1. Sebastian Bitzer (sbitzer@uos.de)sbitzer@uos.de Seminar Neurophysiological Foundations of Consciousness University of Osnabrueck 14.06.2003 A sensorimotor account of vision and visual consciousness J. Kevin O’Regan Alva Noë

2. 14.06.2003Sensory and Consciousness2 Overview standard working hypotheses sensorimotor contingencies visual perception visual awareness visual consciousness bridging the gap

3. 14.06.2003Sensory and Consciousness3 “Standard” view for every perceptual state there is a neural correlate “neural correlates of consciousness” bridge locus (perfect correlate, sufficient to produce the percept) neural substrate produces representations

4. 14.06.2003Sensory and Consciousness4 Problems? even with perfect correlate no explanation for how the neural substrate generates the percept (explanatory gap)  neural substrate alone not sufficient to produce vision (resp. a percept)

5. 14.06.2003Sensory and Consciousness5 Which neurons correlate best with the percept? e.g. motoneurons

6. 14.06.2003Sensory and Consciousness6 Basics (sensorimotor contingencies) structure of the rules governing sensory changes produced by various motor actions two types of sensorimotor contingencies: –determined by character of visual apparatus –belonging to visual attributes of objects

7. 14.06.2003Sensory and Consciousness7 Sensorimotor contingencies Figure 1. Top: The eye fixates the middle of a straight line and then moves to a point above the line. The retinal stimulation moves from a great arc on the equator of the eye to a different, smaller great arc. Bottom left: Flattened out retina showing great arc corresponding to equator (straight line) and off-equator great arc (curved line). Triangles symbolize color-sensitive cone photoreceptors, discs represent rod photoreceptors. Size of photoreceptors increases with eccentricity from the center of the retina. Bottom right: Cortical activation corresponding to stimulation by the two lines, showing how activation corresponding to a directly fixated straight line (large central oblong packet tapering off towards its ends) distorts into a thinner, banana shaped region, sampled mainly by rods, when the eye moves upwards. As explained in Section 2.2, if the eye moves along the straight line instead of upwards, there would be virtually no change at all in the cortical representation. This would be true even if the cortical representation were completely scrambled. This is the idea underlying the theory that shape in the world can be sensed by the laws obeyed by sensorimotor contingencies. SHOW

8. 14.06.2003Sensory and Consciousness8 Visual quality of shape set of all potential distortions that the shape undergoes when it is moved relative to us, or when we move relative to it infinite set but laws can be extracted which describe the set  set of laws codes shape

9. 14.06.2003Sensory and Consciousness9 Mastery of the laws the sensorimotor contingencies are there  mastery = knowing about them (dependent on context of behaviour / habitual setting)

10. 14.06.2003Sensory and Consciousness10 Visual Perception Vision is a mode of exploration of the world that is mediated by knowledge, on the part of the perceiver, of what we call sensorimotor contingencies.

11. 14.06.2003Sensory and Consciousness11 Visual awareness = exploring environment according sens cons + active exercise of mastery of the laws + integration of this mastery with thought or action-guidance = seeing matter of degree but: without current access no perception sens cons = sensorimotor contingencies

12. 14.06.2003Sensory and Consciousness12 Visual Consciousness two types: –transitive visual consciousness (visual awareness) –visual consciousness in general (ability to become aware)

13. 14.06.2003Sensory and Consciousness13 Explanatory Gap Gap? Which gap? there is nothing that fits notion of qualia “the subject matter of phenomenological reflection is not an ephemeral, ineffable, sensation-like momentary occurrence in the mind, but, rather, the real-world, temporally extended activity of exploring the environment and the structure of sensorimotor contingencies”  argument does not apply

14. 14.06.2003Sensory and Consciousness14 Important claims laws of sensorimotor contingencies constitute the way the brain codes visual attributes experience as a mode of skillful activity world as external memory brain as one element in a system

15. 14.06.2003Sensory and Consciousness15 Major drawbacks Has a computer program (e.g. the missile guidance system from the paper), that has mastery of the sensorimotor contingencies and plans with them, consciousness? What are the grounded terms? (If you paraphrase a circle as a thing that becomes, watched from another perspective, an ellipse, what then is an ellipse?)

16. 14.06.2003Sensory and Consciousness16 References O’Regan J.K., Noë, A. (2001). A sensorimotor account of vision and visual consciousness. Behavioral and Brain Sciences, 24(5), 939-973.

17. 14.06.2003Sensory and Consciousness17 BACK