Lecture 17: Pattern Recognition and Representation Bearers (Turvey, 2019, Lectures on Perception)

Last Lecture Turvey reviewed the basics of the computational approach, and highlighted again how it is just the latest iteration of the Cartesian programme. In this Lecture, he explores the specific topic of pattern recognition, which has been a major topic in the computational approach and exemplifies many of the major problems. These problems primarily boil down to systems requiring loans of intelligence to even come close to working.

Brains Don't Have to be Computers (A Purple Peril)

A common response to the claim that we are not information processors is that this simply cannot be true, because it is self-evidently the case that brains are transforming and processing information - they are performing computations. Greg Hickok throws this ball a lot, and his idea is clear in this quote from his book 'The Myth of Mirror Neurons':

Once you start looking inside the brain you can’t escape the fact that it processes information. You don’t even have to look beyond a single neuron. A neuron receives input signals from thousands of other neurons, some excitatory, some inhibitory, some more vigorous than others. The output of the neuron is not a copy of its inputs. Instead its output reflects a weighted integration of its inputs. It is performing a transformation of the neural signals it receives. Neurons compute. This is information processing and it is happening in every single neuron and in every neural process whether sensory, motor, or “cognitive.”

Hickok, pg 256.

There are two claims here. First, neurons are processing information because their input is not the same as their output; they are transforming the former into the latter. Second, this process is computational; 'neurons compute'.

This is a widely held view; psychologist Gary Marcus even wrote about this in the NYT saying 'Face it, your brain is a computer'. In response, Vaughn Bell at Mindhacks posted about this op-ed and this issue in a nicely balanced piece called 'Computation is a lens'. He sums up the issue nicely by asking 'Is the brain a computer or is computation just a convenient way of describing its function?'. The answer, I propose here, is that computation is a fantastically powerful description of the activity of the brain that may or may not be (and probably isn't) the actual mechanism by which the brain does whatever it does. This is ok, because, contra Hickok,  not every process that sits in between an input and a different output has to be a computational, information processing one. 

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