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.
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.
Affordances 1.0
The first attempt to formalise Gibson's definition was, of course, Turvey et al (1981; Turvey, 1992). This defines affordances as dispositions, properties of the world which are complemented by the effectivities of an organism. Framing affordances this way allows them to be defined with reference to the organism; the complete description of a disposition requires the conditions that allow that disposition to manifest itself, and for affordances that includes the organism.
Chemero then distinguishes a second, related version of affordances, in which they remain properties of the world but are not dispositions; instead, they are resources of the environment, properties of objects which an animal might use (Reed, 1996). This makes them a source of evolutionary selective pressure, because they exist prior to the presence of an organism that might come to use them.
Reed's account is selectionist, and tied to evolutionary biology. Chemero contrasts this to the more physics-oriented approach Turvey-Shaw-Mace (TSM) approach. Dispositions can't exert selection pressure, because properties of the world aren't dispositions unless complemented, so properties of the world aren't affordances (by TSM) until an organism shows up. A key question which follows this is to ask what aspects of the organism complement the affordance; TSM suggest effectivities, other empirical work has suggested body scale (e.g. defining the affordance for stair climbing relative to leg length; Warren, 1984).
The compulsory nature of dispositions
This comes up later in the chapter (p. 145) but is relevant now. Part of Chemero's critique of affordances-as-dispositions is that when the disposition and it's complement are present, the disposition simply manifests - it is compulsory and guaranteed. Dispositions do not fail to manifest when all the conditions are present. Chemero thinks that abilities like 'being able to walk' can't be dispositional (effectivities are dispositions too, just mirrors of affordances) because they can fail even when all the necessary conditions are met. Abilities must be functions of an organism's personal and evolutionary history, thus allowing for malfunctions.
Some comments
1. Dispositions
Dispositions do manifest when the conditions are met; but for a complex disposition such as an affordance or effectivity, it seems unproblematic that the required conditions are simply not always met. For instance, I am currently seated - I am literally currently not a walking device, and thus I am in no danger of trying to effect the disposition of the floor to support my locomotion. I can become such a device, and if I manage this I will indeed manifest walking behaviour - but there are many reason why I might fail to establish all the necessary conditions. But critically, I am not always capable of effecting every affordance in my environment. I am a task-specific device (Bingham, 1988) and must become a different one to do anything different.
2. Do affordances persist?
Chemero summarises Affordances 1.0 as describing affordances as properties of the world, with some disagreement between TSM and Reed about whether they exist independently of animals and precisely what properties of the animal they should be defined with respect to. The persistence issue comes up again below, because Chemero thinks only relations solve the problem.
To be honest, I'm not sure I see the disagreement and I don't think there's a problem for the dispositional account. My arguments with Ken Aizawa about affordances and the TSM approach pointed me to the key discussion of anchoring properties in Turvey et al (1981). These are the physical properties of the object which underpin the disposition; salt is soluble in water because of the electrical properties of the ions in the salt. These properties persist. It seems that there is a unbroken chain of links from the world to the dispositional property, such that the entire system is firmly grounded. The physical properties of objects predate organisms, and make it so that a given object non-accidentally has certain characteristics. These act as Reed's resources, defining a niche which can exert selection pressure on an organism (although there are apparently concerns about being selectionist which Chemero mentions but does not go into). Organisms then come to complement the anchored dispositions, and once this process is up and running the dispositions are capable of continuing to exert selective pressure.
This argument needs work, clearly: but as a first pass it seems that there is a perfectly sensible story to be told in which affordances are real properties of the world, if you allow yourself the full range of tools (dispositions and the idea of anchoring properties).
Affordances 1.1
Moving on, Chemero now lays out the basics of his original relational scheme. First, he motivates the move with two arguments.
1. Affordances entail feature placing
Chemero (2001) proposed that a solution to these controversies lies in rejecting the idea that affordances are properties of the world, or even properties at all. Instead, he suggested affordances are relations, between particular aspects of animals and particular aspects of situations (remember, Chemero has broadened his informational account to that covered by situation semantics).
He first notes that affordances seem to be an example of feature placing (Strawson, 1959). The example is the difference between noting your car is dented (identifying a property of the world) and noting that it is raining (placing a feature). What we perceive when we perceive affordances, Chemero argues, is more like noting that a situation has some feature (e.g. perceiving that 'it's time to flex your elbow'; Michaels, 2000). Features are not properties, and therefore affordances aren't either. They also aren't features of the world, they are features of entire situations (which includes the organism) - affordances therefore span the world and organism. Specifically, for Chemero, they are relations between these parts of the situation.
