Category: Autism

Children with autism demonstrate superior change detection skills

Developmental disorders are usually thought about in terms of their impairments. But a welcome trend in recent years is to document their advantages too. I’m not talking about dramatic savant skills like calendar calculating, but rather advantageous manifestations of basic cognitive differences. For example, investigators have shown that children with Tourette’s syndrome – a condition involving involuntary tics – have superior cognitive control and timing, compared with children without Tourette’s. Now Sue Fletcher-Watson and her team have added to this literature with a new study showing that children with autism spectrum disorders (ASD) are quicker than neurotypical children and adults at detecting subtle changes to a visual scene.

The task required that children with ASD and neurotypical children (aged 11 to 16; most were male), and non-ASD adults, look at pictures of non-social scenes (e.g. a furnished room) on a computer. Each scene appeared for just under half a second, the screen would go blank, then the scene would reappear with one subtle change. The changes could be located centrally in the scene or in the periphery, and they could be a change in colour of an object, a change in an object’s presence or absence, or location. The participants’ task was to spot the change as quickly as possible and say what it was.

The headline result is that the 11 children with ASD were often significantly faster at detecting scene changes than the 29 neurotypical kids and the 20 adults. Specifically, they were faster than the neurotypical children at spotting central location changes and peripheral colour and location changes. They beat the adults at colour changes in the periphery. The difference in speed was often dramatic – for example, for a colour change in the periphery, the average response time of the ASD group was just over 5 seconds. For the typically developing children, it was just over 8 seconds, and for the non-ASD adults it was just over 7 seconds.

The researchers said theirs was the first study to show “somewhat enhanced” performance in change detection among children with ASD, “providing further welcome evidence of strengths in this population”. The cautious tone is due to a major caveat in the results. As well as being quicker at change detection, the ASD children were also less accurate – being more likely to describe a change that hadn’t actually happened. This points to a simple speed-accuracy trade-off as explaining the group differences in performance. But the researchers don’t think this is the case. Supporting their claim, they demonstrated that the ASD kids were faster whether all responses were analysed or only accurate responses were analysed. However, they conceded that more research was needed to clarify this issue.

Intriguingly, studies with adults with ASD have actually found that they are relatively impaired at detecting changes in complex scenes, compared with neurotypical participants. Fletcher-Watson and her colleagues wonder if this is because they’ve learned through education and therapeutic interventions to focus more on social information in scenes at the expense of their instinct for focusing on local details. “Since the attentional system can only give enhanced processing to about five items in a scene at once, a focus on social information would have the effect of removing attention from other, non-social features,” the researchers said.
_________________________________ Fletcher-Watson, S., Leekam, S., Connolly, B., Collis, J., Findlay, J., McConachie, H., and Rodgers, J. (2011). Attenuation of change blindness in children with autism spectrum disorders. British Journal of Developmental Psychology DOI: 10.1111/j.2044-835X.2011.02054.x

Post written by Christian Jarrett for the BPS Research Digest.

The psychological barriers facing MMR promotion campaigns

A focus group study of parents’ attitudes towards interventions promoting uptake of the MMR vaccine suggests it is better for health advice to be seen as independent from government.

The findings come after the General Medical Council ruled yesterday that Andrew Wakefield, the doctor who first suggested a link between the MMR vaccine and autism, was guilty of serious professional misconduct.

The MMR vaccine protects children against measles, mumps and rubella. Unfortunately the number of UK parents vaccinating their children plummeted in the wake of Wakefield’s 1998 Lancet study, since discredited and un-replicated, which purported to show a link between the MMR vaccine and autism. Today vaccination rates remain at around 85 per cent, compared with the desired rate of 90 to 95 per cent required for herd immunity (whereby even the unvaccinated are safe).

For the new study, Benjamin Gardner and colleagues analysed five focus group interviews they held with 28 parents in London. The parents were asked for their responses to three ‘motivation-based’ interventions (a website; an information pack; and parent-led group discussions) and three ‘organisational interventions’ (health care workers acting as immunisation champions; mobile vaccination units; legislation to penalise non-compliers).

