Learning a Novel Coordination; Things Get Interesting

Other coordination posts are here.

This will be a brief post to follow on from the last, in which I reviewed the early learning studies of Kelso & Zanone that led to the dynamic pattern hypothesis.

Is Cognition Extended?

Over the past week or two, we've been engaging philosopher of psychology Ken Aizawa on the topic of extended cognition. Ken is co-author of a book, Bounds of Cognition, in which he argues cognition is most definitely not extended in any way. We both think the other is wrong, which is always fun; I've been getting to grips with his argument and trying a few ideas out, and I wanted to take a moment to summarise where I think we're at.

Tools and Brains and Embodied Cognition

Arguing about embodiment with Ken Aizawa over the last few days has opened up a lot of topics that I hope to cover over the next little while. But it also primed me to notice this article at Scientific American by Patrick Haggard and Matthew Longo, summarising a recent paper adding to the growing literature on the neuroscience of tool use. I like this work, and it got me thinking how this relates to the embodied cognition literature; Ken, I'd be interested to hear your thoughts on this on.

Learning a Novel Coordination - The Dynamic Pattern Hypothesis

Other coordination posts are here.

Recall this image:

The HKB potential function, ~1Hz

This basic layout is supposed to describe an intrinsic state of affairs, namely that only 0°and 180°are stable coordinations (+/- 180° are identical except for which limb is lagging and which is leading). If you look at this function, you will see that potential energy is a maximum at +/90; this suggests that 90°is a maximally unstable coordination (i.e. it takes the most energy to maintain and is susceptible to perturbations which will make behaviour 'run off' towards one or other attractor). This is indeed the case, empirically; people can do it but fail to respond to the inevitable errors that accumulate and they lose the coordination very rapidly.

The question then is: can you learn to move at 90°? Is this dynamic pattern modifiable by experience?

Assume the Cow is a Sphere

One of my favourite jokes goes like this:

A physicist, an engineer, and a psychologist are called in as consultants to a dairy farm whose production has been below par. Each is given time to inspect the details of the operation before making a report.

The first to be called is the engineer, who states: “The size of the stalls for the cattle should be decreased. Efficiency could be improved if the cows were more closely packed, with a net allotment of 275 cubic feet per cow. Also, the diameter of the milking tubes should be increased by 4 percent to allow for a greater average flow rate during the milking periods”.

The next to report is the psychologist, who proposes: “The inside of the barn should be painted green. This is a more mellow colour than brown and should help induce greater milk flow. Also, more trees should be planted in the fields to add diversity to the scenery for the cattle during grazing, to reduce boredom”.

Finally, the physicist is called upon. He asks for a blackboard and then draws a circle. He begins: “Assume the cow is a sphere....”.

A brief rant about waist-to-hip ratio

This is a bit off topic, but it's a good illustration of William James' notion of the psychologist's fallacy and it addresses a pet peeve of mine.

Evolutionary psychology is becoming more and more popular and the media is one of its biggest fans.One thing that annoys me is how quickly and uncritically people latch on to these stories and use them to justify the status quo. One of the most popular stories is that men prefer women with small waists and big hips. This is measured using the Waist to Hip Ratio (WHR). The WHR is the circumference of your waist divided by the circumference of your hips. The links below will tell you that men are irresistibly drawn to women with WHRs of .70. This number is apparently imbued with evolutionary significance because prepubescent girls have WHRs close to 1 (their waists are the same size as their hips), while post-pubescent girls have WHR less than 1 (waists smaller than hips); and also because low WHRs are associated with a good hormonal balance. One thing that makes this idea attractive is that it conforms to our modern, western experience - many women who are considered to be extremely attractive have low WHRs and it's difficult to generate examples of women who are famous for their beauty, but who have high WHRs. This evolutionary angle legitimizes our society's standard of attractiveness. We assume that everyone else basically shares our own preferences (the psychologist's fallacy), so, rather than this result simply telling us something about modern, western mens' judgments of attractiveness, there is the irrisitable pull to generalise this preference to ALL men.