2. The problem of two minds
His second point relates to a topic that came up in Heft (2001) and which I blogged about previously: the problem of two minds. The issue is that if two people are directly perceiving the same thing, that thing forms part of the perceptual experience for both people; their minds therefore overlap at the object. Chemero notes affordances, if they are directly perceived properties of the world, suffer from the same problem. You can solve this problem, as Heft noted, if you assume that each person is in a unique relation to that property; I am seeing the object from one place, you are viewing it from another. The relation doesn't overlap, and thus there is no problem.
A comment: Chemero takes this as support that the affordance must be a relation. But as I read Heft, he actually (correctly) places the Gibsonian solution in the information, and not the world. Heft notes that the relational aspect comes naturally from the ecological analysis of the optics - the object is effectively 'multiply realised' in the optics, because each point of observation has a unique view of the object. The act of perception is relational; what you are perceiving is not (I will suggest).
Affordances 1.1
Gibson's ecological psychology is a form of realism, specifically one in which relations are perfectly real things; this means that affordances being relations doesn't immediately cause any ontological trouble for RECS. Relations define the way in which two things (the relata) are connected: for instance
taller-than (Shaquille, Henry) (1)
means that Shaquille is taller than Henry. For affordances, the relata must include the environment and the organism:
Affords-behaviour(environment, organism) (2)
The environmental relata must be features, not properties (p. 142). The organismal relata might be things like body scale, but could more usefully be described as an ability of an organism. Bill Warren ran a key study on affordances, in which he asked people to rate whether they could climb a set of stairs with a given riser height; different people switched from 'yes' to 'no' at different riser heights, but these individual differences vanished when the data were expressed as a function of the individual's leg length (as pi numbers; Warren, 1984). The suggestion is that people perceived the stairs, not in absolute terms, but relative to their own ability to step up. Leg length (body scale) is an easily measured proxy for ability, specifically the ability to climb the stair, an idea backed up by some empirical work by Chemero. So (2) becomes
Affords-behaviour(feature, ability) (3)
Perception of this affordance is, itself, a relation:
Perceives[animal, affords-behaviour(feature, ability)] (4)
but our phenomenal experience is not of the constituent relata, just the affordance:
Perceives[animal, affordance-for-behaviour] (5)
So affordances are relations; the perception of affordances is a relational act; as a flavour of realism, relations are real and so, therefore, are affordances and the perception of them. Everything RECS needs exists - so far so good.
Three brief points then follow, questions supposedly answered by Affordances 1.1 (affordances as relations):
1. Different animals may exist in the same place but occupy different niches, which Gibson took to be the set of affordances for an animal. Affordances 1.1 solves this supposed problem in the same way as the problem of two minds - different animals have different abilities, and thus stand in different relation to the same features of the environment. Like the problem of two minds, I'm not sure there's much of a problem here and if there is, it's solved in information, not the world.
2. Stoffregan (2000) was worried that if events and affordances were different, there would be no reason for an ecological psychologist to think events were perceivable. For Affordances 1.1, events are perceivable because they are a change in the relation between an organism's abilities and features of the environment, i.e. a change in the layout of affordances.
3. If affordances are dispositions, what happens to them when the complementary organism isn't present? Chemero thinks this is a problem for a supposedly realist ecological psychology; his solution at this point is to simply claim that affordances are like being 'lovely' (Dennett, 1998):
Some thoughts
The next section is on Affordances 2.0, an expansion of the affordances-as-relations accounts. But so far I'm not convinced;
Dennett, D. (1998). Brainchildren. Cambridge, Mass.: MIT Press.
Heft, H. (2001). Ecological Psychology in Context: James Gibson, Roger Barker and the Legacy of William James's Radical Empiricism. Mahwah, NJ: Lawrence Erlbaum.
Michaels, C. F. (2000). Information, perception, and action: What should ecological psychologists learn from Milner and Goodale (1995)? Ecological Psychology, 12 (3), 241-258.
Mumford, S. (1998). Dispositions. Clarendon Press.
Reed, E. (1996). Encountering the World. New York: Oxford University Press.
Stoffregen, T. (2000). Affordances and events. Ecological Psychology, 12, 1-28.
Strawson, P. F. (1959). Individuals. London: Methuen.
Turvey, M. (1992). Affordances and Prospective Control: An Outline of the Ontology. Ecological Psychology, 4 (3), 173-187 DOI
Warren, W. H. (1984). Perceiving affordances: Visual guidance of stair climbing. Journal of Experimental Psychology: Human Perception and Performance, 10, 683-703.
