Tag Archives: Asperger’s syndrome

New study with scientifically sound test finds people with Asperger syndrome vary greatly in face recognition ability – can face recognition be a savant ability?

Face recognition performance of individuals with Asperger syndrome on the Cambridge face memory test.
Darren Hedley, Neil Brewer, Robyn Young
Autism Research.
Article first published online: 24 AUG 2011
DOI: 10.1002/aur.214    http://onlinelibrary.wiley.com/doi/10.1002/aur.214/abstract

This article is still in press, but was published online last month. This study had 34 subjects with Asperger syndrome and 42 nonautistic controls. It appears that while around a quarter of the study subjects with Asperger syndrome in this study have prosopagnosia (as defined by a test score from 2 to 3 SD’s below normal or mean), Asperger syndrome (a type of autism) is also not inconsistent with superior performance on the Cambridge Face Memory Test (CFMT), which is the best test of face recognition that I know of. Some features of the study that perhaps distinguish it from other studies of face recognition in autism are the use of a reliable and valid test of face recognition (Duchaine & Nakayama 2006), the study of face recognition in adults, not children, which is really important because face learning ability appears to be a skill that peaks at a surprisingly late stage in the life-span, into the third decade (Germine, Duchaine & Nakayama 2011), and if autistic people have a delay in development that could potentially affect or bias the results of studies of children and youths.

I was particularly interested in looking at the data for individual study subjects, but for some reason, in journal papers this seems to always be included in a miniature table that is either unreadable or unprintable, or both, or is absent altogether. Persevering, I was interested to find that none of the non-autistic study participants got a score in the prosopagnosia range, while eight out of 34 of the Asperger participants did, so there seems to be a definite association between having prosopagnosia and having a diagnosis of Asperger syndrome (AS). But at the other end of the spectrum of ability, the top score of the whole study, which I think must have been close to the super-recognizer range at 1.75, was achieved by a participant with AS, and there were two other with AS who got great scores. It appears that a fair proportion of those with AS got close to average scores. To the naked eye, it appears that there is a greater variation in face recognition ability in those with AS than in the normal adults tested. Why? Should we just accept this as a brute fact about AS, or should we look for special explanations for the top or bottom achievers in the AS group?

Is there something special about the top performers in the AS group? Given that there appears to be a link between autism and synaesthesia, and synaesthesia appears to be sometimes associated with savant-like superior ability in specific sensory or cognitive tasks (Banissy et al 2011) (Banissy, Walsh & Ward 2009) (Baron-Cohen et al 2007) (Simner, Mayo & Spiller 2009), and the association between savantism and autism is generally accepted, should we then ask if the three top-performing participants with AS might be synaesthetes who also have AS? If these connections are found in reality, should we then include superior face recognition (“super-recognizers”) among the many varied areas of mental performance that are regarded as savant skills and abilities? I have already discovered in a 2010 study of face recognition in the broader autism phenotype (BAP) one CFMT score from a father of an autistic child that appears to be close to a super-recognizer level of performance (Wilson et al 2010), as defined as two or more SD’s above the mean. I would have thought that this isn’t what researchers would expect to find in studies of autism or the BAP which use study participants who aren’t selected for any particular level of face recognition ability.

I’ve got to wonder whether people (children?) whose main social disability is prosopagnosia have been clumsily lumped into the category of autism. It appears that over three-quarters of the autistic subjects did not have a “severe face recognition impairment”, so we certainly can’t say that a severe impairment is typical of the group of people who have Asperger syndrome (AS) in this study, and my reading of the “enhanced perceptual functioning model” of autism seems to suggest that autistic people should have an advantage at visual tasks (Samson et al 2011). We know that prosopagnosia is a fairly common but not well recognized disability, and that the diagnosis rates for things like AS and autism have been climbing steadily for a long time. The question of why this has happened is one that has provoked huge controversy – is there a genuine increase in autism rates, or are more and more people being placed into the category, due to lower thresholds of “severity” required for a diagnosis, or the category of autism indiscriminately devouring other categories of people, such as the intellectually disabled and other uncommon or rare disabilities?

