Our brains prefer invented visual information to the real thing

4

By Clare Wilson

Seeing shouldn’t always be believing. We all have blind spots in our vision, but we don’t notice them because our brains fill the gaps with made-up information. Now subtle tests show that we trust this “fake vision” more than the real thing.

If the brain works like this in other ways, it suggests we should be less trusting of the evidence from our senses, says Christoph Teufel of Cardiff University, who wasn’t involved in the study. “Perception is not providing us with a [true] representation of the world,” he says. “It is contaminated by what we already know.”

The blind spot is caused by a patch at the back of each eye where there are no light-sensitive cells, just a gap where neurons exit the eye on their way to the brain.

We normally don’t notice blind spots because our two eyes can fill in for each other. When vision is obscured in one eye, the brain makes up what’s in the missing area by assuming that whatever is in the regions around the spot continues inwards.

Continue reading by clicking the name of the source below.

4 COMMENTS

  1. Stephen, How are you? I don’t think the article takes it quite this far, but regarding Plato’s immortal allegory, Schopenhauer had this to say:

    What Plato says is this: — “The things of this world which our senses perceive have no true being; they always become, they never are: they have only a relative being; they all exist merely in and through their relations to each other; their whole being may, therefore, quite as well be called a non-being. They are consequently not objects of a true knowledge, for such a knowledge can only be of what exists for itself, and always in the same way; they, on the contrary, are only the objects of an opinion based on sensation. So long as we are confined to the perception of these, we are like men who sit in a dark cave, bound so fast that they cannot turn their heads, and who see nothing but the shadows of real things which pass between them and a fire burning behind them, the light of which casts the shadows on the wall opposite them ; and even of themselves and of each other they see only the shadows on the walL Their wisdom would thus consist in predicting the order of the shadows learned from experience. The real archetypes, on the other hand, to which these shadows correspond, the eternal Ideas, the original forms of all things, can alone be said to have true being, because they always are, but never become nor pass away. To them belongs no multiplicity; for each of them is according to its nature only one, for it is the archetype itself, of which all particular transitory things of the same kind which are named after it are copies or shadows. They have also no coming into being nor ‘passing away, for they are truly being, never becoming nor vanishing, like their fleeting shadows. (It is necessarily presupposed, however, in these two negative definitions, that time, space, and causality have no significance or validity for these Ideas, and that they do not exist in them.) Of these only can there be true knowledge, for the object of such knowledge can only be that which always and in every respect (thus in-itself) is; not that which is and again is not, according as we look at it.” This is Plato’s doctrine.

    —Schopenhauer, World as Will and Representation, Volume 1

  2. Hi Dan,

    I’m well, thank you for asking, and you?

    As far as Schopenhauer is concerned; Mods, please bear with, I will link back to the OP … eventually …

    The things of this world which our senses perceive have no true being;
    they always become, they never are: they have only a relative being;
    they all exist merely in and through their relations to each other;
    their whole being may, therefore, quite as well be called a non-being

    Well, isn’t that just too easy Shoppie?

    You perceive that there may be things beyond human understanding; you perceive that we may only sense things as mere phantoms of their true reality.

    Wait, you perceived this … oh, never mind.

    You therefore claim, by fiat, that all the things which our senses perceive have no true being. I remain unconvinced. Prove it.

    All the rest of your assertions, Shoppie, appear to rely on this first assertion – unless I am deceived?

    In the more modern World we know this instinct to be partly true. We have learned to extend our senses by inventing instruments that bring phenomena beyond those senses within their range. X-Rays are an example.

    Now, before we get too comfortable Shoppie, there are some uncomfortable truths to be explored. Circle the wagons, empiricists!

    The first thing to be considered is: How do we know we can trust our senses? The OP – ooh I got there earlier than I expected – is using a headline that suggests our brains are attuned to invented information. Failing to judge the story by its headline, I made the mistake of actually reading the whole story. In précis the story begins by making an assertion – Shoppie style:

    NS: [Someone] who wasn’t involved in the study said: Perception is not providing us with a [true] representation of the world … it is contaminated by what we already know

    Already suspicious, I nevertheless plowed on …

    The piece goes on to describe a series of experiments – it’s a very short report, read it.

    I suffered a sharp pain in my pre-frontal cortex when I got to the part:

    … our two eyes can fill in for each other. When vision is obscured in one eye, the brain makes up what’s in the missing area by assuming that whatever is in the regions around the [blind] spot continues inwards

    One would have thought that the most obvious advantage of binocular vision is that the fields of view overlap and that each eye therefore fills in missing info. from the other, including – drum roll please – the blind spots? To be clear: Yes, I understand that if I close one eye a blind spot does not appear in my field of view – therefore the brain is indeed filling-in.

