Not Every Behaviour Entails an Affordance

There are two approaches to formalising Gibson's notion of affordances. The first is to treat them as dispositional properties of the environment; properties the environment offers the organism to support possible actions. The second is as relations in the organism-environment system; not localised to the environment but formed when the organism-environment system is formed as a perception-action loop. I am firmly Team Dispositional Properties, because I think this best aligns with Gibson's goals, it allows actual science on the coordination and control of action (Wilson, 2026) and because there is currently no working account of how you might perceive a relational affordance. 

Despite all this, the relational account remains alive, well, and probably the main way people think about affordances. One reason is the drive to make ecological psychology align with the commitments of radical enactivism, a drive I have no interest in (I think enactivism is ok but nothing we owe our allegiance). I think the other big reason is that only the relational account really allows you to talk about affordances for things other than the coordination and control of actions, and as the ecological approach expands the things it is trying to explain people want to apply the ecological tools we have, and that means affordances. 

Except actually, it doesn't. 

Events and the Information for Perceiving Events (Gibson, 1979, Chapter 6)

In the previous chapter, Gibson introduced the notion of the ambient optic array and discussed the kinds of information it can have (flow, and invariants). The focus there was what is revealed by a moving observer. This chapter is about what is revealed as the environment changes; when events occur. 

Sabrina blogged this chapter here and here. 

Lecture 26: Strong Anticipation and Direct Perception (Turvey, 2019, Lectures on Perception)

In this final chapter, Turvey lays out the basics of the ecological approach to coordinating action with respect to the future. This is actually a key part of behaviour - we reach for things we know are graspable before grasping them, we move to intercept or avoid things before they are anywhere near us, and so on. The question is how do we do this.

The ecological approach cannot, of course, use prediction to solve this problem. Prediction entails representation, making educated guesses about what is coming up based on loans of intelligence we cannot ever pay off. The whole point of this book has been to lay out the argument that a) this approach is doomed to fail but that b) the ecological approach, grounded in laws, is different enough in kind to be a viable option. 

Coordinating with things not in the immediate present is therefore going to rely on lawful informational coupling to dynamical events, with several interesting consequences. 

Chemero (2009) Chapter 7: Affordances, etc (Pt 1)

If you want perception to be direct (no 'mental gymnastics') you must identify where the content of perceptual experience comes from; when I view a chair, for example, I don't see a meaningless or random collection of surfaces or colours, I see an object that I can interact with in some ways and not others. For traditional, indirect theories of perception, this meaning is constructed internally: mental representations perform transformations (perhaps computational ones) on sensory input to infer what the input means. A theory of direct perception requires that meaning is not added to the signal; this 'enrichment' is not permitted. To solve this problem, Gibson proposed that the world, for a perceiving-acting organism, is not comprised of meaningless bits of physics and chemistry. Instead, he proposed that the world presents itself to this organism in terms of affordances, which are intrinsically meaningful for the organism and are about the possibility of behaviour.

So a theory of direct perception requires an ontology, a theory about the make-up of the world  that means it is intrinsically meaningful. Chemero wants RECS to include direct perception, therefore he needs such an ontology. He is happy with affordances; he is not, however, satisfied with the Turvey-Shaw-Mace approach which defines affordances as dispositions. This chapter will defend an extended version of his theory of affordances as relations: Affordances 2.0.

Affordances have cropped up here, er, a couple of times already - namely here, here, here, and most recently and enthusiastically here, as well as some empirical discussions here and here. The idea that affordances, not physics, is the correct ontology for a theory of direct perception also came up here. To jump ahead, I disagree with Chemero about affordances. I don't think the disposition account is flawed in the way he thinks, and I don't think relations solve the problem anyway. While I obviously agree that an affordance-based ontology is the way to go, I am so far satisfied that the dispositional account is the best current analysis, and I think that trying to make affordances relational is to confuse the world with information about the world.

I'm going to take this chapter in two parts, because this post got long; affordances are complicated things. After this chapter, I think a pause for station identification may also be in order, just to lay a few things out in response to Chapters 6 and 7, the real meat of the book. But first, Affordances 1.0 vs Affordances 1.1.

Reading Group - Gibson (1979) Chapter 6 Part 1

Chapter 6: Events and the information for perceiving events

Thus far, Gibson has been talking about how we perceive objects. But, things in the world often move around, so we'd better be able to perceive things that are extended in time as well. First off, Gibson describes the properties of surfaces that are relevant to events. He then identifies a number of things that can happen to surfaces during events. The nature of these changes will determine what types of optical information might specify particular events (this will be discussed in Chapter 6 Part 2).