The Hawthorne effect refers to a type of reactivity in which individuals modify an aspect of their behavior in response to their awareness of being observed. Descriptions of this well-known and remarkable effect, which was discovered in the context of research conducted at the Hawthorne Western Electric plant.
One of the later interpretations by Landsberger’s suggested that the novelty of being research subjects and the increased attention from such could lead to temporary increases in workers’ productivity. This interpretation was dubbed “the Hawthorne effect,”
Reference : Wikipedia