Connected by threads

The Boston Globe covers several recent studies that have been able to work out sensitive personal details from information made public on social networking sites, possibly including your sexual orientation.

As we discussed earlier this week, huge amounts of information can be gleaned about your life through social network analysis simply from the patterns in your interactions.

In computer security and counter intelligence this is part of a technique called traffic analysis which has a long history in law enforcement. For example, before the days of the internet the UK police would use the Harlequin system to work out social networks from phone call patterns as these were much easier to obtain than court orders allowing phone taps.

Now, we put much of this information online ourselves but are unaware of how much the explicit personal information that we deliberately keep private is still available implicitly in the public data trail.

Sociologists have known this for years but the rapid spread of electronic communication has spurred the development of analysis tools as well as providing the real world data on which it can be applied.

Discussions of privacy often focus on how to best keep things secret, whether it is making sure online financial transactions are secure from intruders, or telling people to think twice before opening their lives too widely on blogs or online profiles. But this work shows that people may reveal information about themselves in another way, and without knowing they are making it public.

Who we are can be revealed by, and even defined by, who our friends are: if all your friends are over 45, you’re probably not a teenager; if they all belong to a particular religion, it’s a decent bet that you do, too. The ability to connect with other people who have something in common is part of the power of social networks, but also a possible pitfall. If our friends reveal who we are, that challenges a conception of privacy built on the notion that there are things we tell, and things we don’t.

Link to Globe article on social networks and personal info (via MeFi).

Oliver Sacks on the varieties of hallucinatory experience

Oliver Sacks has done a wonderful TED talk on hallucinations that has just been released online. He particularly focuses on the hallucinations of Charles Bonnet syndrome where damage or decay of the retina can cause strikingly complex hallucinations of people and animals that seems to be a natural part of the visual scene.

Interestingly, the people affected by the condition are usually well aware that they are hallucinating and remain lucid throughout.

The talk is wonderful and Sacks is engaging as ever, but some of his neuroscience explanation seems a little dodgy.

He discusses the well-known role of an area in the temporal lobes called the fusiform gyrus in face recognition and relates disturbance in this area to face hallucinations:

There’s an area in the anterior part of [the fusiform gyrus] where teeth and eyes are represented and that part of the gyrus is activated when people get the deformed hallucinations [of people with big teeth and eyes].

There is another part of the brain that is especially activated when one sees cartoons. It is activated when one recognises cartoons, when one draws cartoons and when one hallucinates them…

There are other parts of the brain that are involved in the recognition and hallucination of buildings and landscapes.

Actually, all of this seems quite dodgy. I couldn’t find any evidence that part of the fusiform gyrus is specialised for teeth and eyes.

I found one study which linked the viewing of moving mouths or pair of eyes to activation on the superior temporal gyrus, but this is the other side of the temporal lobe. Also, he seems to be suggesting that specific face parts are mapped to specific areas of the fusiform gyrus, again, which I could find no evidence for.

I suspect the bit about specific parts of the brain for buildings, landscapes and cartoons comes from a misunderstanding of neuropsychology experiments as these sorts of pictures are also often used in experiments on face recognition.

One of the big debates in face perception research is whether the fusiform gyrus is dedicated to face recognition or whether it is specialised for any sort of expertise needed for fine grained visual distinction – for example, recognising car types, or birds and so on.

Hence, experiments often will test people on face recognition, but then also on building or drawings so the researchers can find out whether the problem is specific to faces or just a general visual recognition problem. For example, this exact procedure was used in this 2005 study on four people with prosopagnosia, a selective impairment in face recognition.

Apart from maybe a few minor hallucinations from Sacks himself, the talk is excellent and comes highly recommended.

Link to Oliver Sacks TED talk on hallucinations.

Scientists find area responsible for emotion in dead fish

Neuroskeptic covers a hilarious new study that involved brain scanning a dead salmon and finding activation in the brain as it ‘looked’ at photos of human faces.

The authors are not genuinely arguing that dead fish have brain activity but have run the experiment to show that some common statistical methods used in fMRI research will give false positives if they’re not adequately controlled for.

The research, led by neuroscientist Craig Bennett, was presented as a poster at a recent conference and has the brilliant title of “Neural correlates of interspecies perspective taking in the post-mortem Atlantic Salmon: An argument for multiple comparisons correction” and is available online as a jpg.

I’d say that this research was justified on comedic grounds alone, but they were also making an important scientific point. The (fish-)bone of contention here is multiple comparisons correction. The “multiple comparisons problem” is simply the fact that if you do a lot of different statistical tests, some of them will, just by chance, give interesting results.

Most statistics used in psychology, and indeed brain imaging, are based on calculating a p value.