    I took a stiff drink, put on my pith helmet, and re-entered this tangled jungle of nonsense. To remind ourselves, the object of the exercise is to answer the question:

    … do we subconsciously know that this filled-in vision is less trustworthy than real visual information?

    Now, it came to pass, Mormon style, that I remembered that New Scientist has of late been guilty of less-than-stellar communication. Maybe what I was witnessing was in fact not a failure by the researchers but, rather, a journalism failure? Surely not.

    The paper seems to me to be very unclear about the experiment design, and I may be unfair to judge it on that basis. The paper says [abridged]:

    We evaluated two hypotheses on how perceptual decision-making could proceed when people are confronted with an ambiguous decision between true and inferred perceptions
    .

    They are unable to make decisions based on an assessment of differences in reliability between true and inferred stimuli
    .
    They use the information about the reduced reliability of filled-in information to make better than guesswork decisions

    In hypothesis 1: Test subjects would have an equal chance of selecting stimuli presented inside or outside the blind spot (in English: If people are not aware of new information hidden in their visual blind spots their choice of which is true between two patterns is no different to a guess).

    In hypothesis 2: Test subjects are advised that there may be new information in their blind spots for one pattern (one eye). Providing they trust the stimulus presented to the other eye – where the complete stimulus is seen – test subjects will tend to trust that this must, therefore, be more likely to be true and will select the true pattern over the inferred pattern far more often.

    But does the experiment design support that study? Does it answer the question?

    The experiment appears to miss the problem of psychology: You can lead a horse to water but you can’t make it drink. If we tell test subjects that there is something hidden we immediately play to their (our) innate theory of other minds – the What is the real game here? problem.

    Also, nowhere that I can see does the paper explore the question: Do we know that this filled-in vision is less trustworthy than real visual information? I may be at fault here but the paper itself seems clear on the point that there are two hypotheses it is testing and neither answers the above question.

    Also 1,000 people is a lot – but is it enough to be statistically significant for all humans?

    I may have that completely wrong (it’s late, I’m tired, the paper is long … ) and I’ll review it again another time. That still, however, doesn’t let NS off the hook, not only have they missed a golden opportunity to explore exactly the questions I have scratched the surface of, there’s this:

    If the brain works like this in other ways, it suggests we should be less trusting of the evidence from our senses

    If? IF? IF?!

    Back to Shoppie:

    … true knowledge … can only be of what exists for itself …

    Yes, very motherhood and apple pie. I read somewhere that Philosophers make a living out of stating the obvious in the most obscure way possible – that’s unkind, obviously …

    So long as we are confined to the perception of these, we are like men who sit in a dark cave, bound so fast that they cannot turn their heads, and who see nothing but the shadows of real things which pass between them and a fire burning behind them … Their wisdom would thus consist in predicting the order of the shadows learned from experience

    I’m supposed to be impressed by a setup? The allegory of the cave is a myth.

    Humans do not live in a place where we cannot move our heads, and we move about and explore ways to overcome the many shortcomings of our senses – that’s how we discovered X-Rays and how we came to know them so well we use them every day.

    Now, if you’re a Shoppie you may be impressed by severe cases of solipsism – and if you are, good luck with that.

    If you’re a Shoppie you may seize on the blind spot data and say: Aha!

    Yes, it’s true, we have limitations of perception and the indications are that we may one day reach that limit. Does that worry me as I live a longer, more stimulated and healthier life than every one of my forebears ? No. Do I think these advantages have been presented to me by an exploration of truth? Duh.

    If you’re a Shoppie you may claim that there are truths affecting our lives of which we have no knowledge. I call you what you are: Charlatan.

    No, I can’t prove that the universe didn’t just blink into existence – complete with history and memories. But how probable is it?

    To them belongs no multiplicity; for each of them is according to its nature only one, for it is the archetype itself, of which all particular transitory things of the same kind which are named after it are copies or shadows

    Nice one Shoppie, making a few shekels out of that one aye.

    They have also no coming into being nor ‘passing away, for they are truly being, never becoming nor vanishing, like their fleeting shadows. (It is necessarily presupposed, however, in these two negative definitions, that time, space, and causality have no significance or validity for these Ideas, and that they do not exist in them.)

    Whatever.

    Peace.

Leave a Reply