You could convince a blind man that you could see quite easily, by doing things that require vision and that blind people couldn't reproduce. Since the alleged visualizers don't seem to be able to do anything aphantasia-people can't - it makes me think visualization isn't real.

I remember hearing about a study on mental rotation. The time it takes most people to determine whether two shapes are identical (but rotated) is roughly proportional to the angle of rotation between those two shapes. That seems to be close to what you're asking for.

Whenever I have to mentally rotate shapes (only on tests of mental rotation / IQ) I do it by just comparing the features of the original shape to each of the candidates and ruling out options. e.g. noticing that one option has too many vertices or not enough. It's tedious but pretty reliable.

Your comment made me Google "aphantasia mental rotation" and the summary of the first result I got makes me think I'm probably right. As I read the summary, aphantasia people were slower but more accurate. In other words, the aphantasians know they don't have visual imagery and therefore do the slow but steady thing whereas the visualizers think they have visual imagery and are fast but wrong.

Granted, I haven't read the paper, but at first glance I'm counting it as evidence for me.

https://jov.arvojournals.org/article.aspx?articleid=2700106

Or we've spent a whole lifetime training spatial recall, and so we can do that part better. I can spatially "manipulate" scenes I remember well with great precision, and I don't visualise anything. As such I don't think you can reasonably say anything at all about the ability to visualise based on this.

But why would it take visualizers longer to just pretend to rotate a shape over a greater angle? I think the best explanation is that something is really being rotated, however inaccurate, simplistic, or vague.

So here is one potential discriminator. A person that can visualize sees something traumatizing. For example, witnessing someone being killed, or a gruesome accident on the highway. That person will repeatedly have flashbacks re-playing those images again and again. It's horrific.

How do you distinguish that from normal memory recall?

> it makes me think visualization isn't real.

It is. The problem is that it's not a pixel-perfect reproduction of things on a screen. It's not a movie theater, or a computer screen.

The brain is a powerful pattern-recognition machine that gets exceedingly more complex with age and experience. So:

If you ask the person visualize a bicycle, the person will visualize an amalgamation of bicycles that roughly has two wheels, a saddle, and a handlebar. And this will differ from person to person.

A kid will vividly imagine the bicycle he/she has, or the bicycle he/she wants. Same is likely for avid cyclers. For most people it will probably be a superimposed image of many bikes they've seen over the course of their lives blurring together.

The reason is probably because recollection of details is costly, and usually not that important for our very ancient very lizard brain whose primary reaction to things is still fight or fight :)

But then if you ask a person to visualize "a yellow bycice with red tyres", the visualization will become clearer, but still fuzzy and different for different people. If you've seen such a bicycle (esp. recently), you will visualize that, with high degree of fidelity. If not, your brain will once again create an amalgamation of bicycles, and create an overlay of yellow and red that may or may not be of high fidelity (I can't imagine red tyres on a bike for some reason, but I can imagine red rims on a bike, go figure).

Kids are better at visualising and imagining things because they have fewer sources to draw from, and they don't interfere with each other.

For adults it's more like a combination of camera obscura and long exposure:

- You visualize certain details in a sea of recognizable fuzziness. Example: "vizualize a street vendor" can be something similar to this (long exposure): https://lh3.googleusercontent.com/proxy/kIDQANDGRgVD91zdzZpg...

- You visualize a regonizable pattern without specific details. Example: "visualize a passage" can be similar to this (camera obscura): https://i.shgcdn.com/dea29cf1-c27d-4f55-a029-9443222c0a0b/-/...

It definitely is real for 95% of people, you just don't have it. I doubt you could draw well from imagination even with artistic training, so there's that. Everything else is just pure cope.