New dawn in brain-machine interfacing

Image credit: NatureScientists have made a breakthrough in their efforts to bring paralysed people the ability to use thought power alone to control artificial limbs, and to interact with computers and other electrical devices.

John Donoghue and colleagues implanted a tiny array of electrodes into the brain of a 25-year-man who is unable to move his arms or legs following a knife wound that severed his spinal cord. The brain implant allowed him to use his thoughts to check emails, play a simple computer game, change channels and volume on a TV, and to control a robotic arm. It is the first time an implant of this kind has been tested in a human.

The electrode array was implanted into the part of the man's brain that, prior to his injury, would have controlled his left arm. By forming the intention to move his arm, neurons were activated in this region, their pattern of firing was recorded by the implant and then an external computer converted the neuronal firing into a command for a mouse cursor or robotic arm.

The findings represent a significant advance on at least three fronts – the man was able to achieve this control within a few minutes of practice; he was able to chat with researchers while he was exerting mental control of the cursor, TV or robot arm; and his control was in all directions, rather than just left and right or up and down. This is in contrast to non-invasive brain-machine interfaces that rely on recording the surface electrical activity of the brain. They require weeks or months of training, demand the user’s full attention when in operation, and, until recently, only allowed one-dimensional cursor control. This new study also shows that several years after paralysis, neurons that were previously involved in controlling limbs still respond to the will to move.

However, significant hurdles remain. As well as involving surgery and the risk of infection, the device used in this trial was connected by wires to bulky computing equipment and required constant fine tuning. A fully-implantable, wireless device would be preferable. Moreover, the precise control we achieve with our natural limbs depends on constant sensory feedback from touch and proprioception – the sense of where our limbs are in space. Scientists have a long way to go before they 'close the loop' by mimicking this kind of feedback.

Hochberg, L.R., Serruya, M.D., Friehs, G.M., Mukand, J.A., Saleh, M., Caplan, A.H., Branner, A., Chen, D., Penn, R.D. & Donoghue, J.P. (2006). Neuronal ensemble control of prosthetic devices by a human with tetraplegia. Nature, 442, 164-171. Open access.

Link to accompanying videos. Open access.
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Why marginalised minorities may be wary of intergroup contact

When people from different social groups mix, they generally come away with a more positive attitude towards the other social group. However, this benefit is not always symmetrical - people from a minority group are less likely to emerge with improved attitudes. It depends on how they perceive the experience, and how they perceive the dynamics between their social group and the majority group.

Nick Hopkins and Vered Kahani-Hopkins have explored such perceptions by analysing some of the diverse positions on inter-faith dialogue adopted by British Muslims in the 1990’s. For example, they found speakers at one event arguing that inter-faith dialogue was unhelpful until the Muslim community was fully united and better organised.

One speaker said: “At present interfaith dialogue is conducted on both sides by individuals and groups who have no interest in Islam. Under such circumstances interfaith dialogue becomes a tool through which the religious rights of one group - Muslims - are slowly eroded away”.

Hopkins told The Digest: “It seems that for some minority group activists, interventions involving contact could be problematic because they are perceived as undermining group members’ abilities to act collectively and bring about social change”.

However, this was not a feeling held by all Muslims at the time. Hopkins and Kahani-Hopkins also analysed a 1997 report by the Runneymede Trust - ‘Islamaphobia: a challenge for us all’ which represented an important strand of Muslim opinion. The report emphasised the need for inter-group contact if Islamaphobia were to be overcome, and mentioned “the importance of practical projects which require people from different communities and faiths to work as partners on the resolution of shared problems, and to make common cause to other bodies”.

The researchers believe it is only through this kind of careful, qualitative analysis of how people think about inter-group dynamics that a more realistic, politically sophisticated understanding of how different groups feel about intergroup contact can be achieved.

Hopkins, N. & Kahani-Hopkins, V. (2006). Minority group members’ theories of intergroup contact: A case study of British Muslims’ conceptualisations of ‘Islamaphobia’ and social change. British Journal of Social Psychology, 45, 245-264.
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Your trustworthiness is judged in a tenth of a second, or less

It takes just a tenth of a second for people to make judgements about you based on your facial appearance.

