Taste aversion is a learned response to eating food that is toxic, poisonous spoiled, or poisonous. It is based on classical conditioning: if an animal eats food that make them sick, they will then avoid eating that food in the future as they associate it with illness. It was first tested in the laboratory by Garcia et al. (1955), who found that rats that had been made ill through radiation shortly after eating saccharin developed an aversion to it. Being able to quickly develop taste aversions increases the chances of an animal or human surviving, reproducing and passing on their genes to their offspring.