Conditioned taste aversion occurs when an animal associates the taste of a certain food with symptoms caused by a toxic, spoiled, or poisonous substance. Generally, taste aversion is developed after ingestion of food that causes nausea, sickness, or vomiting. The ability to develop a taste aversion is considered an adaptive trait or survival mechanism that trains the body to avoid poisonous substances (e.g., poisonous berries) before they can cause harm. The association reduces the probability of consuming the same substance (or something that tastes similar) in the future, thus avoiding further poisoning. It is an example of classical conditioning or Pavlovian conditioning.