Showing posts with label critical thinking. Show all posts
Showing posts with label critical thinking. Show all posts

Friday 14 February 2014

Cherry Pancakes (DIY Dress) & Confirmation Biases

Dress is DIY | bag is thrifted | shoes are thrifted | ring is DIY | cherries c/o Sarsparilly

Say hello to my brand new pancake dress! I've been planning this particular dress for months, then spent two days sewing it up all perfect, and right now I couldn't be happier with it! And you'd better believe that I wore it with my pancake-stack ring. You can never have too many pancakes. Only problem with this outfit is that I AM CRAVING FOOD ALL THE TIME. It's basic stimulus and response - I see delicious pancakes all around me, I want to make and eat delicious pancakes. All. The. Time.

I also filmed how to make sleeves and how to make a peter pan collar, the first of which was uploaded to my youtube channel the other night and the latter coming soon!

So you all know how one of my favourite science topics on this blog is the psychology of human perception, and I repeatedly tell you how you can't ever trust that your own brain is giving you an accurate representation of reality (examples here, here, here, here, here and here).
But if it's the case that our perception of reality is actually pretty awful, how is it that we can ever "know" anything? How can scientists, for example, ever "know" that one theory is better than another?

The Scientific Method & Confirmation Bias



An example. One day, your phone is ringing and for whatever reason, what immediately pops into your head is "that must be Gary*". When you answer, you are pleasantly surprised to find out that it is indeed your friend Gary calling you.
"Hey! I knew it was going to be you!" you tell Gary.

The next time your phone rings, you have the same thought: "That's Gary."
And you know who's on the other end of the line? It's your friend Gary again!
"This is getting seriously weird," you think.

A couple of days later, when your phone rings, you immediately "know" that it's Gary calling you. And guess what. It is! "Oh my gosh," you tell Gary, "I don't wanna freak you out, but I think that I'm psychic. I always know when you're calling me".

In fact, it seems like you're always getting it right whenever Gary is calling you. Thus, you develop the theory that you have psychic-phone abilities exclusively for your friend Gary.

But what you actually have is confirmation bias.

It turns out that throughout the past couple of days, other people have also called you. A couple of these times the thought of "Hey, that's Gary!" also crossed your mind, but when you picked up the phone it was actually your mum, and once, a telemarketer. But because these instances didn't confirm the above-mentioned theory, you simply forget about them. This is a case of "counting the hits and forgetting the misses". For each case that confirms your belief, you place a big fat tick against the theory. But you simply ignore the times when that didn't happen. Don't feel bad - we all fall victim to this trap, and it's an extremely human thing to do. And it's yet another reason to always second-guess your own brain.

But how can we make sure that this doesn't happen, for example, in an important scientific experiment? Well, how could we test whether or not you're truly phone-psychic for Gary? This is where the idea of "blinding" comes in.

A "Blinded" Study:
Being keen to get to the bottom of your "psychic" abilities, you invite four of your friends, including Gary, over to your house. Gary and two friends go into a separate room, where you can't hear or see them. They all have their phones with them, and they're going to take turns in calling your phone at random. Another friend sits with you - they're there to make sure you don't cheat. You have a pen and a piece of paper. "I'm ready", you say.

Your phone rings. One of your friends is randomly calling you from the other room. Obviously, you can't see a number or the caller ID. You don't answer. You write "test number one", and then write down whether or not you think it's Gary calling you. Your friends in the other room have also written down "test number one", and written down who has called you.
Your phone rings again. You write "test number two", and again you write down whether or not you think that Gary is calling you.
You repeat this 50 times.

You then meet up with your friends, and compare results.

After a statistical analysis of your results, it turns out that you were actually correct in guessing that Gary was calling you only 14.28% of the time. With these results, you abandon your psychic-phone theory.

And this is how scientists avoid confirmation bias in studies as well. A simple "blinded" test, in which you, the subject, doesn't know which condition they're in (i.e. who is calling them), but is still able to respond, can help to eliminate this very human thing we do called confirmation bias.

Read more about blinding in studies (and double-blinding) here.

*Gary bears no resemblance to anyone I know in real life; I named him after Spongebob's snail.

I hope that you have a great day!







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Sunday 9 February 2014

Ghosts and Witches

Shirt, skirt, hat and socks are all thrifted | Shoes are no longer for sale

When you decide to buy most of your clothes second-hand, you have to get over being grossed-out by unclean things first. Don't get me wrong, most of the op-shops that I visit are wonderful; everything has been super-dooper cleaned, though I still always give things a wash after bringing them home. This particular shirt, however, I bought from a market stall the other day and it had obviously been sitting around in someones closet - unclean - for a very long time. When I got home I decided to try it on to see how it fit. I plunged my arms in and a ridiculous volume of sand and lint shot out the other end. I was so shocked to have half a beach suddenly on my bedroom floor, and amazed that neither the seller nor I had realised the large amount of sand residing within the sleeves.
However, as surprising and sometimes gross as they can be, I think that second-hand clothes are more interesting than new clothes because of the questions they raise about the past owners, and what they were doing while they were wearing them. Why was the past owner wearing such a fancy blouse to the beach? Maybe they weren't dressed for the beach and ended up there by accident? And lastly, how on earth didn't they manage to shake all the sand out of the sleeves?

To finish my post today, the following is a quote from science and psychology writer Guy P. Harrison that I really liked, and made into a little image:


You can test just how bad your brain is at giving you an accurate representation of the world here and here.







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