Tag Archives: Books for a Popular Readership

The two most exciting science magazine articles of 2013 (far as I’m concerned)

The most exciting blogging moment of 2013 for me was probably when I discovered that my idea about linking synaesthesia with the immune system, and idea which I published in the winter of 2012 at the blog, had been recycled without my permission in a paper that was published in October 2013 in a journal that is apparently peer reviewed and all that fancy stuff. Of course, the big excitement of 2012 was thinking of this idea along with a suite of more important and related ideas, and the excitement continued this year as I read more about the work of researchers such as Carla Shatz, Ben Barres, Beth Stevens and Marie-Eve Tremblay who are busy pushing back the boundaries of human knowledge about the complex relationship between elements of the immune system and elements of the brain. It’s a wide open and potentially very important new area of scientific discovery, and below are the details of some  items that you can read if you wish to find out what the excitement is about. Have an exciting new year.

Miller, Kenneth Brain benders. Discover. October 2013. p. 30-37.  http://discovermagazine.com/2013/oct/12-brain-benders#.UsL_B_QW18E  (disregard the guff in this article about autism and schizophrenia)

Costandi, Moheb The mind minders. New Scientist. Issue 2938 October 12th 2013. p. 45-47.  http://www.newscientist.com/article/mg22029381.000-the-mind-minders-meet-our-brains-maintenance-workers.html

One thing in the world of popular science writing that hasn’t been so inspiring and exciting in 2013 is the famous Dr Karl Kruszelnicki’s latest pop science book on the 2013 Christmas gift book market, titled Game of Knowns. The book has a chapter in it about the blood-brain barrier. The concept of a blood-brain barrier is an established and accepted idea in medicine, but I think that the new area of research about the varied and important roles in brain development and brain maintenance of cells and chemicals that were previously thought to be limited to playing roles in the immune system are very important exceptions to the old notion that the brain is normally quarantined from the immune system by the blood-brain barrier. I’ve had a quick look at Dr Karl’s new book, and it appears to me that the chapter about the blood-brain barrier fails to mention the role of these immune cells and chemicals in the brain, things such as microglia, MHC1 and complement system proteins. It appears to me that the chapter in Dr Karl’s book is dated and seriously incomplete, and missing some exciting material. Even for a populariser of science, I expect more.

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If I could justify the time……

If I had more time I would write a post about what I think is wrong with Dr Karl’s new book, which will probably sell like hot cakes this Christmas, but has one chapter which is seriously incomplete and out of date. If I could justify spending the time writing this blog for no financial return I might also write lengthy posts explaining more of my scientific ideas about synaesthesia, cognition and memory. But sadly, this blog has no funding and no sponsor and not much of a future. But you will always be able to read about Paris Hilton and Kim Karwhatshername on the internet.

Chapter about a case of acquired prosopagnosia in a fairly new book

Trouble In Mind: Stories from a Neuropsychologist’s Casebook by New Zealander neurpsychologist Dr Jenni Ogden has a chapter in it about Michael who acquired prospagnosia from damage to the right side of his brain. It appears that this book has an Australian edition and another earlier edition. If you have an interest in face recognition, neuropsychology or prosopagnosia it is probably worth a look.

http://www.amazon.com/Trouble-Mind-Stories-Neuropsychologists-Casebook/dp/0199827001

http://www.jenniogden.com/trouble_in_mind_104472.htm

And another story on 60 Minutes about a major personal mystery which was solved by visual recognition and visual memory

Memories of the scenery of a long-ago journey, Google Earth, a very old photograph of a young boy and face recognition – these are the elements that found the solution to an impossible quest. Saroo Brierley’s amazing story of finding a lost mother within the incomprehensibly huge population and landmass of India is a demonstration of the incredible power and potential of the use of images as data in contemporary computer technology and the natural visual processing and visual memory capabilities of the human brain.

