Audio-visual perception

How do we know that we all perceive the same stimuli the same way?
(barring brain damage due to trauma or stroke, of course.)

How can I be sure that, what I perceive like this:

Appears to you like this:

I mean I can’t install Borg/Matrix Jacks into our respective heads and plug us into each other…yet;)

Assuming that you are not doing this just for the Rickroll, this is a philosophical problem that has been recognized at least since the work of John Locke in the 17th century, and continues to be extensively discussed today by both amateur and professional philosophers. (Check that link if you really want to understand the issues rather than just using the question as an opportunity to bullshit.) There is no generally accepted answer, but perhaps the most widely held view is that there is simply no way to tell. Indeed, plausible arguments have been made that imply that we could not tell, even if we could plug into each others brains. (How would we know whether we had wired the plugs the right way round?) Others hold that the question is based on a deep confusion about the nature of perceptual experience, and that in fact our experiences do not and cannot differ in the way suggested.

On the other hand, this recent book may offer the seeds of a possible scientific solution. (Or not: its theories are highly controversial.)

There is not much more factual that can be said about this. If this thread continues, it should go to Great Debates, where some people will no doubt enjoy themselves recapitulating all sorts of shopworn and long-since refuted philosophical arguments.

No, it was not a rickroll, and I did not think of it being a philosophical question, but neurological…a processing of data.

this being a known philisophical question already I think what we should concentrate on now are the similarities. things we all see the same way.

Well, it is a philosophical question, I am afraid. There is certainly no scientific answer, and no conceivable experiment that would settle the issue unless a lot of thorny philosophical problems were solved first. (This, however, is true of a lot of problems at frontiers of our understanding, where science and philosophy seamlessly shade into one another.) A philosophical problem is not necessarily a problem that will forever remain insoluble, but it does mean that it is difficult and that no-one yet has an idea about how to go about solving it that commands any wide acceptance.

This, indeed, is what perceptual scientists mostly do.

Coincidentally enough, I’m planning to serve quail this weekend. With a foie gras farce.

If you are alluding to the word “quale” (singular of “qualia”), it is pronounced quah-lay.

We dont and can’t know that each others’ internal experience of the world is similar - most usually, this idea is discussed in the context of colour perception, but it need not be limited to that. There’s no way to be sure that yourexperience of seeing a blue rectangle wouldn’t be what I would describe as the experience of falling into a bee hive - as long as the inputs and outputs are consistent.

That is almost certainly not true. There is a publicly shareable structure to the space of experiences that is violated if you just arbitrarily transpose any two of them. We all agree that orange is more like red and yellow than it is like green or blue, and much more like any of them than it is like falling into a beehive. Furthermore, falling into a beehive is much more like being hit on the head with a mallet than it is like purple or salty. You can’t even swap orange and yellow around and preserve the known similarity structure of the color space, let alone swapping blue with bee stings. However, you might be able to get away with just turning the whole spectrum round the other way. (Or, some have argued, you might not. The colors we experience are not all spectral colors, after all, so how are you going to preserve their established similarities?)

Or, as some of the people who do this for a living contend (as you would know if you read the article at my link), the whole idea that different people might experience the same qualities differently may be based on a false and incoherent view about the nature of experience itself.

I agree, it seems really unlikely, but I think we might be talking at cross-purposes anyway - all that is required is that the mapping of external stimuli to internal experiences, and the mapping of internal intents to external actions, act in (what appears to be, to the individual) a completely consistent way. If, from the very start of your existence, your perception of blue rectangles had always been an experience that if imposed upon my brain, I would describe as ‘like falling into a beehive’ - it doesn’t matter - your perception of blue rectangles is what you call ‘blue rectangle’ - it only needs be consistent, and work consistently for you and your brain vs the world.

Furthermore, if all your internal experiences (which to me might be completely alien and wrong) blend and combine in a way that is consistent with the range of inputs (despite making no sense to my brain, were it possible to transplant the experiences) - which they would have to, or else you wouldn’t be able to function - then that would just be the way your brain deals with the world.

You can’t blend those external descriptions of the world, because they’re different - and that’s what this whole topic is about - when I look at a blue rectangle, there’s nothing blue or rectangular happening in my brain, only some sort of symbolic representation of it - like a language - and my internal language for dealing with the world may be as different from yours as spoken Spanish is from written Mandarin - or more so.

To expand on this a little more - the objection that falling into a beehive doesn’t blend with (say) the experience of the taste of something salty in the same way as red blends with yellow to make orange, might be the same as saying other languages than English can’t possibly make any sense, because the pairs of words that rhyme in English don’t rhyme in other languages.

Okay, suppose you pile on a whole LOT of data: Get a test subject, and expose him to a WHOLE BUNCH of sensory experiences, and record his reactions.

Now, suppose some of his reactions seem recognizable to you: That is, reactions that you yourself might emit, given the same stimulus. Each such data point tends to suggest that the subject is experiencing the stimulus the same way you would, more or less.

If you doubt this, then you might start trying to formulate an alternate hypothesis: Can you propose a different S-?-R mechanism that would reasonably produce the same result? Okay, maybe you can. Now, as you collect more and more examples, and increasingly complicated examples, of S/R pairings, and continue to find them predictable (that is, similar to what you would expect of your own responses or of many other subjects’ responses), then ask: Can my alternate S-?-R hypotheses cover this case too?

