Is hefting to perceive the affordance for throwing a smart perceptual mechanism?

In the last post, I reviewed Geoff's first paper looking at whether people can perceive the affordance for throwing an object to a maximum distance and a first swing at identifying the information specifying the affordance. People can perceive the affordance. Bingham et al then identified an invariant relation between the timing of the motions of the wrist and elbow when people hefted the balls they chose as optimal for throwing, and showed that this kinematic pattern specified a peak in the function which determined how much kinetic energy was transferred to the ball. They suggested that this relation in the joint movements served as information for the dynamic property which led to a maximum distance throw, and that this is how hefting was able to provide information about throwing. They suggested that this was a smart perceptual mechanism for perceiving the affordance property.

That was where things stood until Zhu & Bingham (2008) ran an extensive replication and extension of the original study, to test the specific smart perceptual mechanism proposed by Bingham et al (1989). 

Hefting for a Maximum Distance Throw

From the task dynamic analysis of throwing for maximum distance, we've identified the fact that for a given release angle and maximum release velocity, there is an object whose size and weight optimises the distance it will travel when thrown. Can people perceive this combination ahead of time? More specifically, can people identify the object which affords throwing to a maximum distance, and if so, how?

Bingham, Schmidt & Rosenblum (1989) is the first paper investigating this question. It is a bear of a paper; I've stripped a lot of the methodological detail out in my summary so I can focus on the bigger picture. That bigger picture is this; Bingham et al first check whether people can identify objects that afford throwing to a maximum distance by hefting them ahead of time (they can). They then investigate the kinematics of hefting to identify an invariant relation in the timing of the wrist and elbow velocities and relate that invariant to the dynamics of throwing (specifically how it maximises the transfer of kinetic energy from the torso muscles to the projectile). They propose that using this invariant reflects a smart perceptual solution (Runeson, 1977) to the problem of selecting objects to throw to a maximum distance - future work (Zhu & Bingham, 2008) will actually show that this specific smart mechanism doesn't hold up, although the replacement is smart too.

Do our fingers wrinkle in the wet to improve our grip?

If you sit in the bath for more than 10 minutes or so, you'll notice that your fingers get wrinkled like a prune. People thought for a while that this was a local response to the wet conditions, but it turns out the wrinkling is an active, neurally controlled process. In 1936 two scientists observed a boy who had suffered some temporary damage to the median nerve; he lost feeling in his thumb, index and middle finger and, surprisingly, those fingers didn't wrinkle in the wet. There's a great post on this case and some more recent work here.

Things that are under active control are usually functional; that is, they're usually doing something useful. In 2011, Mark Changizi and colleagues published a speculative piece in which they suggested that our fingers do not wrinkle randomly. Instead, they noted that the form of the wrinkles match efficient drainage networks, and suggested that perhaps the wrinkles act like rain tread to help water drain away from our fingertips when we grip things.

Using coordination to study learning across the lifespan

What happens to our ability to learn new movement skills as we age? There is surprisingly little research on this topic; a relatively recent review (Voelcker-Rehage, 2008) found only 25 articles about learning in old age, and no systematic programme of work. The answer to this question matters a lot; rehabilitation after events such as a stroke pretty much always entail (re)learning movement skills, and if our ability to learn gets worse with age, rehabilitation faces an uphill struggle. 

I have been studying coordinated rhythmic movement for some time now, and now we have a good handle on the task dynamic my colleagues at Indiana and I have begun using it to study the process of learning more generally. We decided to use it to look at learning in old age, to see what we could see.

This project grew out of a grant I had from Remedi when I was a post-doc in Aberdeen. I wanted to use coordination to look at learning post-stroke. One of the problems with studying this is finding useful novel tasks to learn - you need to give the stroke patients something they've never done before so you can be sure that any improvement is about learning, and not simply recovery of function. My thought at the time was that I could use any changes at 180° to assess recovery and changes at 90° to assess learning. We tested a huge number of patients and age matched controls, but the project didn't pan out because neither group (all aged around 65) couldn't learn to move at 90°. The question remained, what was going on? We now have the first of three papers on this question out in press. 

