Lecture 23: Ecological Optics Primer (Turvey, 2019, Lectures on Perception)

The 'barrage of conceptual details that was Lecture 22' has provided us with the notion of affordances, and these are to be the objects of both perception and action. This means the need to be perceived, and this brings us to the second part of the ecological ontology - information. This chapter will focus specifically on optical information, identify the key characteristics of an optic array, and walk through some ways of analysing perception ecologically by dealing with some problems supposedly raised by illusions. 

Prospective Control I: The Outfielder Problem

A couple of posts ago I raised the distinction between prediction and prospective control. I was trying to make the point that, if you are coupled to the right information, you don't need to be mentally simulating what's happening so you can run this simulation ahead and predict what's coming up. Prediction of this sort is invoked by representational cognitive scientists to cope with things like delays in the nervous system (e.g. Changizi's 'perceiving-the-present' framework). It's a risky business (if you make a mistake, you are suddenly controlling your behaviour according to an incorrect guess), and the better solution is prospective control. This is when you couple your behaviour to information in the world that doesn't tell you about the future, but that, if you use it for a while, will get you where you want to go.

People requested some more on this topic, and so here we go. People also requested something other than the outfielder problem, but I am going to start with this problem because it is still the best example, and I'll get into some more as we go to demonstrate it's not just baseball where this works.

Mirrors are Literally Windows to Another World

The other day, psychologist Tom Hartley tweeted "Your reflection is always half the size of the real thing - no matter how far from mirror. Hard to believe but true." and linked to this post in which someone demonstrates this effect. I had never quite thought about it, but realised it was of course always true: the mirror is at half the distance specified in the reflection. Then I read this post linked from the original, which reviewed an article by Lawson et al (2007) describing how people misjudge the size of objects on mirrors - specifically, they think the projection is larger than it actually is. This got me thinking about some work by Gibson on slant perception (Gibson, 1950) and then I realised that this really is an interesting topic. So I'm taking a break from the brain this week to blog about some optics instead.