At some point, it becomes hard to believe that an alternate hypothesis can produce a WHOLE LOT of similar results as the null hypothesis (that we all perceive things approximately the same way). Unless your alternate hypothesis has enough cases and conditionals in it to account for a whole lot of similar responses to similar stimuli.

Occam’s Razor suggests then, that the null hypothesis (that we perceive things about alike) is much simpler and straightforward than any alternate hypothesis you can come up with, and is therefore the presumptive best theory (that is, most likely to be correct).

This is one line of thinking, by the way, that comes up in comparative psychology (comparing human psychology with other species), and has gained some degree of currency at the expense of the early-20th-century strict behaviorist view. I’ll put up a separate post with a bit of comment about that . . .

You can probably guess where I’m going with this: Going swimming with the dolphins, of course!

Dolphins, being all so cute and cuddly and playful and seeming smart and all, have inspired a fair body of cognitive research with them. You’ve all heard about those chimpanzee language projects. Well, there have been several dolphin language projects as well. And plenty of stories – and whole books – about dolphin behavior, written by people who worked with them day after day. And you’ve all read all those cutesy stories about how brilliantly genius they all are!

Okay. Let’s try to get a little bit serious.

What makes dolphins seem so “human-like” is that they react to a lot of stimuli in ways similar to ways that a human might, and in ways that we don’t immediately expect animals to do. Note, we’re talking about stimuli more complex than just ringing a bell when a light blinks.

Here’s an example (from Marine World/Africa USA, IIRC, from the days when it was in Redwood City): They trained dolphins to fetch any random objects they found in the tank and bring them to any trainer to trade for a fish. This was meant to keep the tank clear of all the random debris and trash that the stupid audience lets fall in. The trainers stand on a platform that juts out over the water a little ways. One day, a dolphin brought a fragment of a brown paper bag, and got a fish. A few minutes later, the same dolphin brought another fragment, for another fish. A few minutes later, another. Repeat several more times.

Trainer begins to wonder. Jumps in the water to see where all these fragments are coming from. Turns out, the dolphin found a brown paper grocery sack, and hid it under the platform, and then was tearing off a small piece at a time to bring to the trainer. Smart, no?

However you might imagine a dolphin is mentally processing all that, I think we’d all agree it’s complex. And it leads to a S->R that humans find very recognizable. Complex + recognizable = smart, right? Or something like that.

According to Occam’s Razor, which seems like the better hypothesis: That the dolphin is experiencing, and mentally processing, that whole elaborate sequence of S-?-R is a way similar to how a human would, or in a way completely alien to how a human would?

Combine this with all those other stories (anecdata) describing elaborately complex things dolphins do, and the case seems to get stronger. If becomes increasingly reasonable to suppose that dolphins experience and process cognitive stimuli similar to the way people do, than to suppose that they don’t.

On the other hand, dolphins don’t experience everything like people do. But, you can test for things like that, and find S/R cases that aren’t like human S/R results.

Take that philosophical argument about how we do or don’t perceive color. Most mammals, dolphins included, are color-blind or have very limited color vision. You can test for that, by training the subject on certain color perception problems, and noting how they respond differently. In principle, this is no different than how we test people for color-blindness with those color chart tests.

And you can prove that dolphins can hear ultrasonic sounds that people can’t hear – again by doing behavioral testing.

So, if people perceive various stimuli in ways very different from one another, and especially when you get into very complex and elaborate stimuli, you ought to be able to devise tests that will demonstrate this. And to be sure, you can find elaborate patterns of stimuli that different people will react to differently. (That’s why, for example, some people become Democrats and some become Republicans.) So, if there are other kinds of stimuli that just about all people react to similarly, it seems reasonable to conclude that, for those kinds of stimuli, people are in fact perceiving similarly.

The experiment would yield the same results either way. That’s the problem - people have to deal with the external world regardless of the language their brains use to represent it internally. We each have the impression that our internal representation of the world is ‘realistic’, but we could not possibly think anything else - we have grown up with it - it’s all we’ve ever known.

I think it’s quite likely that our internal models of the world are broadly similar - just because that’s a simpler answer than any alternative.

I am almaynoother onawares. And if it was all about that, egregious sir? About that and the other. If he was not alluding to the whole in the wall? The as time went on as it will variously inflected, differently pronounced, otherwise spelled, changeably meaning vocable scriptsigns.

Our perception of shapes and forms seems to be consistent, which makes sense from an evolutionary standpoint. To survive, we have to be able to correctly interpret the objective world around us. Wouldn’t it be a radical departure biologically if we evolved the ability to perceive colours but saw them differently?

I was just fighting some ignorance. Words, academic jargon words in particular, do have accepted pronunciations. I am sorry if you don’t like being politely corrected on such a point, but I don’t think it justifies this sort of directly insulting behavior.

For it to be a correction, his statement would have had to be said in earnest, rather than being an obvious joke. Jokes allow for verbal sloppiness.

If you’d said it in real life, I’d actually characterize what you said not as a gentle correction but ruining the joke with pedantry. It’s just too much like how people who do not have a sense of humor respond condescendingly to jokes. Of course, this is GQ, where pedantry is accepted as ignorance fighting, but, still, I would have better qualified the pedantry to avoid coming off as not realizing you were responding to a joke.

Otherwise, I’d very much expect a joking “insult” like you got.