Lost and Found. 60 Minutes (Australia). June 21st 2013. http://sixtyminutes.ninemsn.com.au/article.aspx?id=8678261

Saroo was also a guest on Breakfast on ABC’s Radio National on June 25th 2013, interviewed with her usual skill and intelligence by Fran Kelly. Saroo is promoting his autobiography titled A Long Way Home.

Long Way Home: An extraordinary story. Breakfast. http://www.abc.net.au/radionational/programs/breakfast/long-way-home-an-extraordinary-story/4777562

Confirmation that Harry Lorayne’s “names and faces” method is not designed to address the problem of poor face memory or prosopagnosia

“Most of us recognize faces (did you ever hear anyone say, “Oh, I know your name, but I don’t recognize your face”?). It’s the names we have trouble with. Since we do usually recognize faces, the thing to do is apply a system wherein the face tells us the name. That is basically what Mr Lorayne’s system accomplishes, if it is applied correctly.”

on page 51 of The Memory Book by Harry Lorayne and Jerry Lucas, Ballantine Books, 1974.

Perhaps this method might be of some use to prosopagnosics, but it clearly isn’t designed to aid or replace face memory ability. Normal face memory is assumed.

Don’t forget the parietal lobe – the connections are interesting

If you have been reading this blog for a long time you’d know I’ve been trying to figure out which parts of my brain are responsible for my synaesthesia and related experiences. I’ve found that the right fusiform gyrus is a part of the brain that comes up over and over again, in relation to synaesthesia and also face recognition I experience many types of synaesthesia and also have achieved scores in face recognition tests consistent with being a super-recognizer, so this combination seems significant, and despite a lack of any evidence from other case studies linking synaesthesia with superior ability in face recognition, I still think it is a possible relationship that should be scientifically investigated, especially in light of a pattern of associations which I believe suggests that synaesthesia might be a neuropsychological condition that could be seen as the opposite of Benson’s syndrome, which is a type of dementia that involves a loss of visual perception, apparently including a loss of face recognition ability. While synesthesia is generally an inborn developmental condition, and Benson’s or PCA a neurodegenerative condition with a typical onset late in life, I’ve still got to wonder whether inborn factors contribute towards Benson’s. While Benson’s is considered to be a variant of Alzheimer’s, I don’t think anyone knows why it causes deterioration in different areas of the brain as are affected by Alzheimer’s, apparently the same parts of the brain (at the rear) that appear to be enhanced or hyperactive in my brain, and I also doubt that anyone knows why Benson’s has an onset earlier than Alzheimer’s disease. I’m sceptical of the idea that Benson’s is just Alzheimer’s of the back-end of the brain. I suspect that immune system elements microglia and complement might be central to an explanation for Benson’s syndrome. Reading Dr B. Croisile’s paper about Benson’s I’m struck by the many very strange effects of Benson’s on perception, and I wonder at the ways in which a study of it might inform science about  the workings of the brain. I think it is at least as interesting as synaesthesia, which attracts a lot of attention from researchers. Apparently people with Benson’s cannot imitate movements. Does this mean that the mirror-neuron system which so many neuroscientists have gotten so excited about is located at the rear of the brain? I note that the inferior parietal cortex is one of the parts of the brain that are thought to house mirror neurons.