The first attempt to formalise Gibson's definition was, of course, Turvey et al (1981; Turvey, 1992). This defines affordances as dispositions, properties of the world which are complemented by the effectivities of an organism. Framing affordances this way allows them to be defined with reference to the organism; the complete description of a disposition requires the conditions that allow that disposition to manifest itself, and for affordances that includes the organism.
Chemero then distinguishes a second, related version of affordances, in which they remain properties of the world but are not dispositions; instead, they are resources of the environment, properties of objects which an animal might use (Reed, 1996). This makes them a source of evolutionary selective pressure, because they exist prior to the presence of an organism that might come to use them.
Reed's account is selectionist, and tied to evolutionary biology. Chemero contrasts this to the more physics-oriented approach Turvey-Shaw-Mace (TSM) approach. Dispositions can't exert selection pressure, because properties of the world aren't dispositions unless complemented, so properties of the world aren't affordances (by TSM) until an organism shows up. A key question which follows this is to ask what aspects of the organism complement the affordance; TSM suggest effectivities, other empirical work has suggested body scale (e.g. defining the affordance for stair climbing relative to leg length; Warren, 1984).
The compulsory nature of dispositions
This comes up later in the chapter (p. 145) but is relevant now. Part of Chemero's critique of affordances-as-dispositions is that when the disposition and it's complement are present, the disposition simply manifests - it is compulsory and guaranteed. Dispositions do not fail to manifest when all the conditions are present. Chemero thinks that abilities like 'being able to walk' can't be dispositional (effectivities are dispositions too, just mirrors of affordances) because they can fail even when all the necessary conditions are met. Abilities must be functions of an organism's personal and evolutionary history, thus allowing for malfunctions.
Some comments
1. Dispositions
Dispositions do manifest when the conditions are met; but for a complex disposition such as an affordance or effectivity, it seems unproblematic that the required conditions are simply not always met. For instance, I am currently seated - I am literally currently not a walking device, and thus I am in no danger of trying to effect the disposition of the floor to support my locomotion. I can become such a device, and if I manage this I will indeed manifest walking behaviour - but there are many reason why I might fail to establish all the necessary conditions. But critically, I am not always capable of effecting every affordance in my environment. I am a task-specific device (Bingham, 1988) and must become a different one to do anything different.
2. Do affordances persist?
Chemero summarises Affordances 1.0 as describing affordances as properties of the world, with some disagreement between TSM and Reed about whether they exist independently of animals and precisely what properties of the animal they should be defined with respect to. The persistence issue comes up again below, because Chemero thinks only relations solve the problem.
To be honest, I'm not sure I see the disagreement and I don't think there's a problem for the dispositional account. My arguments with Ken Aizawa about affordances and the TSM approach pointed me to the key discussion of anchoring properties in Turvey et al (1981). These are the physical properties of the object which underpin the disposition; salt is soluble in water because of the electrical properties of the ions in the salt. These properties persist. It seems that there is a unbroken chain of links from the world to the dispositional property, such that the entire system is firmly grounded. The physical properties of objects predate organisms, and make it so that a given object non-accidentally has certain characteristics. These act as Reed's resources, defining a niche which can exert selection pressure on an organism (although there are apparently concerns about being selectionist which Chemero mentions but does not go into). Organisms then come to complement the anchored dispositions, and once this process is up and running the dispositions are capable of continuing to exert selective pressure.
This argument needs work, clearly: but as a first pass it seems that there is a perfectly sensible story to be told in which affordances are real properties of the world, if you allow yourself the full range of tools (dispositions and the idea of anchoring properties).
Affordances 1.1
Moving on, Chemero now lays out the basics of his original relational scheme. First, he motivates the move with two arguments.
1. Affordances entail feature placing
Chemero (2001) proposed that a solution to these controversies lies in rejecting the idea that affordances are properties of the world, or even properties at all. Instead, he suggested affordances are relations, between particular aspects of animals and particular aspects of situations (remember, Chemero has broadened his informational account to that covered by situation semantics).
He first notes that affordances seem to be an example of feature placing (Strawson, 1959). The example is the difference between noting your car is dented (identifying a property of the world) and noting that it is raining (placing a feature). What we perceive when we perceive affordances, Chemero argues, is more like noting that a situation has some feature (e.g. perceiving that 'it's time to flex your elbow'; Michaels, 2000). Features are not properties, and therefore affordances aren't either. They also aren't features of the world, they are features of entire situations (which includes the organism) - affordances therefore span the world and organism. Specifically, for Chemero, they are relations between these parts of the situation.
