Tuesday 25 October 2011

Review: Louise Barrett's "Beyond the Brain"

There are a lot of books about embodied cognition. Like psychology itself, the idea that cognition might not all be in the head has fractured off into about 5 distinct flavours, most of them quite annoying and pointless.There are also quite a few books about the thesis of the 'extended mind' (Clark & Chalmers, 1998) ; the idea that cognition quite literally extends into our bodies and environments, in terms of the tools we use and the objects we interact with. It's getting quite hard to find a book on these topics that isn't a) simply rehashing old ground or b) trying to come up with it's own distinct flavour of embodied, extended cognition that fixes some problem of everyone else's. I find this sort of fracturing and endless bickering quite distracting and troublesome, for reasons best expressed by xkcd. I also agree with Tony Chemero, that much of this work is still, sometimes deep down, representational. I think this is because they fail to embrace a sufficiently useful theory of information, such as that proposed by Gibson. So I often find myself reading these books finding nothing new and far too much that's depressing.

Louise Barrett's book, "Beyond the Brain: How Body and Environment Shape Animal and Human Minds" is, refreshingly, not like this at all. Barrett is a psychologist who studies animal cognition and behaviour, and her book does a lot of things very, very well. I'm not planning on a chapter by chapter book club on this, although I may at some point; Eric Charles has posted a few thoughts on the book as well, here, here, here, and here. To cut to the chase: if you are new to the area of embodied cognition, read this book. If you're familiar with the literature but want a clear, well-structured presentation of many of the key ideas, then read this book. If you're bored with the same old examples and want some new, perhaps more convincing examples of embodied cognition in action, read this book. And if you have heard some of the arguments but still think behaviour really comes from the computational activity of our complex brains, then, for the love of science, read this book.

Old stuff done well
One sign of a good book on embodied cognition is that it handles the classic material well. There's a standard set of important papers and empirical results that form the core of the initial case for embodiment and, specifically, embodiment expressed in terms of non-linear dynamical systems. Among these old favourites is the Watts steam governor to replace the digital computer as a metaphor for the way to achieve controlled behaviour (van Gelder, 1995). Like me, Barrett is entirely unconvinced by the computational, representational accounts of the governor and is happy to take it seriously as an example of how specially built coupled devices can solve complex control problems. Her account of it, and how it works as a metaphor to guide how we think about embodiment and dynamics, is crystal clear.

Other topics done well: a look at the various robotic exemplars of the dynamical, embodied approach (such as work by Pfeifer & Scheier (1999) and Pfeifer & Bongard, 2007), plus a nice review of work by Linda Smith and Esther Thelen on the A-not-B error and infant prehension (see Thelen & Smith, 1994).

The coverage is excellent and clear (I've added Chapter 7, on computational information processing vs. dynamical systems accounts of behaviour to my first year Motor Control module recommended reading list as a summary of two lectures).

New things brought to the table
Barrett specialises in animal cognition, and this angle on embodied cognition is, I think, one of the key novel contributions of this book. I admit, I'm a true believer in embodied cognition, so I'm biased, but I found many of the key ideas about embodiment much less controversial when they arose in the context of non-human behaviour. Chapter 4 (entitled 'The Implausible Nature of Portia') describes the simply astonishing behavioural flexibility of the hunting spiders of the genus Portia. These spiders prey on other spiders. They are capable of all finds of feats, of mimicry (strumming other spider's webs to simulate being prey themselves as a lure), and deception (taking advantage of wind blowing on webs and moving under cover of this 'smokescreen'). Being small spiders, however, they of course have tiny brains.

