Even a small quantity of capsaicin increased the perceived intensity of the solutions ingested.
But indulging in capsaicin does not quite meet the formal medical definitions of addiction.
The spice in some meals can be dangerous, especially to people who may have capsaicin allergy.
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With rather less scientific evidence, a capsaicin product is marketed as an alternative to Botox, a wrinkle-smoothing cosmetic treatment.
Certainly capsaicin can be painful, causing stress: in itself a potential health risk.
The reason may be that capsaicin excites the trigeminal nerve, increasing the body's receptiveness to the flavour of other foods.
Only chemical chromatography that measures several samples for their average level of capsaicin, the chemical that gives peppers their bite, can establish a record claim.
Because it activates pain receptors, capsaicin releases pleasure chemicals called endorphins.
In a study in 1992 by the CSIRO's Sensory Research Centre, scientists looked at the effect of capsaicin on the response to solutions containing either sugar or salt.
The standard measure for such things is the Scoville Heat Unit, or SHU, named after Wilbur Lincoln Scoville, a chemist who in 1912 developed a method of assessing the heat given off by capsaicin, the active ingredient in chili peppers.
Paul Rosin, a psychology professor at the University of Pennsylvania, who is one of the world's best-known authorities on the effects of capsaicin, has had no success in persuading rats to eat chilies, and very limited success with dogs and chimpanzees: the handful of cases where these animals did eat chilies seemed to be because of their strong relationships with human handlers.
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