The possibility that prosopagnosics can be (incorrectly?) identified as cases of autism was demonstrated in a story about prosopagnosia from the Australian science television series Catalyst which was broadcast in 2007 (see link below). An anecdote about two children in a family which was later found to have members with developmental prosopagnosia, who had previously been diagnosed with autism, was recounted by a prosopagnosia researcher from Macquarie University and dramatized on the show. I should point out that neither of the face perception tests shown in this story are the CFMT. One face recognition test shown in the Catalyst story uses the faces of famous people and it relies upon the person being tested already knowing about the famous person and being able to give a name for the famous face, two tasks which are not face recognition, so as a test of face recognition it is far from pure and perfect.

References

Banissy, Michael J., Garrido, Lucia, Kusnir, Flor, Duchaine, Bradley, Walsh, Vincent and Ward, Jamie Superior Facial Expression, But Not Identity Recognition, in Mirror-Touch Synesthesia. Journal of Neuroscience. February 2, 2011, 31(5):1820-1824. doi:10.1523/JNEUROSCI.5759-09.2011  http://www.faceblind.org/social_perception/papers/Banissy11JN.pdf       http://www.jneurosci.org/cgi/content/abstract/31/5/1820

Banissy, Michael J., Walsh, Vincent & Ward, Jamie Enhanced sensory perception in synaesthesia. Experimental Brain Research. 2009 Jul;196(4):565-71. Epub 2009 Jun 17. http://www.springerlink.com/content/406581u3507un270/   http://www.ncbi.nlm.nih.gov/pubmed/19533108

Baron-Cohen S, Bor D, Billington J, Asher JE, Wheelwright S and Ashwin C. Savant memory in a man with colour form-number synaesthesia and Asperger syndrome. Journal of Consciousness Studies. volume 14, number 9-10, September-October 2007, p. 237-251.  http://www.imprint.co.uk/jcs_14_9-10.html

Duchaine, Brad & Nakayama, Ken The Cambridge Face Memory Test: Results for neurologically intact individuals and an investigation of its validity using inverted face stimuli and prosopagnosic participants. Neuropsychologia 44 (2006) 576–585.
http://visionlab.harvard.edu/members/ken/Ken%20papers%20for%20web%20page/137neuropsychologiaDuchaine2006.pdf

Face blindness. Catalyst. ABC. broadcast 19/07/2007  http://www.abc.net.au/catalyst/stories/s1982889.htm  (This story showed face recognition testing at Macquarie University and includes a small sample of the tests which viewers can try)

Germine, Laura T., Duchaine, Bradley, Nakayama, Ken Where cognitive development and aging meet: Face learning ability peaks after age 30. Cognition, Volume 118, Issue 2, February 2011, Pages 201-210http://www.sciencedirect.com/science/article/pii/S0010027710002611

Hedley, Darren, Brewer, Neil, Young, Robyn Face recognition performance of individuals with Asperger syndrome on the Cambridge face memory test. Autism Research. Article first published online: 24 AUG 2011         DOI: 10.1002/aur.214    http://onlinelibrary.wiley.com/doi/10.1002/aur.214/abstract

Samson, Fabienne, Mottron, Laurent, Soulieres, Isabelle & Zeffiro, Thomas A. Enhanced visual functioning in autism: an ALE meta-analysis. Human Brain Mapping. Article first published online: 4 APR 2011 DOI: 10.1002/hbm.21307 http://onlinelibrary.wiley.com/doi/10.1002/hbm.21307/abstract

Simner, Julia, Mayo, Neil, Spiller, Mary-Jane A foundation for savantism? Visuo-spatial synaesthetes present with cognitive benefits. Cortex. Volume 45, issue 10, November-December 2009, Pages 1246-1260.
http://www.cortexjournal.net/article/S0010-9452(09)00221-4/abstract

Wilson CE, Freeman P, Brock J, Burton AM, Palermo R Facial Identity Recognition in the Broader Autism Phenotype. PLoS ONE 2010 5(9): e12876. doi:10.1371/journal.pone.0012876
http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0012876

Anything interesting in upcoming academic book about face processing?

