Brains learn to perceive, not predict, the world

The current trendy way to think about brains is as predictive machines. Bayesian methods, free energy, generative models, and all the other things in Andy Clark's new book are where it's at. Brains have to predict because, in Clark's terms, we are 'surfing uncertainty' - one step from disaster as we control our behaviour using sensory information we had to spend time processing and that is therefore a few hundred milliseconds out of date. Our brains build models of the world that constantly generate active predictions about what sensation will tell us next, and our behaviour holds together to the extent that the models do.

The ecological approach provides a different job description for the brain (Charles, Golonka & Wilson, 2014). We are embedded in environments rich in information that specifies a wide variety of behaviourally relevant properties. Some of that information is prospective, that is, it is information available now that is about something in the future. Two examples are the information variables you can use to catch a fly ball; both are states of the current time that, when used, allow you to achieve a behaviour in the future (specifically, to be in the right place in the right time to catch that ball). Another example is tau and the various other variables for time-to-collision.

This post reviews a paper (van der Meer, Svantesson & van der Weel, 2012) that measured visual evoked potentials in infants longitudinally at two ages, using stimuli that 'loomed' (i.e. looked like they were going to collide with the infants). The data show that the infant brains were not learning to predict the world. Instead, neural activity became more tightly coupled to information about the time-to-collision. We learn to perceive, not predict, the world.

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

Is embodied cognition a "no brainer"?

Brains, HUH, yeah, what are they good for?

When we say "there are no mental representations", people often hear 'the brain doesn't do anything'. Because this is obviously not true, people sometimes just assume we simply cannot be talking sense about cognition and stop listening. 

Of course, we aren't saying this at all. Of course the brain is up to something. I've sketched out a few ideas here and here (some of which is finding it's way into a book chapter we're writing with Eric Charles), and we're working on a Research Topic at Frontiers in Human Neuroscience about how to do radical embodied cognitive science (to which any interested parties are warmly invited to contribute!).

So we aren't denying that the brain is interesting and important. We just think it's doing something very different from what mainstream cognitive neuroscience thinks it is doing. Our embodied cognition (Wilson & Golonka, 2013) redefines the job description for the brain. Whatever it is that the brain is doing, it doesn't have to be representing anything (this is what the 'radical' part means). Instead, the brain is a key player in the system that interacts with information to produce behaviour, and that is a very different thing. 

This basic fact motivates Sabrina's proposed 'new direction for psychology' (which obviously I endorse too). Her argument is that psychologists are interested in explaining behaviour, and that the primary external cause of behaviour is the various kinds of information we are able to interact with. There are interesting contributions to behaviour made by internal factors, including the brain, but these, she argues, have their effects by modifying how and when we interact with different sources of information. Given this, psychology should get very interested in information as quickly as possible in order to really start explaining behaviour; it's paid off in spades in perception and action and there's no reason why it won't pay off everywhere else too (see Sabrina's post on language here and here, plus our handy dandy Frontiers paper).

Of course the brain is a major player in cognitive systems, but in order to really know what it's up to, we have to be sure to ask it the right questions, and this means doing things in the right order. So the argument that 'the behaviour I study clearly requires internal support, and that therefore there are representations doing that work and the brain is important' is not actually an argument against doing your work from an embodied perspective. Throw away your assumptions about representations (see the section of links 'Representations & Why We Should Abandon Them' on the Rough Guide for more reasons), get serious about the information present in your task to support behaviour and only then start speculating about the form of the internal support that is required. We think you'll be surprised where you end up when representations are not the default. 

And please tell us what you're up to - we'd love to help if we can!

References
Wilson A.D. & Golonka S. (2013). Embodied Cognition is Not What you Think It Is, Frontiers in Psychology, 4 DOI: 10.3389/fpsyg.2013.00058

Embodied solutions to neural delays: Information and Network Motifs

One of the bugbears of direct perception is the fact of neural delays. The transmission of signals through the nervous system takes time, and this means that there is a lag between something happening (at, say, the retina) and that event having consequences in cortex, let alone behaviour. In control theory terms, delays in a system can lead to instability in that system's behaviour as you are forced to make corrections that are then incorrect and must themselves be corrected.

It's typically suggested in psychology that these delays are compensated for via computational predictions; the nervous system 'perceives the present' by taking the lagged input and using it as the basis of a guess about what's going on now (e.g. Changizi et al, 2008, plus see this post from a while back). This is a problematic idea: if the perceptual control of actions is based on a guess compensating for a variable time lag, then the stability issue remains, not to mention the consequences for mis-predicting the future. Regardless, it's not really an option for a theory of direct perception, and I want to discuss a couple of options.