Janine Willis and Alexander Todorov asked university students to rate the attractiveness, likeability, competence, trustworthiness, and aggressiveness of actors’ faces after looking at their photos for just 100ms. The ratings they gave the faces correlated strongly with ratings given by other students who were allowed as long as they wanted to rate the faces. The strongest correlation was for trustworthiness. “Maybe as soon as a face is there, you know whether to trust it”, the researchers surmised.

As the time the students were given was increased up to half a second, or to a whole second, their ratings continued to correlate just as strongly with the ratings given by the students who were allowed as long as they wanted to rate the faces. However, with more time, the students’ ratings became slightly more negative and their confidence in their judgments increased.

“These findings suggest that minimal exposure to faces is sufficient for people to form trait impressions, and that additional exposure time can simply boost confidence in these impressions. That is, additional encounters with a person may only serve to justify quick, initial, on-line judgments”, the researchers said.

Willis, J. & Todorov, A. (2006). First impressions. Making up your mind after a 100-Ms exposure to a face. Psychological Science, 17, 592-598.
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'Blind' drunk after one drink

If your attention is elsewhere you can miss something right in front of your eyes – a phenomenon that’s been dubbed ‘inattentional blindness’. For example, witnesses confronted by an armed attacker sometimes fail to remember anything else about the assailant apart from their weapon, so preoccupied were they by the knife or gun. Now Seema Clifasefi and colleagues report that just one stiff drink can exaggerate inattentional blindness, a finding they argue justifies the setting of a lower legal alcohol driving limit.

Forty-seven students watched a short video clip of two teams passing a basketball between their respective team members. The participants’ task was to count the number of passes made by one of the teams. During the clip, a woman in a gorilla suit runs between the players and beats her chest. Crucially, when asked afterwards, only 18 per cent of the students given a drink of vodka and tonic said they’d noticed the woman, compared with 46 per cent of the students given a drink of plain tonic water.

Alcohol clearly exaggerated the inattentional blindness that was also experienced by many of the sober students.

This wasn’t a placebo effect – half the students given plain tonic water were told they had been given vodka, and yet 42 per cent of them noticed the gorilla woman. By contrast, half the students given vodka were told they’d been given tonic water, and yet only 18 per cent of them noticed the gorilla. The alcohol seems to have had a direct effect on the participants’ cognition.

“Even at only half the legal driving limit in the US, our subjects were at significantly increased risk of failing to notice an unexpected object compared with their sober counterparts. In light of this result, perhaps lawmakers should reconsider the level of intoxication deemed legal to operate a vehicle”, the researchers concluded.

Clifasefi, S.L., Takarangi, M.K.T. & Bergman, J.S. (2006). Blink drunk: The effects of alcohol on inattentional blindness. Applied Cognitive Psychology, 20, 697-704.

Did you know?
The creators of the video clip used in this study won an Ig Nobel prize for their efforts. Here's the paper that originally used the gorilla video.
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Mobile phone use can be beneficial

Thirty minutes exposure to a digital mobile phone can improve people’s working memory functioning, at least in the short term, according to Vanessa Keetley and colleagues at Swinburne University in Australia.

The performance of 120 participants on a battery of neuropsychological tests was compared before and after they were exposed for thirty minutes to a mobile phone that was either on full power, or switched off. The phone was clipped to a headset leaving it 0.5 to 1.5 cm from the participants’ heads. The researchers took pains to ensure neither the participants nor experimenters knew whether the phone was on or not. For example, the phone was covered in sound-proofing material to hide the slight buzzing sound it made when it was on, and a piece of foam prevented the participants from feeling whether the phone was warming up.

After exposure to radiofrequency electromagnetic radiation from the switched on phone, the participants were significantly quicker at a trail making task, a measure of working memory performance that required them to join up 25 circled digits, or a mixture of letters and digits, with a line. The researchers speculated the phone might have this effect by altering blood flow in the dorsolateral prefrontal cortex, an area involved in working memory.

However, exposure to a switched on phone slowed down participants’ performance on simple or choice reaction time tasks that required them to press a button as quickly as possible when they saw a particular on-screen stimulus.

