Monthly Archives: September 2011

The more important posts in this blog

A Most Peculiar Experience (my description of The Strange Phenomenon)

Involuntary Method of Loci Memorization (IMLM) – what the heck is that?

The Opposite of Benson’s Syndrome?

Report on my fine motor task -> visual place memory synaesthesia

My Brain Put to the Test

Science Week 2011 – The world of science and me in the past year.

Reflections on The Strange Phenomenon, how I gunned the CFMT, letter personification in advertising and clue to a possible cure for some cases of prosopagnosia after reading an old journal paper.

A brief report on my synaesthesia experiences that involve concepts as triggers or evoked experiences

A type of synaesthesia which I experience in which non-food words or names automatically evoke the concepts of particular foods: is lexical-gustatory synaesthesia an evolutionary adaptation?

Have you seen this interesting study of personification synaesthesia and empathy?

I experience personified numbers and letters of the alphabet, involving genders, ages and personalities. Although this experience does not fit into the popular definition of synaesthesia as a mixing up of the senses, it is considered to be a type of synaesthesia and it often coincides with another type of synaesthesia, grapheme->colour synaesthesia, in which numbers and letters are experienced as having their own particular colours. The proper term for this personification of written symbols is Ordinal linguistic personification, and in a recent journal paper it was described as a “benign form of hyper-mentalizing” (Amin et al 2011).

In this blog I’ve argued a number of times that there is a causal relationship between synaesthesia and enhanced face recognition ability, and I believe that whatever parts of my brain give rise to my very good face recognition ability are also the parts of my brain that are responsible for my ordinal linguistic personification (OLP) and my grapheme->color synesthesia. I explained some of this in my post lengthily titled “Reflections on The Strange Phenomenon, how I gunned the CFMT, letter personification in advertising and clue to a possible cure for some cases of prosopagnosia after reading an old journal paper”.

Here’s some quotes from a journal paper about grapheme personification synesthesia which was published this year in the Journal of Neuropsychology:

“From this mixed pattern of results, we cannot conclude that as a group, personifying synaesthetes exhibit heightened empathy.”

“We suggest that grapheme personification, rather than a peculiar set of claims to be dismissed, is a goldmine for social cognitive neuroscientists and cognitive neuropsychologists alike.”

I certainly agree with that!

Maina Amin, Olufemi Olu-Lafe, Loes E. Claessen, Monika Sobczak-Edmans, Jamie Ward, Adrian L. Williams, and Noam Sagiv
Understanding grapheme personification: A social synaesthesia?
Journal of Neuropsychology. (2011), 5, 255–282.

Reflections on The Strange Phenomenon, how I gunned the CFMT, letter personification in advertising and clue to a possible cure for some cases of prosopagnosia after reading an old journal paper.

News Flash!

I just discovered that I have a close blood relative who experiences mirror-touch synaesthesia. It’s amazing the things that you can discover when you take the time to talk to people. This rellie also shares my grapheme->colour synaesthesia and we also both have colours for days of the week etc and some words, including geographical names. I’d say we have the same gene for sure. I don’t think my rellie is a personifier like me, as I tend to get an amused reaction when I describe the personalities of my letters of the alphabet.

I plan to write a lot more about this, including some of the popular scientific theories to do with empathy and mirror-touch synesthesia. You’ll find it here, if I ever find the time to put my thoughts into type.

Are the flashbacks that are an element of Post-Traumatic Stress Disorder a troublesome variety of synaesthesia and/or related to the Tetris effect?

I’m going to explain why I think this question is worth considering.

I have recently been reading a most interesting book that has been descibed as a “medical memoir”. I have read that the fiction writer Siri Hustvedt has mirror-touch synaesthesia, and I was rather interested in reading about that, but the main topic of Hustvedt’s book The Shaking Woman is her search for an explanation for her seizure-like shaking episodes that are triggered by public speaking.