Usually, a p value of less than 0.05 is considered significant and this means that if there was genuinely no difference in the things you were comparing, you would get a false positive less than 5% of the time.

But your average fMRI brain scan analysis can involve 40,000 comparisons, so even if there’s nothing going on, some bits of the brain are going to seem active just through falsely detecting noise and measurement error as real effect.

To help prevent this, you can correct for multiple comparisons by reducing the 5% cut-off to a smaller amount. Unfortunately, some of the standard methods of doing this can be so strict as to create false negatives, when genuine differences are dismissed as statistical noise.

There is no hard and fast rule about which methods to use, but our salmon neuroscientists have graphically illustrated how misleading results can occur if we naively assume that not correcting accounting ‘multiple comparisons problem’ will give us an accurate picture of brain function.

Kudos to the Neuroskeptic blog for picking up on this and for some excellent coverage of this study.

Link to Neuroskeptic on dead salmon study.
jpg of conference poster.

2009-09-18 Spike activity

Quick links from the past week in mind and brain news:

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Neurophilosophy has an excellent piece on how eye movements can reveal the unconscious detection of changes in a ‘change blindness’ demo that the conscious mind is unaware of.

Illusion Sciences has an an excellent visual illusion that changes direction depending on where you look at it.

The sad case of a 9-year-old girl diagnosed with early onset dementia is covered by The Telegraph.

A new study covered by Science News finds that at least 60% of the population experiences depression, an anxiety disorder or substance dependence by the age of 32 and discusses whether this questions the validity of diagnoses or whether like physical illness, mental illness is actually very common.

The BPS Research Digest has an analysis of Derren Brown’s recent lottery prediction stunt and lambasts him for misinforming people about psychology for the purpose of trickery.

The psychology of gay male sex preferences is discussed in an excellent article by Jesse Bering for Scientific American. At this point I normally compliment Bering for his magnificent column, but I shall refrain on this occasion.

In the same vein (oh stop it) Dr Petra look at a recent study that was widely reported as saying that larger penis size means more orgasms. Needless to say, the devil is in the detail.

Cerebrum, Dana’s excellent online neuroscience magazine, has an interesting piece on how arts training improves attention and cognition.

Some fantastic talks about the placebo effect from the Harvard Placebo Study Group are featured on The Situationist.

Cognitive Daily covers an intriguing study on change deafness.

Uncovered emails from GlaxoSmithKline suggests they were prepared to bury data if it suggested a link between antidepressant drug Paxil and birth defects. Bloomberg on the case.

Seed Magazine has an excellent short article about what visual illusions tell us about the psychology of perception. By one of the writers for Mind Hacks favourite Cognitive Daily.

There’s an article on ‘psychocutaneous disorders’, psychiatric problems affecting the skin, in Psychiatric Times. Some fairly unpleasant photos. Not safe for work, or lunch for that matter.

Not Exactly Rocket Science has a typically excellent piece on how rowing as a group increases pain thresholds. I suspect this effect might be why meetings are so protracted and tortuous.

A study on employee satisfaction finds that promises can be broken but career progression is golden, according to New Scientist.

Neuroanthropology finds an interesting lecture by Antonio Damasio on art and emotion.

The development of brain surgery through the nose is covered by ABC News

A history of the brain frame

Neurosurgical Focus has an excellent article on the development of stereotactic neurosurgery where an external frame is usually screwed into the skull and fixes the head in place to allow surgeons to precisely locate brain areas in a standard 3D space.

In modern stereotactic surgery, the system is usually used with an electronic tracking system that maps the surgeon’s instruments onto a previously acquired brain scan in real-time. The frame allows the brain scan and the actual brain to be precisely aligned.

This means the surgeon can, for example, place a depth electrode into a precise spot without having to physically see that area while still being confident that they’re in the right place.

The system is also used in research labs to ensure that, for instance, the brain is stimulated in precisely the right spot with magnetic pulses, using a technology called transcranial magnetic stimulation or TMS.

For example, if researchers wanted to see the effect of stimulating the auditory cortex they could run a listening experiment in an fMRI machine, see exactly where your auditory cortex is by mapping the activity on your brain scan, and then use a stereotactic system (e.g. this one) to guide the TMS machine to exactly this spot on your actual brain.

With all of its high-tech trappings, I never realised that the first human stereotactic system was created in 1918 with the system you can see in the picture.

The Neurosurgical Focus article looks at how the technology has developed from the original brass contraptions to the modern age of neurosurgery.

Link to Neurosurgical Focus on the history of stereotactic brain surgery.

