Travelling at the speed of thought

Discover Magazine has an excellent Carl Zimmer piece discussing efforts to understand the speed of the human nerves – a quest that has lasted for well over one hundred years.

Although our experience of the world seems instantaneous, different nerves in the body work at different speeds and, of course, cover different distances – to the point where taller people experience a slight sensory lag compared to shorter people owing to the greater length of some of the nerve pathways.

Speed is not necessarily of the essence, however, and as with dancing, it is timing and co-ordination that seems key:

Sometimes our brains actually need to slow down, however. In the retina, the neurons near the center are much shorter than the ones at the edges, and yet somehow all of the signals manage to reach the next layer of neurons in the retina at the same time. One way the body may do this is by holding back certain nerve signals—for instance, by putting less myelin on the relevant axons. Another possible way to make nerve impulses travel more slowly involves growing longer axons, so that signals have a greater distance to travel.

In fact, reducing the speed of thought in just the right places is crucial to the fundamentals of consciousness. Our moment-to-moment awareness of our inner selves and the outer world depends on the thalamus, a region near the core of the brain, which sends out pacemaker-like signals to the brain’s outer layers. Even though some of the axons reaching out from the thalamus are short and some are long, their signals arrive throughout all parts of the brain at the same time—a good thing, since otherwise we would not be able to think straight.

Link to Discover article ‘What Is the Speed of Thought?’

On the soul of robots

Image by Flickr user FlySi. Click for sourceNew Scientist has an interesting article discussing research on how we attribute personality traits to robots. This is not just the human-like android from research labs, it’s the robots that are already in widespread use in the workplace and home like the floor-cleaning Roomba.

This is a fantastic snippet about a study on the commercially available Aethon TUG robot, used to deliver supplies on hospital wards, and what staff made of the machine:

TUG, which is made by Aethon, can navigate a building’s corridors and elevators on its own and tell humans it has arrived with a delivery…

The lack of any social awareness led interviewees to complain that they felt “disrespected” by the robot. “It doesn’t have the manners we teach our children,” said one, “I find it insulting that I stand out of the way for patients… but it just barrels right on.”

Luckily for TUG, its unvarying, one-size-fits-all social skills happened to be a natural fit in the relaxed atmosphere of the post-natal ward, says Mutlu. But the same default settings were interpreted as demanding and attention-seeking on the oncology ward, which is a more stressful and busy place to work. “If you are going to design robots with human-like capabilities you have to design the appropriate social behaviour that goes along with it,” Mutlu says.

This reminds me of perhaps the only study that has evaluated what personality traits people attribute to the synthetic speech on a voice mail system, rating it as practical, intelligent, courteous, efficient, straight-forward, sophisticated, methodical, progressive and alert.

Link to NewSci article ‘Learning to love to hate robots’.

Understanding witchcraft

YouTube has a fantastic documentary about the work of the pioneering anthropologist E. E. Evans-Pritchard who was one of the first researchers to try and understanding the psychology of people he was studying.

He is most well known for his 1937 book Witchcraft, Oracles and Magic among the Azande where he studied the role of magic and prophecy in the lives of the Sudanese Azande people from their perspective.

This was one of the first times that an anthropologist had attempted to understand other cultural beliefs as a coherent system, rather than simply listing the ‘odd’ or ‘irrational’ practices from a Western perspective.

One of his main conclusions was that the Azande were making rational decisions based on different assumptions, in contrast to the general colonial opinion that the people of Africa were somehow ‘backward’.

Evans-Pritchard became one of the founders of social anthropology and was influential in a change of perspective in understanding other cultures.

He was also a keen photographer and there is a fantastic collection of his photos that attempted to record the people he met at the Oxford University Pitt Rivers museum.

The documentary is a great overview of both the man and his work with the Azande and Nuer people in Africa.

Link to documentary ‘Strange Beliefs: Sir Edward Evans-Pritchard’.

The psychiatric bible: the state of play

New Scientist has a good piece which outlines the current state of play in the contentious and recently delayed revision of the forthcoming psychiatric diagnostic manual, the DSM 5.

If you’ve been following the bad-tempered tussling among the psychiatric community over the re-writing of the manual, you probably won’t find much new in the main piece but it is a great summary and is accompanied by some examples of contentious disorders that are being considered for the new version.

These include complicated grief, a form of extended and unresolved grieving; changes to ‘gender identity disorder’, which currently describes the state of feeling like you’re a different gender; and hebephilia, a sexual interest in pubescent children.