2. The problem of two minds
His second point relates to a topic that came up in Heft (2001) and which I blogged about previously: the problem of two minds. The issue is that if two people are directly perceiving the same thing, that thing forms part of the perceptual experience for both people; their minds therefore overlap at the object. Chemero notes affordances, if they are directly perceived properties of the world, suffer from the same problem. You can solve this problem, as Heft noted, if you assume that each person is in a unique relation to that property; I am seeing the object from one place, you are viewing it from another. The relation doesn't overlap, and thus there is no problem.
A comment: Chemero takes this as support that the affordance must be a relation. But as I read Heft, he actually (correctly) places the Gibsonian solution in the information, and not the world. Heft notes that the relational aspect comes naturally from the ecological analysis of the optics - the object is effectively 'multiply realised' in the optics, because each point of observation has a unique view of the object. The act of perception is relational; what you are perceiving is not (I will suggest).
Affordances 1.1
Gibson's ecological psychology is a form of realism, specifically one in which relations are perfectly real things; this means that affordances being relations doesn't immediately cause any ontological trouble for RECS. Relations define the way in which two things (the relata) are connected: for instance
taller-than (Shaquille, Henry) (1)
means that Shaquille is taller than Henry. For affordances, the relata must include the environment and the organism:
Affords-behaviour(environment, organism) (2)
The environmental relata must be features, not properties (p. 142). The organismal relata might be things like body scale, but could more usefully be described as an ability of an organism. Bill Warren ran a key study on affordances, in which he asked people to rate whether they could climb a set of stairs with a given riser height; different people switched from 'yes' to 'no' at different riser heights, but these individual differences vanished when the data were expressed as a function of the individual's leg length (as pi numbers; Warren, 1984). The suggestion is that people perceived the stairs, not in absolute terms, but relative to their own ability to step up. Leg length (body scale) is an easily measured proxy for ability, specifically the ability to climb the stair, an idea backed up by some empirical work by Chemero. So (2) becomes
Affords-behaviour(feature, ability) (3)
Perception of this affordance is, itself, a relation:
Perceives[animal, affords-behaviour(feature, ability)] (4)
but our phenomenal experience is not of the constituent relata, just the affordance:
Perceives[animal, affordance-for-behaviour] (5)
So affordances are relations; the perception of affordances is a relational act; as a flavour of realism, relations are real and so, therefore, are affordances and the perception of them. Everything RECS needs exists - so far so good.
Three brief points then follow, questions supposedly answered by Affordances 1.1 (affordances as relations):
1. Different animals may exist in the same place but occupy different niches, which Gibson took to be the set of affordances for an animal. Affordances 1.1 solves this supposed problem in the same way as the problem of two minds - different animals have different abilities, and thus stand in different relation to the same features of the environment. Like the problem of two minds, I'm not sure there's much of a problem here and if there is, it's solved in information, not the world.
2. Stoffregan (2000) was worried that if events and affordances were different, there would be no reason for an ecological psychologist to think events were perceivable. For Affordances 1.1, events are perceivable because they are a change in the relation between an organism's abilities and features of the environment, i.e. a change in the layout of affordances.
3. If affordances are dispositions, what happens to them when the complementary organism isn't present? Chemero thinks this is a problem for a supposedly realist ecological psychology; his solution at this point is to simply claim that affordances are like being 'lovely' (Dennett, 1998):
Dennett distinguishes between things that are lovely and things that are suspect. To see the distinction, consider that a female hippopotamus in a zoo might be lovely, even if no male hippopotamus has ever seen her. She is lovely just in case if a male hippopotamus were to see her, he would find her to be so. The key is that being lovely depends on a potential observer, not an actual act of observation. Compare this to being suspect. To be suspect, something actually has to be under suspicion. Being suspect requires an actual observer. Whether affordances exist without animals is a matter of whether affordances are lovely or suspect. Affordances, we can see, are lovely. A feature of some situation might exist just as it is even if there are no animals. There will be affordances in which that feature takes part as long as some animal exists with the appropriate ability.This analysis holds for relations, but it's not immediately apparent that it's not just as true for dispositions. In fact, it sounds exactly like dispositions, especially if you remember about anchoring properties.
Chemero, 2009, pg. 149
Some thoughts
The next section is on Affordances 2.0, an expansion of the affordances-as-relations accounts. But so far I'm not convinced;
- I think there is a confusion lurking here. Gibson worked very hard to keep the world and information about the world distinct. These things are not identical; as a simple example, the information for relative phase is not relative phase, but the relative direction of motion. Chemero is correct to note that relations solve the problems he notes: I just think he has put the relation in the world, instead of in the optics, and that this is an error. The critical relation is the act of perception, and what is perceived are properties.
