Is Direct Perception Plausible? The Case for Affordances-as-Dispositions

The first post in this series laid out the rules for what makes a theory of perception direct or indirect. In order to avoid having to require organisms to somehow figure out behaviourally relevant properties (indirect perception), direct perception requires that such properties are out there already, ready and able to be detected. Such properties are a bit weird - by definition, they must be properties of objects that include some reference to the organism doing the detecting (specifically, they are impredicative properties). 

The second post laid out some reasons to think that such circularly defined properties are legitimate options for the physical world. Properties like this are required by the mathematics of the quantum scale; and so, while a bit weird, are possible. Organisms don't work with quantum properties, though, so if they only happen at that scale, this doesn't help a theory of direct perception. The key to making impredicative properties work is measurement. At the quantum scale, all properties are uncertain until measurement collapses the uncertainty of the thing measured. At the ecological scale, properties aren't uncertain in this way, but which properties are 'primary' still depends on the measurement device; to a polar planimeter, for example, the higher order property 'area' is simple and lower order properties such as 'length' must be figured out. The reverse is true of a ruler. 

We have a set of pieces now. Impredicativity requires measurement to affect which properties are immediately available to the measurer, this is possible at the ecological scale, and with the right measurement device higher-order properties can be immediately available. This establishes an in-principle case in favour of direct perception as an option. Next, if we can identify the higher-order form of behaviourally relevant properties, we will identify what kind of measurement device is required for these to be directly available. 

The main ecological hypothesis is that higher-order behaviourally relevant properties, which we call affordances, take the form of dispositional properties. This post will walk through how this works and how it fulfils what's required to support direct perception.

(As many of you know, not everyone is happy with the dispositional ontology, and propose instead that affordances are relations. I am not going to lay out the parallel case for how this ontology fulfils the requirements I have been laying out, for the simple reason that I do not think it can do any such thing and I have yet to see any successful attempt to make it work. I talk about this in this paper, currently still living in review limbo.)

You Cannot Perceive a Relational Affordance (A Purple Peril)

One of the more enduring arguments in ecological psychology is about the best way to formally describe affordances. The two basic approaches are that they are dispositions (Turvey, Scarantino, me) or that they are relations (Reitveld, Kiverstein, Chemero). The argument has mostly settled down into just agreeing to disagree, but I am still convinced that the relational analysis is critically flawed and I want to try and either get them to solve the problem or end the debate once and for all. I've reviewed this in a bunch of places (e.g. here, here, and here)  but this post is just setting out my challenge once and for all; you cannot perceive a relational affordance, and there is as yet no good story about how to learn new affordances.

My problem stems from this Gibson (1979) quote (we all have our favourite, but this one seems to cut to the heart of it)

The central question for the theory of affordances is not whether they exist and are real but whether information is available in ambient light for perceiving them.

Right now, the affordances-are-relations camp have no story for how these can structure light (or other energy media) and therefore create information about themselves. They are therefore, as currently formulated, not even in principle perceptible. This means affordances-as-relations is of zero use to the ecological approach. 

Bruinberg et al (2018) tried to address this problem, but as I blogged here their solution is not ecological information and it reveals that these authors do not as yet understand what information actually is. My challenge is therefore this: tell me a story in which affordances-as-relations are able to create ecological information in energy arrays, and might therefore be learned, and the debate will be back on. Until then, affordances-as-dispositions is the only account that formalises the right properties and the debate is over. 

Affordances are Not Relations, Part 1: Chemero (2009)

Affordances are on my mind right now as I develop the throwing research programme, and a major commitment of that work is that affordances are (dispositional) properties of the environment picked out by organisms in the context of tasks. This commitment has become important enough that it's time to get into developing specific arguments against the various 'affordances are relations' papers that are out there. I am working towards a paper summarising my objections to the relations account that also strongly advocates for the properties account on the grounds it enables a lot more science. This will be an occasional series of posts as I read and draft my arguments; as always, feedback welcome.

In this first post, I want to draft a response to 'Affordances 2.0', from Chemero's (2009) book Radical Embodied Cognitive Science. I previously blogged this chapter in two parts here and here. 

