Fascinating that Behrens reward game showed that humans were able to mentally model volatility at the level of an "ideal learner". But in the variation of the game where there was punishment instead of reward, non-anxious people still performed as "ideal learners" whereas anxious people's predictions became totally out of whack. In other words, the overly anxious mind temporarily lost its capacity to correctly formulate heuristics, which can lead to all kinds of mental chaos.

Personally, I remember that I was once in a job interview where I had to code on a whiteboard. I was so overwhelmed with anxiety that I was temporary incapable of completing simple coding tasks. In the face of extreme anxiety, I literally become stupid.