Confirmation bias: One researcher called this the biggest limiter to our knowledge.

What is the biggest interference on human reasoning?

According to Psychologist Raymond Nickerson, Confirmation bias is a major contender (Nickerson 1998, 175).

So what is it, and how can we overcome it?

What is confirmation bias?

Imagine you saw two sets of data, one that confirms your beliefs, and one that goes against them.

Which would you trust?

Confirmation bias is the fact that we are more likely to trust that which confirms our existing beliefs.

That causes problems. We ignore data that goes against our beliefs and worse still, it causes us to seek data that confirms our beliefs and not look for that which disagrees with them.

And marketers use it against you too.

How marketers use confirmation bias against you

As Zig Ziglar said

“People buy on emotion and justify on logic.”

– Zig Ziglar

When we come to choose between two options, we are looking for evidence to back up our beliefs and the option we want.

And confirmation bias means we find it.

Marketers just need to give us excuse structures we want to buy what we want.

How can we overcome confirmation bias?

Badly. That’s the honest answer.

Confirmation bias affects all of us to some degree, the best we can do is try to fight it by

  • Being okay with being wrong
  • Testing your beliefs
  • Trying to disprove your beliefs

When it comes to purchases, that means laying out the clear criteria for your purchase as well as red lines.

  • What MUST it have,
  • What would be nice to have
  • What won’t work

These criteria can help guide our decisions. But confirmation bias will still affect us.


Confirmation bias causes us to look for favour evidence we like.

The best tool against it is to be humble and look for evidence to disprove our beliefs.

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