Wednesday, 8 February 2012

Cognitive Illusions

or how your mind plays tricks on you.

People who regularly read my blog may be aware that I have a keen interest in psychology and how it can relate to testing. If you have not read my blog before wow welcome first timer I hope you enjoy and come back for more articles in the future.

I have in the past written a few articles about bias (here, here, here and here) and how it can be dangerous when we are testing. Having just read an excellent book called Bad Science by Ben Goldache I thought I would revisit this subject since Ben has a whole chapter on this very subject called

‘Why Clever People Believe Stupid Things’

It is a very interesting chapter and it made me re-think about the need to be careful when we are testing and reporting what we believe has happened. The human mind is a tricky beast and there are various methods it uses to try and trick us into believing things which are not true.

For example take a look at the following picture by French artist Felice Varini (the site is in French) This is a fantastic anamorphic illusion in which our mind joins all the pieces together to make us see something that in reality is not real.

Looking at it from a different perspective shows us this.

An important lesson in testing is not to look at things from only one point of view. See how our mind tricks us in to thinking something is real when it is not.

Ben Goldache manages to breakdown some of the common tricks our mind plays into the following:

# Randomness
# Regression to the Mean
# The bias towards positive evidence
# Biased by our prior beliefs
# Availability
# Social influences

Which he concludes with the following statements

1 - We see patterns where there is only random noise.
2 - We see causal relationships where there are non
3 - We overvalue confirmatory information for any given hypothesis.
4 - We seek out confirmatory information for any given hypothesis.
5 - Our assessment of the quality of new evidence is biased by our previous beliefs.
6 - Our assessment of the quality of new evidence is biased by our social influences.

(I added the 6th one myself)

Once we become aware of these illusions that our mind plays on us we can start to put practices in place they helps to try and remove them. I should warn you it is impossible to remove them entirely since we are only human after all, but being aware that they exist is a good start.

Over the next few blog articles I will be taking each one of these topics and applying it to testing

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