There's More Than One Way to Rhythmically Move a Lobster

I'm slowly working my way through Olaf Sporn's excellent book, Networks of the Mind. The purpose of this book is to introduce neuroscientists to network theory, and vice versa; I'm eavesdropping and tooling up on both. It's slow going only because it's pretty much all new territory to me, but I'm seeing a lot of potential in the overall approach to the brain, and this just confirms for me that Sporns understands what he does pretty deeply. 

Anyway, a while back, Bruce Hood tweeted the following:

Fact: in the digestive tract of the lobster, its nervous system can have 100k-200k different neural states that produce the same behavior

This struck me as an astonishing fact; to my mind, it throws the idea that hunting for the neural correlates of behaviour into serious doubt. At the very least, it needs to radically change what you expect to find. I finally found the reference for this fact in Sporns' book (Prinz, Bucher & Marder, 2004; download), and Sporns has some interesting context for this fact (which Hood undersells - see below) and why it's interesting, rather than soul-crushingly depressing. There are some interesting potential consequences relevant to my current ponderings on the brain, although it's definitely still at the 'these sound like the same sort of principle' level of analysis. 

Mirror Neurons, or, What's the Matter with Neuroscience?

One of the problems I face as I try to figure out what the brain is up to, if not representing, is that I can't rely on the neuroscience literature to back me up. The problem is that, while there has been a lot of data collected over the years, very little of it has been collected within an ecological framework. Neuroscientists are looking for how the brain represents information, not how it perceives it; they're looking to see where perception and action are integrated in the brain, not how the brain-body-environment system produces stable, functional behaviour. This matters because there's no such thing as theory-free observations - all data comes from this experiment rather than that experiment, and even simply reporting a result is laden with theoretical assumptions, even when these aren't explicitly identified. So until I can find a neuroscientist interested in collecting a little data (and I would love to hear from any such person!) I'm limited to laying out the consequences of taking the ecological route and critiquing what's out there already. 

The worst offenders, in terms of theory-laden data disguised as 'merely the observed facts', are mirror neurons. They are, I think, the text book example of what's the matter with neuroscience, and I thought it was about time to talk about them a little. For those interested, the most recent exposition of what mirror neurons are and do can be found in a recent (and currently open access) issue of Perspectives on Psychological Science: there's a brief introduction (Glenberg, 2011a), a detailed Q&A paper (Gallese et al, 2011) by five main figures in the field, and a summary (Glenberg, 2011b).(Update: recent meta analysis finds mirror type activity all over the brain, including the cerebellum!)

What Does The Brain Do, Pt 2: The Fast Response System

I want to continue thinking about the implications of the claim that the brain does not trade in representations. I'm not looking to defend this view here; we got into it a bit last time, I've talked about it here, and if you can't imagine what cognition without representation might look like, then you should read this post by Sabrina and then Radical Embodied Cognitive Science before worrying me with your lack of imagination. If you then feel like getting into it, Sabrina is tackling this topic in detail, beginning here.

If the brain isn't mentally representing, what is it doing? Last time, I got into the idea that the brain is part of a embodied cognitive system. It's in the middle of a rich information flow, with access to perceptual information about the world and ourselves, and it's a critical part of the action system, involved in our responses to that information. I talked about it as the fast response system in the set of inherent dynamical resources available for us to use to form task specific devices; I want to expand on that a little.

There's More to Us Than Our Brains - So What Does The Brain Do?

I'm not that interested in the brain.

It's hard to be this way in modern psychology. Cognitive neuroscience is where it's at, and I think I come off as  a bit of a Luddite when I try to convince people fMRI is a bit of a waste of time. Not caring much about the brain is certainly a sociological reason why ecological psychology doesn't get taken very seriously; we're just the crazy people who don't think there are mental representations, based on some work from the 50s-70s. Surely modern imaging has shown us the activity of mental representations? Clearly, the brain is the source of all behavior! Popular science writing on psychology is all cognitive and representational; most of the psychology blogging I come across is neuroscientific. What else could it be?

I've certainly spent a lot of time waving the flag against the infiltration of neuro-talk into places it doesn't yet belong; but to be honest, as I get older, I've begun to worry that I'm trying to be 'fair and balanced' in the sense Fox News is fair and balanced: relentlessly playing up one side to offset a perceived imbalance elsewhere. What I actually want to do is be actually fair and balanced: I want my own discussions about these issues to be internally balanced and coherent, giving credit where credit is actually due. I want to start teasing apart a few issues I've conflated over the years, so that my strong concerns about the relevance of fMRI  and cognitive neuroscience work stop getting swallowed up in a general dismissal of the brain's role in our lives. The brain is clearly interesting, but it's not representing, and if not that, what is it doing?

This post is therefore a first swing at integrating a lot of the things I've been blogging about for a while and doing so in a way that leaves a sensible role for the brain. I'm going to need some neuroscientists to talk to, though; I'd appreciate it if people could spread the word on this a little, because there are just some things I want to go a few rounds on with people who know what they're talking about.