Five key themes emerged. Parents felt they didn’t have enough information, especially in relation to the dangers associated with not vaccinating. Government sources were not trusted. By contrast, other parents were trusted: ‘Parents trust advice from other parents,’ one mother said. ‘[You] take it on board. You listen to them.’ Parents also revealed they were biased towards risk-related information. And they misunderstood balance, believing that pro- and anti-MMR arguments should be given equal weight even though the scientific evidence overwhelming favours MMR vaccination.

Gardner’s team said a number of practical implications emerged from their findings. In particular, promotional MMR campaigns are likely to be better received if they appear to be independent of government and if they are fronted by parents. More information is needed about the risks of non-vaccination. And care should be taken when highlighting the small risks associated with vaccination – parents are likely to zoom in on these.

The researchers acknowledged their study has some limitations, most notably that the majority of the parents involved had actually vaccinated their children. Nonetheless, they said their results ‘highlight important psychological barriers and facilitators that may determine whether MMR promotion interventions are effective.’

ResearchBlogging.orgGardner B, Davies A, McAteer J, & Michie S (2010). Beliefs underlying UK parents’ views towards MMR promotion interventions: a qualitative study. Psychology, health & medicine, 15 (2), 220-30 PMID: 20391239

Post written by Christian Jarrett (@psych_writer) for the BPS Research Digest.

Also on the Digest: How to promote the MMR vaccine.

Calendar calculating savants with autism – how do they do it?

Savants with autism are people who exhibit an exceptional ability whilst also having social and cognitive impairments. One such ability is calendar calculating – being able to say, with astounding accuracy and alacrity, what day of the week a given date falls on. Just how some savants with autism are able to achieve this feat has baffled researchers. It’s been suggested that they use complex algorithms, but this seems implausible given that the same individuals often struggle with maths.

To help solve the mystery, Anna Dubischar-Krivec and colleagues recruited three savant calendar calculators with autism and pitted their calendrical skills against three neuro-typical calendar calculators recruited through a Swiss science TV show.

The participants were tested with questions that took the following form: “Is it true that 6 November 1974 = Thurs?”. The savants with autism beat the neuro-typical calendar experts, in terms of speed and accuracy, for past dates (these went back fifty years) and dates from the current month. By contrast, the performance of the two groups was matched for future dates, which were taken from up to fifty years ahead.

As usual, the savants were unable to say how they achieved their calendar skills. However, the researchers said the pattern of results implies that the savants were using different strategies from the neuro-typicals. Whereas the neuro-typicals relied on algorithms for past, present and future dates, the savants probably relied on rote memory for past and present dates, the researchers said, hence their superior speed and accuracy for these, whilst they probably fell back on some kind of algorithmic system for future dates.

These conclusions were supported by the fact that the savants’ answers seemed too quick, at least as regards dates in the current month (their average response time was less than three seconds), for them to have performed algorithmic calculations. Also they appeared to have made use of memory “anchor dates” based around the month of December, as betrayed by their reaction times tending to be quicker for months later and earlier in the year.

However, the mystery remains far from solved. For example, if the savants were relying on memory for their astonishing calendrical feats, you’d think a memory test would reveal their unusual memory ability. Yet a standard psychometric comparison of memory performance between the savant and neuro-typical calendar calculators found no differences, except the neuro-typicals were better on a form of working memory.

ResearchBlogging.orgDubischar-Krivec, A., Neumann, N., Poustka, F., Braun, C., Birbaumer, N., & Bölte, S. (2008). Calendar calculating in savants with autism and healthy calendar calculators. Psychological Medicine, 39 (08) DOI: 10.1017/S0033291708004601

Post written by Christian Jarrett (@psych_writer) for the BPS Research Digest.