- I have to thank Ken's assault on the TSM approach for making me aware of anchoring properties; it's been a long time since I read the laws paper in that much detail. I think these serve the critical role of grounding the affordance to the physical world.
- I also have the hunch that the account of dispositions currently available to ecological psychology is out of date; since Turvey (1992) there's been a major research programme in philosophy about dispositions, which I believe was kicked off by Stephan Mumford (1998). I would actually like to bring these developments to ecological psychology, because I think we might find it useful. Maybe I'll send him an email one day. Regardless, there's work available to improve any problems with the dispositional account before we need to throw it out.
Dennett, D. (1998). Brainchildren. Cambridge, Mass.: MIT Press.
Heft, H. (2001). Ecological Psychology in Context: James Gibson, Roger Barker and the Legacy of William James's Radical Empiricism. Mahwah, NJ: Lawrence Erlbaum.
Michaels, C. F. (2000). Information, perception, and action: What should ecological psychologists learn from Milner and Goodale (1995)? Ecological Psychology, 12 (3), 241-258.
Mumford, S. (1998). Dispositions. Clarendon Press.
Reed, E. (1996). Encountering the World. New York: Oxford University Press.
Stoffregen, T. (2000). Affordances and events. Ecological Psychology, 12, 1-28.
Strawson, P. F. (1959). Individuals. London: Methuen.
Turvey, M. (1992). Affordances and Prospective Control: An Outline of the Ontology. Ecological Psychology, 4 (3), 173-187 DOI
Turvey,
M. T., Shaw, R. E., Reed, E. S., Mace W. M. (1981). Ecological laws of
perceiving and acting: In reply to Fodor and Pylyshyn (1981) Cognition, 9 (3), 237-304 DOI: 10.1016/0010-0277(81)90002-0
Warren, W. H. (1984). Perceiving affordances: Visual guidance of stair climbing. Journal of Experimental Psychology: Human Perception and Performance, 10, 683-703.
Posts
Before I work on a substantive post / while I try to decide whether one would be helpful....
ReplyDeleteI wanted to mention that this seems like the type of hairsplitting that indicates almost complete agreement. Where "this" = [Chemero's discussion of affordances, your critique of Chemero, and anything I might say]. I suspect that most (but not all) investigations one could do with any of these affordance concepts would be very similar. Based on that, I suspect that a lot of the issues at stake are how people talk about what they are doing, not what they are doing (if that makes any sense).
The one piece of substance I will add, I guess, is to backtrack (slightly) my criticism of the TSM model from the Chapter 6 commentary. I probably should have said that the problem is that TSM hold that position while denying they are radical behaviorists. -- They are claiming that if we define your present state down to a low enough level of detail (I suspect a cellular description will do), we can say that you are, at this exact instance, exactly the type of animal that would reach out to grab a door handle, were a door handle five inches in front of you, and at waist height. We can then place a door nob at that location, and observe you grabbing it. -- As those same people claim that we should revere Gibson, in part, for his not being a behaviorist, that seems an odd position to embrace.
Again though, a perfect example of an issue that probably shouldn't make much difference to the practicing researcher.
I don't know anyone who doesn't agree that Gibson was a (molar) behaviourist.
ReplyDeleteAs for whether Affordances 1.0 and 1.1 are the same; Tony's mentioned to me that he and Turvey have a paper out somewhere showing they are formally equivalent (I think; the paper's pretty technical). I'm not convinced that makes much sense, but then I didn't really get the paper. But I don't think they're functionally equivalent, and I think the affordance-as-relation description has some issues that cause trouble.
Dispositions seem much more tractable, and I think they can guide a research programme: your earlier comment about effectivities-talk making things trivially true is not correct. Saying something can effect an affordance simply provides a theoretically constrained space within which you think all the relevant resources exist. You can then perturb the effectivities to see whether you're right or not. So while yes, you can make the error of leaving the analysis too soon, that's an error by the scientist, and not by TSM.
Re effectivities:
ReplyDeleteWell, I posit the following claim as obviously true, and uncontroversial:
What an organism could potentially do depends on the organism's abilities and the structure of the world.
However, "effectivity" includes what we would normally call "abilities", and what we would normally call "motivation" or "intention" and what we would normally call "knowledege" (and maybe a bunch of other stuff). So, for example, I have the ability to walk up the stairs in my house, and do so readily if I need to use the restroom.
As I read Gibson, the stairs afford my going up. [Period.] They afford it at all times. If I am searching for my remote control, and pass the stairs, then I could perceive the affordance and yet walk on by. If the stairs were transported to China, we would still say that they "afford my going up," adding only a caveat like, "if I could get to them." It is not I get some other such physical malady, a broken leg perhaps, that the affordance goes away.
