Video: Flashing creates illusion of motion
There are flaws in our intuitive beliefs about what makes us who we are. Who are we really?
Read more: "The great illusion of the self"
THERE appear to be few things more certain to us than the existence of our selves. We might be sceptical about the existence of the worldaround us, but how could we be in doubt about the existence of us? Isn't doubt made impossible by the fact that there is somebody who is doubting something? Who, if not us, would this somebody be?
While it seems irrefutable that we must exist in some sense, things get a lot more puzzling once we try to get a better grip of what having a self actually amounts to.
Three beliefs about the self are absolutely fundamental for our belief of who we are. First, we regard ourselves as unchanging and continuous. This is not to say that we remain forever the same, but that among all this change there is something that remains constant and that makes the "me" today the same person I was five years ago and will be five years in the future.
Second, we see our self as the unifier that brings it all together. The world presents itself to us as a cacophony of sights, sounds, smells, mental images, recollections and so forth. In the self, these are all integrated and an image of a single, unified world emerges.
Finally, the self is an agent. It is the thinker of our thoughts and the doer of our deeds. It is where the representation of the world, unified into one coherent whole, is used so we can act on this world.
All of these beliefs appear to be blindingly obvious and as certain as can be. But as we look at them more closely, they become less and less self-evident.
It would seem obvious that we exist continuously from our first moments in our mother's womb up to our death. Yet during the time that our self exists, it undergoes substantial changes in beliefs, abilities, desires and moods. The happy self of yesterday cannot be exactly the same as the grief-stricken self of today, for example. But we surely still have the same self today that we had yesterday.
There are two different models of the self we can use to explore this issue: a string of pearls and a rope. According to the first model, our self is something constant that has all the changing properties but remains itself unchanged. Like a thread running through every pearl on a string, our self runs through every single moment of our lives, providing a core and a unity for them. The difficulty with this view of the self is that it cannot be most of the things we usually think define us. Being happy or sad, being able to speak Chinese, preferring cherries to strawberries, even being conscious – all these are changeable states, the disappearance of which should not affect the self, as a disappearance of individual pearls should not affect the thread. But it then becomes unclear why such a minimal self should have the central status in our lives that we usually accord to it.
The second model is based on the fact that a rope holds together even though there is no single fibre running through the entire rope, just a sequence of overlapping shorter fibres. Similarly, our self might just be the continuity of overlapping mental events. While this view has a certain plausibility, it has problems of its own. We usually assume that when we think of something or make a decision, it is the whole of us doing it, not just some specific part. Yet, according to the rope view, our self is never completely present at any point, just like a rope's threads do not run its entire length.
It seems then as if we are left with the unattractive choice between a continuous self so far removed from everything constituting us that its absence would scarcely be noticeable, and a self that actually consists of components of our mental life, but contains no constant part we could identify with. The empirical evidence we have so far points towards the rope view, but it is by no means settled.
Even more important, and just as troublesome, is our second core belief about the self: that it is where it all comes together.
It is easy to overlook the significance of this fact, but the brain accomplishes an extremely complex task in bringing about the appearance of a unified world. Consider, for example, that light travels much faster than sound yet visual stimuli take longer to process than noises. Putting together these different speeds means that sights and sounds from an event usually become available to our consciousness at different times (only sights and sounds from events about 10 metres away are available at the same time). That means the apparent simultaneity of hearing a voice and seeing the speaker's lips move, for example, has to be constructed by the brain.
Our intuitive view of the result of this process resembles a theatre. Like a spectator seated in front of a stage, the self perceives a unified world put together from a diverse range of sensory data. It would get confusing if these had not been unified in advance, just as a theatregoer would be confused if they heard an actor's lines before he was on stage. While this view is persuasive, it faces many difficulties.
Consider a simple case, the "beta phenomenon" (see diagram and video above). If a bright spot is flashed onto the corner of a screen and is immediately followed by a similar spot in the opposite corner, it can appear as if there was a dot moving diagonally across the screen. This is easily explained: the brain often fills in elements of a scene using guesswork. But a tweak to this experiment produces a curious effect.
