The concept of affordance has become an important component in explaining the nature of perception. The idea of affordance was introduced and developed by J.J Gibson as a radical reinterpretation of perception, one that champions direct perception. Instead of saying that we perceive the features of the world around us, and from this construct a model of what we are perceiving (indirect perception), Gibson suggested that we directly perceive possible actions in the world. So a flat surface affords the possibility of walking upon it; a small rock affords the possibility of being picked up and so on.
In contrast, the perception of features involves detecting the property of flatness, stableness etc., to then represent these properties and from that make an inference that the surface can be walked upon. While the inference model is still the most popular theory in terms of explaining cognition (the representational theory of mind), there is a renewed appeal for direct theories of not just perception but cognition in general. This appeal is driven by the simplest of ideas: in order to perform day-to-day tasks we don’t interact with objects in our head but with the world directly. There are also several arguments against the the inference model (especially mental representations) that also give direct cognition more credence. However, like many, my main reason for being attracted to the theory is that there does seem to be something direct about a lot of our cognition.
Even with that said, I am not a full blown supporter. In short I think the conclusions that are derived from this claim are often too strong; taking the idea too far without extra steps of justification. This doubt comes through in the use and explanation of affordances. Specifically when we ask: what types of information do affordances give us access to? In the most sloppiest of uses, the concept of affordance becomes synonymous with direct perception and in this way fails to offer an explanation of what affordances are.
Before discussing the criticisms, I want to point out the cases where affordances are a constructive and useful idea. There is a good reason that the walkability (affordances are normally talked about the abilities they present) of a flat surface is the de rigeur example introduced by Gibson. If we consider such things as new born foals being able to walk soon after birth this seems to say something about their ability to use their perception to know where they can and can’t move about. Contrast a foals movement with a newly hatch spider and its freedom to climb vertical surfaces. Or consider how new born turtles use gradient and light to guide them towards the sea. To say that the turtles use the light and gradient to deduce the position of the sea seems to create an overly complex model, one in which the turtle needs time to pause to think. The idea of affordance helps remove this extra layer of complexity. For the baby turtle to see the light is to see not the world but the instruction: move in this direction (or perhaps the more catchy: walk this way).
This does not mean that the turtle has some semantic content about movement, rather it is the idea that the light is a cause of its movement not a step in a long process. The ambient energy perceived by the turtle is meant to activated the actual perception of possible movement, not some secondary semantic content. This also gives insight into the nature of direct cognition.
This idea of directly perceiving actions seems a plausible explanation for such cases, namely cases of innate or instinctual behaviour. While representationalists can still argue that there is the possibility that inferences are occurring even in these instinctual cases they have other concerns they must overcome, the most talked about currently being the frame problem. My concern, however, is though we can accept affordances working at this innate level, does the concept extend further? What about behaviours that are learnt, ones in which the association between perception and action is not always so straightforward?
Here I am thinking of cultural practices, consider the use of chopsticks or a fork to eat with. Is there anything about a fork or pair of chopsticks that goes from them being perceived to being used to put food into a person’s mouth? Both might be perceivable as being pick-up-able, but does this then lead to put-food-in-mouthable? If affordances are directly perceived it cannot be claimed that that to see a fork is to make an association that this is a tool to eat with, rather, to see the fork should mean an actual perception of using the fork to eat with. However, for those unfamiliar with forks, or with chopsticks, I think there is no such immediate perceptual act going on. There instead seems to be an association between what is perceived and how it can be used. With theories of direct perception there seems to be no room for a mental thing that makes such association possible.
To step back a little, the idea of affordance claims that when an organism perceives a particular feature of the world, that very act of perception reveals the affordance. This idea was challenged by Fodor and Pylyshyn (1981), arguing that the ambient energy that we interact with (ie the stuff that engages our senses, like light rays or sound waves) must only carry information relevant to its medium. Light rays carry vision specific information, sound waves, hearing specific etc. This was shown to be a faulty argument by Turvey et. al. (1981) in that the Fodor and Pylyshyn did not give a great enough role to the act that perception plays in an affordance. Affordances are a union between an organism (organic or not) and the world. That organism does not just perceive like a video camera but has needs and ways to move about to get those needs. In his description of an affordance Gibson stated an affordance must be understood as the coming together of the needs and ways to move of an organism with ambient energy from that organism’s surroundings (Gibson 1979, p. 129). Affordances need this union between world and organism in order for them to avoid Fodor’s criticism. For this reason I think those that claim that affordances are ontological independent of this union are mistaken.
However, even with this clarification, we can see why learnt behaviour is such a problem. If affordances are the relation between the ambient energy and the organism, then what changes when a behaviour is learnt is only the organism. The ambient energy remains the same. Nor, can it be said that the perceptual capability of the organism has changed (there are a handful of exceptions to this, namely being able to actually disambiguate ambient energy, as when seeing through a microscope). When I personally learnt to use chopsticks it was not due to some perceptual awakening, they did not glow or present themselves in a new way. Instead, I can now associate the shape with the act of picking up food and eating even though the shape of the object was one I was able to perceive before I knew they could be used to eat with. In this way learnt behaviour is about the change that the cognitive agent has gone through. And these changes do no involve the a change in the nature of perception but a response to a perception.
At this point I suspect those wanting to extend affordances to learnt behaviour will appeal to some type of dispositional based behaviour. That by developing different types of responses to certain environmental conditions, learnt behaviour can still be explained by affordances. Here I agree that the ability to deploy certain behaviours in particular circumstances does offer some way forward in solving this problem. However, as I will argue another time, it isn’t enough. Just like the idea of affordance, dispositions emphasis the link between the state of the world and possible actions that can be taken. And just like with affordances there is still no additional cognitive mechanism to account for association. Thereby falling to the same criticism presented here.
This problem I find especially interesting if one rejects the temptation to fall back on representations. How is it that perceiving something in the world allows for not just one act of learnt behaviour to be considered, but also allows for a raft of possibilities, ones that we may never have even encountered before (for example, a fork can, in hopefully rare circumstances, quickly turn from a tool to eat with to a tool to injure with). As it stands I think affordances tie the relationship between world and organism too closely together. There needs to be more space for cognitive agents to develop and influence their own behaviour.
