Figure 1.

Illustration of the experimental behavioural procedure. Participants attended a clock and were asked to either press a button at their own pace or listen to a tone occurring at random, and then report the time of the event in -these- baseline conditions. The means of these baseline estimation errors were subtracted from those in the corresponding operant conditions, when the button press was followed by the tone. On any given trial, participants reported either the time of action or tone.