Now, as I read TSM, with both the disposition-talk and the effectivity-talk, the story goes differently. In TSM, every time I walk by the stairs and do not go up them, we must conclude that I lacked the effectivity. We must conclude this, because dispositions necessarily manifest. Hence, the me that intends to go to the restroom HAS the effectivity that complements the stairs; the me that is looking for my remote LACKS the effectivity. Even this might be tolerable, except that effectivity and affordance are symmetrical. So we must also say that the stairs HAVE the affordance climb-up-able when I need to go to the restroom, but LACK the affordance climb-up-able when I am looking for the remote.
It is definitely possible to take the TSM system and do stuff with it, but I am not sure we can do all the things I want. Certain popular methods of experimenting, for example, become weirdly incoherent. You could not, for example, measure someone's body, and then adjust a doorway to a width that you (the experimenter) knew would narrowly afford the participant's passage. That is, you cannot adjust the doorway and then make assertions about the affordances present. The doorway might well be big enough for the participant's body to pass through, but if the participant feels like sitting instead, then, by TSM definition, the affordance of walk-through-able is NOT present. One way to create the affordance might be to offer them $100 to walk through the door. -- If offered $100, then they have the effectivity and the door has the affordance; if no $100, then they lack the effectivity and the door lacks the affordance. Weird, weird, weird.
It will only get weirder when we start talking about information, and perception of affordances. Under TSM, I submit, it is impossible to perceive an affordance and not take advantage of it. (No behavior -> disposition did not manifest; disposition did not manifest -> no effectivity; no effectivity -> no affordance.)
----
To be fair, I'm not sure exactly where I'm going with this, and nothing I said above indicates that TSM is wrong per se. I think at best I am hopping to convince you that the rabbit hole you are going down is deep, and it is more mysterious than it initially appears.
So we must also say that the stairs HAVE the affordance climb-up-able when I need to go to the restroom, but LACK the affordance climb-up-able when I am looking for the remote.
ReplyDeleteThis is precisely the thing that I think is not true under the dispositional account. The reason is simple: dispositions exist even when their complement is not present. Salt is always disposed to dissolve in water, even when not wet. This persistence is grounded in the anchoring properties - salt is always an ionic salt.
This persistence is actually what I think relations don't do, for roughly the reasons you attribute to dispositions, and therefore the weirdness you talk about is more an issue for relations than dispositions.
Aha!
ReplyDeleteYou are trying to put all the weirdness resulting from TSM into the effectivities. I see the weirdness as impacting effectivities and affordances relatively equally. I will meditate on a response.
No, I'm saying the weirdness you suggest is only a feature of the relations account, and not the dispositional account.
ReplyDeleteQuick questions:
ReplyDeleteYou argue that from the dispositional point of view the walk-up-ableness of the stairs is like the disolvableness of salt. You state that the affordance of the stairs is stably present, even when I do not take advantage of this. This leads me to believe that you think any situation in which I do not walk up the stairs indicates a problem on the effectivity side of the equation. To work the metaphor, I am like water when I need something from upstairs, but not like water when am looking for something downstairs. Question 1: Can you confirm that I am characterizing your position fairly?
If that is the position, then the odd thing might be that you are claiming the stairs afford climbing up, without specifying who they afford climbing up to. That is, typically I think of affordances as requiring a referent organism (or category of organisms) to which the behavior is afforded. But if I do not have the effectivity, then the stairs cannot afford climbing up to me. Question 2: Are you comfortable saying that the stairs stably afford walking up, but that we can see rapid fluctuations in whether or not the stairs afford walking up to any particular person? If so, Question 3: Are you comfortable with those fluctuations being caused by a change in what I am searching for in my house at a given moment? (e.g., a remote control vs. a new pair of pants)
This leads me to believe that you think any situation in which I do not walk up the stairs indicates a problem on the effectivity side of the equation. To work the metaphor, I am like water when I need something from upstairs, but not like water when am looking for something downstairs
ReplyDeleteIt's not necessarily a problem (right now I'm seated and that means I can currently do some things and not others) but that's about right otherwise.
If that is the position, then the odd thing might be that you are claiming the stairs afford climbing up, without specifying who they afford climbing up to.
Not at all. As per the solubility of salt, laying out the disposition entails describing the solvent, even if the solvent is currently absent. Affordances are dispositions for behaviour by an organism; you need an organism in the story or else you're just describing some physical properties of the world.
