Why Does Sour Food Make Us Cringe? (asked by Anonymous)
Turns out, not many people have directly looked at this – the scientific literature has relatively little to say on the topic of cringing at sour food. However, what it does say is this: the cringing facial expressions are part of a general ‘disgust’ response that we make towards unpleasant smells and tastes. Some aspects of the face we pull when we eat sour sweets or a particularly tart tangerine are also produced when we smell off milk or bite into a rotten apple. The disgust response is designed to stop us from eating poisonous or rotten food, and to communicate with others around us that the food is bad. It probably formed a key part of social foraging, enabling early humans to avoid bad food and share information within their social group.