Monday, February 28, 2011

NEUROSCIENCE CASES: THE MAN WHO COULD NOT FORGET


How many times have you been sat revising for an exam wishing that you had the power of a perfect instantaneous memory? Well, for a tiny number of people that isn’t just a pipe dream. Known as mnemonists these individuals have unfathomable memories and data recall. This is the story of one of the first properly studied, and most interesting cases, Solomon Shereshevskii.
Born in Russia in 1886 to a Jewish family Shereshevskii, or simply ‘S’ as he is sometimes referred in literature externally appeared to lead a normal life. As an adult, after failing as a musician he embarked on a career as a journalist. It wasn’t till a chance meeting with the Neuropsychologist Alexander Luria (one of the founding fathers of the discipline) that his gift became apparent.
Alexander Luria
Shereshesvkii was reporting on a talk given by Luria. At one point Luria looked around the room and noticed that, unlike all the rest of the journalists, there was an individual not taking any notes. Luria confronted Shereshesvkii asking why he was not taking notes, at this point Shereshesvkii recited his entire talk back to word for word. Luria was stunned, as was Shereshesvkii who at this point had never realised that no one else had his perfect recall. This began a friendship and research partnership that lasted many years, with Luria conducting many studies into what might be the cause of his incredible abilities.

Luria’s studies revealed many interesting things about the workings of Shereshesvkii mind. His descriptions indicate that Sherevskii had “at least six different types of synaesthesia” triggered by at least four different sensations (Figure 1).
Figure 1: The synysthetic links outlined by Luria in his book “The Mind of a Mnemonist: A Little Book about a Vast Memory” (The page numbers indicate the pages of evidence for each link)
Sherevskii synaesthesia was very vivid describing the reaction he got when thinking about numbers as:
“Take the number 1. This is a proud, well-built man; 2 is a high-spirited woman; 3 a gloomy person; 6 a man with a swollen foot; 7 a man with a moustache; 8 a very stout woman—a sack within a sack. As for the number 87, what I see is a fat woman and a man twirling his moustache”
Shereshevskii’s ability to recall numbers was a particular area of study for Luria. The tests began with Luria giving him 30 numbers to memorise and testing him soon after, unsurprisingly given his previously demonstrated abilities this was no problem. He was then given longer and longer sequences (peaking at 70) and was able to recall them all. Curious about Shereshevskii’s long term memory Luria then asked him 15-16 years later for the original sequence of numbers, and he was able to remember the sequence.
However, having such vivid and accurate memory did have its problems. Due to the connection between his senses he sometimes had unpleasant reactions to stimuli, saying:
“One time I went to buy some ice cream … I walked over to the vendor and asked her what kind of ice cream she had. ‘Fruit ice cream,’ she said. But she answered in such a tone that a whole pile of coals, of black cinders, came bursting out of her mouth, and I couldn’t bring myself to buy any ice cream after she had answered in that way”
He also had a difficulty recognising faces, which he saw as “interchangeable”, occasionally had problems reading (due to the distracting sensations the words could cause) and grew frustrated with his inability to forget.
Luria said of Sherevskii that he “had no distinct limits . . . there was no limit either to the capacity of S.’s memory or the durability of the traces retained”.
Towards the ends of his life Sherevskii claimed to have discovered a way of selectively forgetting memories, although this was never scientifically tested.
Sources:
ResearchBlogging.org
Yaro C, & Ward J (2007). Searching for Shereshevskii: what is superior about the memory of synaesthetes? Quarterly journal of experimental psychology (2006), 60 (5), 681-95 PMID:17455076
Alexander Luria (1988). The Mind of a Mnemonist: A Little Book About a Vast Memory (reprint).PsycCRITIQUES, 33 (3) DOI: 10.1037/025559

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