When I set out to write this post I had actually planned to write about a fairly recent review journal paper focusing on recent research about the most common and well-known types of synaesthesia: coloured hearing, coloured graphemes and time units in space synaesthesia. I really like the paper cited below by Professor Karsten Specht from the University of Bergen in Norway, and I’d recommend it to anyone who wants to learn about the latest knowledge about synaesthesia from just one paper. I only have a couple of gripes about he paper. I wouldn’t describe synaesthesia as “rare” as Specht does. Ward, Sagiv and Butterworth wrote in 2009 that around 12% of the population have number forms, and that estimate doesn’t surprise me. Synaesthesia in general can’t be rare if it includes one type that isn’t rare. Time-space synaesthesia or number forms is one type of synaesthesia which the synaesthete can have but not suspect that it is synesthesia, or anything out of the ordinary, so I’d guess it could be very much under-reported and under-estimated. My other gripe with Professor Specht’s paper is this bit; “In recent years, several studies have attempted to investigate whether synaesthesia is primarily a perceptual or conceptual phenomenon.” I think Specht is here presenting the reader with a false dichotomy. In some of the types of synaesthesia and related phenomena which I experience sensory perception, memory and conceptual thinking are connected with synaesthesthetic linkages, so I doubt that there is much point in trying to characterise synaesthesia as one or another type of phenomenon. I was very excited when I read the book Beyond Human Nature by philosopher Jesse Prinz. Professor Prinz argued that we think in mental images rather than in language. He wrote that “It used to be thought that the back part of the brain is used for perceiving and the front is used for thinking. But we now know that the back part of the brain, where most of the senses are located, is very active when people think. Moreover, we know that the front part of the brain does not work on its own, but rather coordinates and reactivates sensory patterns in the back. Recent evidence from Linda Chao and Alex Martin has shown that reading activates the same areas as looking at pictures, suggesting that we visualize what we read.” In a post that I wrote a while ago I described involuntarily “seeing” in my mind’s eye visual images of landscapes and building interiors from imagination and memory while listening to an autobiographical audio-book. I thought it was probably related to synaesthesia, but it appears that everyone’s brain illustrates text with images when reading. Perhaps synaesthetes do this to a greater degree or in a way that is more available to conscious awareness.

Anyway, back to Specht’s paper. Having read it I now suspect that the parts of my brain that are bigger or better connected or more active or something are: the right fusiform gyrus (including the FFA), the left parietal lobe including the left intraparietal sulcus, the right inferior parietal lobe, the hippocampus (I’m sure is involved with IMLM) and the parahippocampal gyrus. I’d guess that these are the places where interesting things are happening. It appears that the role of the parietal lobe in synaesthesia has been understated in the past. It is now thought that synaesthesia does not solely involve the cross-activation of two different sensory areas (as if it was ever that simple!), but it also requires a “binding” process to happen in the parietal lobe. There is no underestimating the importance of this binding.

If you are as interested in synaesthesia and bits of the brain as I am, you might also like to read a much longer journal paper by Rouw, Scholte and Colizoli that was published last year. It is available in full text at no cost, but I don’t think it covers non-colour types of synaesthesia. Details can be found below. One part of the parietal lobe mentioned in that paper, which is cited by a few studies as involved with synaesthesia is the inferior parietal lobule (IPL, Brodmann areas 39 and 40). It is also known as Geschwind’s territory because the neurologist Geschwind predicted in the 1960s that the parietal lobe played a role in language, and was proven right when the IPL was found to include a second connection between Broca’s area and Wernicke’s area, which are of central importance in language. The IPL is very interesting as a part of the brain involved in synaesthesia because according to a 2004 article in New Scientist magazine the IPL matures at a late age, between the ages of five and seven years, which just happens to be time in life when children typically learn the ability to read and write, and it is also the age range in which some children develop grapheme-colour synaesthesia. I find this very interesting because in my family we have at least three closely related grapheme-colour synaesthetes who are unusually high achievers in reading and writing in testing and academic achievement. Two of these synaesthetes were early readers and also talented at language learning. What’s the betting that some gene that alters the development of the IPL is behind this? The author of the most interesting little science magazine article that brought me this news, Alison Motluk, is herself a synaesthete. Is it just a coincidence that a journalist with a well-connected brain has pointed out a number of interestingly related facts that are connected around the conceptual hub of the inferior parietal lobule?