I’ve had a quick look at an upcoming large academic book about face perception that is currently listed and searchable at the Amazon.com website. The title is Oxford Handbook of Face Perception and it is due for publication this October. For a book of this size and price it looks like there will be surprisingly little in it of interest to me, despite my interest in face recognition and other neuroscience subjects.

It looks like there will be little or no discussion of the subject of synaesthesia in the book, which would be something of an oversight considering that there appears to be a fair amount of evidence supporting the idea that under-connectivity in the brain could be cause of serious deficits in face recognition (prosopagnosia) in at least some cases of prosopagnosia, and under-connectivity could be seen as the opposite of synaesthesia, a harmless neurological condition of which some varieties are associated with increased connectivity in the brain’s white matter. The upcoming book does appear to have some discussion of under-connectivity and prosopagnosia, but it appears nothing much about conditions that can be found the opposite end of the spectrum of face processing ability, things such as super-recognizers and synaesthesia. There is a whole section of the book devoted to disorders including prosopagnosia, while I can find no indication from the contents or searching the text of the book that there will be any coverage of superiority in face recognition. It also appears that there is no coverage of superiority in facial emotion perception. I was recently fascinated to learn that a number of studies have found that superior identification of emotional expressions is associated with some disorders, including borderline personality disorder. As far as I can tell there’s nothing about this in this book. This lack of coverage of superior face perception doesn’t surprise me. I believe that, unless confronted with contrary evidence, most people, including academics and teachers, assume that the clever end of the bell curve is just the result of normal brains that are just lucky enough to have missed out on the types of problems that might impair cognitive performance. If this were true, there wouldn’t be anything terribly interesting to find in studying people who have very high IQs or people who have specific areas of high intellectual ability such as superior interpersonal skills, musical gifts, ease in language learning, impressive calculation abilities or an unusual facility in recognizing faces. If these talents and abilities were just the result of lots of practice and/or a super-normal brain, then these abilities would hardly be worth studying. Of course, we all know that there are some most unusual people who have special gifts, the male autistic or disabled savants that we read about in books by Oliver Sacks, but such people are thought to be rare as hen’s teeth, and kept hidden away.

Everyone knows what a savant is, but no one expects to ever meet one. I think this could be one reason why the teachers from the gifted and talented program that is run through our local government school district thought it was necessary to conduct a talk a few years ago for the parents of gifted students, to explain how these students are often quite different from bright but not gifted students. The teachers introduced us to the concept of asychronous development in gifted children. Gifted children often develop on a schedule that is unique to them and may develop in different domains on very different timetables. We were told that gifted kids can have intellectual, social and emotional development that are at very different stages, and such kids can have uneven levels of achievement across the range of school subjects. There is an obvious similarity between the concepts of asynchronous development in the gifted and the concept of the savant, which is generally thought of as a disabled or autistic person who has one area of cognitive brilliance that contrasts with overall poor performance (the reality of savantism isn’t really this simple). A clear point of distinction between the savant and the gifted child with uneven development is a hard thing to find. Another thing that the parents of the gifted were told that night is that the group of kids who passed the testing to get into the gifted program included some children who were already diagnosed with something from a range of psychiatric diagnoses such as ADHD, Asperger’s Disorder or Autistic Disorder. The gifted aren’t just super-normals. The gifted are unique. The gifted are often different, not just in level of achievement, but in type. Are there more or less synaesthetes among the gifted than we would expect to find, given what we know about the commonality of this interesting neurological condition? I don’t think this has been researched yet. The gifted are different. This is why I believe that there could be a lot of interesting things to find if scientists would study the gifted with as much enthusiasm as they target the deficient. This is why I think it is a pity that in this day and age we have textbooks about reading that have a chapter about dyslexia but nothing about advanced or precocious readers, and door-stopper texts about face perception that appear to ignore super-recognizers and expert emotion-readers. Maybe next decade.

