RETRACTED ARTICLE: Dishonesty is more affected by BMI status than by short-term changes in glucose
Authors: Marie Claire Villeval
Benedikt Herrmann
Eugenia Polizzi di Sorrentino
Journal: Scientific Reports (2020)
Discipline: Multidisciplinary
Keywords: decision-making; body energy levels; physiological states; obesity; dishonesty
Affiliations: European Commission, Joint Research Center (JRC), 21021, Ispra, Italy. ., Institute of Cognitive Science and Technologies, National Research Center, 00185, Rome, Italy. ., European Commission, Joint Research Center (JRC), 21021, Ispra, Italy., Univ Lyon, CNRS, GATE, UMR 5824, 69130, Ecully, France., IZA, Bonn, Germany.

Abstract:  There is evidence that human decision-making is affected by current body energy levels and physiological states. There is less clear evidence linking decision-making to long-term changes in energy, as those associated with obesity. We explore the link between energy, obesity and dishonesty by comparing the behaviour of obese and lean subjects when hungry or sated while playing an anonymous die-under-cup task. Participants performed the task either before or after breakfast. We find that short-term switches in energy have only a mild effect on dishonesty, as only lean females lie less when sated. By contrast, obese subjects lie more than lean subjects in both conditions, and they lie more to avoid the lowest payoff than to get the highest payoff. Our findings suggest that the observed patterns are more likely mediated by factors associated with obesity than by short term energy dynamics, and call for a better integration of the psychological, economic and biological drivers of moral behaviour. 

Retracted: Yes

PubPeer comments:
 This study claims that BMI is associated with dishonesty. Any study that calls a particular group of people more honest than others deserves some scrutiny, so here we go. In the study, people had to roll a 3-colored dice two times, and report the color that was shown. Blue did not earn them money, yellow a little bit, and red had the highest monetary reward. The researchers could not check for the outcome, so participants could cheat and report e.g. yellow or red if they had gotten blue. The first roll counted towards the reward, the second roll was to see if the dice worked (negative control). Some people had to do the test after an overnight fast, others after breakfast. Here are the results of the first dice roll (Figure 1). One would expect that each color would be reported about 1 3 of the time. However, everyone cheated and reported the red color more than expected. Obese people reported yellow more than expected. ![file] Some remarks and questions: * There are important differences between the obese group vs the lean group. The obese group had more women (who might be more affected by being  hangry ), was slightly less educated, was older, and less likely to be a student. Any of those factors could be a confounding factor in dishonesty. Which factors were significantly different between the lean and obese group (irrespective of fasting)? ![file] * Everyone cheated in this test (everyone reported red more than expected). The obese group appeared to have played it smarter, though, by reporting yellow when they had thrown blue. So they did more  small lies , not more  big lies . Is this dishonesty, or intelligence? Using the same data you could also conclude that people with high BMI women are smarter than lean people. * How were the subjects recruited? What type of study were they asked to sign up for? They all had to fast and knew they would get breakfast, but first some had to be weighed and do the test. So some people might have expected that this could be a test about obesity. That could affect obese people s mood more than lean people, and it might not be measured by glucose levels. Could obese people have been more angry at the start of the test (because they had to be weighed, and felt ashamed, for example)? * Why were gender and percentage of students reported with a standard deviation? * Did the authors report on the outcome of the second dice roll? That is the negative control, to make sure the dice was balanced, but I could not find any data on that. , 
 https: twitter.com GidMK status 1291178572879736833 , 
 See [this Twitter thread] in which I wonder what the relation is between the dataset variables  Income (which seems to correspond to  Weekly spending ) and  Status (which seems to be some other measure of income or economic status, as used in the t test on p. 4 that claims to show that there was no difference between the lean and obese participants. That thread URL in plain text: twitter.com sTeamTraen status 1291524709763424262 , 
 Could the authors explain how it is possible for participant A362 to have a negative value of hunger at time 2? ![file] , 
 January 12, 2021, retraction: https: www.nature.com articles s41598-020-80528-2  The Editors are retracting this Article. After publication concerns were raised with respect to the data suggesting a significant positive association between dishonesty and obesity. Independent post-publication peer review has confirmed that this conclusion extends beyond what the data show, given the lack of overall group effects. In addition, multiple comparisons were not appropriately controlled for, and the inclusion of gender in the analysis should have been emphasized as an exploratory addendum to the main analysis. The Editors therefore no longer have confidence in the conclusions presented. The authors disagree with the retraction. ,