Answer:
Experimenter effect
Step-by-step explanation:
Experimenter effect: The experimenter effect is also known as the observer effect. It refers to the process of influence or impact of the experimenter or the researcher conducting an experiment on the performance of the participants involved in that experiment and on result interpretation.
The researcher can minimize the experimenter effect by recording the actual statement of the participants and not what the researcher thinks they mean, statistical analysis, and by avoiding data interpretation during the study.
Even though rats were randomly assigned, when the experiment concluded, Group 1 rats had learned the maze much more quickly because of the experimenter effect.