Scarantino (2003) “Affordances Explained”

Turvey, Shaw, Reed and Mace (1981) laid out an ontology of affordances; a formal account of the kind of things they are. They described them as dispositions, properties of the world constituted by sets of anchoring properties that offered an action to an organism whose dispositions could complement the affordance. Making affordances dispositions makes them real, makes them pre-date the interaction with the organism, and accounts for their odd ‘not doing anything until interacted with’ kind of existence. I am firmly Team Affordances are Dispositions and I have yet to meet an alternative account that supports a science of affordances or even allows them to be perceived.

The literature on dispositions was somewhat limited in 1981, but in 1998 Stephan Mumford published the definitive work on what they are and how they work. I always hoped someone with the necessary philosophy chops would use this work to strengthen the foundations of affordances (I even almost talked a philosopher into doing it!) but it turns out I’m covered. Andrea Scarantino (2003) published ‘Affordances Explained’ and did much of the necessary work, and there are some very useful things in the analysis. This post is me working through this material, translating from the technical philosophy into words I can understand better.

The Field is Full, Just Not of Affordances - A Reply to Rietveld & Kiverstein

I recently posted about relational accounts of affordances and how one way to summarise my objections to them is that they cannot support mechanistic models of cognition. I came to this after reading Rietveld & Kiverstein's 'Landscape of Affordances' paper and chatting to them both at EWEP14. Eric and Julian have been kind enough to send through some detailed comments (beginning here and split over three comments due to character limits). This post is me replying to these comments as a way to get them somewhere a little more visible. I haven't gone point by point, I've just pulled out the key stuff I wanted to address; read their comments for the whole thing. I appreciate their willingness to get into this with me; their account is becoming wildly influential and their papers and feedback are helping me immensely as I work to articulate my concerns. 

To preview: my fundamental objection remains the same and as yet unanswered - while it is indeed possible to identify relations between 'forms of life' and 'socio-cultural environments' there is, as yet, no evidence that these relations create perceptual information. If they do not create information, they are not ecologically perceived, and they cannot figure in the online coordination and control of behaviour. And if they can't do that, then they sure as hell aren't affordances.

So my challenge to Reitveld & Kiverstein (R&K) is this - work up an example of an affordance that fits their definition and not mine and that creates information. Then we can test to see whether people act as if they perceive that affordance and can try perturbing the information to confirm how they are perceiving it. Then, and only then, do we have a ball game.

Relational Theories of Affordances are Functional, Not Mechanistic (A Purple Peril)

Everyone and their dog has a theory about how to interpret Gibson's famously vague definition of affordances;

The affordances of the environment are what it offers the animal, what it provides or furnishes, either for good or ill....an affordance is neither an objective property nor a subjective property; or it is both if you like. An affordance cuts across the dichotomy of subjective-objective and helps us to understand its inadequacy. It is equally a fact of the environment and a fact of behavior. It is both physical and psychical, yet neither. An affordance points both ways, to the environment and to the observer.

There are two basic flavours of theories: affordances as dispositional properties of the environment (Turvey, Shaw, Reed & Mace, 1981; Turvey, 1992) and affordances as relational features of the animal-environment system. (A recent paper has just claimed they should be best understood as events, but to be honest I don't really know what's motivating this). The two most recent and popular relational accounts are Chemero's book (Chemero, 2009; see these posts on the relevant chapter) and Rietveld & Kiverstein (2014) in a paper entitled 'A Rich Landscape of Affordances'. Their goal, like most of the relational accounts, is to handle higher-order cognition by scaling up affordances to support it (our move, in contrast, has been to expand the uses of perceptual information; Golonka, 2015; Golonka & Wilson, 2016 preprint).

I am firmly in the 'affordances as dispositional properties' camp (see, for example, the discussion section of my recent throwing paper for an extended analysis). Specifically, they are dynamically defined dispositional properties of objects and events in the context of tasks. The reason is that this is the only way affordances can be the kind of thing that can create information and therefore be perceivable. They have to be 'out there' and made of things that light can bounce off, for example, and relations between organism and environments are not typically such things. In addition, if they do not exist until perceived, we need a story to explain how we come to learn to perceive them, and there is no viable ecological framework that will make this happen (Wilson et al, 2016).

Reading this material with my new mechanism glasses on has given me a new, concise way to identify the problems with these relational accounts:

Affordances-as-relations theories are all functional explanations, and not mechanistic explanations

Chemero (2009) - A Brief Pause to See Where I'm At

There are still a couple of chapters left for me to go over in Chemero, but the last two were the crux of the book for me, and I want to try and summarise where my analysis has left me before I go on holiday for Easter.

