A doozy of a thing went viral this week. A body language expert, Patti Wood, told Cosmopolitan Magazine that the way you eat pizza can tell a lot about your personality. http://www.cosmopolitan.com/food-cocktails/news/g4973/pizza-personality-reveal/ Specifically, she states that there are four ways to eat, each associated with a different personality type. I am not familiar enough with Ms. Wood’s larger body of work to comment on whether she might have some expertise to offer in other areas, but her pizza hypothesis is a pretty good example of bad pop psychology, and I kind of viral story that we should probably just ignore.
First, people are not types. Vox http://www.vox.com/2014/7/15/5881947/myers-briggs-personality-test-meaningless has done good work a few times pointing out shortcomings of the Myers-Briggs test and one of the big ones is that even if you’re type XYZ today, you might take the same test and be type ABC tomorrow. This is one of the reasons why the kinds of personality tests that are used in research and clinical applications (such as the “Big Five” https://en.wikipedia.org/wiki/Big_Five_personality_traits) focus a lot more on saying how much of a trait you have, and not whether you are this or that. In other words, if I take a test Monday, and am in the 51st percentile for extraversion, and then take it Tuesday and I’m in the 49th, we’re still working in the same ballpark and can say that this trait is right in the middle for me (maybe it’s a little different because of my mood). If I take it Monday and I’m an “extrovert” and then Tuesday and I’m an “introvert,” I have apparently shown a fundamental shift in who I am. The pizza test uses types, and a measure that will change from minute to minute if I eat my first slice of pizza folded, and then my second slice crust first.
The other big problem is that when you say something indicates something else, you need to show it. There is a big enough set of research on IQ tests that when I give one, I know that a person who gets a certain score should then get a close score on an achievement test and that if they don’t, something might be wrong (such a learning disability). Some research with The Big Five shows interesting findings like people with high openness being more tolerant of people with different beliefs. There is no research in correlates of pizza eating behaviors. I’d need at least a few times where the person who eats their pizza crust first (does anyone?) are actually anything that could be described as an “influencer.”
I’m not that worried about this article about pizza, but I am worried by how much it looks like a lot of other articles that get passed around. This is a case where we have someone identified as an expert who says something that is uncritically passed around by news and blogs. In Ms. Woods’ defense, she does appear to point out that it’s not really a great measure of personality, but not every news outlet that passed the story along bothered to do the same. It’s the same mechanism that has people treating their children’s ADHD with St. John’s wort, or denying that it exists at all. The same goes for astrology and “what your name says about you” quizzes. Whether cute or serious, it is always worth thinking a bit more about these viral stories, and maybe not bothering to pass them along.