Specht, Karsten Synaesthesia: cross activations, high interconnectivity, and a parietal hub. Translational Neuroscience. Volume 3 Number 1 (2012), 15-21, DOI: 10.2478/s13380-012-0007-z
http://www.springerlink.com/content/512306132j162437/

Croisile, Bernard Benson’s syndrome or Posterior Cortical Atrophy. Orphanet. September 2004. http://www.orpha.net/data/patho/GB/uk-Benson.pdf

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

Rouw, Romke, Scholte, H. Steven, Colizoli, Olympia Brain areas involved in synaesthesia: A review. Journal of Neuropsychology. Special Issue: Synaesthesia. September 2011 Volume 5 Issue 2 p.214-242. Article first published online: 16 SEP 2011 DOI: 10.1111/j.1748-6653.2011.02006.x  http://onlinelibrary.wiley.com/doi/10.1111/j.1748-6653.2011.02006.x/full

Motluk, Alison Two links good for kids’ language comphrehension. New Scientist. Issue 2478. December 18th 2004. p.12. http://www.newscientist.com/article/mg18424784.300-second-link-discovered-in-human-language-circuit.html

Time-blind, face-blind, smell-impaired, touch-disabled, dyslexic – there’s an amazing variety of disabilities of perception

It goes to show how common synaesthesia is, when a host of a radio show episode about super-recognition that I have referred to previously at this blog just happens to be a synaesthete. I know this because she was on the radio yesterday morning promoting her latest pop psychology book, which looks like it will be an interesting read. The BBC broadcaster, author and psychologist Claudia Hammond experiences the days of the week as having their own colours and insists that Monday is a pillar-box red, an assertion which to my mind does not seem odd but simply incorrect. Sure enough, the letter M is red (but certainly not pillar-box red) but surely it is plain to anyone that Mondays are white? Hammond and the cheery radio show host Natasha Mitchell also discussed other varieties of synaesthesia: time-space synaesthesia and mental number lines. Hammond’s new book is about the perception of time and it looks like it will include discussion of disability in perceiving time, and will also probably cover time-space synaesthesia.

I’ve had a look on the internet for more info about Hammond’s new book titled Time Warped, and while reading an excerpt of the book at Amazon I’ve found yet another obscure and highly specialized type of disability of perception, an inability to sense the passing of time, a condition which appears to be so obscure that it still has no name. Hammond gives a fascinating description of Eleanor, who has a deficit in sensing the passing of time that goes way beyond poor time management skills, and also has dyslexia, probably not coincidentally.

In this blog which is primarily about exploring possible links between synaesthesia and high ability in face perception and also an exploration of the opposite condition of prosopagnosia or face-blindness, I have discovered that prosopagnosia is by no means the only highly specialized disability of perception. Prosopagnosia is only one of a range of visual agnosias, which is a sub-set of the agnosias, which are a huge range of brain-based diabilities (not associated with memory loss) in recognizing specific things such as people, voices, shapes, smells, time, faces, colours, classes of objects, images of objects, pain, speech, text, body language, intonation, etc. Prosopagnosia appears to be often associated with another agnosia which is a disability in establishing visual memories of scenes, including things like streetscapes and buildings, and it seems possible that it could be linked with other better-known disabilities such as dyslexia. Each case is different, and prosopagnosia and other agnosias can be caused by genetics or damage in the brain, so one should not make sweeping generalizations. There appears to be no standard term or definition of the issue with place memory, with a variety of terms in use. I guess most people would be aware of the sensory and perception disabilities of blindness, deafness, paralysis and dyslexia, but there is also a huge range of other specific disabilities and disorders of perception and understanding, some affecting taste, smell, balance, mathematical and number sense, touch, music and tone perception. Many of these can be naturally-occuring or the result of brain injury. New Scientist magazine reported a while ago that a deficit in the sense of touch appears to be genetically linked with deafness. Scientists are only now beginning to establish knowledge about the nature of these disabilities and possible relationships between them. On top of this bewildering range of agnosias and disabilities are sensory disorders and visual disturbances that can be asociated with mental illness or are similar to mental illness. And on top of that are sensory-cognitive experiences that are simply odd or unusual but not disordered or a deficit. Synaesthesia fits into this category, of which there are more types than any sensible person would claim to know.