But if I do not have the effectivity, then the stairs cannot afford climbing up to me.
Not quite. If you are not currently complementing the affordance you cannot currently effect it. Time is in the mix.
Question 2: Are you comfortable saying that the stairs stably afford walking up, but that we can see rapid fluctuations in whether or not the stairs afford walking up to any particular person?
The stairs always afford climbing to an organism like me, but whether or not I can effect that affordance varies over time. In the dispositional account, 'affordance' is the name we assign to the properties of the world that are involved in the disposition, so they don't swing in and out of existence unless the world does.
If so, Question 3: Are you comfortable with those fluctuations being caused by a change in what I am searching for in my house at a given moment? (e.g., a remote control vs. a new pair of pants)
Your intentions don't change the affordance properties of the stairs; they (may) change your ability to effect that affordance at that moment in time (so, roughly, if you are hunting for that remote down the back of the sofa, you might not currently be a locomoting device).
The dispositional ontology is that the affordance is a property of the world. It is made of things in the world, and those bits exist independent of us, but the affordance they make is defined with respect to us. The stairs have certain physical features regardless of whether I exist or am in the room; but when a perceiving organism measures those properties using it's own capacities as the ruler, then those properties can be described as an affordance property.
Maybe we are veering too far off of Chemero here, but I'm not sure you can make the moves you are making within TSM. Let me work this through more explicitly...
ReplyDeleteNote, that no where will I questioned the following, which I take to be true by definition: Stairs have stable properties, and so always afford walking-up, to an organism with the proper effectivity, even should no such organism exist.
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You chose as your primary metaphor for the affordance-effectivity pairing the disposition of salt to dissolve in water. If salt and water come together, the salt necessarily dissolves in the water (we assume). The salt's solubility in water is determined by properties of the salt that would be present even if no water existed in the universe. The water can dissolve salt due to properties of the water that would be present even if no salt existed in the universe. When the two meet, the disposition manifests, and we get salty water.
I take the intended meaning of this metaphor to be as follows: The stairs are like the salt. The stairs afford walking-up, due to properties of the stairs that remain even if no organism exists that could walk up them. Some organisms are like the water, they are not only able to walk up the stairs, they NECESSARILY walk up the stairs whenever stairs are encountered. This is due to properties of the organism that maintain even if no stairs existed in the universe. Whenever the two meet, we get stair climbing.
From your initial metaphor, I could generate the following experiment: Take a mystery liquid and add salt; if the salt does not dissolve, it cannot be water. (A & B)-> C, A & not C, therefore not B.
From the affordance-effectivity example, I could generate the following experiment: Walk an organism past stairs; if the organism does not walk up the stairs, it lacks the effectivity. (A & B)-> C, A & not C, therefore not B.
Continuing the initial metaphor: Following the experiment, I could conclude - Whatever my liquid is, salt will not dissolve in it.
Continuing the affordance-effectivity example: Following the experiment, I could conclude - Whatever organism I have, the stairs do not afford walking-up for it.
Either a) I have screwed up keeping the examples parallel, or b) in TSM, effectivities are fickle things, and so therefore are the list of things afforded any given organism at any given time.
Everything in the analogy (it's not really a metaphor, the claim is that affordances are dispositions) seemed ok to me, up until
ReplyDeleteContinuing the affordance-effectivity example: Following the experiment, I could conclude - Whatever organism I have, the stairs do not afford walking-up for it.
Either a) I have screwed up keeping the examples parallel, or b) in TSM, effectivities are fickle things, and so therefore are the list of things afforded any given organism at any given time.
The problem seems mostly a matter of applying labels to the right things. In the dispositional account, the affordance is a property of the world. So the stairs always afford climbing. The organism did not effect the affordance. So the conclusion must be that the organism is not currently a stair climbing device; you would then start asking why, and testing things like did they not see the stairs, or were they in a rush to work, etc. Effectivities are indeed a bit fickle; perception/action is a high dimensional system.
This makes perfect sense. To a human with functioning legs, a staircase can always be climbed. If the person doesn't climb it, then clearly something else is going on that took precedence.
Everything in the analogy (it's not really a metaphor, the claim is that affordances are dispositions) seemed ok to me, up until
ReplyDeleteContinuing the affordance-effectivity example: Following the experiment, I could conclude - Whatever organism I have, the stairs do not afford walking-up for it.
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But salt does not dissolve in just anything, the disposition of salt is specifically to dissolve in water.
The stairs similarly do not afford climbing up to just anything, the stairs only afford climbing up to an organism with the correct effectivity.
