Thursday, August 12, 2010

On Confirmation Biases, Twitter and Blogs

Confirmation bias is something I mention here from time to time.

While simple in principle, in practice it's really quite important, especially for people who read blogs, or use Twitter or Facebook.

Confirmation bias dictates that most people prefer information that supports their own beliefs. In turn this tends to lead people to accept things as true with lesser amounts of evidence if they agree with their preformed beliefs, and dismiss things, sometimes irrespective of the evidence, if those things don't agree with them. Like the cartoon above, it can also lead people to hear what they want to hear, rather than what's actually being said.

My bet would be that as a consequence of confirmation bias we tend to only follow and read folks who more often than not espouse opinions with which we agree which in turn may serve only to further solidify our own confirmation biases.

Of course there are a lot of folks who'll staunchly state that they don't have a confirmation bias, that they're evidence-based thinkers.

I can't help but doubt them.

Confirmation bias is something that's tough to shake, and while I like to think of myself as evidence-based, I'm sure that over the years confirmation bias has swayed me one way or the other on many occasions, both in my interpretation of research and my writings therein.

To help readers of this blog navigate my postings, and while I believe the current state of the evidence supports the following statements, I'd like to lay bare my biases. So here are the most salient (and obvious) of the lot as they pertain to my regular postings:

- Food, not fitness, is the primary societal driver of obesity.
- The food industry only cares about your health when it affects their bottom lines.
- Obesity's primary cause is environmental change, not individual lack of willpower.
- Calories are the currency of weight, not fat, carbs or proteins.
- Whole grains are healthier than refined.
- The risks of red meat consumption greatly outweigh the benefits but ultimately are small when considered absolutely.
- Dairy is not a magic food worthy of its own "group"
- The Canadian Government panders more to industry concerns than public health concerns when it comes to nutrition

There are probably more, but those are the ones that leap to mind.

So happy reading and while I promise to try to not let my confirmation biases get the best of me (or you) and will do my best to accurately and fairly interpret studies and report, the likelihood is they'll probably still be there sometimes lurking in the shadows.

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  1. Those are pretty good biases to have and I'd say most are evidence based.

    I'm curious. Where would you put dairy? In with meat?

  2. Hi Bill,

    Dairy? Currently there's more evidence to suggest risk than benefit, though the evidence regarding risk isn't particularly scary.

    I encourage my patients to enjoy the smallest amount of dairy they need to be happy but don't come down hard on those who need a lot to be so.

  3. Hellcat138:35 am

    And my confirmation bias says dairy = the food of Gods. My dad was a cheesemaker for years ;)

    But my rational brain knows that all good things should be had in moderation, so I try to fight my instinct to devour half a block of cheese at one sitting. When my dad stops eating cheese, he can drop 30 pounds in weeks. There's some pretty solid evidence right there that moderation is key

    You should read Dan Gardner's Risk, if you haven't already. He touches quite a bit on confirmation bias.

  4. My confirmation bias is that people who are "evidence-based thinkers" have a confirmation bias against confirmation bias.

    And speaking of all this Confirmation Bias you might find this interesting:

  5. - Calories are the currency of weight, not fat, carbs or proteins.

    I've been reading you for some time now and have a question about this one. Are there differences in carbs as far as they affect weight such as glycemic index? Or is it simply that some carbs are better for you but have no bearing on weight loss?

    Atkins, South Beach, The Zone are all variants of the school of good carbs vs bad carbs. Should these be just good food vs bad food?

  6. Hi John,

    Where macronutrients seem to matter most in regard to weight is satiety or fullness.

    Protein and fat are both more satiating than carbs and hence have indirect effects on calorie consumption.

    That said, there are major differences in the health benefits and risks with different sorts of protein, carbs and fats that are independent of weight related impacts.

  7. One brief comment. You said that "fitness" is not the societal driver of obesity - I think you meant to say "physical activity". I don't think anyone is arguing that lack of fitness is driving the obesity epidemic.

    Now we can have a good discussion about physical activity's role in the obesity epidemic, but that's for another day :)


  8. Marc Morris4:59 pm

    Hi Dr. Freedhoff,

    What is the opposite of a confirmation bias?

    Like I hear something and I automatically disregard it as a something valuable because it doesn't fall in line with my current beliefs. Has anyone coined a term for this phenomenom?

  9. Hi Marc,

    Meaning when someone disagrees with you their thoughts get filed away as brilliant?

    Wish my wife were more like you!

    (and no, I'm not aware of a name for that phenomenon)


  10. Confirmation bias probably explains why I diligently read this blog ;) Keep up the great work.