A single traumatic event can lead to one-trial learning, conditioning an animal to dislike a previously attractive taste if associated with malaise.

“Well, there are events that a single event is so traumatic that it activates the circuits in a way that it's a one trial learning. And the taste system is literally at the top of that food chain. And there is a phenomenon known as conditioned taste aversion. You can pair an attractive stimuli with a really bad one, and you can make an animal begin to vehemently dislike for example, sugar. And that's because you've conditioned the animals to now be averse to these otherwise nice taste because it's been associated with malaise.”