Tuesday, 21 June 2011

Chemero (2009) Chapter 9 - The Metaphysics of Radical Embodiment

The final chapter of RECS tackles the metaphysical implications of the radical stance. Gibson was a staunch realist, but there are some odd elements to entities like affordances that, to certain minds, sound like idealism or antirealism of some kind. Realism is, essentially, the claim that there is a world independent of our experience of it, and that we can have basically accurate knowledge of that external world. In modern times this reality has been equated with the description given by physics. Affordances don't belong to physics, however; whether relations or dispositions, they are, at heart, facts which span the organism and the environment. This sounds wrong to a lot of ears (as Ken's comments on that post readily show!). Chemero therefore devotes the final chapter to defending the claim that RECS can be realist; this matters, because people tend not to like idealism in their science these days, and it's going to be a standard philosophical objection to the RECS programme if not addressed.

Tuesday, 14 June 2011

Task Specific Devices and the Perceptual Bottleneck

I've been wanting to blog this paper, Bingham (1988; download link), for some time, and I've had the excuse to be reading it this week as I develop a grant. There's a lot here, and many of these brief points are worth posts in and of themselves. My goal here was to create a walk through of the paper, and I hope to dive into some of these issues in more detail.

This paper comes from Geoff Bingham, my PhD advisor at IU. And, like most of the good things Geoff has taught me over the years, this paper is a gift that keeps giving as I come to grips with what's in it. What it does is lay out a methodological problem (the massive redundancy and complexity of the human action system), proposes a solution (studying task-specific devices) and firmly embeds the idea that these devices are intrinsically perception-action devices (by discussing the so-called perceptual bottleneck). In effect, it lays out a way to be a productive scientist studying a hugely complex system without shying away from the complexity. This paper blew my fragile little mind when I first read it, and I'm still pulling good ideas from it today.

This paper is what I think the science of perception-action should look like. It's the piece I think Chemero (2009) is missing for his radical embodied cognitive science, and it contains (oddly without a lot of specific references) all the key ideas that have come up on this blog in a single coherent frame work (e.g. Gibson & specification; Turvey et al on the symmetry principle). Frankly, if you want to study perception-action systems from a dynamical systems perspective, this is what you have to acknowledge is the lay of the land and these are the beginnings of the tool kit you'll need.

Tuesday, 7 June 2011

Perceiving long distances in action scaled units

I have so many things I need to write up just now, but it's been a struggle finding the time. I hope to post on Chemero's last chapter, task-specific devices, calibration and some new coordination data soon. In the meantime, I thought I'd take advantage of the fact that I'm reading some new articles on an interesting topic, and I wanted to organise some thoughts and see if anyone had any comments!

Perception is action-scaled

Traditional theories of perception claim that we perceive the world in generic terms, and must transform that perception into a task relevant variable after picking the information up. The ecological suggestion is that the act of perception itself is directly scaled in action-relevant units, and that this perception will therefore be task-specific. In order to directly perceive action relevant properties (i.e. affordances) perception must be smart (think of the analogy of the polar planimeter).

We are capable of perceiving the distance of things in the world; but we don't perceive them as being '6m away'. Instead, the system is interested in how to reach for an object, so you need to calibrate your perception of distance in terms of, say, arm length units. Calibration is the process of placing a measurement on a scale, and the ecological approach has been interested in action relevant scales such as arm lengths (for reaching; Mon-Williams & Bingham, 2007) and leg lengths (for stair climbing; e.g. Warren, 1984). One of Chemero's points is relevant here; body scale is probably only a proxy measure for ability to perform the action and the real action scale the system is using (the effectivity) will be more complicated. But body scale is mostly where the field is at right now.