References

Andy Calder, Gillian Rhodes, Mark Johnson, Jim Haxby Oxford Handbook of Face Perception (Oxford Handbook Series) Oxford University Press, USA; 1 edition (October 1, 2011) http://www.amazon.com/Oxford-Handbook-Face-Perception/dp/0199559058/ref=sr_1_43?s=books&ie=UTF8&qid=1310687539&sr=1-43

Tolan, Stephanie Giftedness As Asynchronous Development.  http://www.stephanietolan.com/gt_as_asynch.htm

Domes G, Czieschnek D, Weidler F, Berger C, Fast K, Herpertz SC. Recognition of facial affect in Borderline Personality Disorder. Journal of Personality Disorders. 2008 Apr;22(2):135-47. http://www.ncbi.nlm.nih.gov/pubmed/18419234

Fertuck EA, Jekal A, Song I, Wyman B, Morris MC, Wilson ST, Brodsky BS, Stanley B Enhanced ‘Reading the Mind in the Eyes’ in borderline personality disorder compared to healthy controls. Psychological Medicine. 2009 Dec;39(12):1979-88. Epub 2009 May 22. http://www.ncbi.nlm.nih.gov/pubmed/19460187

Wagner AW, Linehan MM. Facial expression recognition ability among women with borderline personality disorder: implications for emotion regulation? Journal of Personality Disorders. 1999 Winter;13(4):329-44.  http://www.ncbi.nlm.nih.gov/pubmed/10633314

Prevalence rates of some interesting neurological conditions and disorders

Number form synaesthesia   ~12% (Ward, Sagiv & Butterworth 2009)

Dyslexia   5-10% English-speakers (Mitchell Feb 2011)

Dyscalculia   5-6% (Mitchell Feb 2011)

Congenital amusia (tone deafness)   4% (Mitchell Jan 2011) (Mitchell Feb 2011)

Day of the week -> colour synaesthesia   2.8% (Banissy et al 2009)

Prosopagnosia   1-2% (Mitchell Feb 2011)

Congenital prosopagnosia 2.5% (Mitchell Jan 2100) (This figure is inconsistent with the above figure as people with congenital prosopagnosia should be a sub-set of all people who have prosopagnosia)

Mirror-touch synaesthesia   1.6% (Banissy et al 2009)

Grapheme -> colour synaesthesia   1.4% (Banissy et al 2009)

ASD including autism   ~0.6% (Wikipedia)

So this means that, if the disorders besides autism listed above do not overlap in the people they affect, possibly almost a quarter of the population either can’t read, can’t do maths, can’t comprehend music normally, or can’t recognize faces adequately, while diagnosable autism is thought to only be found in less than a percent of people. So why so much hysteria and research funding about autism and so little funding for research into all the other issues?

The total number of synaesthetes in the population cannot be calculated by simply adding up the different types of synaesthesia listed above, because we know that individual synaesthetes often have a number of different types. Regardless, it is clear that synaesthetes make up a sizeable proportion of the population, and synaesthesia isn’t rare at all. So why is it that most teachers that I have spoken to have never heard of synaesthesia, a neurological condition (not disorder) that can directly affect learning (positively and on occassion negatively) and can affect the student’s sensory experience in the classroom?

References

Banissy, Michael J, Kadosh, Roi Cohen, Maus, Gerrit W, Walsh, Vincent, Ward, Jamie Prevalence, characteristics and a neurocognitive model of mirror-touch synaesthesia. Experimental Brain Research. (2009) 198:261–272. Published online: 3 May 2009. DOI 10.1007/s00221-009-1810-9 http://www.springerlink.com/content/26mh37152110617x/fulltext.pdf

Mitchell, Kevin The Neuroscience of Tone Deafness: The strange connection between people who can’t sing a tune and people who are “face blind”. Scientific American. January 18th 2011. http://www.scientificamerican.com/article.cfm?id=the-neuroscience-of-tone

Mitchell, K. J. Curiouser and curiouser: genetic disorders of cortical specialization.Current Opinion in Genetics & Development. 2011 Feb 4. [Epub ahead of print] http://www.ncbi.nlm.nih.gov/pubmed/21296568

Ward, Jamie, Sagiv, Noam and Butterworth, Brian The impact of visuo-spatial number forms on simple arithmetic. Cortex. Volume 45 Issue 10 Pages 1261-1265 (November 2009). http://www.cortexjournal.net/article/S0010-9452(09)00213-5/abstract