Head size and attention-to-detail are linked in children with autism

Like many people with autism, the celebrated artist Stephen Wiltshire has an incredible ability to focus on small details, as evidenced by his beautifully intricate art-work (see image). However, in the lab, psychologists have struggled to pin down this feature of autism.

Some studies have revealed a global-processing deficit, some haven’t. Others have shown a local-processing bias, some haven’t. The very latest findings suggest that some, but not all, children with autism specifically show an exaggerated difficulty switching from the local detailed level to a more big-picture global level: an anomaly that can actually lead to advantages when attention is left focused on tiny details. Now a new study has linked this attentional style with head size. It’s an exciting finding that could help explain why not all children with autism show the attentional anomaly, and which could also help link the cognitive anomaly with a neurological mechanism.

Sarah White and colleagues tested 49 high-functioning children with autism and 29 neurotypical controls on a task that required them to flick their attention back and forth from a local to a more global level. Specifically they had to either identify large letters made up of smaller blocks, or they had to identify lots of smaller letters that were the size of those blocks.

Consistent with recent findings, a portion of the children with autism showed a very specific deficit – that is, their performance was poorer than the other children when switching from processing at the local to the global level. Crucially, it was the autistic children with abnormally big heads who were the ones to show this anomaly.

A possible neural mechanism underlying this local-global switching deficit seen in some autistic children is abnormal brain wiring, perhaps originating during the pruning phase of neural development when many neurons and synapses are destroyed in a carefully controlled biological process. The new findings suggest that an enlarged head could be a marker for the existence of this abnormal wiring.

A follow-up study tested 12 neurotypical children with big heads and found that, unlike autistic children with big heads, they did not show a deficit in switching from local to global processing. However, these neurotypical children were physically larger in height as well as head size, unlike the big-headed autistic children who were the same height as their smaller-headed peers. This reinforces the idea that it is only when head size is a marker for abnormal brain wiring – as seen in some children with autism – that it is linked with a cost switching to global processing.

“The tentative hypothesis can therefore be proposed,” the researchers said, “that head size may be a biological marker of abnormal neural connectivity, resulting in a locally oriented processing style, and may provide a useful endophenotype for investigating the genetic basis of a subgroup of individuals with autistic spectrum disorder.”

ResearchBlogging.orgWhite, S., O’Reilly, H., & Frith, U. (2009). Big heads, small details and autism Neuropsychologia, 47 (5), 1274-1281 DOI: 10.1016/j.neuropsychologia.2009.01.012

Post written by Christian Jarrett (@psych_writer) for the BPS Research Digest.

Fetal exposure to testosterone linked with presence of autistic traits in childhood

The idea that autism may be the manifestation of an “extreme male brain” has received support from a study showing that higher levels of fetal exposure to testosterone are associated with the later presence of autistic traits in childhood.

Bonnie Auyeung and colleagues found that among 235 mothers, those who had higher levels of testosterone in their amniotic fluid during pregnancy, subsequently rated their children, when aged between six and ten years, as showing more autistic traits, such as avoiding eye contact. This was true whether the children were studied as a group, or if the analysis was done on just girls or just boys.

It’s not yet known for sure whether fetal exposure to testosterone causes the presence of these autistic traits or whether a third unknown factor affects both testosterone levels and the presence of the traits. It is also worth remembering that the children in this study were not actually diagnosed with autism. Fetal exposure to testosterone has only been linked by this study with the presence of autistic-like traits. However, the researchers are planning to test the significance of fetal testosterone exposure among children with an actual diagnosis of autism.

“If, according to the extreme male brain theory, autistic spectrum conditions are an extreme of male-typical behaviour, exposure to elevated levels of fetal testosterone could be one important factor that is involved with the development of the condition,” the researchers said.

The findings from this study led to discussion in the media about the prospects of a fetal test for autism. For example, co-author Simon Baron-Cohen wrote this piece for BBC News online.

