New Psyche on ‘action in perception’

wider_than_the_sky.jpgA new edition of Psyche, the journal of the Association for the Scientific Study of Consciousness, has just been published online, and is a special issue on ‘action in perception’.

The edition is curated by philosopher Alva Noë and takes a novel approach to understanding conscious perception.

The main idea of this book is that perceiving is a way of acting. Perception is not something that happens to us, or in us. It is something we do. Think of a blind person taptapping his or her way around a cluttered space, perceiving that space by touch, not all at once, but through time, by skillful probing and movement. This is, or at least ought to be, our paradigm of what perceiving is. The world makes itself available to the perceiver through physical movement and interaction.

This has some similarities with the later work of psychologist J. J. Gibson, who argued in his book The Ecological Approach to Visual Perception that perception could only be understood by accounting for the way in which in an organism uses vision to act within its environment.

Link to Psyche.

Sport psychology

supplement_sport.jpgThe Lancet medical journal has published a special sports supplement that for one month is available to view free as an e-magazine.

The 76 page publication includes features on aggression in sport (p.35); depression in sport (p.41), including comment on double Olympic gold medallist Dame Kelly Holmes’ admission earlier this year that she deliberately cut her arms with scissors during a frustrating period in her career when she was unable to train because of injury; and risk taking in sport (p.38) – with discussion of the idea that extreme sports enthusiasts may use danger to kick-start their lower-than-average dopamine levels.

The risk inherent in climbing such mountains carries its own reward, deep and abiding, because it provides as profound a sense of self-knowledge as anything else on earth. A mountain is perilous, true; but it is also redemptive“. David Breashears, mountaineer and creator of IMAX film Everest, speaking about mountain climbing. From the article by Matt Pain and Matthew A Pain on risk taking.

Link to the supplement.
Link to high wire walker Philippe Petit talking to Sue Lawley on Desert Island Discs.
Link to editor Pia Pini talking about her favourite highlights from the supplement.

Non-invasive neuroprosthetics

eeg_street.jpgNature reports that by simply recording the brain’s electrical signals from electrodes on the scalp, researchers have enabled trained participants to reliably control computer equipment, a feat normally associated with physical implants in the brain.

This is part of the growing science of neuroprosthetics, that aims to create technology that directly interfaces with the brain.

It is being particularly championed for people with paralysis, who do not have the use of their limbs, or people with damaged sensory organs, who might have their senses improved by technological replacements.

Previous trials of the technology have resulted in electronic implants to replace damaged retinas and a microchip implant that allows a paralysed man to control a computer.

These sorts of technologies typically require complex, experimental and invasive surgery, so being able to control technology via a skull cap and surface electrodes would be a more convenient option.

One of the disadvantages, well known to scientists who use forms of EEG recording to research the brain, is that the skull ‘smears’ the signal from the brain. Furthermore, muscle activity can introduce large amounts of electricial noise into the recording.

To get round this, mathematical analysis is used to filter out the unwanted interference, usually by averaging over several trials of the same task, allowing underlying brain activity to be inferred.

This is not an exact science, however, meaning the moment-to-moment ‘decoding’ of electrical activity needed for instant control of technology is more difficult to acheive.

Link to article ‘Computer users move themselves with the mind’.

Getting to grips with grasping

grasping.jpg Reach and grasp a willing colleague by the arm, now let them go, and pick up a pen or pencil instead. The first movement requires a power grip, flexing all the fingers together towards the palm, the second movement uses a precision grip involving the thumb and forefinger. Easy to do? Apparently yes, but the ease and accuracy with which we reach and grasp objects (or people!) belies the complexity of the neural processing underlying such movements. Now the journal Nature Reviews Neuroscience has published a comprehensive review on the neuroscience of grasping, by Umberto Castiello.

Castiello describes how studies on the ‘kinematics’ of grasping have shown there is a reliable ‘landmark’ during reaching movements: when the hand is between 60 to 70 per cent of the way towards its target, the gap between the thumb and fingers always reaches its largest point, the precise moment correlating highly with the size of the object to be grasped. Other object characteristics – its weight, texture, surface – also affect aspects of the grasping movement in a lawful way.

