The Agreeable Power of Sugar


New research (summarized in the BPS Research Digest) confirms an old cliche: you are what you eat. A team of psychologists recently found that not only are sweets-lovers perceived as more agreeable, but they may actually be more agreeable:

Students who rated their own personality as more agreeable also tended to have a stronger preference (than their less agreeable peers) for sweet foods and drinks. Among a different set of students, a stronger preference for sweet foods correlated positively with their willingness to volunteer their time, unpaid, for a separate unrelated study – considered by the researchers as a sign of prosocial behavior.

Are the sweets actually responsible for this behavior?  Perhaps — in another study, “students given chocolate to eat (either a Hershey’s Kiss or a piece of Dove Silky Smooth chocolate), rated themselves as more agreeable and actually volunteered more of their time to help an unknown researcher, as compared with students given a sour sweet or a water cracker.”

Surely, there’s a greater use for this research: chocolate at the United Nations?


Spare me. I believe sugar is poison at the cellular level. Who funded these studies? I don't care if the findings are accurate or not. Somebody must of had a motive to waste their money on this kind of research.

Marci Kiser

I don't follow. Everything you eat is ultimately metabolized as glucose sugar, so unless you've got some alternative theory of biochemistry, I don't understand how sugar can be 'poison at the cellular level.'


students given marijuana to eat rated themselves as more agreeable than students given a water cracker

Michael Lynch

Sweets are seen as rewarding, whereas a water cracker is not. In fact, to some a water cracker may seem like a punishment. By giving someone a 'reward' one may feel more inclined to behave or do something in which they believe satisfies that reward, as if they needed to accomplish something to justify the sweet they had been given. I remember I once read somewhere that people act on incentives. If only I could remember where.


Please, for the sake of all that is rational, please please don't cover correlative studies like this....


i would belive this if it were rats being tested. i don't trust humans, who'll likely do or say anything to receive something free.
now, is there any candy left in the gedunk machine?


Sugar is not the culprit, sweet perception is the culprit. since the sour sweet has sugar and citric acid (for the sour). A better version of this study would be to provide several types snacks say a pretzel, nuts, fruits, and let them decide on one. Then see if they are as agreeable.


I'm sorta surprised to even see this study here at freakonomics. It sounds like total hogwash, with relatively few insights.

For one, does the study account for potential biases in a self-reported survey (especially with kids, who are notoriously unreliable survey takers)? Without knowing the sample size, given the legal limits on using children in research (parental permission, etc.), I doubt that it was large enough to combat these biases.

Do they posit a theory, grounded in scientific knowledge, to explain the correlation? A reasonable alternative explanation might be that "agreeable" kids are more prone to positive preferences on a Likert scale. Its an interesting idea, but the research design would probably be better suited for a middle school science fair project than a legitimate academic paper.


Every time I have a vanilla milkshake I'm happy. Damn they're good!


this would be much more persuasive if the agreeabilty was peer reported or measured by some test rather than self reported agreeability