Confirming What You Already Know

May 30, 2010

Confirmation bias is the most potent of all the cognitive misconceptions. Often referred to as a critical thinking shortcut, you start out with a rational thought and then warp it into a poorly conceived notion where real evidence is supplanted by personal experience. We are all guilty of it. Each time you say “I think bottled water tastes better than tap water” or “I can tell the difference between organic fruits and conventially grown fruits” you are lying to yourself. 

Consider that Aquafina is merely bottled tap water. Why does it seem to taste better? The explanation is much simpler than the idea that you have a superhuman ability to taste properties of water that are unknown to science. It could be as simple as when you purchase a bottle of Aquafina, it comes perfectly chilled in a cool looking bottle. Isn’t that more appealing than drinking a lukewarm cup of water straight from the tap in a boring ceramic mug?

The great irony in this is that confirmation bias is demonstrably wrong.  Penn and Teller did an episode with blind taste testing. They took people who were absolutely convinced that organic foods taste better or bottle water tastes better and what they found is that people could not tell the difference. In fact, people often picked the opposite. This is hardly scientific evidence that organic does not taste better, but it interesting and entertaining nonetheless. However, here is an actual blinded and controlled study from the journal Nutrition and Food Science. They concluded “that the global claim that “organic food tastes better” is not valid.” They found that some organic products tasted better and some conventional products tasted better. Exactly what you would expect from a random sampling.

So why do we select data to confirm what we already “know?” It is simple, we value or own experiences over that of what science has to say. Anecdotes are valued over data. People often fall back on “well I don’t care what the studies say, in my experience…” Human experience is limited. Our logic is flawed. This is why science exists and this is why scientists collect data. They are seeking to overturn our misconceptions. So the next time you find yourself selecting experiences to agree with your preconceived thoughts, ask yourself if it is scientifically plausible. And the next time you eat a juicy and delicious organic grape don’t try to justify your purchase by saying it tastes better. It doesn’t. Your just forgetting all the good conventional grapes you’ve had, while simultaneously remembering only the best of the organics.


One Response to “Confirming What You Already Know”

  1. Michael Says:

    “The most difficult subjects can be explained to the most slow-witted man if he has not formed any idea of them already; but the simplest thing cannot be made clear to the most intelligent man if he is firmly persuaded that he knows already, without a shadow of doubt, what is laid before him” – Leo Tolstoy

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