Confirmation Bias

… a core concept used in Implementation and Delivery and Atlas107

Concept description

ScienceDaily (reference below) defines confirmation bias (or confirmatory bias) as “a tendency to search for or interpret information in a way that confirms one’s preconceptions, leading to statistical errors.”

ScienceDaily goes on to say:

“Confirmation bias is a type of cognitive bias and represents an error of inductive inference toward confirmation of the hypothesis under study.

“Confirmation bias is a phenomenon wherein decision makers have been shown to actively seek out and assign more weight to evidence that confirms their hypothesis, and ignore or underweigh evidence that could disconfirm their hypothesis.

“As such, it can be thought of as a form of selection bias in collecting evidence.”

As Peter Wehner (reference below) writes in the New York Times that confirmation bias helps to explain political polarization:

“I’m convinced we’re seeing a severe case of confirmation bias, the tendency to interpret new evidence as confirmation of one’s existing beliefs.

“But here’s the thing: What’s easy to see in others is hard to see in ourselves. I can assure myself that my intellectual integrity is superior to theirs, yet in my honest moments I recognize that I struggle with these same human frailties and flaws.

“… confirmation bias is far more difficult to overcome than most of us like to admit. “We are ever in search of data that confirms what we want to believe. “Illusion is the first of all pleasures,” Voltaire said. We’re particularly tempted by delusions if they constitute bricks in the walls we have chosen to build and to live behind.

“We’re also learning that there is a physiological appeal to confirmation bias (processing information that supports our belief system triggers a dopamine rush) and that our brains are hard-wired to embrace or reject information that confirms or challenges our pre-existing attitudes. Our beliefs are also often tied up with our ideas about who we are individually and our group identity. The result is that changing our beliefs in light of new evidence can cause us to be rejected by our political community. No one likes being accused of disloyalty.”

Atlas topic, subject, and course

Organizing and Measuring for Performance (core topic) in Implementation and Delivery and Atlas107.


ScienceDaily (n.d.), Confirmation bias, at, accessed 7 October 2017.

Peter Wehner (2017), Seeing Trump Through a Glass, Darkly, New York Times, 7 October 2017, at, accessed 7 October 2017.

Page created by: Ian Clark, last modified 7 October 2017.

Image: Michael Aagaard (2017), Your Brain is Lying to You – Become a Better Marketer by Overcoming Confirmation Bias,, 13 February 2017, at, accessed 7 October 2017.