One thing that I’ve noted is that both Siri and her late father have experienced PTSD-type flashbacks of traumatic memories (warfare, car accident). Like myself, Siri Hustvedt has also experienced the Tetris effect, which is like PTSD flashbacks in that it is an involuntary experience of a visual memory. I don’t experience the Tetris effect much these days, but when I do it is typically in response to a full day of weeding or some other outdoor repetitive work. I don’t think scientists know how common the Tetris effect is, and if it is a thing that everyone experiences then it wouldn’t mean a thing that the novelist and I both experience it. I have at least one other close blood relative who has also experienced the Tetris effect quite a few times. The Tetris effect operates through an unknown memory system, possibly related to procedural memory, according to the Wikipedia. I would think that the Tetris effect would have some type of visual memory system as its basis. It is interesting that Hustvedt’s mysterious shaking episodes were dampened-down but not completely cured by the drug propranolol, which (according to the book) is also used to treat high blood pressure, migraine, performance anxiety and PTSD. Hustvedt seems to have a lot of whatever mechanism is the basis of PTSD, which I guess might be a very strong or hyperconnected visual memory system in her brain. I would think this system is also probably responsible for the Tetris effect. Another reason to believe that the Tetris effect and PTSD operate in the same brain system is that a study described in the Wikipedia found that playing a Tetris-like video game soon after a traumatic event “….reduces the number of flashbacks that are experienced afterwards”. I guess a specific memory system becomes overloaded with memories if the game is used as preventative treatment, so less of the traumatic memories can be encoded properly for long-term storage.

Hustvedt and I have quite a few things in common. We are both synaesthetes, we have both experienced the Tetris effect, we have also both experienced and migraine headaches, and we have both apparently had brain-based experiences of involuntarily-retrieved visual memories. In her book Hustvedt did not spell out explicitly that her flashbacks included visual content, and she did mention the memory of sound, but I’m happy to assume that anything labelled as a “flashback” included visual content. My involuntarily-retrieved visual memories are two different types of synaesthesia which I’ve experienced which trigger visual memories of scenes or a face. Hustvedt’s shaking episodes are like synaesthesia in that they have a very specific trigger (public speaking) and a very specific manifestation (violent body tremors without apparent anxiety, or under the influence of propranolol, an “electric buzz” quiver throughout the body).

There seem to be a lot of things here that are inter-connected. My experiences of my fine-motor->visual memories of scenes synaesthesia and The Strange Phenomenon, which is I believe a hybrid of face recognition and synaesthesia in which seeing one face under very specific conditions triggers an involuntary experience of a very old memory of the face of another person, show that synaesthesia concurrents or triggered additional sensory experiences can be in some ways similar to PTSD flashbacks, but without any accompanying psychological distress. My fine-motor-triggered visual memories are very subtle and hardly noticeable, while the face memory evoked in The Strange Phenomenon is more of an intrusion into ordinary consciousness. I’d like to put forward the theory that the flashbacks of PTSD (and not any of the other distressing features of PTSD) are synaesthesia concurrents that just happen to be distressing visual or sensory memories. I guess they must have some type of trigger, and I guess could be something purely sensory, very subtle or ordinary. I have never experienced PTSD myself, probably because I have fortunately never been in the type of extremely traumatic situation that causes this psychological syndrome, so I can only guess at what PTSD flashbacks are really like from what I’ve read. Are PTSD flashbacks the result of a type of synaesthesia that can manifest as quite a subtle experience, but are only troublesome or exceptional because of the very unpleasant nature of the memories evoked? Are synaesthetes more likely to develop PTSD if exposed to trauma than non-synaesthetes exposed to equivalent situations? It’s just a theory!

Wikipedia contributors Tetris effect. Wikipedia, The Free Encyclopedia.

The Shaking Woman. The Book Show. Radio National. April 22 2010.

Fancy That! There is a name for it, and there is also a page for it at the Wikipedia! And I’m not the only person who experiences it!

Wikipedia contributors Tetris effect. Wikipedia, The Free Encyclopedia.

I would never have figured that the Tetris effect and earworms and sea legs are all the same type of phenomenon. I’ve experienced all three at one time or another. I wonder if everyone experiences these brain phenomena, or just a sub-set of the population?

If you experience the Tetris effect as the result of work activity, you should feel satisfied that you have earned your pay that day for sure.

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

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.


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

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.

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.

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.

Face blindness. Catalyst. ABC. broadcast 19/07/2007  (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 201-210

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

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

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.

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