Ever wondered why you feel sick at the smell of a food item and thus avoid it? Research shows our immune system plays a crucial role in changing behaviours, particularly in the case of an allergy.

Researchers from Yale University in the US showed that the immune system recognises allergens and pathogens in the environment and allows the brain to take defensive measures, such as avoidance. The same avoidance behaviour is exhibited by people who develop food poisoning after eating a certain meal.