Why do you keep eating what’s in front of you even when you’re full?

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Imagine that you are eating a bowl of tomato soup. Depending on how hungry you are, you will either reach the end of the bowl or stop somewhere along the way because you feel full.

“But what if,” say the authors of the new study, “the laws of physics were broken and that bowl refilled with soup after every spoonful you took?” Yes, it’s a strange thought, but just do it: the question is whether it will make you eat more soup than usual. Will you trust your gut feeling about how full you are or what you see in front of you?

This is a more interesting question than it seems at first glance: if we want to help people lose weight or generally eat healthier, we need to know as much as possible about the psychology of satiety.

This is where the self-filling soup bowl comes into play. The scientists behind the new study really went to great lengths to create it: They installed a series of tubes under a table that were secretly connected to a soup bowl. When soup was removed from the plate, more soup was automatically added from a large pot at the end of the table.

It’s a surprisingly creative—if quirky—setup for an eating psychology experiment. But before we get to the results, let’s take a quick tour of the career of the man who originally invented the bottomless soup bowl study: Brian Wansink.

The Rise and Fall of Brian Wansink

Wansink was a professor of psychology at the famous Cornell University in the USA. He and his Food and Brand Lab have authored many highly cited scientific publications and have advised the US government on food strategy. Er tauchte regelmäßig in YouTube-Videos auf, in denen er über seine seltsamen und wunderbaren Studien sprach, beispielsweise die, bei der sein Team den Blickwinkel von Zeichentrickfiguren auf Müslischachteln maß und feststellte, dass sie nach unten blickten, vermutlich auf Kinder, um deren Interesse call. .

You’ve probably heard of some of his research: If you’re familiar with the idea that people eat more when they’re served larger plates at a buffet, then you’re familiar with Wansink.

In 2005, he published the original “self-filling bowl of soup” experiment. The experiment earned him an Ig Nobel Prize, an ironic scientific prize for research that “makes us laugh and then think.”

So Wansink was very good at spreading his ideas. The problem was that he didn’t know much about real science. In 2016, he wrote a blog post explaining how he taught his students how to conduct research. Essentially, he encouraged them to look at the data set, “try out” a number of different hypotheses, and then publish only those that produced the desired results.

Of course, this is not what we expect from scientists: if their hypothesis doesn’t work, they should be honest and publish “null” findings. After all, the fact that a hypothesis was not supported by data is still an advance in our knowledge of the world. And hiding the results harms the scientific literature.

Worse, it means that the results you publish may be false positives: they are simply false statistical matches that no one can reproduce. In this sense, Wansink’s ill-conceived blog post was seen as a symbol of the “replication crisis” in science.

This was followed by an extensive examination. Scientists examined Wansink’s research papers and found many very bad papers. In total, he eventually had to delete eighteen of his studies from the literature and correct even more of them.

Cornell investigated and found that he had committed many forms of scientific misconduct, including “misreporting of research data, problematic statistical methods, failure to properly document and preserve research results, and improper attribution.” Shortly thereafter, he resigned as a professor.

All this poses an interesting question. Were his results real? The fact that he committed misconduct in conducting experiments and reporting experiments does not mean that this is the case. necessary means that someone else could not come to the same conclusions with proper research.

That’s exactly what happened with the bottomless soup bowl study.

Replica

The new study had a much larger sample size than Wansink’s original: 464 people compared to 54. Otherwise, they tried to make it as similar to his study as possible – exactly the same arrangement of bowls for refilling and the same questions asked of participants . asked how much they had eaten and how hungry they were. The soup pots also allowed them to measure exactly how much each person ate.

Here’s what they found: People who ate from self-filling bowls consumed 32 percent more soup than those who ate from regular bowls (which the researchers filled manually and clearly so participants could clearly see that they would be eating more). . . This was a statistically significant effect and in the same direction as Wansink’s original study.

In Wansink’s study, the satiated group ate 73 percent more soup—a much larger effect. It is unclear why this constituted a form of misconduct in the original study. Just random statistical fluctuations? However, the fact remains: the basic idea was repeated. In the end, Wansink was right.

The key point is that in both experiments, the people who ate from the self-filling bowl ate an extra portion of the soup. without noticing it they did (in a new experiment, they excluded data from the 190 people who figured it out, ruining the study design). This suggests that people, at least to some extent, eat mindlessly: they are not really aware of how many calories they are consuming, simply because they have an internal feeling of fullness or fullness, and they can do this through external ones. clues like how much soup they eat will confuse them. is in her bowl.

This is interesting and potentially important for people planning diet or health measures. But it’s also a good lesson for those of us interested in the dubious side of science: Just because a researcher falls out of favor for doing bad research doesn’t mean all of his research should necessarily be abandoned.

I was surprised to see that Wansink’s results, which I thought were absurd, were replicated in this completely independent study. Overall I’m still a little skeptical (like over 190 people noticed or at least suspected what was going on but just didn’t say anything?) but I need my mental model in this direction. This ridiculous study is actually a valuable addition to the scientific literature.

But wouldn’t it be great if we could trust him from the start? What if Wansink himself ran it again to see if it was a coincidence? What if someone else in the last twenty years had thought about doing this again, without the added incentive of Wansink’s resignation?

Bottomless bowls of soup do exist, but truly scientifically sound studies in which researchers take replication seriously are still a long way off.

Science Link of the Week

The secret is that I’m not here this week. I should be in Australia while you’re reading this. So, a variety of things could happen in science this week, but I don’t know which ones. The newsletter will have a holiday next week and will be published on December 7th.

Until!

This Science fiction with Stuart Ritchie, subscribers-only newsletter I. If you’d like to receive it straight to your inbox every week, sign up here.