If the spots are different colours – for example a red spot followed by a green spot – observers see a moving spot that changes colour abruptly around the mid-point of the diagonal (see "Spotted trick"). This is very peculiar. If the brain is filling in the missing positions along the diagonal for the benefit of the self in the theatre, how does it know before the green spot has been observed that the colour will switch?
One way of explaining the beta phenomenon is by assuming that our experience is played out in the theatre with a small time delay. The brain doesn't pass on the information about the spots as soon as it can, but holds it back for a little while. Once the green spot has been processed, both spots are put together into a perceptual narrative that involves one moving spot changing colour. This edited version is then screened in the theatre of consciousness.
Unfortunately, this explanation does not fit in well with evidence of how perception works. Conscious responses to visual stimuli can occur at a speed very close to the minimum time physically possible. If we add up the time it takes for information to reach the brain and then be processed, there is not enough time left for a delay of sufficient length to explain the beta phenomenon.
Perhaps there is something wrong with the notion of a self perceiving a unified stream of sensory information. Perhaps there are just various neurological processes taking place in the brain and various mental processes taking place in our mind, without some central agency where it all comes together at a particular moment, the perceptual "now" (see "The self: You think you live in the present?"). It is much easier to make sense of the beta phenomenon if there is no specific time when perceptual content appears in the theatre of the self – because there is no such theatre.
The perception of a red spot turning green arises in the brain only afterthe perception of the green spot. Our mistaken perception of the real flow of events is akin to the way we interpret the following sentence: "The man ran out of the house, after he had kissed his wife". The sequence in which the information comes in on the page is "running–kissing", but the sequence of events you construct and understand is "kissing–running". For us to experience events as happening in a specific order, it is not necessary that information about these events enters our brain in that same order.
The final core belief is that the self is the locus of control. Yet cognitive science has shown in numerous cases that our mind can conjure, post hoc, an intention for an action that was not brought about by us.
In one experiment, a volunteer was asked to move a cursor slowly around a screen on which 50 small objects were displayed, and asked to stop the cursor on an object every 30 seconds or so.Self-delusion
The computer mouse controlling the cursor was shared, ouija-board style, with another volunteer. Via headphones, the first volunteer would hear words, some of which related to the objects on screen. What this volunteer did not know was that their partner was one of the researchers who would occasionally force the cursor towards a picture without the volunteer noticing.
If the cursor was forced to the image of a rose, and the volunteer had heard the word "rose" a few seconds before, they reported feeling that they had intentionally moved the mouse there. The reasons why these cues combined to produce this effect is not what is interesting here: more important is that it reveals one way that the brain does not always display its actual operations to us. Instead, it produces a post-hoc "I did this" narrative despite lacking any factual basis for it (American Psychologist, vol 54, p 480).
So, many of our core beliefs about ourselves do not withstand scrutiny. This presents a tremendous challenge for our everyday view of ourselves, as it suggests that in a very fundamental sense we are not real. Instead, our self is comparable to an illusion – but without anybody there that experiences the illusion.
Yet we may have no choice but to endorse these mistaken beliefs. Our whole way of living relies on the notion that we are unchanging, coherent and autonomous individuals. The self is not only a useful illusion, it may also be a necessary one.
This article appeared in print under the headline "What are you?"I am the one and only
Think back to your earliest memory. Now project forward to the day of your death. It is impossible to know when this will come, but it will.
What you have just surveyed might be called your "self-span", or the time when this entity you call your self exists. Either side of that, zilch.
Which is very mysterious, and a little unsettling. Modern humans have existed for perhaps 100,000 years, and more than 100 billion have already lived and died. We assume that they all experienced a sense of self similar to yours. None of these selves has made a comeback, and as far as we know, neither will you.
What is it about a mere arrangement of matter and energy that gives rise to a subjective sense of self? It must be a collective property of the neurons in your brain, which have mostly stayed with you throughout life, and which will cease to exist after you die. But why a given bundle of neurons can give rise to a given sense of selfhood, and whether that subjective sense can ever reside in a different bundle of neurons, may forever remain a mystery.Graham Lawton
Jan Westerhoff is a philosopher at the University of Durham, UK, and the University of London's School of Oriental and African Studies, and author of Reality: A very short introduction (Oxford University Press, 2011)