Discover magazine has a fantastic Carl Zimmer piece about a man who lost the ability to see things in his mind’s eye after a minor neurological procedure.
Zimmer covers a recently published study on patient MX who lost his conscious visual imagery but could still do tests, like mental rotation, that were assumed to need the ability to mentally picture the procedure to work it out.
All the exams the scientists gave MX confirmed his claim that he was missing his mind’s eye. And yet he could do lots of things that would seem impossible without one. Without any effort he could give the scientists detailed descriptions of landmarks around Edinburgh, for example. He could remember visual details, but he couldn’t “see” them. Della Sala and Zeman asked MX to say whether each letter of the alphabet had a low-hanging tail (like g and j). He got every one right. They asked him about specific details of the faces of famous people (“Does Tony Blair have light-colored eyes?”). He did just as well as the architects.
The key insight came with a test derived from a classic psychological experiment invented in the 1970s by Stanford University psychologist Roger Shepherd. Della Sala and Zeman showed MX pairs of pictures, each one consisting of an object made up of 10 cubes. MX had to say whether the pairs of objects were different things or actually the same thing shown from two different perspectives. Normal people solve this puzzle in a strikingly consistent way, with their response time depending on how much the angle of perspective differs between the two objects: The bigger the difference, the longer it takes people to decide whether the objects are the same…
MX’s results flew in the face of that explanation. When he solved the puzzles, he always took about the same amount of time to answer—and he got every one right.
We still understand relatively little about the role and importance of visual mental imagery or what role it takes in problems or impairments.
A study I was part of found that people with congenital prosopagnosia, a genetic inability to recognise faces, had virtually absent visual imagery despite having no signs of brain damage or neurological abnormalities.
Patients who acquire prosopagnosia after brain damage often report that they can no longer imagine what faces look like, but in MX’s case, he seems to have lost his ability to mentally ‘see’ faces but has no problem recognising people.
The Discover article is a concise yet comprehensive take on this new study that helps us understand the link between how we experience the world and how we construct it inside our heads.
Link to Discover article ‘Look Deep Into the Mind’s Eye’.
4 Comments
Fascinating – I have a mild-to-moderate case of prosopagnosia. (If I meet you today and again next week, I won’t know you’re the same person unless you have a distinctive haircut or hat or voice or walk or clothing style, but I don’t have trouble with people I see regularly.)
And I have almost no visual imagery. Various threads on Ask Metafilter and elsewhere have convinced me that this isn’t that unusual – people vary in their capacity for mental imagery, with a small percentage being like me.
I never made the connection with the facial recognition issues. Maybe it’s the fact that I can’t mentally “see” a face that makes it hard to recognize.
This is a very intriguing article. I’ve had experiences that have convinced me that the mind’s eye is something I use to confirm what I already know – and that it actually slows me down. I start out mysteriously knowing the answer, and then I have to confirm it to myself so I picture it, often enough second-guessing myself into giving a different answer that turns out to be wrong. It’s really quite frustrating sometimes.
Until about 2 years ago, I thought that when people said “mind’s eye” or “mental image” that they were just using a figure of speech. I was a little shocked to discover that they meant it *literally* — it seemed, to me, hallucinatory and bizarre. As peculiar to me was the realisation that most people have no idea what shape (in a tactile rather than visual sense) ideas are (although it does explain why their thinking is so muddled).
I’m 33 and a visual artist. I recognise faces just fine (I just don’t really remember them), but I’m terrible at pre-visualisation (I have to actually see something in order to know what I think about how it looks). I’m unusually good, though, at seeing deep structural connections between superficially unrelated pieces of information.
I only figured out that other people actual do have “mental images”, and that my sense of ideas having shapes is unusual, because my Art School training required us all to think and talk a lot about our “process”. If I hadn’t been required to do that kind of self-conscious thinking-about-thinking, I probably never would have noticed. I suspect that that’s not all that uncommon: our language contains a lot of sense-based metaphors that aren’t literal, so absent some specific reason for asking other people a lot of questions about how they think they think, if one doesn’t literally see things in one’s head, one has no reason for assuming that others might do something so alien.
Both of these things (my shapes and the “mind’s eye”) are just forms of synaesthesia, after all. To be visually dominant isn’t necessarily “normal”, it’s just hegemonic. Those of us who don’t process information in that way — and who assume it’s just a figure of speech — may be a lot more common that is assumed.
This is very much the same as me. I have never been able to see with my ‘mind’s eye’ but I didn’t even really realise that I was different in that way until university. A lecturer decided to show the group she was teaching ‘the power of the mind’.
She told us to picture a kitchen, and walk over to the refridgerator, take out a lemon and slice it. We then had to eat a slice.
I could not picture a kitchen but I could imagine how it smelled, and my saliva glands reacted almost painfully at thinking of tasting it.
When I told the lecturer, she just told me that I obviously have no imagination. I was rather offended considering I am a budding writer.
I can remember and describe what I see, but I cannot ‘see’ it in my mind. I remember peoples faces when I see them, but I often have problems putting names to the faces.
It’s nice to know I am not a weirdo to be honest.