I find these things endlessly fascinating because it gives an insight into the significant fact that there can be many important differences between the way that apparently normal, intelligent people percieve and understand what appear to be simple sensory inputs from the world around us. The more I study this subject, the more I understand that there is nothing simple about perception and the understanding of sensory inputs. This kind of brain-work is hugely complex and it is no wonder that many areas of the brain are involved in this kind of work, and that sensory processing is very much involved in thinking in general. It is impossible to guess how many different ways that the person sitting next to you on the train might differ from you in perception and sensing, and it isn’t only about disability. For many of the agnosias and diabilities of perception and sensing there are conditions that are opposites or give rise to superior abilities that are like opposites. Does the old bloke across the way see violet mauve in his mind’s eye when he hears the train driver sound her horn, because the horn is at a pitch that his mind links with this colour, in an interaction between his perfect pitch and his coloured sound synesthesia? Does the super-recognizer in the carriage feel a tingle of familiarity from looking at two of the faces in the carriage? Is the super-taster still recovering from the second-rate coffee that he paid too much for at a fancy cafe? Is one passenger watching the screen display of info about which station the train is at like a hawk, instead of using her spare time to catch up on some reading, because she was born without any sense of time passing and can’t remotely judge the duration of her planned train journey?

Time warped: changing your perception of time. Life Matters. Radio National. July 2 2012. http://www.abc.net.au/radionational/programs/lifematters/claudia-hammond/4100994

Book review in the works…………

I’m very much enjoying reading the new popular science book Beyond Human Nature by Professor Jesse J. Prinz. I’m excited by his writing about Empiricism in the study of psychology, and I wish my local library had his 2004 book titled Furnishing the Mind: Concepts and Their Perceptual Basis in stock, so that I could read that book as well.

Jesse Prinz http://subcortex.com/

 

Listening to Heather Sellers’ autobiography

I’ve been listening to the interesting autobiography by prosopagnosic Heather Sellers, titled You Don’t Look Like Anyone I Know, in a compact disc format. I had wanted to borrow the book from the public library, but for some reason or another they decided to order it in a spoken word form. Perhaps they thought that face-blindness is a sub-set of ordinary blindness, and the readers who would be interested in the autobiography would have visual impairments or dyslexia. Actually, I’d like to know if there is any link between dyslexia and prosopagnosia, but I know for sure that there are plenty of prosopagnosics who do not report any issues with vision or reading at all.

I’ll admit that I haven’t found the time to listen to all nine discs. The content of disc number seven was particularly of interest to me, covering Ms Sellers’ discovery of her own prosopagnosia, the dreadful way that she was treated during the process of getting professionally diagnosed, in the time when prosopagnosia was thought of as a rare effect of stroke affecting mostly middle-aged men, and speculation about any possible link between her prosopagnosia and her mother’s mental illness. Some useful resources that Ms Sellers wrote about discovering were an academic reserch book by Andrew W. Young and the website Faceblind.org, which is still a very important resource about prosopagnosia. Ms Sellers contacted the face recognition researcher Brad Duchaine and also discovered an online community of prosopagnosics, mostly developmental cases who often saw prosopagnosia in family members, and some acting in the role of disability activist. Different approaches to disclosing prosopagnosia as a disability are touched upon. It’s interesting stuff for sure, and I thank Ms Sellers for sharing her story.

