The truth may be out there, but it sure ain’t in here.

If you think your senses give you a direct line to reality, you might be in for a shock. In Mind Tricks: Six ways to explore your brain, the cover story of a recent issue of New Scientist, Graham Lawton explores many of the ways our brains mislead us about the alleged real world.

Lawton compares the workings of our visual system to ‘a man blundering around in the dark waving around a flickering torch with a very narrow beam’. This is because our eyes continually dart about, processing pretty much nothing in between these fraction-of-a-second fixations.

Even face perception is wonky. When we look at a face we’re biased toward the left side – as processed by the right cerebral hemisphere. We perceive a chimeric face (a composite image with one side neutral and the other smiling) as whatever expression is on the left.

Nor is our hearing system any more reliable. Much of what people say to us is distorted, but we happily fill in the blanks through top-down influence – that is, we use what we know to round out what we hear. Listen for yourself how ‘knowing’ changes hearing.

Not only do the visual and auditory system each perpetrate their own trickery, they can also obscure one another. Sometimes seeing wins – as when the sound ‘ba ba ba ba’ is overridden by seeing someone mouth ‘ba da la va’. At other times sound trumps sight – as when a single flash accompanied by two beeps appears as two flashes.

Okay, so our tools of perception don’t exactly map reality one-to-one. But it gets worse. The information bits we process, however dysfunctionally, are only the bits we notice – and we only notice what’s relevant right now, carelessly filtering out the rest.

We suffer change blindness, can only attend to five or six items at most, completely miss gradual changes (you might need to jiggle the control to see what you missed) and even fail to realize that the person who asked us directions before a pair of door-carrying workmen passed between us is not the person we directed to the post office. If you think it wouldn’t happen to you, try to count the number of passes made by the basketball team wearing white T-shirts.

Lawton also explores how easy it can be to plant a false memory – as was done to Alan Alda (they made him think he’d been a doctor during the Korean War – only kidding! – it was a memory of overeating eggs as a child); and how implicit assumptions can lead to prejudices we don’t even know we have. Or did I just think he did all that?

My 2 cents

The approximations, simplifications and distortions entertainingly highlighted by Lawton are designed to help us navigate all the data we’re exposed to and zero in on what matters most. If we received all the external inputs ‘correctly’, whatever that means, we’d suffer information overload in the truest sense – we just wouldn’t be able to process it. So funky perception is good. Most of the time it gives us what we need.

What’s it got to do with happiness?

Well, it shows we make a lot of stuff up – what we see, what we hear, what we notice, what we completely miss, what we remember. Our perceptions are by no means an exact representation of what’s out there. Given all the filling in and leaving out, it makes sense to recognize the bias in how we perceive the world. Perhaps we can even choose our own bias – one that helps us to be happy rather than one that makes us miserable.

Now let’s take another look at that glass.