Our first paper based on the blog is out in time for Christmas!

Last year we were invited to contribute to a special issue of Avant, an interdisciplinary open access journal that publishes in English and Polish. The issue is on affordances, and we were asked to contribute a piece detailing the contribution ecological psychology is making to modern cognitive science. Our paper is here; the complete issue is open access and available here (as separate files, a single issue pdf, and an ongoing Polish translation).

We had a lot of fun with this paper. The core of the paper comes from our posts about how psychology lacks a central theory and how Gibson serves as a good model for why theory matters, as well as being a key part of any more complete theory. We take a quick swipe at Daryl Bem and JPSP and then use the contrast between dynamic pattern vs. perception-action approaches in explaining coordinated rhythmic movement. In particular, we highlight Geoff's model as an exemplar of what psychologists should be up to - not just models, but theoretically motivated models.

We'd like to thank Tony Chemero for mentioning us to the people at Avant, and to the Avant team who do interesting work and gave us space to write what we hope will be a fun and useful paper. 

By the by, Avant are hosting a very interesting looking conference next year:

THINKING WITH HANDS, EYES AND THINGS. The 1st edition of the International Avant-Conference “Trends in Interdisciplinary Studies”, 8-10 November 2013, Torun, Poland

Radical Embodied Cognitive Neuroscience - A Frontiers Research Topic

UPDATE: This topic is now live! We welcome all and any submissions that fit the remit. Please email Andrew if you are interested and I will add you to the contributors list, or you can also simply contribute via the Frontiers page. 

A couple of years ago, Sabrina and I were chatting about the brain and running into the problem that we just don't know enough about how it works. We realised that what we needed to do was host a conference, invite some useful people, and pick their brains for a few days. 

We've had two goes at funding such a conference; we've had a lot of interest from the academics we've contacted but no luck convincing anyone to give us any money. Over the process, however, we got Tony Chemero (author of Radical Embodied Cognitive Science) involved, and he recommended Louise Barrett to us (that's how we came across her excellent book). The four of us have been scheming for a while to try and make this a reality, and two things have developed.

First, we are going to host a workshop on Radical Embodied Cognitive Neuroscience, hopefully at the Lorentz Centre in the Netherlands. Before that can really be worth doing, however, we've realised we need a little more momentum, so we've advanced our plans and are about to announce a Research Topic at Frontiers in Psychology. We'd like to invite all interested parties to play.

The goal is simple: we want this to be a virtual conference, in effect, where people pose problems and offer solutions to the problem of developing a radical (non-representational) embodied cognitive neuroscience. We want real collaborations to come out of this, so we want people coming looking for ways to help and be helped. And we want to create a resource that we can point to to shape discussions at future workshops. 

What we need from you
I've pasted the text of the call we will run below. If you are interested in submitting something to  this, send us your name, affiliation and email address (either in the comments below or email us, psychscientists@gmail.com). At this point, this commits you to nothing; we just need a decent length list of people to initially invite to submit, to indicate that there is going to be enough interest. If you change your mind later there's no problem.

Any thoughts on the call, let us know. We all like that this call is short, direct and to the point; too many of these research topic calls are inflated by too much detail. But if there's any flags, let us and know.

If you can help us by promoting  this post on social media, that would also be excellent. We are looking to cast a wide net.

The Task Dynamics of Throwing to a Maximum Distance

In my last post I went over the formal concept of task dynamics as a way of analysing a task to identify the affordances in that task. This post will examine the task dynamics of projectile motion and relate these to throwing to a maximum distance.This version of the task has been studied in detail over the last few years. There is another version of the task, namely throwing to hit a target (same dynamic, different parameters, therefore same task) and we will get to that later; we're working now on data from this task.

Part of my goal here is to lay out the research programme you should be following, if you want to study anything to do with perception and action. If you are interested in movement, and you aren't doing this kind of analysis as part of your work, then, I will suggest, you are doing it wrong. As we will see in future posts, this level of detail isn't just playing with numbers; a formal understanding of the underlying dynamics governing the task we are studying is utterly crucial if we want to be able to understand what people are doing, rather than simply describe their behaviour. 

Also it's fun :)