Wednesday, 19 April 2017

Some Thoughts on Handwriting

A few years a go I reviewed a paper about a method, the sigma-lognormal model, to quantitatively assess handwriting (Plamondon et al, 2013). I was interested because I had in the past worked with children with developmental coordination disorder on a project developing ways to take better movement assessment out of the lab and into the clinic, and handwriting is a) something kids and their parents value and want to improve but b) is a beast to quantify. 

Réjean Plamondon kindly sent me his analysis software to play with, and I have three experiments worth of data I am currently analysing in an effort to assess whether it can help me find what I want. Here I'll briefly review the model, the experiments and some lessons I've learned training myself to write with my nondominant right hand.

Wednesday, 5 April 2017

The Ecological Approach, Explained to an 8 Year Old

About 3 weeks ago I got an email from a person who had found our blog via Robert Epstein's piece 'The Empty Brain'. The email said
I've had a good read this afternoon, and it has been informative to some degree, however ...
I have an 8 year old son, and due to questions we both have, we have had some very interesting laypeople's conversations about the nature of experience and "the mind" (is it a thing, a physical thing, a process?) as well as such things as memory, embodiment and perception.
It seems it would be really helpful for us (and by extension, possibly many others?) if you could summarise the broad strokes of your theory in some way in which an intelligent 8 year old (and his father!) could understand.
Would this be possible?
Ed Yong has taught me that good science communication doesn't have to be dumbed down, it just has to be pitched right, and while I am no Ed Yong, I say, challenge accepted! Let me know how it goes!

Saturday, 25 March 2017

Language, thought and the ecological approach; A Purple Peril

As part of a class on cognitive psychology, I give a seminar in which we talk about the research on the relationship between language and thought. In particular, I show this great talk by Lera Boroditsky as a starting point. She talks about the kind of research in this area, and talks about results such as how we linguistically interact with space and time affecting how we physically interact with these things. For example, some languages like English use an egocentric frame of reference when talking about space (e.g. describing things as being to the left or right, where the origin of this space is the speaker). Other languages use a geocentric frame of reference (e.g. describing things as being to the south of you). In order to be able to speak and understand the language, you therefore have to be able to remain oriented in space, and speakers of these kinds of languages have been shown to be capable of impressive feats of dead reckoning previously thought impossible in humans. 

The reason this is all interesting is in the context of how the field is changing how it thinks about language; is it magical, or merely interesting? If the former, language becomes a unique human cognitive capacity that requires specific neural mechanisms that serve language and nothing else. If the latter, language becomes an integrated part of our cognitive systems and we should expect it to show these connections to other capacities. 

The weight of evidence right now I think favours the latter view. In fact, one whole strand of embodied cognition (Shapiro’s ‘conceptualisation’ hypothesis strand) explicitly pursues these connections between language and other capacities, for example Lakoff’s work on metaphors being grounded in action. Language, while still phenomenal in what it can do, is not different in kind to the rest of cognition. 

The field is still very much at the ‘functional model’ stage of developing explanations, however. The research mostly just catalogues linguistic differences and cognitive differences and works to map those onto each other in a fairly metaphorical, word-association kind of way (e.g. politics is talked about in terms of left and right wing so this should connect to physical movements to the left and the right). Our ecological questions has become, what kind of mechanism might allow this kind of cross-talk, and as I’ve been chatting to students I’ve been connecting a few dots for myself. This post sketches the outline of a mechanistic, ecological research programme for attacking the fascinating problem of the relationship between language and thought.