“The negative effects of digital mobile phone exposure on reaction time performance indicate that the more basic functions were adversely affected by exposure. In contrast, the improved performance reaction time for the trail making working memory task suggests that digital mobile phone exposure has a positive effect on tasks requiring higher level cortical functioning, such as working memory”, the researchers concluded.

Keetley, V., Wood, A.W., Spong, J. & Stough, C. (2006). Neuropsychological sequelae of digital mobile phone exposure in humans. Neuropsychologia, 44, 1843-1848.
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Reading to babies gives them a head-start

Image by superhuaToddlers read to daily by their mothers from an early age have bigger vocabularies and superior cognitive skills.

Helen Raikes and colleagues asked 2,581 mothers from poor families enrolled on the Early Head Start programme in America how often they read to their child at age 14, 24 and 36 months. At each time point, children read to daily, or several times a week, had a larger vocabulary.

Of course it’s probable that parents are more likely to read to children if they have a larger vocabulary, but the researchers also found that children read to more at 24 months had a larger vocabulary at age 36 months, irrespective of how much they were read to at that later time point. Moreover, among English speaking families only, those children read to daily at the age of 14, 24 and 36 months, had superior cognitive skills when tested at the age of 36 months.

“This study shows relations between reading to children and children's language and cognitive development begin very early and implies that parent-child bookreading and other language-oriented interventions for vulnerable children should begin much earlier than has generally been proposed”, said lead researcher Helen Raikes of Nebraska-Lincoln university.

The researchers also found first born children were more likely to be read to, as were girls, and the children of better educated mothers.

Raikes, H.H., Raikes H.A., Pan B.A., Luze, G., Tamis-LeMonda, C.S., Rodriguez, E.T., Brooks-Gunn, J., Constantine, J. & Tarullo, L.B. (2006). Mother-child bookreading in low-income families: Correlates and outcomes during the first three years of life. Child Development, In Press.
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Other new research and reviews of note -

A woman recovers her ability to see depth after years of stereo-blindness, thus providing further evidence of the brain's adaptability even into adulthood.

The neural basis of human dance.

Autism more common than previously thought. But see here.

The benefits of playing video games.

Is Bush unintelligent really?
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The Special Issue Spotter

Advances in developmental cognitive neuroscience - an evolving field that investigates the relations between brain maturation and cognitive development. (Neuropsychologia).

'Memory editing' - a study of the interplay between those mechanisms that distort memory and those mechanisms that protect memory against distortion. (Memory).

If you're aware of a forthcoming journal special issue in psychology, please let me know.
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Well, it can't hurt to ask...Yes it can!

Asking someone how likely they are to take illegal drugs in the future can actually increase the likelihood that they will indeed take drugs – a finding with worrying implications for health research.

Patti Williams and colleagues recruited 167 undergrads and asked some of them about their intentions to take drugs, and the others about their intentions to exercise. Two months later, the students were contacted again, and those who had been asked about drugs reported taking drugs an average of 2.8 times in the intervening period, compared with an average of 1.1 times among the students previously asked about exercise.

The effect was even more dramatic when those students who said they hadn’t taken any drugs at all were omitted from the analysis. Among the remaining students, those asked about their drug-taking intentions said they’d used drugs an average of 10.3 times over the past two months, compared with an average of 4 times among the students previously asked about their exercise intentions.

This observation, together with further analysis, suggested it wasn’t that new drug users had been created, but rather that the questioning had led to increased use among current users who presumably had a positive attitude towards drugs in the first place.

“The results of the current study may well be troubling for researchers trying to survey respondents in at-risk populations”, the researchers said. “By virtue of surveying the at-risk population in an attempt to help them, serious harm may actually be done to the sampled group”.

It wasn’t all bad news – those students asked about their intentions to exercise subsequently reported having exercised more than the students who were earlier asked about their drug-taking intentions. But the message remains – asking someone a question about their intentions can alter their future behaviour, sometimes in negative ways.

Williams, P., Block, L.G. & Fitzsimons, G.J. (2006). Simply asking questions about health behaviours increases both healthy and unhealthy behaviours. Social Influence, 1, 117-127.

UPDATE: Click 'comments' below - one of the authors of this research answers a reader's question and kindly provides a link to some forthcoming research that expands on the current findings.
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Was altruism borne out of a universal willingness to punish?