I have avoided bringing it up, but salt very often does not dissolve in water. There are many possible reasons for this, an cheap shot would be to point out that the salt is not dissolved if the water is very cold (i.e., very frozen).
So, if we wanted to expand the metaphor/analogy*, then I am like water when I have to go to the bathroom and the downstairs lu is taken; I am like ice if pass the stairs on my way to the fridge. As you point out, when on my way to the fridge, I am not the type of thing that climbs up stairs. If on my way to the fridge, I find nature calling, I suddenly am the type of thing that climbs stairs.
How can stairs afford climbing up to the type of thing that does not climb stairs? If I had all my same properties, but with two broken knees, or with atrophied leg muscles, or with a brain injury that made my legs shake convulsively when under strain, the stairs would not afford my climbing up... because I lack the effectivity, Right?
*I have a weird philosophy of science bias that says all explanations are metaphors.
I have avoided bringing it up, but salt very often does not dissolve in water. There are many possible reasons for this, an cheap shot would be to point out that the salt is not dissolved if the water is very cold (i.e., very frozen).
ReplyDeleteHardly a cheap shot. You've identified a situation in which the key anchoring properties of the two halves of the disposition don't match. 'salt is disposed to dissolve in water' is extreme shorthand for the full account, which includes the full list of necessary and sufficient conditions for the disposition to manifest.
I don't see the problem. This is just how dispositions work. Part of our job is to enumerate and lay out the full list for our particular class of dispositions; so we need to discuss information, but also capabilities, current states of the system, etc.
How can stairs afford climbing up to the type of thing that does not climb stairs? If I had all my same properties, but with two broken knees, or with atrophied leg muscles, or with a brain injury that made my legs shake convulsively when under strain, the stairs would not afford my climbing up... because I lack the effectivity, Right?
Critically in these cases, you lack the possibility of effecting the affordance. So the stairs would not afford climbing to you (although you could still perceive that the stairs would afford climbing if only you could overcome that limitation - this is something I don't see relations as capable of).
In the other cases, you have the ability to become a stair climbing device, but don't effect it because something is intervening and making you a different device.
Good post. On an unrelated note, I am enjoying the joke in your blog name - 'scientific' psychologists! Haha, when everyone knows psychology isn't a science!
ReplyDeleteI can only imagine that, with all the talk of salt, this post has attracted the heckling of rogue chemists!
ReplyDeleteThere is something in what you say that is more arbitrary than TSM. Unless we are suddenly dualists, 'lacking strength in my legs' and 'lacking the intention to use the upstairs bathroom' are two physical facts about me (or about me relative to the environment). Both can be changed - I could exercise to strengthen my legs, I could drink a pint or two to fill my bladder - no real difference.
ReplyDeleteAnother way to say this is that I don't think the TSM model allows for your talk of "possibilities." (For the record, I think you are right to talk that way, but I think that in doing so you are going against TSM.) The claim that it IS POSSIBLE for dispositions to obtain when the two parts come together, is very different than the claim that dispositions MUST obtain. The crux of the salt-water example is that it is not only possible for water to dissolve salt, but that dissolving necessarily happens whenever the two come together.
There is something in what you say that is more arbitrary than TSM. Unless we are suddenly dualists, 'lacking strength in my legs' and 'lacking the intention to use the upstairs bathroom' are two physical facts about me (or about me relative to the environment). Both can be changed - I could exercise to strengthen my legs, I could drink a pint or two to fill my bladder - no real difference.
ReplyDeleteI was pointing out that in the examples you had at the end (brain injuries) it was all a bit more permanent than 'I don't currently need to pee'. If the effectivity can be changed the it reopens the possibility.
Another way to say this is that I don't think the TSM model allows for your talk of "possibilities." (For the record, I think you are right to talk that way, but I think that in doing so you are going against TSM.) The claim that it IS POSSIBLE for dispositions to obtain when the two parts come together, is very different than the claim that dispositions MUST obtain. The crux of the salt-water example is that it is not only possible for water to dissolve salt, but that dissolving necessarily happens whenever the two come together.
I draw this entirely from TSM and from the dispositional literature.
Let me back track a little to clarify what I meant: in the case where I thought you were suggesting permanent changes to a person, I suggest that the stairs no longer afford climbing for that altered person. Secondly, by possibility of effecting, I mean that if I, an able bodied human, walk past some stairs, I am capable of effecting that affordance because I am able to fill the dispositional requirements. But I don't always fill them.
Dispositions only manifest when all their conditions are met. It is easy to manifest the solubility of salt; get some room temperature water and you're done. It is harder to manifest the disposition 'affords-locomotion' - ask any 12 month old trying to figure out how to effect it.