Answer:
hindsight bias
Explanation:
Hindsight bias is the bias that makes us believe that our past events are more predictable than they really were before the events took place. In other words after the occurrence of an event a person would have predicted what the outcome of that event would be before the event occurred.
For example, you ask a friend to predict which face of the coin will land when you flip it. Your friend predicts heads. You flip the coin and it appears as tails. Then your friend says that he knew it that it heads would appear.
Here, everyone in both the classes has some belief of how alcohol affects sexual desire and when the professor gives them any information regarding the relation, the student's hindsight bias makes them believe whatever the professor says.