If human nature has been shaped entirely by evolutionary pressures, then why are so many people prepared to help complete strangers? Surely those ancestors of ours with an altruistic bent would have been wiped out by the more ruthless and self-serving among our forebears. Joseph Henrich and colleagues believe the answer lies, somewhat paradoxically, in the universal human willingness to punish unfair behaviour.

Henrich’s team used three economic games involving real money to test the behaviour of 1762 participants from 15 different societies on five continents. Across the world, from the Samburu in Kenya to the Sursurunga in Papua New Guinea, they found people playing anonymously were willing to sacrifice their own winnings to punish a player who was unfair in the way they shared money with themselves or a third party.

Willingness to punish varied across the cultures, but in every society, less equal sharing was more likely to be punished. And crucially, those societies that showed the greatest willingness to punish unfair behaviour also turned out to be the most altruistic, as judged by their performance in the games. “You evolve into a more cooperative being if you grow up in a world where there are punishers” Joseph Henrich told Science.

However, whilst welcoming the cross-cultural nature of the study design, and acknowledging the contribution it makes to the debate on altruism, evolutionary psychologist John Tooby told Science that he was wary of reading too much into these anonymous games – “…in ancestral societies, people lived in small groups where everybody knew each other. In that environment, anonymous punitive interactions would have been rare to nonexistent, so there would have been no selection to adapt to such situations”.

Henrich, J., McElreath, R., Barr, A., Ensminger, J., Barrett, C., Bolyanatz, A., Cardenas, J.C., Gurven, M., Gwako, E., Henrich, N., Lesorogol, C., Marlowe, F., Tracer, D. & Ziker, J. (2006). Costly punishment across societies. Science, 312, 1767-1770.

Supplementary material on the methodology.
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Communicating off the top of your head

Forget lip-reading, the way the top of the head moves as we speak also plays a part in communication, a finding that has implications for creating more realistic animated characters.

In an initial experiment, Chris Davis and Jeesun Kim presented students with silent videos that showed the top half of a man’s head as he read out various sentences.

When presented with two pairs of such videos, one in which the man read the same sentence out in each video, and another in which he read different sentences, the students were able to use the movement of the top of his head to judge better than chance which pair was the same and which was different. Note that in the matching pair, the videos were not identical – the man was recorded reading the same sentence on two separate occasions.

Performance was also better than chance when the students had to match the sound of the man reading a sentence with the correct silent video that showed only the top half of his head as he read the same sentence.

In both cases, performance was better when the man was reading an expressive sentence like “that is really annoying; I have to let you know” rather than a mundane sentence like “the jacket hung on the back of the wide chair”.

In a further experiment, the sound of a person speaking was deliberately distorted. This time, the student participants were able to correctly recognise more words if the sound was accompanied by a video showing only the outline of the top of half of the head of the person who was speaking. Again, the sight of the top of the head provided greater advantage if the speaker was uttering an expressive sentence.

“That people are sensitive to speech related upper head movements makes it clear that the production of natural looking virtual characters will need to consider more than the correct animation of the mouth and jaw”, the researchers said.

Davis, C. & Kim, J. (2006). Audio-visual speech perception off the top of the head. Cognition, 100, B21-B31.
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One-year-old babies predict other people’s intentions

Babies as young as 12 months already have a rudimentary understanding of other people’s intentions. That’s according to Terje Falck-Ytter and colleagues who observed babies’ eye movements as they watched a video presentation of a person picking up toys and putting them in a bucket.

Six-month-olds tended to follow the trajectory of the toys through the air. By contrast, 12-month-olds’ eyes jumped ahead to the bucket as if they were anticipating the person’s intentions, just as happened when adult participants watched the video.

However, this jumping ahead to the bucket only occurred when a person was moving the toys. It didn’t occur when the video showed the toys flying through the air apparently self-propelled, or they were moved mechanically, in which case the 12-month-olds and adults both moved their eyes as the 6-month-olds had done – that is, they were mostly fixated on the toys and didn’t jump ahead to the bucket.

