A recent blog post by the economist John J Horton observed that potential employers using Amazon’s Mechanical Turk service were offering a rate of $1.38 an hour. Not only is this low pay, it is a strange figure. Why $1.38? Mr Horton, of New York’s Stern School of Business, surmises that the figure came from a seven-year-old paper he had co-authored reporting $1.38 as the median reservation wage (the level below which individuals will not accept work) in an experiment conducted on MTurk.

He suggests this is an example of “performativity” in economics. This term originates in linguistic philosophy, where it refers to statements whose very utterance is the action referred to: “I name this ship the QE2” or “I promise I’ll do the washing up.”

Some sociologists have applied the concept to economic theory. One of the most notable examples is the Black-Scholes-Merton model of option pricing. Professor Donald Mackenzie, of University of Edinburgh, argued that before the publication of the model, no market for options was possible as nobody was sure how to price these instruments. Once there was an agreed pricing model, the market sprang into existence.