NB: I majored in Neuroscience. I use it all the time in everything I do, mostly to screw with people. So I’ve decided to be nice and share a little of what I’ve learned….
The perception of words is, obviously, an incredibly important part of being a writer. Readers see words, and the associated memories evoke in their heads a particular visual image. The more detail you add to your description, the greater the constraints on the images evoked. Which does mean that readers will see what you want them to see–what’s in your in mind–but it can also mean that there is no visualization.
Think of it like pressing buttons on a keyboard. Each button you press generates a particular string, and by pressing multiple buttons you can reach the end result–say, opening a program–but if you press the wrong button then the entire string will fall apart. Similarly, the neocortex–plus hippocampal areas and, well, pretty much the whole shebang–is driven by circuits. Triggering the circuits starts with sensory input: a smell, an object, a sound (here encoded as words), and ends with a combination of memories that generate imagery. Hobbes in ‘Leviathan’ calls imagination the mere degradation of memory, but if you drop the pessimism it does make a lot of sense: we take elements that we’ve experienced and put them together in new ways, like the infinite possible combinations of Lego blocks.
The following paragraph will hopefully provide an example of this: as I add details, it should increase in realism until an unfamiliar element appears.
Waves crashed against the sand. Overhead, faint rays of sunlight struggled through clouds. The sea was a dull blue-grey capped by white froth. The sand was shining black, glistening from the water that sloshed back and forth over it. Further away from the tide, black and red and bluish pebbles grew in size until they became the cliffs that surrounded this small bay.
For myself–it’s directly out of real life until I get to the cliffs, and then the full image dissipates.
Anyway, the point is about words. You have to know your audience to know what they’ll see: I would expect the image to remain familiar until it gets to the black sand; if I were properly going to write this and the sand mattered then I’d put in some details, like the sand actually appearing more of a dull grey and being rather warm underfoot. (I’d dump the pebbles entirely–it’s not worth trying to explain how they press into the most annoying parts of the feet no matter where you stand, how they rub into your back and resist moving with you, like you’d expect from something more rolly….)