This is an addition to an earlier posting regarding the evolution of cognition and the role of sensorimotor activity and the function of something like ‘action representations’.
A useful distinction to begin to draw here may be that between ‘sensation’ and ‘perception’. I would like to offer that the first of these terms, sensation, refers to the operation of the sensorimotor system in relation to the environment, whereas the second term, perception, is a higher order process. For example; there is a part of the sensorimotor system associated with ‘seeing’ which consists of the eyes and parts of the visual cortex, and also the motor mechanisms which focus the eye, saccade the eyeball in its socket, adjust the dilation of the pupil according to light levels (and the desirability of the object looked at), etc. Together this combination of sensory and motor activity produce the sensation of seeing. This is not the same as perception as I want to use the term however. In order for the results of this sensational seeing to be perceived there needs to be a further operation in which this sensorimotor activity is held as a representation and then made available to other, perhaps specially evolved, cognitive processes. It is this secondary or higher order processing of sensation and action that constitutes perception. To paraphrase Antonio Damasio (2000), sensation is what happens, perception is the feeling of what happens.
Nicholas Humphrey presents an interesting narrative description of this distinction in his essay ‘The Privatization of Sensation’ (2000). He suggests that a simple organism, perhaps something like an amoeba, having only the simplest form of sensorimotor engagement with the world, is capable of sensation but not perception. Such an organism, in the presence of a chemical salt would, he claims, react to that chemical according to the physiological inevitabilities of its embodiment. The composition of its cell walls and its own internal chemistry would be affected by the saltiness of its environment and this affect would express itself in, for example, a characteristic wriggling. Alternatively, if light of a particular wavelength, say a wavelength that would be visible to us as ‘red’, were to fall across this creature another, very different, set of physiological changes would be initiated, perhaps noticeable as a different but equally characteristic wriggling. Humphreys suggests that it would not be irrational to think of the first of these ameobic behaviours as ‘wriggling saltily’ and the second as ‘wriggling redly’. Of course, this perception of different wrigglings as characteristic of different environmental stimuli would not be available to the organism itself since it does not have the necessary cognitive apparatus for this kind of secondary observation, (basically an apparatus in which this sensorimotor engagement was represented in some way). If it were to evolve such a capacity however, then it would be able to not only actively participate in the production of sensation but also to have perception of this sensorimotor engagement. It would not only be part of what happens it would also perceive the feeling of what happens.
DAMASIO, A. R. (2000) The feeling of what happens: body and emotion in the making of consciousness, London, Heinemann.
HUMPHREY, N. (2000) The privatization of sensation. IN HUBER, L. & HEYES, C. (Eds.) The Evolution of Cognition. Cambridge, MA, USA, MIT Press.
In the last posting I spoke of the ‘phenomenal space’ of subjective being and how the facts of our embodiment bring with them an intuitive understanding of space. This space has particular characteristics that flow from the nature of our embodiment and from the environment in which that embodiment comes together. What I would like to indicate here is that we also live in other, complementary spaces which also inform how we construct thought and meaning.
In the appendix to his book on relativity theory (2003) the physicist David Bohm addressed some of the issues around perception that come out of some of the idea in that book. Part of this concerns the relationship between perception and space and how the ability to occupy different positions in space changes the nature of perception and the objects that such perception embraces. He gives the example of seeing an ellipse, perhaps the ellipse formed by looking at the top of a coffee cup as it is held in the hand prior to drinking from it. Even though the visual image presented to the organ of sense, the eye, is this ellipse it is not seen as such. Perception seamlessly interprets the top of the cup as circular, even though we at no point see this circle in its most essential form (if we did we would have a lapful of coffee). The process at work here is that the visual sensorimotor system responsible for engaging with the top of the cup is not stationary, fixing its gaze unswervingly on this object. Instead it is an eye in motion (even if that motion is relatively slight) and each motion of eye, head, hand, and arm changes the orientation of the cup to our eye and simultaneously changes the shape of the ellipse in lockstep with this motion. Extrapolating from this constantly changing but systematically related data the perception of the top of the cup is made up not from a single viewpointed image but of this extrapolation, the circle we rarely see. This process points up an understanding of space in which it is not only egocentrically oriented around the axis of the unmoving situated body. The space that Bohm indicates is one in which our ability to move and to quite literally see things from different angles is taken into account. In this space there is no inevitable perspectivalism, and the railway tracks which lead off toward the horizon are seen as the parallel lines that they surely are. This is the scientific method in miniature, in which the evidence of the senses are peer reviewed by those same senses but from other places and at other times.
