Here's an experiment. Look around the room you're in and notice all the yellow things.
Little yellows, big yellows, off yellows, odd yellows. Yellow, right. Yellow.
Then, without looking up or around any more, try to list all the red things in the room.
Tricky, eh?
That little loop of seeing what we look for and believing what we see.
That's one reason why people are so shocked at things like election results not going according to popular plan.
But, but, but, we cry, my social media feed was completely green.
Green everywhere.
What happened?
Targeted ads, like-minded people, deadly basilisk algorithms - they all reinforce what we thought we were looking for.
Still, blinkeredness, or confirmation bias, has its uses.
If you pay attention only to media that either tells you what you already suspect to be true or things you'd like to believe, you live in the world you want to, regardless of the handcarts of hell tolling the other point of view.
Take coffee. Yes please, I will. Medium black thanks. No sugar. No, I'm not anti-sugar. Just very pro coffee.
And stoked to read this week that three to five cups a day is actually brilliant for you and that sitting on the sofa with a whole pot of coffee and a newspaper, surrounded by wireless radio waves, can only do good things for your body and brain.
Perhaps I made the last bit up but see, don't you feel better about your hyper-yellow wi-fried coffee-filled life, now you've had that particular bias confirmed?
You've got be a bit careful, though.
A while ago a good friend decided to try to eat right for her blood type.
Which has a catchy ring to it and definite merit when you consider type B people are supposed to munch primarily on red meat, wine, coffee and chocolate.
And live forever and have genius children.
Yezzah! More coffee!
What a brilliant theory.
What a great lifestyle choice.
It confirmed everything I thought I needed in a healthy outlook.
I fully, totally, scientifically agreed.
For days at least.
Except then I realised I am a blood type A, and who really wants to subject themselves to a forevermore of grains?
Rubbish idea, I always knew it.
Who would organise their model of the world around their blood type?
Pah.
Confirmation bias is at work everywhere, from shut up you noisy child, to honey, I looked really hard and I'm absolutely sure the butter isn't in the fridge.
Are we wired that way?
To seek to reinforce what we think we know?
What we know from when?
How far back does it go?
Is it that we look for safety in shared information, territory and beliefs, as in churches and social media groups, or as birds of a feather migrating to Earl's Court flats together?
One of the sneakily interesting things about confirmation bias is that the smarter we think we are, the more likely we are to suffer from it.
True.
When we think we know how something is, we're actually less likely to engage with other perspectives.
It's the same for people with uberstrong religious or political convictions.
Not necessarily clever people. Given a set of articles to read, they're more likely to go to the ones that reinforce what they already think.
It's as Terry Pratchett wrote: ''What people think they want is news, but what they really crave is olds.''
Too conformable, comfortable.
Too busy looking at the yellow.
So if perceived cleverness keeps us blinkered, what's going to save us from living in our more and more disparate realities?
Actively engaging with other opinions, perhaps.
Kindness.
An open mind.
Being blooming grateful that other viewpoints exist, that we don't live in a monostate.
Accepting that there is another way.
No, wait, that there are many other ways.
Yellow is not the only colour.
Coffee (though it pains me to admit it) is not always the saviour.
• Liz Breslin