To the extent that fears of a crash had been widespread in the months preceding October 1987 and Shiller's survey suggests they were they would help to explain the growing popularity of portfolio insurance, and also would add an element of self-fulfilling prophecy to the October events: large numbers of investors who feared a crash responded to price declines by all running for the exit and finding "it was large enough to accommodate only a few" (Brady Commission 1988, p. 57).

Donald MacKenzie, An Engine, Not a Camera, loc. 859