It is a good question because aphantasics that can dream normally are far less likely to engage in the sort of "aphantasia is just semantics" denalism that is largely disproven given modern science and online discourse. I.e. it is a very strong credibility signal that what follows is not just cope / self-delusion, but actually potentially useful and interesting self-report.
The distinction between imagination and seeing is regularly blurred, most commonly in dreams, but also on psychedelics or quasi-psychedelics (e.g. cannabis), and also in altered spiritual states (meditative practices).
The two experiences are different, most of the time, yes, but only "completely 100% different" IMO to aphantasics, or those who are high in aphantasia. I.e. hyperphantasia is a thing, and a normal thing for most people in altered states (and schizophrenia might be seen as involving an extreme form of hyperphantasia intruding where it shouldn't, in some cases).
This is partly why only aphantasics argue for the "it is only semantics" explanation. For anyone else, this explanation makes no sense, because they have at least one vivid example showing otherwise. Only if you have no vivid visual experiences does this argument have any appeal.
Also the well-documented cases of acquired aphantasia are especially troubling for the skeptical "semantic disagreement" cases, given that acquired aphantasia is entirely within-person.
Yeah, that is my experience too. I consider myself to have aphantasia - I have had that one vivid experience outside my dreams. Outside of that it's all been blank my whole life. Without that one experience maybe I'd doubt it too, but it really is fascinating how many of the people who insist it can't exist give descriptions of their experience that suggest they have it.
There is some truth in this, but evidence sometimes suggests worse visuospatial memory, at least under some very specific operationalizations. E.g. less detail can be remembered overall, even though crucial details remembered are the same: https://pmc.ncbi.nlm.nih.gov/articles/PMC10598423/
More likely than not there are tradeoffs to using strictly visual vs. visual+ vs. strictly non-visual mental models in all domains, and there is no universally optimal strategy (and that teams of mixed cognitive styles are best overall). You know, no free lunch.
> I've also wondered whether this entire conversation is just all of us collectively talking past each other for the entire conversation and we all in fact have quite similar experiences
This is fairly conclusively disproven by far more than just fMRI / brain-imaging studies. E.g. aphantasics have problem with visual memory recall, visual priming, pupil dilatory and skin conductance responses when imagining light and/or fearful stimuli, and many other results (especially acquired aphantasia) that don't depend on brain imaging and obviously rule out semantic explanations. Likewise, rejecting the reality of the phenomenon also seems to require believing an extraordinary amount of error and/or conspiracy on the part of highly educated and insightful people that explicitly are saying the issue is not one of semantics / description. This is also not to mention the rich history of visualization practices in much of the worlds religions and esoteric practices (which make basically zero sense if this is all metaphor). See e.g. the discussion in a previous HN thread (https://news.ycombinator.com/item?id=49464414).
> I invite you to feed your own friendly AI these references then ask it to analyze the recent papers [...]
Likewise, an unbiased AI prompt (or two prompts in separate sessions, with opposite biases) will clearly reveal the "semantics denialist" case has very little to stand on here. Yes, there are communication and linguistic issues, but these only cover a subset of ambiguous cases. Rejecting or denying the reality of aphantasia is an extremely strong indicator you are aphantasic, to some considerable degree.
It's possible, but "aphantasia is fairly rare" and "aphastastics abound on HN, even moreso than is apparent if there's a number of people like jerf who are aphantastic and still unaware despite even posting on stories about it" is a bit of an odd combination that I'm struggling with. Yes, I am well aware of the bias that only certain people post, as well as the distinct possibility that there are underlying correlations that could lead to our industry abounding in them. Though prior to this I would have thought quite the opposite given the association between visual processing and success in STEM and engineering.
One easy answer up there with "more study is needed" in terms of being a bit cliche, but cliche because it's often true, is that there may be a richer spectrum or something that isn't even 1-dimensional then we're currently able to grasp, which will become more clear over time and more study. Perhaps it's less rare than we think and the rareness is only those we can talk into agreeing their qualia really is different from others. Or the way we are describing it leads people in the "1-2 out of 5" category to declare themselves aphantastic on HN when they aren't really properly so.
I don't think that it is that the industry abounds with us, but it is natural that those of us who have strong opinions on aphantasia and/or feel affected are far more likely to post on stories about it.
That a larger proportion of HN users are aware of their aphantasia is another matter - the renewed research over the last 10 years got a lot of attention.
It is very clear that there is a spectrum - hence why the typical test goes from seeing nothing at all via various degrees of seeing blurry or monochrome shapes to full colour vision. Going by Ed Catmull's survey of staff at Pixar, you will also find it extending further into hyperphantasia: People (and there's at least one in this thread too) who can "watch movies" in their head and can rewind and fast forward.
