The Matrix that is Your Mind

I have been banging on about how our brain constructs our reality in my books, lectures and most recently the Royal Institution Christmas Lectures (which are now permanently up on the Ri Channel). This reality even includes our sense of self – book out in a couple of months! The examples I usually give come from Gaetano Kanizsa’s seminal work with subjective contours. Not only do you see illusory shapes but you can record from brain regions that register these illusions as if they are really there.

Recently, a group of vision scientists demonstrated that individuals who were told that there were faces present in half of 10,000 random dot images believed that they detected them. Not really that surprising because we tend to believe what people (especially scientists in white coats) tell us. For me the interesting finding was differential brain activity on trials when they thought there was a face present.

Differential brain activity is a bit of a methodological nightmare as the past decades of brain imaging research has proven. What does that activity mean? There are a number of real problems unpicking what this activity reflects. I don’t think imaging by itself is going to convince critics. But here is one demonstration that I learned about this week that blew my mind for elegance. Take a look at these images.

A brightness illusion - the centre on the left looks brighter

This is beautiful brightness illusion. The centre of the pattern on the left looks much brighter – but it isn’t – it’s an illusion. But here’s the kicker. If you measure pupil size of the viewer, there is significant decrease in pupil size. This is normal response to brightness and has always been considered a basic low level reflex to calibrate for the amount of light entering the eye. Clearly, an illusion produces a change in the brain and its activity from the top-down all the way to lower level mechanisms.

The British philosopher Julian Baggini recently presented a great TED talk on the self “Is there a real you?” which I highly recommend. It is aimed at a young audience but none the less makes some critically important points. However, I think that he has misrepresented my position (and Susan Blackmore’s) when I say that the self is an illusion. That’s because I don’t think that Baggini (and many other smart people) understand my use of the term “illusion.” An illusion is not what it seems and I make this point explicit every time I talk about the mind.

The experience of self is very real, just like illusions, and this sense may even produce changes that are measurable. But consider the reality of ghosts. If we think we see a ghost, then to all intents and purposes, effectively we have. That does not make ghosts real. In the same way, if we think we have a self, and indeed measure activity of the self, that also does not make it real. Just like the Matrix, you do not have any direct contact with reality.

20 Comments

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20 responses to “The Matrix that is Your Mind

  1. Zuleika Brown Yanez

    Do you mean that illusions exist, as a positive ontological thing, that an illusion has in a sense existence? That seems a little confusing as it seems to be saying something (self) is real in being a not real thing. Illusion seems to have an idea of not real (ontologically) as part of the idea of what an illusion is, but interesting idea to perceive it as something defensibly real just not as it seems. Has Susan Blakemore written about this? I’d love to read more about this idea.

    • brucehood

      I am not sure what you mean as a positive ontological thing but let me put it another way. A hole is a real thing in that it is something you can pass through but clearly it is not there. My contention is that people perceive that the hole is real when in fact it is defined by the surround. Does that help?

      • Zuleika Brown Yanez

        Thank you for your reply. I’m beginninh to realise that illusions are much more complex than I previously thought. Very interesting subject. Look forward to reading the full book.

  2. Rox

    This is a beautifully produced illusion, but really a very familiar one. Every time you look at a photograph or painting and see a bright light (for example, a street light at night) it is only the whiteness of the paper.

  3. Zuleika Brown Yanez

    Thinking on this a little more. Would it be accurate to say that you accept that we have subjective experiences (which are in fact brain states) and the brain causes or interprets these subjective experiences in such a way that it seems to us (but is illusion) there is an observer within us who is aware of the experiences happening when in fact there is no observer who is aware of the experiences over and above the experiences themselves?

    • brucehood

      Yes, that is what I am saying exactly – well done – I have trouble with it myself sometimes.

    • Rox

      I find this very convincing, but surely there is a real observer of real experiences. There is a street lamp and we do observe it. Only then is our real observation of real light on the retina converted to the subjective experience, and thus to the non-observation that you describe. But it is based on reality, or we would never have hunted wild animals successfully and evolved into internet browsers.

      There are points in the history of Art where this is crucial. The pre-Raphaelites were trying to reproduce in one picture every tiny detail, every blade of grass, just as it is, just as they rationally knew it to be from close and detailed observation. On the other hand, Turner and the Impressionists knew that you can’t be aware of all these details all at once, and were aiming more at the “impression” or “subjective experience” of a scene.

      With the coming of photography, everyone seemed to accept that the camera cannot lie, and that was the end of it. Not really: for one thing, for many years most photographs and films were in black and white, and the brain had to get used to interpreting this as if it were “real”. When we are suddenly exposed to a black and white film nowadays, it takes a while to adjust into this skill. Then there is the technical necessity in many photographs of some distances being out of focus, and this is readily accepted by the brain because if you are concentrating on something nearby you are not usually interested in distant things at the same time, even if they are technically in focus on the retina.

      Time and opportunity comes into this too. If there was a quick distant movement and it is then gone, the brain only has time to know that there was a movement, which it may decide to sent the body towards or away from. In an exhibition, one might walk past the pictures and gain a sequence of impressions; but if there is a pre-Raphaelite hanging on the wall day and night at home, there is time to examine every detail just like the room itself. So the first subjective impression would prove inadequate. There would be more than had met the eye initially, revealing the details of the scene laboriously painted; whereas if it was an Impressionist at home, what would become increasingly obvious would be the details of the technique the artist had used to create the original impression.