Carl Jung’s mythical Red Book to be published

The New York Times has a huge article on the forthcoming publication of the Swiss psychiatrist Carl Jung’s ‘Red Book’, the notebook he kept during the six years of his ‘creative illness’ in which he was clearly psychotic but found inspiration for some of his most influential ideas.

Jung is one of the most interesting people in the history of psychology. He was both an experimentalist and an analyst in the Freudian tradition, before rejecting Freud (causing him to feint at one point!) and branching out into his own system of analytical psychology.

His works are often concerned with interests that even at the time were considered a little outlandish, such as the far reaches of world religions, UFOs and myths, but he explained almost all of them in terms of psychological phenomena.

He was the first to create a comprehensive classification of personality and his work still forms the basis of the Myers-Briggs personality inventory. He has been accused of being a Nazi, and, although untrue, it is clear that he was ambiguous about the Third Reich when a firm rejection was needed.

And most interesting, perhaps, was what he called his ‘confrontation with the unconscious’, shortly after his split from Freud, when he spent six years, largely isolated at home, having visions, hearing voices, fighting what he interpreted as his own internal forces.

Jung came out of this period with some of his most distinctive ideas all of which he noted in his ‘Red Book’ which has been kept behind closed doors by the Jung family for years.

The book has gained an almost mythical status and The New York Times article is as much about the long saga of getting into print, almost 90 years after it was written, as it is about Jung himself.

It also gives an interesting insight into the culture of Jungian analysts themselves, who have been a breed apart ever since their subversion of the Freudian mainstream after Jung went his own way.

A fascinating piece of psychological history.

Link to NYT on ‘The Holy Grail of the Unconscious’.

Mass hysteria, crazes and panics

The Fortean Times has an article and some fantastic excerpts from a new encyclopaedia on mass hysteria, social panics and fast moving fads called Outbreak: The Encyclopedia of Extraordinary Social Behaviour.

The book tackles some of the most curious and surprising outbreaks from medieval times to the present day, covering everything from medieval dancing plagues to modern day penis theft panics to the worldwide hula-hoop craze of 1958.

It’s by sociologists Hilary Evans and Robert Bartholomew both of whom are well known for their work on how unusual beliefs and experiences are shaped by culture. However, mass hysterias and the like and still one of the most mysterious aspects of human psychology.

There have been many attempts to account for the kinds of outlandish collect­ive behaviour that so fascinate forteans – the book provides entries on many of these related theories and explan­ations, from Altered States of Consciousness and Anxiety to False Memory Syndrome, Hysteria and Psychosomatic Phenomena. Many once-favoured ideas don’t really stand up to much scrutiny: consider the fad among 19th-century physicians for ‘curing’ masturbators with bizarre surgical ‘intervention’ and for terrifying their hapless patients with the prospect of bodily ruin and eternal damnation. It could be argued that none of the theories that have been put forward – even the more promising ones – actually applies in all cases.

Ultimately, it’s clear there is no consensus on just why human behaviour should include such anomalies, or how and why they occur. Just possibly, they may be pathological forms of the more healthy processes that cement our personal and social lives and which are only noticed when they go wrong. In many cases, the best that can be done is to understand the local social, political and cultural dynamics, but even so the causes of many such outbreaks remain obscure. This is important, because such erratic collective behaviour casts an awful shadow over human history, and we are no closer to understanding it now than Mackay was in 1841.

In fact, Bartholomew wrote one of my favourite books of all time. Called Little Green Men, Meowing Nuns and Head-Hunting Panics: A Study of Mass Psychogenic Illnesses and Social Delusion (ISBN 0786409975) it was the first book that made me wake up to the power of social influence on individual psychology.

In the interest of full disclosure, I must say that I was sent a PDF of the new encyclopaedia some months ago in the hopes that I would write some blurb for the back, which I was more than happy to do as it is a wonderfully complete collection of social curiosities.

The Fortean Times article has some great excerpts covering an outbreak of feinting in a marching band in 1973 Alabama (a classic case of mass hysteria), an outbreak of cat-like meowing in India in 2004, the 1958 hula-hoop craze, a goblin scare that affect Zimbabwe in 2002, a ‘culture bound syndrome’ with the unusual name of the jumping Frenchmen of Maine from the 18th and 19th centuries, various outbreaks of fears about chemtrails, a giant earthworm hoax that panicked a Texas town in 1993, and a version of Orson Well’s War of the Worlds that caused widespread rioting in Ecuador in 1949.

And if you want more on ‘mass hysteria’, I highly recommend a 2002 article from the British Journal of Psychiatry by Bartholomew and psychiatrist Simon Wessely.

Link to Fortean Times article ‘Outbreak!’
Link to more details on the book.
Link to BJP article on mass psychogenic illness.