Brain Porn and Pop Neuroscience

How to think critically about neuroscience, statistics and more.

Are You An Exception to the Rule?

Can personal anecdotes reduce clear thinking in the face of data?

An Exception To The Rule Vowels
by Janan Sarwar
Psychology is one of those fields where just about everyone feels as if they have some insight.  In medicine or physics, we are more likely to rely on the experts.  But for whatever reason we feel that in the field of psychology our personal experiences somehow provide us with a direct window into the workings of the human psyche.

And in many ways we don't rely on the experts because we feel we are an expert in ourselves.

But that is precisely the danger: That we are so much an expert in ourselves that when we are faced with data that does not fit our personal profile, we tend to disregard it.

You can see this tendency here on Psychology Today, where many intelligent commentators will point out that their personal experience shows just the opposite of the finding of the article, or that their uncle Bob was an exception to the rule.

Findings in psychological research are often based on averages.  For example, in my article How Brainy Is Your Major? I compared the average ability levels of the various major groups (for example, engineering was higher than social science).  I stressed throughout the article that this data was based on averages and this did not mean that all individual cases were at the average of their respective group.  In fact, the majority were not.

I mention this article in particular because whenever I have presented this research-even to extremely smart researchers-there has inevitably been someone who notes that they are an exception to the rule.  For example, a psychologist has told me that there are many psychologists who are smarter than many engineers.  And this is most certainly true because the groups overlap.  But this does not remove the fact that there are average differences between the groups and that on average engineers are smarter than psychologists.  I also was confronted by a professor of education at a prestigious university when I was giving a talk about this article and he told me that if there were not equal numbers in each group how could I make appropriate comparisons?  I had to patiently explain to him that there were huge samples within each group so that average comparisons could be made.  I have yet to have an engineer, mathematician, or physicist (the groups at the top) confront me about the results of my study.

Another area of research that is highly documented is that people who score higher on standardized or intelligence tests tend to perform better in education and work, on average.  This past year I went to a medical specialist at Duke University who kindly asked what my research was about.  When I explained how standardized tests such as the Scholastic Assessment Test can be used to predict success on important real world outcomes such as earning a Ph.D., patent, publication, a higher income, and even tenure at a top university, he politely listened.  Then, he proceeded to tell me that he had performed poorly on standardized tests and that he didn't think that these tests predicted anything important at all.  And he was proof, because he had performed well in medical school and beyond.  I had to explain to him that he was an exception to the rule, or in the famous name of Malcolm Gladwell's book, one of the Outliers.  And this was a trained medical professional who I'm sure understood the importance of using statistical averages within the context of his discipline.

I provide these examples to simply make the point that our personal experiences bias us heavily when we are making assessments of research findings, in particular findings in the field of psychology.

Ralph Wiggum Simpsons Picking Nose
So remember, the next time you don't agree with a finding because your personal experience tells you the opposite, keep in mind that your personal anecdote is precisely that-an individual experience that cannot falsify the finding that is based on an average.  Certainly our personal experiences can help us generate hypotheses and be useful in thinking about a problem or issue.  And perhaps you may be right and the finding you disagree with is wrong.  But you should always keep in mind that even the plural of anecdote is not data.  And it is findings based on large samples of data that begin to allow psychology to be considered a science.

© 2012 by Jonathan Wai

You can follow me on Twitter, Facebook, or G+. For more of Finding the Next Einstein: Why Smart is Relative go here.

The initial photo is by Janan Sarwar.  More of her work can be found here.

For more on whether psychology is a science see: Can Psychology Be Considered A Science?