My contribution for the Guardian's Science Blogging Festival has been posted!
Healthy, sane humans do not stab themselves in the thighs, or bathe their eyes in lemon juice. So why do we so love to assault one of the most sensitive organs in the human body, the tongue, with what amounts to chemical warfare? Chillies are unique among foods that we should otherwise not enjoy. For example, humans also have natural aversions to the bitterness of coffee or the harshness of tobacco, but those substances have some addictive qualities, which might make them desirable. Capsaicin, the compound that provides the mouth-watering punch of chillies, does not seem to have any addictive qualities whatsoever. And yet the preference for capsaicin is almost universal; nearly every culture has incorporated it into their cuisine in some way, for milllennia.