Confirmation Bias - 99% do it ; 1 % actually rise above it.

Confirmation Bias. This is so eloquently written by the psychologist Ralf Dobelli in his standout book "The Art of Thinking Clearly" which has been on the bestseller charts for years. A Swiss national by birth, I am very fascinated by this concept Confirmation Bias.

Essentially, many of us think we are very clever. Cleverer than the person next to you. If that is the case, what justifies the normal distribution curve (standard deviation) in society for IQ ? Or EQ for that matter. If everyone was so smart, there would be no 'ordinary people' in our midst.

Dobelli cited, this case of the professor who put this little experiment to a test. The esteemed professor wrote on the whiteboard the 3 numbers :

" 2 , 4 , 6 ... " 

and asked the class to do the following :

a) state the next number in the series

b) what was the basis or logic for their guess ?

He told the whole class that he had written down the basis or logic for the series of numbers.

So, 90% of the class wrote the number "8". The basis or logic for the next number was that the series was a linear arithmetic addition of 2 to the previous number.

The professor replied : "No" that was not correct.

Many in the class went " Huh ?"

We have been taught for years in primary and secondary schools arithmetic, calculus, algebra, integration and differentiation that we assume that these series are the be all the in the logical sequence of things.

Not true. 

Hence our Confirmation Bias is such that when confronted with a problem such as this, we are sure, cocksure of our theorems that it must be the correct answer - by all accounts, it may be. But it could be a subset of a much more complex or even simpler sequence.

However, as time goes by and the sequence gets expanded, we find out we are wrong and we fall flat in our face.

We all have this Confirmation Bias in our Minds. 

Answer

The logic in the Prof's mind was this " the next number must be higher than the previous one in the string"

Hence, 5,7, 10, 15 all qualifies as being correct. 

To Do 

Always fact check, and test out your theory with more data. If some doesn't fit your theory, Question your theory as being wrong. 

Many heads studying the approach and giving honest opinions MAY be better than just your own. It improves the chances of your theory ultimately being the right one.

So Question and find faults in your theory. After numerous iterations and more data, can you say, tentatively that it is correct. 

Don't let ego get the better of you. If you do, you ultimately FAIL.