The researchers believe the 12-month-olds’ ability to anticipate people’s intentions is based on the functioning of mirror neurons that are activated both when the baby performs a movement and when they see that same movement performed by someone else. Crucially, the 12-month-old babies, but not the 6-month-olds, have themselves mastered the action of putting toys in a bucket, thus allowing them to map their observation of someone else performing the action onto their own neural representation for performing the action.

“We have demonstrated that when observing actions, 12-month-old infants focus on goals in the same way as adults do, whereas 6-month-olds do not”, the researchers said.

Falck-Ytter, T., Gredeback, G. & von Hofsten, C. (2006). Infants predict other people’s action goals. Nature Neuroscience, 9, 878-879.
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Hey girls: Science helps people!

The story of women’s under representation in science begins at school where fewer girls than boys choose to pursue science, especially physics. According to Erica Weisgram and Rebecca Bigler, the secret to enticing more girls into science could be to show them that science helps people, and that it contributes to the overall well-being of society. But the hard part is finding an effective way to convince them of that.

Weisgram and Bigler assessed hundreds of girls before and after they completed a programme in America called ‘Expanding Your Horizons’ that’s designed to increase girls’ interest in science.

The programme involved the girls attending four one-hour sessions on different scientific subjects such as earth science and engineering. The sessions were all presented by a female scientist and involved hands-on activities. Half the girls went on a special version of the programme in which the presenters took extra care to emphasis how their work as a scientist helps people and society.

After the programme, the girls who believed in the altruistic value of science also tended to report having more interest in it, to believe it was more important, and they had stronger belief in their own scientific ability. But the bad news was twofold: firstly, the girls who attended the special version of the course emphasising altruism were no more likely to believe in the altruistic value of science, so in that sense it failed. Secondly, although the course did increase the girls’ interest in science overall, their belief that science is equally appropriate for men and women actually dropped, perhaps because the exclusive use of female presenters focused the girls’ attention on the need for women in science.

“To encourage more women to enter scientific fields, public advertising campaigns, vocational counselling programmes, and educational materials might usefully highlight the ways in which science fulfils individuals’ altruistic values”, the researchers said.

Weisgram, E.S. & Bigler, R.S. (2006). Girls and science careers: The role of altruistic values and attitudes about scientific tasks. Journal of Applied Developmental Psychology, 27, 326-348.

Link to previous, related Digest item.
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Don't suppress negative thoughts about yourself

Most of us have those horrible nagging thoughts of self-doubt that begin ‘I wish I weren’t so…’ or ‘I hate that I’m so…’ but apparently the worst thing we can do is push them out of mind. According to Jennifer Borton and Elizabeth Casey at Hamilton College in New York, not only does this cause us to have more of such thoughts – a phenomenon known as the 'rebound effect' – it can also detrimentally affect our overall mood and self-esteem.

Previously evidence for this has come from laboratory studies, but now Borton and Casey have conducted a field experiment to test the effect of negative thought suppression on participants going about their everyday lives.

Before completing a web diary every evening for 11 days, 57 students were asked to bring to mind their most upsetting thought about themselves. Crucially, 29 of them were also given the following instruction:
What I’d like you to do over the course of the next 11 days is to work particularly hard at SUPPRESSING this negative thought, pushing it from mind, trying not to think about it. If the thought should pop into your head, do your best to just push it away and try not to think about it”.
At the end of the 11-day period, the web diaries were analysed, and it was found the students instructed to suppress their negative thoughts about themselves actually had more of such thoughts, reported more anxious mood, more depressed mood, and if their negative thoughts made them feel ashamed, then they also tended to report lower self-esteem too.

So rather than suppressing these kinds of thoughts, what should we do? Lead researcher Jennifer Borton told the Digest: “Moving one's attention away from the negative thought and onto something else is different from the ‘non-strategy’ of simply erasing the thought from mind. Of course, if the thought about oneself is true, one may need to deal with it later. If the thought is not true or exaggerated (e.g., ‘I'm ugly’), one should pick a single replacement thought on which to focus when the negative thought comes to mind (e.g., ‘I have a nice smile’; ‘I am smart’).

Borton, J.L.S. & Casey, E.C. (2006). Suppression of negative self-referential thoughts: A field study. Self and Identity, 5, 230-246.

Link to Daniel Wegner of Harvard University - his webpage contains useful links to loads of research in this area.
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