Tuesday, July 15, 2008

The fallibility of the human brain

I posted a brain-teaser in Numbers don't lie?. Let me recap here:

Three men go to dine together in a restaurant. The bill comes to $25 and they each contribute $10. The waiter takes the money to the cashier, who gives the waiter the $5 in change. Being a non-assuming waiter he takes the change back to the three men. The men take back a dollar each, hence effectively paying $9.00 each, and they leave the $2.00 as a tip for the waiter. On their way out, one of them points out that they each paid $9.00 for the meal, amounting to $27.00, and the waiter was left with $2.00. What happened to the other remaining dollar? Did the cashier pocket it?

Before reading on, if you have not tried it, give this puzzle a go. I guarantee that you will have some amusing and illustrative time.

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Lets’ analyze the puzzle a bit. Firstly the line of reasoning proposed in the puzzle is wrong. The three men paid a total of $27, of which $25 went to the restaurant, and $2 went to the waiter.

The equation is very simple:
$27 = $25 + $2

You CANNOT add $2 to $27. The belong to different sides of the equation, and the result is a meaningless number.

$29 is a meaningless number, and so is the $1. It is completely meaningless to ask what happened to it.

Now the crux of the puzzle. Observe how the question was phrased. The reader was asked to figure out what happened to the missing $1. It was an intentional device to mislead the reader to believe in a false proposition – and then asked to figure it out. This is a puzzle that has stood the test of time. Most people will fall for it because it worked on a fundamental mechanism of the mind.

I had some good fun teasing a few of my colleagues a while back - all of them are pretty good programmers. A new colleague who is a fresh graduate got it right away, so I got him to shut up.

After some 10-15 minutes of puzzled look and convoluted reasoning, a couple of them are beginning to get it. But then I interjected and reassert the question: "What happened to the $1", and all of them are hopelessly lost again. A colleague that catches a ride home with me could not get it even after 3 days. He is a brilliant programmer. But every time he is getting near, I would ask the magic question, and it would throw him back into bewilderment again.

This puzzle illustrates a fundamental mechanism of the brain. The brain is a habitual machine. It learns by repetition and reinforcement. The 'learned' skills/behaviors are stored in the mid-brain, which is usually referred as the sub-conscious or the emotional brain. Once something ‘learned’ it will continue to repeat and reinforce itself until it is being replaced.

It applies to our motor reflexes, our emotional responses, and as this puzzle illustrates, even our logical/reasoning brain. Once a false conclusion is accepted it seeks to reinforce itself – and everything is reasoned using it as a starting point. This simple puzzle is particularly illustrative. The mathematics is dead simple, but even though the false proposition is leading to obvious contradictions, many people are not able to resolve it. They would rather give up than resolving the inconsistencies.

I actually think that the term sub-conscious is a misnomer. The behavioral pattern of a person is completely obvious to everybody else. But for the person concerned it is quite automatic and no longer under the awareness of the discriminative part of the brain. It applies to believe systems as well as habits of reasoning. It is actually very easy to see the bullshits and inconsistencies that someone is up to as an observer, but it can be extremely difficult to have the person concerned see it himself or herself.

This is a survival mechanism. Without it we do we will not even be able to do simple things like tying a shoe lace or riding a bicycle. There are indeed people with such functional disabilities, and many are extremely gifted in other areas, the so called idiot savants.

This survival mechanism makes us extremely vulnerable and susceptible to being manipulated. This is why propaganda is extremely effective and dangerous. The message needs not be true. In fact the message can be completely wrong and evil, and often they are. All that is needed is repetition, repetition and repetition. With the right propaganda apparatus it is easy to drive the whole country into hating each other or even killing each other.

I have always advocated boycotting Malaysia’s mainstream media. And I will say it again. Stop reading those lies and bullshits. They have been screwing us up for the past 50 years and will continue to do so until we are wizen up. Save you money, save the planet, save your discrimination, save your sanity.

We have been under the spell of Barisan Nasional racial politics for far too long. There is a lot the different races need to work together to unlearn and undo. Every race and every religion has contributed their fair share of bullshits. Be strong with each other, but have compassion as well. The voice of tolerance and cooperation has to arise otherwise I don’t think we have any chance of surviving the current local and global crises.


All have suffered. All are equally full of nonsense. Therefore, in principle, there must be a new and universal politics — a politics of no praise and no blame. By these means, reconciliation must be achieved — cooperatively, in a disposition of mutual tolerance, trust, and respect.

Adi Da
Humankind Is Literally One Family

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