A man’s baffling inability to see certain numerical digits might provide insight into how our brains work. According to the scientists who have studied him, the nature of his condition — which makes him see spaghetti-like shapes in place of the numbers 2 through 9 — suggests that our brains can recognise complex concepts such as numbers before we’re consciously aware of them.
The man, known as RFS, began suffering episodes of headaches, memory loss, and other neurological symptoms in late 2010. By early 2011, he had been diagnosed with a rare degenerative brain disorder called corticobasal syndrome. The syndrome tends to affect older people (the man was in his 60s) and primarily causes symptoms such as muscle spasms, an inability to move your limbs, and other sensory problems, which worsen over time.
In addition to these symptoms, RFS also started reporting that he couldn’t see the numbers 2 through 9. When he looked at those numbers, all he could see were squiggly black lines. If the digits were printed in a colour, that colour became the background to the black squiggles. And every time he looked away and then back at the number, the lines changed shape, making it impossible to discern their identity through inference.
At the time of this discovery, the man had been receiving care from a neuropsychologist at Johns Hopkins in Maryland. Once he reported his trouble with numbers, the psychologist consulted a team of fellow Johns Hopkins researchers who went on to study RFS over the next eight years. The fruits of that research were published today in Proceedings of the National Academies of Science.
“The thing is, he’s really good with numbers. He’s an engineer, and uses numbers in his work all the time. And he can still do maths, and he still knows what numbers are and understands them,” senior study author Michael McCloskey, a cognitive scientist at Johns Hopkins who studies the human perception of reading and spelling, told Gizmodo. “It’s just when he looks at the digits, like he looks at an eight or a three, it looks all scrambled up — it’s total spaghetti, as he calls it.”
It’s an impairment that’s all the stranger, McCloskey said, when you remember that plenty of other symbols in our daily life resemble the digits 2 through 9, such as 8 and the upper case letter “B.” Yet RFS doesn’t have trouble recognising those things (he did report some distortion when seeing the letters M, N, P, R, S, Z but not to the point where he can’t identify them). And it’s not even all kinds of numbers, either, since he can still read Roman numerals correctly, as well as the numbers 0 and 1.
McCloskey and his team’s work with RFS indicates that the brain can process information even further outside our awareness than we knew. Among other experiments, they measured his brain activity via EEG while having him look at the distorted digits. The researchers would then embed faces or words he had been shown earlier. RFS reported that he couldn’t see anything but the squiggles as usual, but his EEGs revealed something else.
There are certain parts of the brain that light up when we see faces. And when the researchers looked at RFS’s brain activity, they could see those parts light up. They also saw other distinct parts of the brain activate when he looked at the numbers embedded with words.
“He has no idea there’s any kind of word there or any kind of face. Yet, it looks like his brain is not only aware that there’s something there, it’s doing a lot of complicated analysis of it,” co-author David Rothlein, who worked as a student at McCloskey’s lab during the study and is now a cognitive scientist at the Boston Attention and Learning Lab, told Gizmodo. “This is the sort of processing that we would intuitively think you have to be aware of. But this is showing us that very complex, very sophisticated processing — what we call high-level cognition — is clearly going on without awareness here.”
In other words, there’s at least another step (maybe even lots more steps) that still has to take place between our brains identifying an example of a complex concept like numbers and communicating that to our conscious surface. It’s possible this complex information is sent to a higher level of the brain before it reaches our awareness, Rothlein said, but it’s also possible that higher-order information needs to be cycled back to the lower levels of the brain before it’s fully understood, as some scientists have theorised.
Regardless of how it happens, something has gone awry in RFS’s translation process. There are other people with similar dysfunctions of information blindness, most prominently people who’ve become unable to recognise faces. But try as they might, McCloskey and his team haven’t yet found anyone else, past or present, who exactly resembles RFS, even among other people with his condition.
Their research was at least able to provide RFS some comfort. McCloskey’s team devised a separate numerical system for RFS to memorise, which he successfully used in his daily routine and even at work up until his retirement in 2014. Sadly, RFS’s condition has deteriorated since the study ended, and the researchers say he is now in very poor health (the average life expectancy for someone with corticobasal syndrome is eight to 10 years after diagnosis). For now, McCloskey said, his cognitive functions are still largely intact.
Tragic as his condition is, RFS’s willingness to be studied all these years may end up providing us crucial information into how our brains work, much as the cases of patients like Phineas Gage and HM did.
“Single case studies like this are a very remarkable way to illuminate the inner workings of the mind in a way that we often can’t do with other methods,” Rothlein said.