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First installment in a series on confirmation bias.


“I disagree with what you’re saying, frankly. Strongly disagree.”

I guess I ought to delight in this kind of challenge, critical thinking enthusiast that I am. But I’m a chimp, too, which means instead of delighting, I have to suppress an urge to fling feces and hoot.

The disagreement came from a gentleman in one of my early seminars. I had suggested we allow our kids to try on different worldviews without pushing one direction or another. I put it this way in an earlier post:

I encourage my kids to try on as many beliefs as they wish and to switch back and forth whenever they feel drawn toward a different hat, confident that in the long run they will be better informed not only of the identity they choose, but of those they have declined. Were I to disown my kids each time they passed through a religious identity, I’d have to keep a lawyer on retainer.

He didn’t like this one bit. “Children need to be made to recognize the difference between faith-based thinking and EVIDENCE-based thinking,” he said. “They need to hear the word EVIDENCE from the very earliest age, as often as possible. ‘What’s your EVIDENCE? What is the EVIDENCE for that?’ Allow them to ‘try on the hat’ of mythical thinking and they just might not take it off!”

Hoo boy.

I gave my usual answer about having confidence in reason, but I knew there was more to it than that. I know my kids really well, and despite my failure to sprinkle the word EVIDENCE throughout my parenting, I know that all three would laugh at the idea that an opinion without evidence is worth squat.

One anecdotal exception doesn’t disprove his assertion, of course. Maybe my kids lucked into their rational hats despite my dippy incompetence. But I had the nagging feeling that this guy had made a more fundamental error — and that night, on the plane home, I realized what it was.

The evidence-free worldview is a straw man. A myth.

It’s the rare believer indeed who tethers belief to faith alone. Religious folks have evidence to support their beliefs — mountains and mountains of evidence. No one says, “I have absolutely no evidence for the existence of God, but I believe anyway.” If the man in the seminar were to offer his challenge (“What’s your EVIDENCE?”) to these folks, they’d offer the human eye, a sunrise, a seemingly answered prayer, a feeling of transcendence, a near-death experience, the Bible, a random act of kindness, Mother Teresa, “the starry heavens above and the moral universe within.” These add up to evidence of a particular kind: bad. It’s all gift-wrapped and insured by statements of faith, but it’s also evidence.

I’m not playing word games here. If we really want to understand the difference, it’s crucial to recognize that both the religious and scientific worldviews are evidence-based. That science does so well at uncovering reality and religion does so poorly is mostly due to the different ways in which the two approaches handle evidence.

The scientific method is largely devoted to neutralizing a single fallacy called confirmation bias — our strong tendency to find and collect whatever evidence supports our preconceptions and desires while ignoring the rest. Francis Bacon and the rest didn’t invent the idea of evidence — they laid the foundation for a systematic method of controlling the incredibly strong human tendency we all have to cherry-pick evidence to confirm our biases.


Both the religious and scientific worldviews are evidence-based. That science does so well at uncovering reality and religion does so poorly is mostly due to the different ways in which the two approaches handle evidence.

In a post two months back I demonstrated my own ability to put on the blinders of confirmation bias. I had come across the most amazing statistic…(wavy lines and harp music)…

I recently came across a statistic about scientists that, given my own background, ranks as the single most thought-provoking stat I have ever seen.

As I’ve mentioned before, my dad died when I was thirteen. It was, and continues to be, the defining event in my life, the beginning of my deepest and most honest thinking about the world and my place in it. My grief was instantly matched by a profound sense of wonder and a consuming curiosity. It was the start of the intensive wondering and questioning that led me (among other things) to reject religious answers on the way to real ones.

Now I learn that the loss of a parent shows a robust correlation to an interest in science. A study by behavioral scientist William Woodward was published in the July 1974 issue of Science Studies. The title, “Scientific Genius and Loss of a Parent,” hints at the statistic that caught my attention. About 5 percent of Americans lose a parent before the age of 18. Among eminent scientists, however, that number is higher. Much higher.

According to the study, 39.6 percent of top scientists experienced the death of a parent while growing up—eight times the average.

While researching the chapter of Raising Freethinkers on dealing with death, I had come across some random website [RED FLAG 1!] that mentioned the claim that 39.6 percent of scientists had lost a parent as a child. The website also cited the 1974 Woodward study.

“Wow!” I thought. “This precisely bears out my own personal narrative as a person whose thirst for knowledge was fueled by my father’s death! [RED FLAG 2!] Better still, it joins me at the hip to the great scientists I admire! [RED FLAG 3!] In short, this huge and unexpected percentage [RED FLAG 4!] dramatically confirms all of my dearest biases!”

If I had actually thought that in those words, or thought for a moment about what Huxley might say (“Science warns me to be careful how I adopt a view which jumps with my preconceptions, and to require stronger evidence for such belief than for one to which I was previously hostile. My business is to teach my aspirations to conform themselves to fact, not to try and make facts harmonize with my aspirations”), I might have spared myself the public error. Instead, I made a halfhearted attempt to confirm the stat, couldn’t easily access the original article, and decided to swallow the thing whole without looking further.

The Woodward article, it turns out, was largely devoted to debunking the claim. As blogreader Ryan pointed out, the parent-loss stat was a rough estimate based on a small sampling of scientists in the 500-year period from 1400 to 1900 — a span during which 40 percent of garbage collectors and astrologers also surely lost parents when they were young. The same article notes that 20th century records show little difference between scientists and non-scientists in parent loss.

We ALL do it. The trick isn’t to lead our children into a magical life free of confirmation bias, but to get them to fall so deeply in love with reality that they work hard to fight this tendency in themselves and others — precisely because it deludes us and blinds us to reality more than any other error.

[More on confirmation bias next week.]

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Dale McGowan is the author of Parenting Beyond Belief, Raising Freethinkers, and Atheism for Dummies. He holds a BA in evolutionary anthropology and a PhD in music.