The NewSci article is also accompanied by an interesting editorial that argues that the American Psychiatric Association should ditch the book and move to a database format where individual diagnoses could be updated when necessary as new evidence requires.

Link to NewSci article ‘Psychiatry’s civil war’.
Link to editorial ‘Psychiatry’s bible: Its time has passed’.

A great write-up of Project HM

Neurophilosophy has an excellent write-up of Project HM, the ongoing mission to thinly slice and digitise the brain of Henry Molaison, famous as amnesic Patient HM, who died last year.

Molaison was only one of a very few patients who had a radical operation that removed inner sections of both temporal lobes to cure otherwise untreatable temporal lobe epilepsy.

At the time, it wasn’t known that removing the hippocampus on both sides of the brain would lead to a profound amnesia that left the patient with the inability to create new ‘declarative’ memories – ones that can be recalled into the conscious mind.

The procedure was only carried out on a handful of patients before the profound effects became clear. The neurosurgeon William Scoville later campaigned against its use.

The rest, as they say, is history and owing to Molaison’s cheerful participation in numerous memory experiments we know a great deal more about the neural basis of memory. Hopefully the new high resolution digitised brain slices will allow a fine detail look at the relationship between HM’s brain and his abilities.

You’ll not find a better account of the project, so do head over and check out the Neurophilosophy piece.

My only slight addendum would be that the distinction between short and long-term memory was not initially drawn from HM. This distinction was originally made by ‘father of psychology’ William James who described it as ‘primary’ and ‘secondary’ memory in his 1890 book Principles of Psychology.

However, because HM had intact short-term memory (for example, he could repeat telephone numbers back to himself) but was not able to store anything effectively in long-term memory, he gave the first clues that this distinction was reflected in the structure of the brain.

This was all but confirmed in 1970 when neuropsychologists Tim Shallice and Elizabeth Warrington reported on Patient KF who had the reverse pattern of impairment – no short term memory, but with with normal long-term memory.

This showed that each of the two forms of memory could be independently impaired after brain damage and so almost certainly depend on distinguishable brain systems.

Link to Neurophilosophy on ‘Project H.M. Phase I’.
Link to Project HM website.

Ad Nauseum

adnauseam.jpgI am reading Ad Nauseam: A Survivor’s Guide to American Consumer Culture, edited by Carrie McLaren and Jason Torchinsky. The book is a funny, smart and sometimes shocking collection of articles from Stay Free Magazine and blog. I first came across Stay Free when I was researching the psychology of advertising and was impressed by their sophisticated take on how adverts affect consumers’ decision making. They discuss in Ad Nauseam how advertising is often misunderstood, with people relying on an intuitive ‘Advertising doesn’t effect me’ view or swinging to the opposite extreme of the ‘Sinister Advertisers Manipulate Consumers with their Mind Control Tricks’ position. Both positions distract from the very real, but not magical, power of advertising.

The book has a great discussion of Wilson Bryan Key’s Subliminal Seduction, the book that launched the idea that subliminal, and often sexual, figures are embedded in random features of adverts such as in ice cube shadows. The idea of these ’embeds’ is nonsense, of course, but great fun to look for and a great distraction from the real persuasive content of the advert. The book also has a chapter on the origins of modern advertising practice in 19th century pharmaceutical advertising (the manufacturing of ailments for which ready made ‘cures’ can be sold has been covered by Vaughan on before, in relation to the mental health). Packed with critical analysis of the advertising industry, more informative history and some shocking examples of how consumerism has worked its way into many aspects of our daily lives, this book is essential intellectual self-defense, managing to be critical and aware without ever being sanctimonious or hysterical.

Cross-posted at

Psychology in the New York Times Year in Ideas

I really recommend the 2009 Year in Ideas review from The New York Times as it is packed full of developments in the world of psychology and social science.

If you’re a regular Mind Hacks reader you’ll recognise some of the ideas from experiments and studies we’ve covered during 2009, but there are many more curiosities that make for compulsive reading.

Probably the majority of the articles will be of interest to mind and brain enthusiasts but I particularly enjoyed Literary Alzheimer’s, Lithium in the Water Supply, Treating P.T.S.D. With Tetris, Cognitive Illiberalism, The Counterfeit Self, Drunken Ultimatums and to be fair, pretty much all the others too.

My only complaint is the short pieces don’t link to the original sources (suggestion for Year in Ideas 2010: inline links!) but otherwise if you like the sort of stuff we post on Mind Hacks there’s plenty to keep you occupied here as well.

Link to NYT Year In Ideas 2009.