Hawthorne effect
noun
Haw·thorne effect ˈhȯ-ˌthȯrn- 
: the stimulation to output or accomplishment that results from the mere fact of being under observation
also : such an increase in output or accomplishment
Word History
Etymology
from the Hawthorne Works of the Western Electric Company, Cicero, Illinois, where its existence was established by experiment
First Known Use
1962, in the meaning defined above