how is the brain able to give us images when we are imagining something?
In: Biology
Sorry bub, no-one really knows the answer to this one. And it’s even harder to explain in a simplified way.
If I had to give a response, based on current theories, I’d say that this phenomenon is performed by a part of the brain called the central executive. You can think of this sort of like a cross between an admin assistant and a 911-operator. It tends to do jobs that coordinate brain resources, but it also has roles in filtering/processing incoming information and ensuring the correct brain areas deal with the information/stimuli appropriately. If parts of this system are damaged or congenitally absent, then a person is not able to call up images or contort or change objects in their mind’s eye. So this sorta provides evidence that generating these kinds of visual images is a process that involves multiple parts of the brain working as one – via the central executive.
One theory is that the admin assistant has a little sketchpad by their desk (in the literature it’s literally named the visuo-spatial sketchpad), and based on (1) the information coming in via the senses, (2) your volition (your active desire to do something), and (3) your current emotions at the instant this is all happening, they sketch something down on the pad and that’s the image you see in your mind’s eye.
The important thing to note here is that the assistant doesn’t know what the final image will look like – they’re just sketching a hot-take of some object based on properties sent in via your senses, i.e. your eyes sending in an image that resembles something you’ve seen in the past, or your ears listening to something that sounded similar to something you’ve already heard. So let’s say your friend asks you to imagine a television, your assistant isn’t just going to sketch a Sony XBR 900F. You remember that a television could be a black rectangle, you remember that it could be perhaps thin, and you remember the context of a television (it’s usually inside a house, there are usually pieces of furniture around, it might be on a stand, etc). Importantly, the form and the color of the object is assessed and sketched. Then, some physics is added and simulated. If it’s light, then you might imagine yourself holding it. If you know it to be heavy, then it’s likely situated a few arms lengths from you (and if you were to imagine yourself throwing a tennis ball at the TV, it wouldn’t be knocked over). All of this is sketched roughly on the pad by the assistant (again, not knowing it’s a TV because it doesn’t interpret objects in that way).
Then your emotions add a dash of personality to it – perhaps you were feeling happy the last time you watched TV. So your assistant might add some imagery to it that aims to replicate those emotions (because you know there should be an image but you can’t recall exactly what image was on the screen the last time you saw a TV).
And then with all those inputs combined, the sketch is completed and you see it! There’s a bunch of stuff I left out, but this was getting long haha.
ETA: Here’s something even crazier – none of this really makes sense without considering evolution. Within this framework, it’s reasonable that being able to conjure mental images would be a selected trait from generation to generation. Even in the way I described above. For example, if our ancestors were out hunting and came upon a predator, it’s reasonable that the faster we could interpret the pattern of signals we’re seeing – say, a large black bear, then remember a previous danger, imagine that previous danger in the mind’s eye (color and shape and physics), the better we’d be able to alter our behavior to avoid a bad encounter. And I’m not even getting into the process your brain can use to project/extrapolate your visual perception a few hundred milliseconds into the future to allow you to catch balls! Now THAT is some Matrix-level shit.
In reality, this specific bear might not even be the same species, or it might not even be a bear! But your brain has evolved to keep you alive and it heavily, HEAVILY uses pattern recognition to do that. So with all that in mind, it’s better to prioritize the speed of image construction/imagination in the brain (by the sketchpad), rather than the accuracy of the image.
As they say, I’d rather be wrong and alive than correct and dead 😱.
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