Ballet and the mirror system

Beatriz Calvo-Merino and researchers from University College London have been investigating how the brain understands other people’s movements with the help of professional ballet dancers and experts in capoeira.

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It is thought that the human brain has a ‘mirror system’, that simulates the actions of others as we observe them. This might be the basis of a number of important skills such as observational learning and communication.

This system seems particularly tuned to biological motion, as it doesn’t seem to activate when mechanical motion is viewed, or, for example, when an obviously artificial hand is watched while it moves.

Calvo-Merino used the brain scanning technique fMRI to investigate whether the mirror system of expert dancers would react differently when watching their own dance style, when compared to a dance style they didn’t know.

They found that when dancers viewed moves which they were expert in, their brains were more active in areas associated with action planning, body image, motion perception and, unexpectedly, and reward and social behaviour.

The results suggest that the mirror system is involved in understanding the movement of others by combining it with our own repertoire of skills and experience, and that this may be a crucial part of our social interaction.

Link to story from sciencedaily.com
Link to the abstract of the study from the journal Cerebral Cortex.

Eyes wide with fear

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Here’s another story related to Vaughan’s post of a couple of days ago about the amygdala and fear perception.

A brain imaging study reported in the journal Science [1] found that showing the silhouettes of fearful eyes for just 17 milliseconds was enough to increase activity in the amygdala’s of human subjects – the effect is something like just seeing the whites of someone’s eyes in the dark (as shown in the picture, along with the comparison condition – the silhouette of the eyes of someone showing a happy expression).

The two things struck me about this. The first, obviously, is how brief the exposure is. If you are shown something for 17ms you will probably be unable to tell that you’ve been shown anything at all (you might see a flash), you certainly won’t be able to tell what it is. In this study the 17ms picture of eyes was immediately followed by a picture of a normal, expressionless, face – which makes perceiving the eye-silhouettes even harder (and, indeed, none of the participants in the experiment reported that they noticed anything unusual).

But their brains did. The amygdala was already ramping up, ready to signal ‘be afraid’ to the rest of the brain. And this to something that isn’t actually scary in itself – but a social signal that there is something to be afraid of nearby. Social and emotional information is being priority-routed through the brain’s processing streams.

Continue reading “Eyes wide with fear”

Fear can be found in the eyes

Neuroscientist Ralph Adolphs has been working with a woman known only by the initials SM. She has damage to the amygdala on both sides of the brain, and although she can recognise emotions such as happiness, anger, surpise, sadness and disgust on people’s faces, she can’t recognise fear.

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Adolphs investigated exactly what SM was looking at when she viewed emotional expressions and found that she rarely looked at the eyes. Most other emotional expressions can be recognised from other parts of the face, but recognising fear seems to particularly involve viewing the eyes.

When prompted to look specifically at the eyes, SM became a lot better at recognising fear, although quickly reverted back to avoiding them if not reminded.

The amygdala has been traditionally associated with emotion, particularly the negative emotions, but Adolphs suggest that maybe it has a wider function, also involving visual attention and analysis.

Why damage to the amygdala might specifically cause problems with viewing the eyes of other people remains to be investigated, as does whether SM’s ability to focus in on other parts of the face is entirely normal.

Link to story on nature.com

Face recognition might be innnate

Researchers from the Universities of Queensland and Denver have found that newborn babies preferentially look at human faces, but not human body shapes in general. This seems to suggest that face recognition might be innate in some way and might be one aspect of our genetic inheritance which promotes social interaction and allows us to develop subtle social communication skills needed for the complexity of human interaction.

A study published in 2004 suggested that this is more than just a simple preference for any face-like shape, but that newborn babies prefer attractive rather than unattractive faces. It is still unclear why this might happen, although it perhaps hints that attractive faces may seem more attractive because they more closely match a configuration passed down to us via our genes.

The excuse “Sorry honey, I was just looking to see if their face matched my genetic template of innate face shapes” is of course unlikely to get you out of trouble, regardless of your ability to describe the science behind it.

The Social Yawn

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All animals yawn (see animalyawns.com) and in humans yawning seems to be contagious. Seeing another person yawn, or even just reading about yawning can make you yawn. (We talk about unconscious immitation in chapter 10 of the book). James Anderson from the University of Stirling gave a lecture in Sheffield last week about yawning – in the introduction he told us that when he lectures on yawning lots of people in the audience, well, yawn. But his talk was only yawn-inducing in the social-contaigon sense.

Yawning, it seems to me, may provide us with paradigm case of an automatic behaviour that, moving along the phylogenetic scale, has become co-opted into a quasi-voluntary social signal.

Continue reading “The Social Yawn”

The face, the brain and Marilyn Monroe

Researchers from London and Italy have just published a study on the brain areas involved in perceiving and understanding faces. They created an elegant experiment where they used morphing to compare how brain activity changes as a photograph is gradually blended from one person to another, for example, from Marilyn Monroe to Margaret Thatcher.

They found that the brain did not respond in the same gradual manner, and that activation shifted to specific areas at certain points in the blending process. When the blending was in its early stages, participants perceived the picture as the same person with physical changes to their face, an experience which caused activation in the inferior occipital gyrus. When the level of blending affected recognition of the pictured person, the right fusiform gyrus was activated, an area thought to be involved with judgements of familiarity for faces. When a participant was already familiar with the people in the pictures, the temporal lobes became active when the final face became clear. These areas have been linked to semantic memory and naming.

This study is important as it shows specialised areas of activation for different stages in the face perception process in a single experiment.

These stages have been hypothesised to exist for quite some time in a model developed by psychologists Vicki Bruce and Andy Young, largely from studies on people with prosopagnosia, a condition where face recognition can be impaired, usually after brain damage.

Link to BBC News story.
Link to story in The Guardian.
Link to abstract from Nature Neuroscience.

Imaginary friends

Psychologists from the University of Oregon have been studying children’s imaginary friends. Their study found that 65% of children had imaginary friends at the age of 7, a much higher rate than expected, and that the presence of an imaginary friend is linked to better emotional understanding and ‘theory of mind’ skills (the suggested ability that allows us to figure out and represent others’ beliefs and intentions).

Other studies on imaginary friends in children have also shown that they seem to be quite normal and generally linked to positive psychological development.

Interestingly though, some of the children report that their imaginary playmates don’t always do what they’re told and sometimes won’t go away when expected to, or bother them inconveniently. It seems that even from quite a young age, we are not always master of our own imaginations.

Link to story in Seattle Post-Intelligencer.