A field spotter's guide to embodied cognition

I've spent quite a bit of time lately on the blog and Twitter talking about what embodied cognition is not. For example, it's not about moving through time (Miles et al, 2010), and it's not about leaning to the left (Eerland, Guadalupe & Zwaan, 2011). It is about finding new solutions to old problems by expanding the resources available to a perceiving-acting organism; for instance, allowing it to move so as to produce useful information, as in the outfielder problem (e.g. McBeath et al, 1995). Embodiment produces radically different solutions - for instance, instead of Asimo, you get Big Dog.

We still get asked about various new studies coming through; what about 'enclothed cognition' (Adam & Galinsky, 2012), is it embodied? (No). It occurred to me that it might be useful to lay out how I know when something isn't embodied cognition (the easy thing to spot) and when it is (a little harder).

Embodied cognition: A field spotter's guide

Question 1: Does the paper claim to be an example of embodied cognition?

If yes, it is probably not embodied cognition. I've never been entirely sure why this is, but work that is actually about embodiment rarely describes itself as such. I think it's because embodiment is the label that's emerged to describe work from a variety of disciplines that, at the time, wasn't about pushing any coherent agenda, and so the work often didn't know at the time that it was embodied cognition.

This of course is less true now embodiment is such a hot topic, so what else do I look for?

Question 2:  What is the key psychological process involved in solving the task?

Embodied cognition is, remember, the radical hypothesis that we solve tasks using resources spanning our brain, bodies and environments coupled together via perception. If the research you are reading is primarily investigating a process that doesn't extend beyond the brain (e.g. a mental number line, or a thought about the future) then it isn't embodiment. For example, in the leaning to the left example, the suggestion was that we estimate the magnitude of things by placing them on a mental number line, and that the way we are leaning makes different parts of that number line easier to access than others (e.g. leaning left makes the smaller numbers more accessible). The key process is the mental number line, which resides solely in the brain and is hypothesised to exist to solve a problem (estimating the magnitude of things) in a manner that doesn't require anything other than a computing brain. This study is therefore not about embodiment.

Question 3: What is the embodied bit doing?

There's a related question that comes up, then. In papers that aren't actually doing embodied cognition, the body and the environment only have minor, subordinate roles. Leaning to the left merely biases our access to the mental number line; thinking about the future has a minor effect on bodily sway. The important bit is still the mental stuff - the cognitive process presumably implemented solely in the brain. If the non-neural or non-cognitive elements are simply being allowed to tweak some underlying mental process, rather than play a critical role in solving the task, it's not embodiment.

So what does embodied cognition research look like then?

Genuine embodied cognition research is focused on tasks, not mental processes, and the solutions tend to be smart (Runeson, 1977) and task specific (Bingham, 1988) rather than simply local tweaks to general solutions. Embodiment research proceeds with an analysis of four things:

1. What is the task to be solved?
2. What are the resources that the organism has access to in order to solve the task?
3. How can these resources be assembled so as to solve the task?
4. Does the organism, in fact, use these resources?

I know I go on about it, but the outfielder problem really is quite a good example of this; the research programme has followed these four steps really closely. Specifically:

1. The task to be solved is moving yourself so that you arrive at the right place at the right time to intercept a fly ball. Sometimes you are in a direct line with the flight of the ball, but the general problem to be solved involves you being off to one side.
2. Your resources include your ability to locomote over a range of speeds; the ability to visually perceive kinematic (motion based) information about the flight of the fly ball; and the fact that fly balls follow a parabolic trajectory.
3. The parabola of a fly ball means that, if you move so as to cancel out one component of the motion of the ball and make it appear to be either a) moving in a straight line or b) with constant velocity you will arrive at the right place at the right time. If you are not moving fast enough to produce the optical effect, this is information telling you to speed up; if you are running too fast and overshoot the effect, this is information telling you to slow down; if you are running at full speed and still can't produce the effect there is information that the ball is uncatchable and you should plan to intercept it on the bounce.
4. These strategies predict you will move in very particular ways; either curved paths (for the 'linear optical trajectory' solution) or with a particular velocity profile (for the 'optical acceleration cancellation' solution); when tested, people produce both these effects although are more likely to use the LOT solution.

Embodied cognition in action

Note the resources brought to bear on solving the task span body and environment. The fact that fly balls follow a parabolic trajectory is an essential feature, because it is this geometry that make LOT and OAC viable solutions. In addition, we not only need to be able to perceive the motion of the ball, but move so as to make the ball appear to move in a particular way; perception and action are always critical features.

The solution is smart, in that it takes advantage of certain stable facts of the matter (e.g. the parabolic flight) and uses them to find locally reliable solutions, rather than trying to apply some general strategy that must be tweaked. This solution is therefore task-specific - it's not a general solution to the problem of interception, and it only works for the case of the fly ball. But it works extraordinarily well in this case, and thus organisms are 'smart' to rely on it.

Other resources
Louise Barrett's excellent Beyond the Brain handles this topic clearly and well, with some great examples and explanations of work that is genuinely embodied. I thoroughly recommend you read it if you're interested in this topic.

Summary
Doing embodied cognition correctly is hard. You have to have a careful task analysis - what is it that the organism is trying to do? What are the available resources? This analysis has to be from the point of view of the organism. You then need an account of how the resources are being coupled together to form a task specific, smart solution to the problem at hand; this means talking about perception. Finally, you need evidence that organisms actually use the solution you propose, and this usually means showing they can do the task in the presence of all the required elements, and fail entirely in the absence of one or more (e.g. Wilson & Bingham, 2008). Small effect sizes are another hint that a given paper isn't doing embodied cognition.

So if you see a paper claiming to be embodied cognition, check it out against this guide and don't fall for the hype. 

References
Adam, H., & Galinsky, A. (2012). Enclothed cognition Journal of Experimental Social Psychology DOI: 10.1016/j.jesp.2012.02.008

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

Bingham, G. P. (1988). Task-specific devices and the perceptual bottleneck Human Movement Science, 7 (2-4), 225-264 DOI: 10.1016/0167-9457(88)90013-9

Eerland, A., Guadalupe, T., & Zwaan, R. (2011). Leaning to the Left Makes the Eiffel Tower Seem Smaller: Posture-Modulated Estimation Psychological Science, 22 (12), 1511-1514 DOI: 10.1177/0956797611420731

Miles, L., Nind, L., & Macrae, C. (2010). Moving Through Time Psychological Science, 21 (2), 222-223 DOI: 10.1177/0956797609359333

McBeath MK, Shaffer DM, & Kaiser MK (1995). How baseball outfielders determine where to run to catch fly balls. Science (New York, N.Y.), 268 (5210), 569-73 PMID: 7725104

Runeson, S. (1977). On the possibility of "smart" perceptual mechanisms Scandinavian Journal of Psychology, 18 (1), 172-179 DOI: 10.1111/j.1467-9450.1977.tb00274.x

Wilson, A., & Bingham, G. P. (2008). Identifying the information for the visual perception of relative phase Perception & Psychophysics, 70 (3), 465-476 DOI: 10.3758/PP.70.3.465