> Or the way we are describing it leads people in the "1-2 out of 5" category to declare themselves aphantastic on HN when they aren't really properly so.
People at the lowest end of the scale absolutely have aphantasia, but there's no "official threshold".
but also, if I could see even the vague outlines that'd place me one level up, it'd be very obviously different to my experience. I score the minimum possible 32 on the VVIQ2 test:
The median score on VVIQ2 is 79. The median for VVIQ is around 60, and the thresholds used for aphantasia on the VVIQ test is 24 or 33 depending on who you ask.
I can very occasionallypossibly see brief flashes of vague imagery, and as I've mentioned elsewhere, I have had a single experience of what was probably at hyperphantasia levels, so I don't think there's some inherent physical limitation preventing me from seeing more. But it is also very clear to me especially because of that experience that I do in fact not see more.
> Yes, I am well aware of the bias that only certain people post, as well as the distinct possibility that there are underlying correlations that could lead to our industry abounding in them. Though prior to this I would have thought quite the opposite given the association between visual processing and success in STEM and engineering.
I agree this is an annoying confound, and also that it feels highly intuitive that being able to consciously visualize ought to correlate with better visuospatial (and thus much mathematical) cognitive ability.
I think the solution is recognizing that the reason cognitive deficits are mostly unobserved (visual memory recall studies aside) is recognizing that aphantasia is almost certainly a conscious access problem, i.e. most aphantasics are still using imagery too, just unawares. Last I checked, this is the leading hypothesis / explanation.
Also, plasticity and the ingenuity of the brain is clearly such that an aphantasic can also find other ways (e.g. other sensory modality imagery, pure logical relations, etc) of representing the problems that seem like they should rely on visualization. It seems obvious to me that these other ways can be both advantageous/disadvantageous, depending on the situation / phenomenon.
"The brain is not a computer" != "Parts / aspects of the brain do computation".
"A computer" in the first statement is IMO obviously intended in the common usage sense of the term, i.e. the brain is not a desktop computer or smartphone, or Turing machine, or etc, and thinking of it like these things will cause more error than insights. Also, billions of interlinked mini bio quantum computers arguably produce something with emergent properties and behaviour much, much more complex than "a computer". I am with GP, the analogy to "a computer" is not super helpful here unless you highly restrict the meaning.
But yeah, the Shereshevsky case is a super interesting one, thanks for linking!
You are wrong, as I didn't limit the analogy specifically to desktop computers only, try reading the rest of what I wrote. The original analogy was obviously hedging against simplistic brain-computer analogies (GP could be read as: "the brain is not a simplistic computer"), so the response demanding to "live with that" citing computational aspects of the brain was misguided and arrogantly wrong.
Multiple other responses also point out the definition given leads to absurdities / triviality (the liver is a computer in this context), so the "correction" with citations is both inept and inapt.
> SSRIs have an NNT around 7, depending on the study you look at [...] Which sounds terrible if you know nothing about NNT. But when you learn that Tylenol has an NNT of almost 5 and even a powerful drug like Xanax has an NNT of 4, you realize that NNT is a difficult measure of drug efficacy
This kind of comparison is utterly meaningless (like saying a Cohen's d of 0.3 is large for phenomena X, so if we see 0.4 in phenomena Y, it is large in Y), and is just one part of why NNT as usually reported is basically deceptive for antidepressants.
What qualifies as an effective "treatment" has to be anchored to a minimal important difference, and this is what antidepressants really don't clearly have, on average. I.e. saying the NNT of SSRIs is around 7 is not really practically interpretable, because they tend not to base NNTs here on the amount of patients that actually experienced a clinically meaningful change, they just count the number that exceed some arbitrary (usually purely statistical) threshold.
If you reformulate NNT competently to count number of people needed to be treated to ensure one has (on expectation) a minimally important difference in the depression scales, then the NNT gets even larger than is typically reported.
This is why the denialism about differences in visual experience are so indefensible: they basically require an assumption that the whole world is out to lie and deceive.
Like, so, people just say things like "I see it in my mind's eye", and insist it is not a metaphor... why, exactly? If the typical mind fallacy assumption of denialists was correct, then no one would have any incentive to use such metaphors, because they would feel false. So clearly minds do in fact differ.
To state otherwise is a kind of narcissism / solipsism, or at least there is something monstrous about this kind of denial. "Everyone else is clearly wrong about their experience and their descriptions of it. I know better".
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