It is perhaps worth mentioning that as I listened to the CDs of Ms Sellers’ autobiography, as visual illustration of the story in my mind’s eye, my mind automatically retrieved some old visual memories from my past in Perth, Western Australia as settings for the story, even though they were probably not a close fit to the real settings of the real events described by the author Sellers from the US. For scenes set in the university in which Sellers was a student, my mind used my visual memories of the Joondalup Campus of the Edith Curtin University, specifically the lunch bar area next to a stairway. For scenes of the story that were set in residential areas my mind used old memories of old and run-down unrenovated two-story blocks of flats in Subiaco (which have probably been fixed up or demolished by now), and for interior shots of the author’s university residence my mind came up with some imagined spaces. Perhaps this effortless, involuntary and unconscious visualization while listening to a story is completely typical of the way all people listen to stories. Whether it is or not, it shows how visual memories are involuntarily and centrally involved with thinking processes that aren’t explicitly remembering or memory-related. Visual memory is not just a isolated function summoned up when we want to remember what something looked like. Visual memory is in the guts of cognition, it is more than a record of past sensory experiences, and this is why I am not surprised that visual memories come up so often (in my own experience) as synaesthesia inducers and concurrents associated with other cognitive functions that appear to have little relation with visual memory, such as fine-motor learned skills and thinking about very abstract concepts. The automatic use of visual memories when I am thinking about a story that I’m listening to shows that visual memory is not just a narrow function of the mind, and I think it also shows that there is little point in trying to make a distinction between memory and imagination, as both appear to be functions that are beyond conscious control, at least in some situations.

Synaesthesia linking concepts with scenes – maybe not so hard to explain, and maybe not really so strange?

I have recently been reading the chapter about synaesthesia in V. S. Ramachandran’s latest book about neuroscience, and among many other interesting things Ramachandran explained that some simple concepts are processed in the temporal lobes. This is the general part of the brain that I believe is hyper-developed or hyper-connected in my case, and it is the part of the brain in which the fusiform gyrus is located, where the recognition of faces, bodies, scenes, numbers and words is done, and colour is processed. I know as the result of testing that I have an above-average ability in face recognition, possibly in the super-recognizer class, and I also experience types of synaesthesia that involve faces, scenes, colours, words, letters and numbers, so I think I’m on solid ground when I assert that there is something interesting about my fusiform gyrus. Like many synaesthetes I also experience synaesthesia triggered by listening to music, and I believe that appreciating music has an unusual prominence in the lives of me and some of my synaesthete relatives. This type of thing is thought to be associated with the temporal lobes which do auditory processing among many other things, so I believe that whatever is different about my fusiform gyrus or (gyri?) is not limited to it but extends into the temporal lobes. So I was particularly interested that the processing of simple concepts goes on in the temporal lobe, because another type of synaesthesia that I experience links concepts with visual scenes which are processed in the fusiform gyrus in the temporal lobes. If these concepts are also processed in the temporal lobes, that would be another type of synaesthesia of mine that is a purely intra-temporal lobe phenomenon, and therefore a scientific explanation of many of the synaesthesia experiences of mine could be explained in one very short phrase; bushy temporal lobes. But I’m not completely sure that the types of concepts that my mind links with scenes are the same type of thing that goes on in the temporal lobes. This is the passage from page 104 of the book The Tell-Tale Brain by V. S. Ramachandran:

“Brain damage can make a person lose the ability to name tools but not fruits and vegetables, or only fruits and not tools, or only fruits but not vegetables. All of these concepts are stored close to one other in the upper parts of the temporal lobes, but clearly they are sufficiently separated so that a small stroke can knock out one but leave the others intact. You might be tempted to think of fruits and tools as perceptions rather than concepts, but in fact two tools – say, a hammer and saw – can be visually as dissimilar from each other as they are from a banana; what unites then is a semantic understanding about their purpose and use.”

This is a list of some of the concepts that are involved with the concept->scene synaesthesia of mine:
the concept of a bad “state housing” area that one could conceivably find one’s self living in if one’s life went to hell
the concept of Charles Darwin
the concept of Charles Darwin coming to terms with the death of a child
the concept of adoption
the concept of doing one’s own tax return
the concept of cooking with lard
the concept of Bettina Arndt
the concept of the toy the sketch-a-graph.

