What social and industrial research has not sufficiently realised as yet is that... minor irrationalities of the “average normal” person are cumulati… - Elton Mayo

It had become clear that the itemized changes experimentally imposed, although they could perhaps be used to account for minor differences between one period and another, yet could not be used to explain the major change - the continually increasing production. This steady increase as represented by all the contemporary records seemed to ignore the experimental changes in its upward development.

The history of the twelve-week return to the so-called original conditions of work is soon told. The daily and weekly output rose to a point higher than at any other time and in the whole period "there was no downward trend." At the end of twelve weeks, in period thirteen, the group returned, as had been arranged, to the conditions of period seven with the sole difference that whereas the Company continued to supply coffee or other beverage for the mid-morning lunch, the girls now provided their own food. This arrangement lasted for thirty-one weeks—much longer than any previous change. Whereas in period twelve the group's output had exceeded that of all the other performances, in period thirteen, with rest-pauses and refreshment restored, their output rose once again to even greater heights

The statements of academic psychology often seem to imply that logical thinking is a continuous function of the mature person — that the sufficiently normal infant develops from syncretism and non-logic to logic and skilled performance. Such a description seems to be supported by much of the work of Piaget, of Claparede, and, with respect to the primitive, by Levy-Bruhl. If one examines the facts with care, either in industry or in clinic, one finds immediately that this implication, so flattering to the civilized adult, possesses only a modicum of truth. Indeed, one may go further and say that it is positively misleading.