[SirRoderic]

Speaking from experience as an aphantasic person, I think it is definitely possible to test objectively. For instance certain IQ tests will test the subject's ability to identify what a pictured object would look like if it were rotated in a certain way.

I have taken just such a test where spatial rotations, IIRC including multi-step ones, were a component, and I scored close to 99th percentile on every section except that one... where I scored 1st percentile. If that's not a strong sign of aphantasia I don't know what is!

[SaidinWoT]

This is actually one of the things about aphantasia that has already had a (small) study[0], and the results are actually the opposite! The participants with aphantasia were more likely to both (a) take longer to answer and (b) be _correct_.

I personally have aphantasia and have quite good spatial reasoning, including with mentally rotating objects. I think it's fair to assume that visualization and spatial reasoning are mostly (but not entirely) orthogonal spectra, and it's completely possible for people to fall anywhere on either, just based on how their brain developed its internal strategies throughout normal life.

[0] https://www.researchgate.net/publication/26792259_Loss_of_im...

[auggierose]

Yes, objective tests must somehow take into account the multitude of coping mechanisms that people with the condition have developed. "Spatial reasoning" for example is very close to logical reasoning, and I don't see why people with Aphantasia shouldn't be very good at that, albeit slower in "spatial" mode.

[listenallyall]

Can you read text when a book is upside down?