 (9).

Schwitzgebel, E. (2007), Do you have constant tactile experience of your feet in your shoes? Or is experience limited to what’s in attention? Journal of Consciousness Studies, 14 (3), 5-35.

Searle, J.R. (1992), The rediscovery of the mind. Cambridge, MA: MIT.

Simons, D.J. (2000), Attentional capture and inattentional blindness. Trends in Cognitive Sciences, 4, 147-155.

Note to blog visitors: One aspect of the question I've omitted is the old debate in introspective psychology about whether experiences of objects to which one is attending differ in some qualitative attribute like "clearness" or "attensity" from experiences of unattended objects. But this hasn't exactly been a hot topic in the last 100 years; and the more basic question of whether there even is experience outside of attention needs to be settled first.