Bonnie Auyeung, Simon Baron-Cohen, Emma Ashwin, Rebecca Knickmeyer, Kevin Taylor, Gerald Hackett (2009). Fetal testosterone and autistic traits. British Journal of Psychology, 100 (1), 1-22 DOI: 10.1348/000712608X311731

Post written by Christian Jarrett (@psych_writer) for the BPS Research Digest.

How to promote the MMR vaccine

Rather than stressing its benefits, health promotion campaigns for the MMR vaccine should emphasise the protection that is lost by failing to have a child inoculated.

That’s according to Purva Abhyankar and colleagues who said finding the most effective way to promote the triple jab is of vital importance because uptake has dropped in the UK in the wake of health fears that the vaccine is associated with side-effects such as autism.

One hundred and forty-two women, some were mothers, some not, with an average age of 35 years, were asked to imagine that they had to decide whether or not to have their child vaccinated with MMR. They were then presented with one of two possible messages about the MMR vaccine (alternative wording is in brackets):

“By vaccinating (not vaccinating) your child against mumps, measles and rubella, you will be able to (fail to) protect your child against contracting these diseases and take (will fail to take) advantage of a safe and lifelong immunization, which will make you feel less anxious (anxious) and safe (unsafe).”

Afterwards, the women presented with the message version that emphasised the protection and reassurance that would be lost if the vaccine were not given, were significantly more likely to say that they intended to give their child the vaccine, than were the women who read the alternative version. This difference was particularly pronounced among the women who had vaccinated their children previously in real life.

The researchers said their finding can be understood in terms of Prospect Theory – our willingness to take risks in the context of possible losses, in contrast to our aversion to taking risks in the context of possible gains. In other words, because people tend to see the MMR vaccine as risky, Prospect Theory suggests it is better to promote the vaccine in terms of what will be lost if that risk isn’t taken, rather than in terms of what might be gained – a prediction that is supported by the current results.

The researchers concluded their finding shows: “that interventions aimed at promoting high perceived risk prevention behaviours are likely to be more effective if designed in terms of messages emphasising the disadvantages of failing to perform the behaviour.”

Abhyankar, P., O’Connor, D.B. & Lawton, R. (2008). The role of message framing in promoting MMR vaccination: Evidence of a loss-frame advantage. Psychology, Health and Medicine, 13, 1-16.

Post written by Christian Jarrett (@psych_writer) for the BPS Research Digest.

Children with autism are immune to contagious yawning

Have you ever noticed that yawning is so contagious it can spread round a room like a Mexican wave? Scientists still aren’t in agreement as to why this happens but one idea is that the phenomenon depends on our capacity for empathy. This finds support in a new study showing for the first time that children with Autistic Spectrum Disorder, in whom empathy is believed to be impaired, are immune to the contagious effects of yawning.

Twenty-four children diagnosed with autism spectrum disorder – mostly boys aged between 7 and 15 years – and twenty-five age-matched non-autistic children, watched a series of 7-second videos showing people yawning. Control videos showed people opening their mouths but not yawning. Between each video, one-minute long silent cartoons kept the children’s attention.

Footage of the children taken while they were watching the videos showed, as expected, that the non-autistic children yawned more during and after seeing a video of a person yawning, than after watching a control video. By contrast, the children with autism yawned no more after seeing a yawn video than after a control video – they appeared to be immune to the contagious effects of yawning. This remained true even after the researchers controlled for the effects of age and intelligence.

Past research has found that seeing the eye region of someone yawn is key to the yawn’s contagious effects. So perhaps the fact that people with autism are known to focus more on the mouth region of people’s faces, rather than the eyes, could partly explain the current findings.

Atsushi Senju and colleagues said their results “support the claim that contagious yawning and the capacity of empathy share common neural and cognitive mechanisms.” They added it would be interesting for future research to look at whether contagious yawning is impaired in other conditions in which empathy is compromised, such as psychopathy or frontal-temporal dementia.