      • roxks

        I wanted to get a little picture to go with this, but I found that the only way to do it was to change my name from rox to roxks, because three letters is not acceptable, and everything else vaguely similar is already in use by someone else.

        Funny this, because rox always seems to have worked perfectly well !

        Anyway, please note that rox and roxks are the same person.

      • Rox

        People are sending me their seasonal photographs of snow scenes. Paradoxically, it is only the dark shadows, especially around indentations in the snow, which make the snow seem real, white, and even bright.

  4. It is quite something to see scientists (and atheists, for that matter) tackling topics like free will or illusions when they clearly have not explained their respective definitions. Although I am a fan of Baggini for taking on the Atheists’ hijacking of science.

    I’m not up on the properties of light, but regarding the picture: obvioiusly there is no light coming through the center. But if there were a measure of reflectivity, the picture on the left would measure higher, would it not? There must be something making the pupil respond.

  5. Anonymous

    Well, maybe Rox will do !

    Wonderful things, computers.

    (But I don’t know if this will show as Rox or Roxks)

  6. Rich

    The ‘illusion’ here is created and augmented by the contrast and gradient of light intensity in the diagram . Perhaps the narrowing of the pupil occurs because the retina does not like too much contrast in one area .
    For the left diagram there is a first contrast between the ring of ‘petals’ and the white page at the periphery and then a second between the centre and the petals (with a subliminal signal of rising intensity given by the isertion of a colour gradient ?) . The inner white is no brighter than the outer in either diagram but the contrast in the right hand diagram only occurs once at its central circle , the second being dissipated by the tapering black petals into a much greater area .

    I’m very much thinking that there is a distinct drift towards ‘all is illusion’ in this thread . While in oriental mode and thinking of your ‘hole’post – I’ll throw in a verse from the Tao Teh Ching :

    11. The Utility of Not-Being

    Thirty spokes unite around the nave;
    From their not-being (loss of their individuality)
    Arises the utility of the wheel.
    Mold clay into a vessel;
    From its not-being (in the vessel’s hollow)
    Arises the utility of the vessel.
    Cut out doors and windows in the house (-wall),
    From their not-being (empty space) arises the utility of the house.
    Therefore by the existence of things we profit.
    And by the non-existence of things we are served.

    I greatly enjoyed those Tele-lectures too , you really should not be surprised to have a lot of young fans ! All the best .

  7. Sheree Curtin

    I know what the Matrix is, Bruce. I have woken up within it. The matrix is what you are left stuck in when you realise that you reincarnate. You realise that all the people around you are crazy. That they are nuts because they think that they are human. That they have been brainwashed by tv, media, intellectuals, education. Then you realise that they are all trying to kil you with their flouride, talking
    of final death, sugar in your food.
    You find out that you didn’t come from this world. That this isn’t your home. That you came from the discarnate world. And you long to go home to that place where you don’t have to reeducate those around you anymore.
    Add ‘close minded skeptics’ to those people who are nuts. The science has already proven that they are.

  8. Nonmystical

    I don’t quite get the assertion of fact: “there is NO ‘you’ inside your head.” Certainly there is “part” of me… and pretty darn important part of “me”… inside my head. In a more objective, non-mystical sense, the “THING” you identified as having a head (which I will label as “me” to which the word “your” is directed) and which by reference thereto you have asserted implicitly is real (an existent, a physical system which you are addressing), surely does not have a physical existence extending beyond, nor encompassing and including things outside of, the “thing’s” physical body… that “connectedness” is starting to sound too mystical and superstitious.
    I am confused, somewhere between being inside my body and not in my head… could you clarify?

  9. Nonmystical

    OK First here’s a link to a web site with >90 optical illusions (many interactive) which also includes some info about what actually is happening according to what scientists know.
    http://www.michaelbach.de/ot/
    Second: It just dawned on me that the “common” usage of the word “head” can denote not only the concept of the knobby bit at the top of a human, but also the brain inside the knobby bit. Unfortunately when I read the “subtitle” on the UK book cover, I immediately misapprehended the meaning of “head” to be “skull”. I am so embarrassed and no longer am I confused.
    I am completely in agreement, since I have always identified “me” with a brain (and perhaps the extended me as my life support system, appendages, and such), ergo, taking “head” to mean “brain”, then, according to logic (and science as shown by yourself), there can be no ‘me’ inside my “head” because I *am* a brain (head=brain), and something cannot at once be “a thing” and also only be “inside the thing”. Of course no one is disputing the fact that there is a “me” (brain) in my skull… which is what I was initially confused about and somewhat disturbed by.
    When I was very young I used to have lucid dreams, and upon reflection at the time (I was a very inquisitive and thoughtful child), I became aware of the fact that I was never “inside” a dream, the character I identified with admittedly was, but so were all the other characters, and the buildings and the sky… all of what was being imagined was inside me. I knew right then that my identification with the “character” who was “me” was incorrect, although I did accept the fact that it at least was a psychological locus, or vantage point for me, sort of like how my eyes form a physical viewing vantage point for me (my sight) even though I am not “at” my eyes… if that makes any sense.

  10. Chrissy Philp

    As I said, I have a model of mind that needs to be checked out. It suggest the sense of self is created by entailed opposites within the brain. Here is an example of one of the opposites; looking/seeing. See the front door of your home in your mind’s eye (imagination). Now look at this computer screen. Can’t do both at once yet they work together. You know it’s a computer screen because you have a memory (seeing) of what a computer screen is. Consiousness can only be in one end of opposition at a time. According to model sense of self results from tension between opposing modes of perception.