These concepts aren’t quite as simple as the conceptual categories of “fruits” or “tools”. Is this really the same type of conceptual thinking as that described by Ramachandran? I really don’t know. Maybe I would have more of a clue if I could find the time to read through an interesting-looking paper that I have found on the internet; The Representation of Object Concepts in the Brain by
Alex Martin. I’ve had a quick look at the paper, and I have spotted a couple of interesting things on page 32, a truly amazing misspelling of the word “synaesthete” and what appears to be confirmation that different types of grapheme -> colour synaesthesia involve different parts of the brain. I’m betting that my grapheme -> colour synaesthesia involves the ventral temporal cortex rather than sites in the occipital cortex, because for me the colours of the alphabet are experienced as knowledge of the colours of letters more than a perception of the colours of letters. This doesn’t make the experience any less real or specific. I can still “see” the colours very clearly in my mind’s eye.

I’ve had some thoughts about my concept -> scene and scene -> concept synaesthesia, and I think it could be the case that it only seems to be a strange and nonsensical way of thinking because it has been taken out of the context in which it evolved, and placed into this abstracted, complex, high-speed modern world that we live in. As I have previously observed, often there is a semantic relationship between the place seen in the scene and the concept, and sometimes the scene is of a place that I visited or frequented during the period of time when I was introduced to the concept or was thinking intensively about that concept. This would appear to be a completely useful and sensible way to think, with a thought triggering a real and visible scene illustrating and spatially locating the concept. Maybe a pre-historic human thinking with this type of synaesthesia might experience an appetite for a particular type of seafood, and then in her mind, helpfully, in response to the concept of that specific type of seafood, flashes the scene of the exact beach where she previously went hunting successfully for that particular seafood delicacy. I’ve had a little bit of experience hanging out with fishermen who knew what they were doing, and I know that catching a fish often requires knowing and doing exactly the correct thing – being in the right place at the right time with exactly the right bait and tackle for the specific thing that you are hunting. Casual attitudes and fuzzy thinking don’t get results. The exact nature of synaesthesia seems to fit in with this type of task. In the stable, predictable world of the hunter-gatherer in which there isn’t much abstract thinking to complicate life, this type of synaesthesia could possibly be a most useful tool of the mind, retrieving memories of exact locations just when they are required. One has to wonder if this type of thinking would have been so useful that everyone should have evolved to have it. Was synaesthesia the norm rather than the exception in early humans? Is my mind an atavism, or could it be a souvenir of a liaison between Homo sapiens and the Neanderthal race? Or is it true that this phenomenon isn’t synaesthesia at all, but a completely normal synaesthesia-like thing that is so ordinary that people don’t notice or discuss it?

Having a mind that automatically connects concepts with scenes might have been a very useful and sensible thing in the early times of our species, but when we link concepts with scenes in a mind that is living in the modern industrialized world, things can start to look a bit weird, because there has been an explosion of more abstract thought and complex learning, bringing with it a massive range of possible concepts to think about. In prehistoric times there were no tax returns or underclass suburbs or female sex therapists with gruff voices and high media profiles. It’s a strange old world that we live in, and as synaesthesia involves our thoughts and perceptions of this world, it should probably look just as strange.

References

A brief report on my synaesthesia experiences that involve concepts as triggers or evoked experiences https://superrecognizer.wordpress.com/2011/03/11/a-brief-report-on-my-synaesthesia-experiences-that-involve-concepts-as-triggers-or-evoked-experiences/

Martin, Alex The Representation of Object Concepts in the Brain. Annual Review of Psychology. 2007. 58:25–45.
First published online September 1, 2006.
The Annual Review of Psychology is online at http://psych.annualreviews.org
This article’s doi: 10.1146/annurev.psych.57.102904.190143
http://psychology.stanford.edu/~jlm/pdfs/MartinAnnRevPsych07.pdf

Ramachandran, V. S. The tell-tale brain: unlocking the mystery of human nature. William Heinemann, 2011.