Wednesday, 22 April 2015

Function vs Structure (A Purple Peril)

One of the apparently controversial things that I say is that psychology, as a science, needs to address function before it gets worried about structure; what is the brain trying to do, vs how is it doing it? This Peril lays out the argument in a little more detail. As always, this is my current thinking not my final thinking and I am happy as ever to hear arguments for and against this proposal.

Structure (the details of how a function is implemented) is important, there is no doubt. But I see two related arguments about putting function first, or at least giving it the driver's seat in our science.

Monday, 13 April 2015

Specification and Some of Its Consequences (A Purple Peril)

Perception is how we maintain psychological contact with functionally relevant objects and events in our environments. Explaining how we do this means describing that environment in appropriate terms and investigating what information might possibly exist for that environment, given that description. The ecological hypothesis is that the correct level is dynamics, and that describing the environment this way allows there to be information that can specify those dynamics. This information can support the kind of behaviour we need to exhibit. 

This Purple Peril describes what is meant by specification, and what that implies for how information comes to mean something to an organism. There is more detail in the various links, so check those for information too.

Friday, 10 April 2015

(Re)Introducing "The Purple Perils"

'Note for a tentative redefinition of behaviour', 1975. 
James J Gibson ran an afternoon seminar for many years at Cornell. This seminar was widely attended by a variety of students, professors and visiting scholars, and Gibson used them as a place to try out new ideas, new ways of describing those ideas and generally hammer his theory as hard as he could to see where the weak and strong points were.

Before many of these seminars, he would write and distribute a note, often fairly detailed, detailing the topic of that week's meeting. These were copied as he typed by 'ditto' sheets which transferred the text onto multiple sheets of paper. The ink on these sheets was purple, and the notes became known as the Purple Perils. (There is a nearly complete archive of these online hosted by Bill Mace.) 

These Perils were never the final word on anything. They reflected Gibson's current thinking and were always up for debate. That debate often found it's way into the next week's seminar and Peril, so these were always works in progress.

I've just finished reading Ed Reed's Gibson biography (there's a couple of taster chapters here) and I've been inspired by his description of the kind of scientist Gibson was; the Perils and his seminar were good examples of the kind of rigour and openness he embraced in his science. So, in this spirit, we are going to start posting some shorter, more focused posts on specific topics and ideas from the ecological embodied cognitive science we are developing. They will reflect our current thinking on the topic, but not necessarily our final thinking, and they will not aim to solve everything, just move it forward. They will typically include some 'facts of the matter' as seen from the ecological view, and some analysis to reach some conclusions and hypotheses based on those facts. The goal is to stimulate debate and discussion and come away with a better, clearer theory. 

We would like to invite you all to come get into it with us; ask questions, challenge us, agree with us (we like this too!), talk to each other in the comments and argue/agree with each other. Keep it friendly, keep it a little focused on the topic and try to be specific, detailed and clear in your arguments. If specific parts of topics become sticking points they will likely show up in future Perils for a more focused discussion; otherwise they will be what we're trying to clarify for ourselves. If there are particular topics that are bugging you about radical embodied cognitive science, post about it here and they may show up as future Perils. "What about language then, huh? Huh?" is not something we can work with, though, sorry - be specific :)

We cannot promise to have time to do one every week (Gibson didn't have to teach anything else!) but we will post them as frequently as we have things to post. Feel free to steal the idea and host something similar on your own blogs; we will link to them here. Gibson valued a good argument above all other things in science, and I entirely agree, so please take any opportunity you see to make this a dialogue people can all take part in. 

Thursday, 2 April 2015

What Kind of Thing is an Information Variable? The (Annoying) Case of Tau

The central contribution of the ecological approach is the idea of ecological information. Information variables are higher order relations that remain invariant over time as the elements of the pattern change. These relations are the kind of thing that can specify a dynamical property of the environment and support direct perception of that environment. 

This is all a little abstract. One nice, simple example is the variable tau which specifies time-to-contact (TTC). TTC is an important property of objects approaching you that, if perceived, would support you intercepting or avoiding the object. Tau is one variable that specifies TTC and therefore might get used by organisms to perceive TTC.

This post will use tau as an example of information because it's straight forward and has lots of the relevant key features. However, tau is a pain in the ass because organisms typically don't actually use it - it's too limited in its scope to be the best information. People discussing this fact sometimes says it reveals a weakness in the ecological approach. It doesn't; it just reveals a weakness in tau (and the error ecological psychologists made getting as excited as they did about it as an exemplar). It highlights a lot of useful issues, though, so I thought it was still worth the post.

Friday, 27 February 2015

Are we Infomation Processers? (A brief note)

I thought about it a lot and I kept thinking: OK, he’s right, I guess, the information is in the light, it has to be there, because where else are you going to get it. It has got to be there and if it’s there, there’s a sense in which you don’t have to process it at least not in the way that I used to say “process.” But if he’s right, what am I going to do about cognitive psychology? How can I reconcile cognitive psychology, as I knew it, with this theory of Jimmy Gibson’s?
Ulric Neisser, from Szolkolszky, 2013

Are we information processors? No. At least, not if Gibson was right.
Information is clearly important, though, because we talk about it a LOT according to this Wordle.
For James Gibson, information is external to the observer. Information is structure in energy arrays (e.g. the optic array for light) that is specific to the object or event in the world that caused the structure. This structures becomes information when we use it to coordinate and control our behaviour.

