Answer: making an arbitary assumption
Explanation:
The cognitive theory of psychology is an attempt to explain the human behavior by understanding the thought process. The assumption of the cognitive theory are determinants of the behavior and emotions. How one process the information is the common characteristic of the functioning of the mental process. If the action, decision or rule is considered arbitary assumption on the basis of the cognitive theory then it can be considered that it is not based on the plan, system or principle.
According to the given situation, the Beyonce is making arbitary assumption about the professor response as Beyonce as there is no evidence and reason provided in the situation for such ignoring response given by the professor.