Their most remarkable ability is that they can approach a target web via quite complex detours if necessary; they are able to navigate to a target that is not currently in their view. Their behaviour looks remarkably like 'insight'; they spend time sitting and examining their environment, not moving through it, until suddenly they pick a route as if they had finally arrived at a decision. The spiders, of course, are doing no such thing: there is no mental manipulation of a representation of their route options required. Instead, the spiders are scanning the environment with their very specifically built eyes, and scanning in a very particular way. These spiders have 16 eyes, some of which work like our fovea (high resolution over a small area) and some like the periphery (low resolution but excellent motion sensitivity). Portia scans the environment using these independent, mobile eyes, and experiments show it simply moves to solve a series of local problems, making the route up as it goes. It doesn't need to 'know' anything about gaps or obstacles, it simply moves according to a simple strategy of 'find the horizontal path'. Portia doesn't need a big brain to 'think about things in their absence', because she instead has a sensibly built body - truly embodied cognition.

Other examples include the caching behaviour of scrub jays. and how crickets choose mates according to their song; the 'decision making' is implemented via a simple neural circuit between two ears spaced a particular distance. This work is especially interesting as it includes discussion of Barbara Webb's work on this system; Webb has built simple robot crickets in which she can manipulate the neural circuit and the nature of the ears to confirm that the crickets aren't making decisions, they are responding to signals in a manner dictated by their design; representations not required!

Has she read her Gibson?
One of my requirements for a good book on embodied cognition is an honest discussion of Gibson. The reason is simple: if you want cognition to be a process that spans the brain, body and environment of an organism, you need a theory of how these elements can be coupled together to form systems. In short, you need a theory of perception, and Gibson is really the only candidate up to the task. There are many people trying to do embodied cognition representationally, and this is just an error,as far as I'm concerned.

The good news here is that Barrett knows her Gibson, and explains it well. Chapter 6 is an excellent review of Gibson's theories, and the context in which they arose. It's been a long time since I read something not written by me or Geoff Bingham about Gibson and enjoyed every word; the experience is deeply satisfying. She also ties Gibson's ideas to the work of biologist Jakob von Uexküll, and his notion of the umwelt (roughly, the world as it is experienced by a particular organism). Two organisms can occupy roughly the same space but experience very different umwelts (e.g. the ladybug on my finger and I are having very different experiences).Organisms are sensitive to some but not other aspects of the environment, and taking the organism's perspective on the world seriously is a key part of good biology.Barrett argues convincingly that it should really form part of good psychology too.

'Beyond the Brain' is an excellent introduction to the logic underlying embodied cognition (why it's a good idea) and to the various candidate mechanisms that support it (how it might work, via Gibson and the architecture of the body). Barrett's background in animal cognition means she has bypassed many of the annoying arguments typically raised by people who only talk about human cognition and who have fallen into the trap of thinking our cognition must somehow be different in kind to these simpler solutions. This has given her a very uncluttered view of the intellectual landscape, and she brings that view to this book. That's not to say she isn't aware of the various annoying arguments; quite the contrary. She spends some time on Adams and Aizawa's 'bounds of cognition' arguments and cuts through a lot of the distracting gloss on their argument that I must admit I had gotten overly concerned with. She also tackles the critique that embodied, perception-action style accounts can only handle movement and things in the now, and can't address 'representationally hungry', 'thinking about things in their absence' problems. The discussion of Portia addresses this; she also describes a simple robot mouse that can, without any memory built into it at all, achieve delayed reinforcement learning. This continues a recent trend in these kinds of books (Chemero's being the obvious other example) of embodied cognition people looking to address not only the new questions our approach asks, but also some of the old questions people think we can't handle. I admire this a lot, and it's a trend I hope continues.

Read this book, and give it to your friends to read.

Barrett, L. (2011) Beyond the Brain: How the Body and the Environment shape cognition. New Jersey, Princeton University Press. Amazon.co.uk Amazon.com


  1. if you want this book to get some greater exposure, why not submit this (very nice) review to Nature or something?

  2. I've been thinking about submitting a version of this somewhere. Does Nature do book reviews?

  3. Yup, although I dunno if you have to be invited. Cortex does them as well (Dave has submitted many to them in the past), and that gets pretty good exposure these days