There is also another space, perhaps an extension of the last, which arises from our being in a world shared by other beings with similar senses. The space that I occupy is also entertained by you and by others, and the number of eyes which look out onto this space multiply accordingly. Experiencing this space involves social processes and the sharing of sense through interpersonal and extrapersonal means. This is the kind of sense which one gains from learning and becoming informed. It is common sense because it is held in common, available not only to one individual through the intuitive sense of their subjective embodiment but to anyone who cares to learn. The common sense alluded to here, whilst it may offer a viewpoint on the universe which seems, to some at least, arbitrary, gyratory, and lacking the privilege of centeredness, is also a sense which places our eyes everywhere and gives us what Thomas Nagel (1986) paradoxically referred to as ‘the view from nowhere’. In the vast incomprehensibility of space there is not a single place anywhere that one cannot conceive oneself as occupying and the totality of one’s image of the universe is a collation of all these possible viewing positions.
It seems likely, therefore, that we are creatures who simultaneously inhabit not one space but several. There is the space of subjectivity and self-centeredness, in which the world radiates out from one’s body, diminishing with distance in both size and importance until it disappears over the horizon, and there is the space of experience which presents the world to us in the different ways available to mobile animals; And then there is the space of objectivity, in which we occupy all the centres of the universe at once and the peripheral horizon disappears. The first space is our birthright; the product of our animal embodiment and our embeddedness in the environment. The second we earn through motion and exploration. The third is our New Found Land; the result of the gradual enlightenment of our species and the vision admitted by that light.
When Primack and Adams (2006) draw attention to the potential for existential anomie afforded by the internalization of Newtons’s impersonal space, they are reminding us that such learning is not only the acquisition of rational, disembodied facts. They recognize that the images we hold of space, on the grandest scale possible, are also constructive of the fabric of our understanding. The intuition that comes with subjective embodiment is joined by other intuitions, which may at times be at odds with the first. Each of these spaces is at work in our cognition, and each is active in our intuitions. Each appears, unbidden and often invisible, in the poetics of our language, and each space is used to contain the ideas and objects of our experience, the stuff of meaning and thought.
BOHM, D. & NICHOL, L. (2003) The essential David Bohm, London, Routledge.
NAGEL, T. (1986) The view from nowhere, New York, OUP.
PRIMACK, J. R. & ABRAMS, N. E. (2006) The view from the centre of the universe, London, Fourth Estate.
As has already been argued, perception is a function of the sensorimotor systems, and the different modalities in which that sensorimotor system operates, the different physical senses of touch, taste, sight etc, gives structure to that perception. If Mark Johnson is correct in claiming that perception is one of the capacities from which meaning and thought emerge then the structure of meaning and thought, the organised and coherent relationships between ideas, must in turn emerge in part from structures within perception. In other words, our ability to think in organised and meaningful ways is reflective of our ability to perceive the world in organised ways.
The organisation of perception comes from the regular and consistent ways in which the physical senses operate. To take the visual sense as an example, different wavelengths of light appear to the visual system as different colours, but these differences are not random or disorganised. The colours of the spectrum always follow one another in regular and predictable ways and this regularity (as well as the range) provides an organising template for meaning and thought to base themselves upon. Similarly, there is a consistant relationship in the apparent visual size of an object and its distance from us; objects that are further away seem smaller than those close up. This also is a feature of visual experience which has structure and regularity that can be adopted by conceptual cognitive functions. Other sensory modalities, hearing, touch, taste, olfaction, proprioception, have their own set of organised variables which enlarge the number of possible structures that might be utilised as frameworks for meaning and thought, and the relationships between the modalities provides additional complexity. Some sense perceptions echo one another closely; the shape of an object tends to be similarly perceived both by the hands and the eyes; whereas other senses complement one another through their difference; the colour and the sound of a musical instrument overlap one another only at the margins.
In ‘The senses considered as perceptual systems’ J.J Gibson writes that “the senses can obtain information about objects in the world without the intervention of an intellectual process” (1966:1). It may be more accurate to say that it is not that the senses work without the intervention of intellectual processes, but rather that their operation is constructive of intellectual processes. Furthermore, the structured differences that the senses detect in the world and which we experience as perceptions give structure to the meaning and thought that make up these intellectual processes.
Gibson, J. J. (1966). The Senses Considered as Perceptual Systems. Boston: Houghton Mifflin.