First, I'd like to separate out a couple of themes. First, there's the overall 'radical embodied cognitive science' programme, and second is the specific form of the 'shored up ecological psychology' that Chemero advocates as a basis for this programme. I am entirely on board with the basic idea of RECS; specifically, I think that cognition, whatever that is, is non-representational and that we can make great progress by making our science non-representational. I think Chemero has written a clear exposition of what such a radical science might look like, and why we might want to bother, and I think this makes RECS a must read for the field. 

Second, I think that Chemero is right to go to ecological psychology for a theoretical basis. The more I look, the more I have come to believe that James Gibson is about the only psychologist to have actually proposed a genuine scientific theory in psychology. A true theory provides you with tools to empirically attack novel problems in your domain, and provides you with a clear basis to interpret the results of your tests and to begin to tell a coherent story. Psychology has been chasing phenomena for most of it's scientific life, with no clear framework emerging to tell us a story about why things are the way they are. Ecological psychology is a genuine theory, and it's about a critical feature of our psychological lives: how we maintain contact with our world and move through it successfully. Regardless of what topic you're specifically interested in, you need to understand how we come to have knowledge about our environments.

Finally, though, I have problems with the proposals Chemero makes about the two pillars of an ecological psychology, affordances and information. It's these problems I want to try and sum up here, to focus the conversation a little.

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.

F*cking affordances - how do they work?

Over on Bounds of Cognition, Ken has been doggedly pursuing what he thinks is a critical problem with the concept of affordances as described by Gibson (1979) and expanded on by Turvey, Shaw, Reed & Mace (1981; hence TSRM). I feel the need to spend some time consolidating my responses and some ideas in one place; every time I try to lay out why the problem is ill-posed or a potential route out, Ken just says I'm clouding or avoiding the issue or throwing out red herrings.

I actually think Ken has identified one very useful critique of the affordance concept: the lack of care with which we attach '-able' to words. But Ken isn't just making a methodological point; he thinks he's shown that affordances cannot structure light in a way that can specify the affordance, and that's the argument that needs to be tackled.

Saddle up: this is going to take some time, and I'm not going to solve everything. But to get a little ahead of myself, the answer to the problem is that it's complicated.

Affordances, Part 3: Dispositions or relations - which is it?

Affordances are difficult entities to wrap your head around. We talk about them imprecisely, they seem like odd, ghostly entities that couldn't possibly exist, and even when we get precise about them, we end up with two different accounts of the kind of thing they are.

Gibson did not have a logical framework with which to express what he mean by affordances, although his verbal formulation is quite clear:

An affordance is neither an objective property nor a subjective property; or it is both if you like. An affordance cuts across the dichotomy of subjective-objective and helps us to understand its inadequacy. It is equally a fact of the environment and a fact of behaviour. It is both physical and psychical, yet neither. An affordance points both ways, to the environment and the observer.

(Gibson, 1979, p. 129)

There have been two attempts at formalising this definition, with two incompatible results: for Turvey, an affordance is a dispositional property of the environment, like solubility, which is complemented by an effectivity of an organism. For Stoffregan and Chemero, affordances are relations between the organism and environment. These are not the same and the difference matters: so which is it?

Affordances, Part 1: Affordances are real dispositions of the environment

It turns out I've been pretty confused about affordances for a long time. This is partly due to the fact that I don't (yet) do research on affordances and so don't spend much time thinking about them. However, it is also partly due to the fact that affordances are fucking weird and much has been written that is confused, incomplete and wrong.

I got back into thinking about affordances in detail by reading Anthony Chemero's mostly excellent new book, Radical Embodied Cognitive Science (Google Books preview). Actually, everything I've written so far is actually me getting my head in the game to go after something I think Tony has gotten needlessly wrong; for various reasons he thinks its time to lower the specification requirement for perceptual information. I think the reasons are flawed and that it's not even close to being an empirical reality that specification is not needed; but this is all material for later on.

When Tony talks about affordances, he proposes that they are relations. He contrasts this to the generally accepted Turvey formulation, that affordances are properties, specifically dispositional properties. This, it turns out, is a key internal battle that is ongoing within ecological psychology. I was initially on Tony's side: Turvey's account has always seemed wrong to me. But after some discussion with my PhD advisor, and after reading Heft's summary of what Gibson meant, I'm back on the side of affordances as properties.