In part 1 we introduced the work of James J. (“JJ”) Gibson on the ecological approach to visual perception, encapsulated in the phrase ecological optics. There were several really good comments by readers at the end of part 1, and they dovetail nicely into part 2.
If you attended SUNY College of Optometry, or were a faculty member there, chances are you know this gentleman. Harold Sedgwick, Ph.D., is an Associate Professor of Vision Sciences at the College, known to his colleagues as Hal. Owing in part to the layout of real estate in Manhattan, SUNY-O always had a vertical arrangement such that clinical entities and classrooms were on relatively lower floors, and as you worked your way up in the building you passed administrative offices to faculty offices and labs where the PhDs did their thing. It wasn’t until I read the acknowledgment in the preface of Gibson’s last book that I realized Hal was Gibson’s student. It’s in Sedgwick’s bio: Cornell University, PhD (Experimental Psychology) with James J. Gibson, 1973.
Why do I bring this up? Because in my 15 years at SUNY I don’t recall hearing the phrase “Ecological Optics”, or “The Ecological Approach to Visual Perception” yet that was the underpinning of much of what was happening in vision therapy. I wish I could go back in time to when I first arrived there in 1982, and I would have picked Hal’s brain much more than I did at the time. This is why I was pleased to read Dr. Hillier’s comment at the end of part 1 that Gibson is incredibly influential to how he evaluates the visual system. Dr. Hillier asked that I mention that JJ’s wife, Eleanor Gibson was an accomplished experimental psychologist in her own right. Her seminal co-authored article on The Visual Cliff in Scientific American (1960) is iconic in every introductory textbook on development, psychology, and perception, so it’s entirely possible that you’re more aware of Eleanor’s work than JJ’s, but both were deeply rooted in the ecological approach to visual perception.
What I’m calling “Eco-Optics”, a contemporary phrase for ecological optics, has the concept of Optic Flow at its core. Before illustrating that, let me parenthetically add that an appreciation of what JJ trying to get across not only relates to dynamic visual acuity, as Dr. Hillier noted in his comments at the end of part 1, but to the very notion of how the eye is designed, whether its aberrations are intentional, and how it interfaces with the brain and the rest of the body, as discussed here. Back to Optic Flow, of which there are two primary kinds, radial – which is forward and backward movement, and translational – which is side to side movement. The visual experience while driving is a great example of both. When the car is in motion, you primarily experience radial optic flow, with the speed and complexity of the world moving opposite to the direction you’re heading serving as an index of relative position and speed among other factors.
When you’re stopped at a traffic light, as you track the cars moving perpendicular to the direction you’ve been heading, your ocular following response engages you in translational optic flow. Even as you proceed through the intersection, you subconsciously remain vigilant to interruptions in the side-to-side movement. Of course, while driving, there is an ever-changing array of optic flow due to curves uphill/downhill effects. So think of optic flow as you drive as an undulating series of vectors in multiple dimensions, as depicted nicely in BU’s Cognitive and Neural Systems Vision Lab tutorial on visual navigation in a cluttered world.
The impetus for me spending considerable time on this with you is that Sue Barry and I have been exploring this topic in detail in preparation for our upcoming talk in England on Emotions and Embodiment in Strabismus at the International Congress of Behavioral Optometry (ICBO). I’ll take you into the flow of our presentation in Eco-Optics Part 3.