Senju, A., Maeda, M., Kikuchi, Y., Hasegawa, T., Tojo, Y. & Osanai, H. (In Press). Absence of contagious yawning in children with autistic spectrum disorder. Biological Letters.

Post written by Christian Jarrett (@psych_writer) for the BPS Research Digest.

Link to full-text pdf.

The way children with autism draw people

Drawings of humans by children with autism tend to lack variety, researchers have found, possibly reflecting the unusual way they think about and relate to other people.

Anthony Lee and Peter Hobson compared drawings by 14 autistic children (aged 8 to 15) with drawings by 14 non-autistic children who were learning disabled. When the children were asked to draw two houses followed by their own house, they all tended to draw three houses each looking different to the next. However, when the children were asked to draw a female person, a male person and to also draw themselves, crucial differences between the groups emerged – the non-autistic children tended to draw three distinct figures, but the autistic children tended to draw three human figures that varied little from one to the other. The autistic children’s drawings of people were just as detailed but they lacked variation.

“…[T]here is evidence that [autistic] children’s sense of individual kinds and characters of people, and their concepts of themselves, are less infused with personal qualities than are those of people without autism – and undifferentiated human figures would be one result”, the researchers said.

Lee, A. & Hobson, R.P. (2006). Drawing self and others: How do children with autism differ from those with learning difficulties? British Journal of Developmental Psychology, 24, 547-565.

Post written by Christian Jarrett (@psych_writer) for the BPS Research Digest.

Rare counting ability induced by temporarily switching off brain region

A minority of people with autism have one or more extraordinary intellectual talents, such as the rapid ability to calculate the day of the week for a given date, or to count large numbers of discrete objects almost instantaneously – they’re often called ‘autistic savants’ or ‘idiot savants’. Now Allan Snyder and colleagues have shown that by placing a pulsing magnet over a specific area of the brain, these kind of abilities can, to some extent, be induced in people who aren’t autistic.

Twelve healthy participants were given several chances to estimate, from 50 to 150, how many blobs appeared on a computer screen. The blobs appeared for just 1.5 seconds, and the number of blobs changed on each attempt. Remarkably, the performance of ten of the subjects improved drastically after Snyder’s team applied 15 minutes of low frequency transcranial magnetic stimulation (TMS) to their left anterior temporal lobe, a brain region that’s been implicated in autistic people with rare counting and calcluating abilities.

For example, before the TMS, one participant had 20 goes at estimating the number of blobs onscreen, and each time she was more than 5 away from the true figure. Yet immediately after receiving the TMS, she made 6 out of 20 guesses that were within 5 blobs of the true figure. Before TMS, another participant scored 3 estimates out of 20 that were within 5 of the true figure, compared with 10 out of 20 immediately after the TMS.

The enhanced ability was gone within an hour, and moreover, no such improvements followed application of a sham version of the TMS that made all the same noises, but was applied only weakly over a different brain region. In fact, the participants’ performance deteriorated slightly in this condition.

The researchers think that by temporarily inhibiting activity in the left anterior temporal cortex, the TMS allowed the brain’s number estimator to act on raw sensory data, without it having already been automatically grouped together into patterns or shapes. In other words, they believe it caused the ‘normal’ brain to function more like an autistic ‘savant’ brain. “We argue that it removes our unconscious tendency to group discrete elements into meaningful patterns, like grouping stars into constellations, which would normally interfere with accurate estimation”, the researchers said. “By inhibiting networks involved in concepts, we may facilitate conscious access to literal details, leading to savant-like skills”.

Snyder, A., Bahramali, H., Hawker, T. & Mitchell, D.J. (2006). Savant-like numerosity skills revealed in normal people by magnetic pulses. Perception, 35, 837-845.

Post written by Christian Jarrett (@psych_writer) for the BPS Research Digest.

Update: Not all people who show the rare counting and calculating abilities discussed in this report are autistic. However, according to the source paper, most are.