For something so influential and intuitively appealing, it turns out that the Hawthorne effect is remarkably hard to pin down.

ECONOMIST: Being watched may not affect behaviour, after all

This could be interpreted as a subtler version of the Hawthorne effect, if you believe that workers were aware that changes in artificial light were induced by the experimenters, whereas natural light was changing on its own.

ECONOMIST: Being watched may not affect behaviour, after all