Most of our knowledge about the brain networks involved in grasping come from intrusive experiments on monkeys that are simply not possible or ethical in humans. These point to a circuit involving the primary motor cortex, the premotor cortex and the anterior intraparietal sulcus. How similar things are in the human brain is a matter of controversy and ongoing investigation using brain imaging and studies with brain-damaged patients. These suggest many of the grasping-related areas implicated in the monkey brain are activated in the human brain too, but that other regions are also involved, including the prefrontal, somatosensory and cerebellar areas.

Castiello describes one patient, A.T., with extensive damage to the parietal lobe and secondary visual areas, who had problems grasping neutral, laboratory objects but was okay at grasping familiar items such as a lipstick. This suggests that, in humans at least, brain areas involved in interpreting the meaning of an object also influence the brain’s grasping circuit.

Indeed, Castiello says more research is needed into whether and how the meaning of an object, and intentions for what to do with an object, affect grasping in monkeys in the same way research has shown these more ‘cognitive’ variables influence grasping in humans.

“It will only be through careful and thoughtful experimentation, using converging techniques from the brain and behaviour, that we might completely understand the grasping function of the human hand”, Castiello’s review concludes.

Link to abstract of the review.

Scott Adams and focal dystonia

Scott Adams, the artist behind the comic Dilbert, has a movement disorder called focal dystonia that prevents him from drawing in the regular way. It, and his response to it, are discussed in an article in the Washington Post.

Focal dystonia, which can affect the hand (where it’s commonly called “writer’s cramp” when it affects writing), the neck (the most common site), eyelids or vocal chords, is something of a mystery. First reported in people who do fine finger work, including writers, seamstresses and musicians, it affects an estimated 29.5 individuals per 100,000 population […] Often, focal hand dystonia patients are people who use the small muscles of the fingers and hands.

What I find most interesting about this condition is its neurological roots, as the fine finger work coupled with the stress that often triggers focal dystonia appears to “teach” part of the brain some broken connections:

“We think the disorder is largely associated with the basal ganglia,” which are deep brain structures that help regulate movement, Karp [Barbara Karp, deputy clinical director of the National Institute of Neurological Disorders and Stroke (NINDS)] said. One theory is that repetitive movements or some other cause somehow trigger abnormal learning patterns in the brain.

One therapy for focal dystonia is “sensory training,” changing techniques of practice so that the sensory areas of the brain can learn again how to give proper feedback to the motion parts. Adams, in his case, now uses a graphics tablet and draws Dilbert at many times the final size.

Link to Scott Adams, Drawing the Line in the Washington Post.

Tyrannosaurus reflex

In a wonderful comic strip, dinosaurs explain the neural mechanism of why locking the hands together can release the knee jerk reflex.

dinosaur.jpgIt’s not often the finer points of neurological examination are explained by cartoon dinosaurs, but may this be the first in a long line of comic book / neuroscience fusion spectaculars.

Link to dinosaur / neurophysiology comic strip (via
Link to information about the reflex examination.

Size and selection times: Fitts’s Law

Oo Oo – Just when I thought I was settling down to do some of the work i’m actually paid to do, I discovered a bit of psychology that is relevant to interaction design:-
Did you know that the time it takes you to point your mouse, or your finger, at something is predictable from the size and distance of the object using an equation known as Fitts’s Law?

Nope, neither did I till today. But if you apply it right it shows how you can get a big gain in how quick and easy it is to select something with just a small change in the selection interface.

Continue reading “Size and selection times: Fitts’s Law”

Waving, not designing

I got a wave messaging power-up cover for my Nokia 3220 phone. It’s got a line of LEDs along the back of the phone, and when you wave it, you can spell out messages in the air. Check this out:


(That’s me, by the way. I posted more about this to my other weblog, if you’re interested, but I’m going to continue here about embodied interaction and visual affordances.)

Continue reading “Waving, not designing”

Sinister Research

A couple of interesting bits of research on handedness in the news today.

Chimps brains are asymmetrical in similar ways to human brains, and this is reflected in whether they’re left or right handed too. Why we have a preferred hand is still being debated, but this research shows handedness isn’t a consequence of the same brain asymmetry which arose with language (the language centres are on the left side of the brain). Handedness must have arisen much earlier, and been present 5 million years ago.

Continue reading “Sinister Research”