Our colleague Dr. Carl Hillier has influenced me to think more about embodied cognition, and since it isn’t a topic we’ve addressed before in any detail I thought it might be interesting to pay it a visit. If you want a quick primer on what embodied cognition is, take a look here. Briefly stated, it’s the notion that cognitive processes are operative throughout the body, not just in the brain. This is mindful of what Dr. Harry Wachs has been addressing for years in terms of visual-spatial thinking, and every time I re-visit his chapter on the subject I gain a new found appreciation for the distribution of intelligence throughout the body.
There’s a nice book pictured here that’s actually a collection of papers presented at the 34th Carnegie Symposium on Cognition, held at Carnegie Mellon U. in 2006, that bears directly on emobdied cognition as applied to vision. Background concepts include material I blogged about previously in Part 1 and Part 2 regarding the sensorimotor dynamics of visual space. To briefly review, there are two primary spatial coding systems, egocentric (in reference to the position of one’s body) and allocentric (in reference to the external features of the world). This becomes highly relevant in strabismus, where oculocentric localization often results in a shift of the egocenter away from the midline and referenced more toward one eye. In acquired brain injury the opposite often occurs, where oculocentric localization remains on the midline as long as the eyes are aligned, but egocentric localization undergoes a midline shift.
This was part of the genius of Dr. Fred Brock, who introduced the notion of using a string connecting the oculocenter, or cyclopean visual midline, with one’s egocenter, represented by holding the string to one’s nose on the body midline. But here’s the real kicker: Brock’s technique is one of very few I can think of that directly links egocentric space with allocentric space. By that I mean that we are asking the patient about the visual appearance of two distinct spatial frames of reference. One is the appearance of the ropes as they leave the body on the way to the bead (egocentric), and the other is the relative relationship between the bead being fixated and the inter-relationships in object space proximal or distal to the point of fixation (allocentric).
While the technique remains very useful regarding the appearance of physiological diplopia and signs of suppression as related to binocular vision, it is under-appreciated in terms of its uniqueness in linking egocentric and allocentric spatial frames of reference. Particularly in acquired brain injury, this becomes an incredibly powerful feedback and therapy tool. I’ll link this directly to embodied cognition in Part 2.