Students who used the difficulty of exams as a basis for rating all other aspects of Professor Young's performance were probably influenced by

Horn's error

Explanation:

The Horn's error is related to the halo effect, it's a form of cognitive bias where someone uses a perspective to judge or conclude on a scenario. Where someone allows one trait, either good or bad, to judge a scenario. The students used the failure in this aspect, and it stands as the Horn's error or Halo effect.

i believe the answer is:   psychological  experiment

in this experiment, wilhelm wundt became the first person that implement scientific method in analyzing the pyschological phenomenon.

due to this result, wilhelm wundt also able to make psychology to be acknowledged as a separate scientific field from biology.

i heard they are taking it off i hope this isn't true but otherwise if it doesn't get taken off it will probably be in early december or early january of 2018-2019