This information is not transmitted. At any given possible point of observation, there is a uniquely structured optic array that an observer can interact with by going to (or more likely through) that point of observation. That structure is there as soon as the lights have come on and the light is done filling up the space.

This information is also not processed, because it does not 'get into the system'. The nervous system doesn't take information onboard, it resonates to that information; it's dynamical behaviour is altered by detecting that information

What about all the steps that have to happen once the information is detected? Doesn't the information have to be transformed into a behaviour? No. Behaviour simply is the activity of the kind of embodied system that we are in the presence of that particular information. We can alter the kind of embodied system we are via learning, but all the way through learning, the behaviour you exhibit at any given moment simply is that activity.

Therefore, in the radical embodied, ecological approach, it makes no sense to say that cognition involves information processing. This is due to 'information' in REC referring to Gibson-information, not Shannon-information. Shannon-information is not something that exists. It is an abstract description of how to reduce uncertainty between a sender and a receiver. It's an amazing idea; it's the heart of the digital revolution we live in and it's a powerful analysis tool (read James Gleick's great book, The Information for the history). It's just not describing what biological organisms are interacting with. 

Is this merely a semantic issue? Are we cheating by just defining away the problem? No. It's about precision in terms. Information means something very specific in the REC framework, that meaning is not the same as it is in the information processing framework and this difference has consequences. Following up on those consequences is what radical embodied cognitive (neuro)science is up to. We will either be right or wrong, and the data will tell us which, but only if we stop making this basic confusion.

Thanks to Greg Hickok (Twitter, blog) for arguing with me a lot on Twitter about this which helped me clarify a few things, and to everyone else who got into it too. You guys are a big help with your obstinacy and your refusal to take what I say at face value :) I think this post might be the first of a series of 'Brief Notes' where I just try to lay out one thing as clearly as I can. In true Gibson style, I reserve the right to keep critiquing and modifying the details as new evidence comes in!

References
Szokolszky, A. (2013). Interview with Ulric Neisser. Ecological Psychology, 25, 182–199. Download

Tuesday, 20 January 2015

It's Time to Relabel the Brain

Another day, another study finds that 'visual' cortex is activated by something other than information from the eyes:
A research team from the Hebrew University of Jerusalem recently demonstrated that the same part of the visual cortex activated in sighted individuals when reading is also activated in blind patients who use sounds to “read”. The specific area of the brain in question is a patch of left ventral visual cortex located lateral to the mid-portion of the left fusiform gyrus, referred to as the “visual word form area” (VWFA). Significant prior research has shown the VWFA to be specialized for the visual representation of letters, in addition to demonstrating a selective preference for letters over other visual stimuli. The Israeli-based research team showed that eight subjects, blind from birth, specifically and selectively activated the VWFA during the processing of letter “soundscapes” using a visual-to-auditory sensory substitution device (SSD) (see www.seeingwithsound.com for description of device).
There's lots of research like this. People are excited by mirror neurons because they are cells in motor cortex that are activated by both motor activity and perception of that motor activity. It's incredible, people cry - cells in a part of the brain that we said 30 years ago does one thing seem to also do another thing. How could this be??

I would like to propose a simple hypothesis to explain these incredible results and that is that we have been labeling the brain incorrectly for a long time. The data telling us this has been around for a long time too and continues to roll in, but for some reason we still think the old labels are important enough to hold onto. It's time to let go.

I'm going to go out on a limb and say it's a bit more complicated than this

Thursday, 15 January 2015

The Size-Weight Illusion Induced Through Human Echolocation

Echolocation is the ability to use sound to perceive the spatial layout of your surroundings (the size and shape and distance to objects, etc). Lots of animals use it, but humans can too, with training. Some blind people have taught themselves to echolocate using self-generated sounds (e.g. clicks of the tongue or fingers) and the result can be amazing (I show this video of Daniel Kish in class sometimes; see the website for the World Access for the Blind group too).

In humans, this is considered an example of sensory substitution; using one modality to do what you would normally do with another. This ability is interesting to people because the world is full of people with damaged sensory systems (blind people, deaf people, etc) and being able to replace, say, vision with sound is one way to deal with the loss. Kish in particular is a strong advocate of echolocation over white canes for blind people because canes have a limited range. Unlike vision and sound, they can only tell you about what they are in physical contact with, and not what's 'over there'. 'Over there' is a very important place for an organism because it's where almost all of the world is, and if you can perceive it you give yourself more opportunities for activity and more time to make that activity work out. This is why Kish can ride a bike.

A recent paper (Buckingham, Milne, Byrne & Goodale, 2014; Gavin is on Twitter too) looked at whether information about object size gained via echolocation can create a size-weight illusion (SWI). I thought this was kind of a fun thing to do and so we read and critiqued this paper for lab meeting.