Sunday, 26 February 2017

Evidence for the Kinematic Specification of Dynamics

Gibson’s most detailed analysis of the KSD problem came from work on the perception of dynamic occlusion (viewing one surface become progressively hidden behind another as they move; Gibson, Kaplan, Reynolds & Wheeler, 1969; Kaplan, 1969). As one surface goes behind another, the sensations coming from the rear surface stop hitting the retina; they disappear. However, was is perceived is the progressive occlusion of a persisting surface; it is not disappearing, it is going out of view. Gibson and his students identified the kinematic pattern of transformation of the optic array that was specific to occlusion and distinguished it from the pattern specific to a surface actually going out of existence. In the former case, optical texture from the rear surface is progressively deleted over time from the optic array at an edge as it goes in behind the closer surface, and that texture progressively accretes as it comes back into view. In the latter case, there are a variety of transformations depending on how the surface is disappearing (melting vs being eaten, etc). Each event creates a specific optical pattern, but these patterns are not identical to the underlying dynamics. Observers, however, readily and easily perceive and report the underlying dynamics, not the optical patterns. Additional evidence that people are perceiving the dynamics comes from work in multiple object tracking (Scholl & Pylyshyn, 1999). People can track multiple moving targets over time, and can continue to do so even if the objects move in and out of view, but only if they do so in an occlusion event. If the objects go out of view by imploding, tracking goes to chance. In the occlusion case, the visual attention system continues to perceive a persisting object and can often pick it back up when it returns to view. In the imploding case, this system perceives that the object has ceased to exist, and it no longer tracks it. 

Saturday, 18 February 2017

The Nature of Ecological Perceptual Information

The central issue in the perception of the world is how the perceptual system comes into contact with that world. In vision, the assumption for centuries has been that the experienced world must be recovered somehow from the 2D image of the world projected onto the retina by the lens of the eye. Scientists therefore hunted for patterns on the retina that preserved critical structure from the world by copying some part of that critical structure. 

James J Gibson was, for a long time, no exception to this hunt. His early empirical work (grounded in the theory he laid out in The Perception of the Visual World; Gibson, 1950) created and manipulated retinal images that, for example, contained gradients of optical texture that matched gradients of physical texture created as surfaces receded in depth, or changed their shape or orientation relative to a point of observation. But time and again, Gibson found that perceptual experience was not any straight-forward function of retinal stimulation (i.e. sensations). People did not ‘see’ what was on the retina (Reed, 1988). The most powerful demonstration of this fact is Gibson’s analysis of dynamic occlusion (Gibson, Kaplan, Reynolds & Wheeler, 1969; Kaplan, 1969) to which we will return below.
Gibson’s later career was defined by the search for an explanation of how perception could be possible if it wasn’t based on sensations and retinal images. Gibson’s solution was his theory of the ecological information available for visual perception published in The Ecological Approach to Visual Perception (Gibson, 1979)

What follows is a description of ecological information with reference to some of Gibson’s work and the extensive research literature that has taken place since Gibson’s death in 1979. The focus will be on the information in light for vision, because that has been the focus of the research. However, the principles hold for all the various energy media our perceptual systems interact with, and we will review this briefer evidence as well.

The Ecological Approach - The Accidental Textbook

Over the years this blog has collected 232 posts on a wide range of topics and we have multiple papers out and forthcoming working on the ecological approach to psychology and the behavioural sciences more generally. On the plus side, I have material all over on a wide range of topics; on the down side, I have material all over on a wide range of topics and it's hard sometimes to hand someone a useful entry point. 

I always figured we would accidentally write a textbook on this blog and while we aren't there yet, we are working on a fairly comprehensive paper that tries to walk through the entire approach. Over the next few weeks, I'm going to post some excerpts from that work to a) have some focused information in the them and b) get some feedback about whether it makes sense.


At this point, I assume you are sufficiently intrigued by the ecological approach that you would like to know how it works. One motivation for getting to that point is the fact it allows mechanistic models of psychological phenomena; another may be a desire to be more embodied or enactive in your science. I'm not going to work on convincing you at the moment; I'm just going to try out the clearest explanations of all the key ideas I currently have in order to educate and get feedback. 


I will come back and update this post with links to all future posts on this topic, in order (you can also search with this tag). If by any chance you are finding this material useful, drop me a line and let me know. 

Textbook Posts