Figure 2.

The arrangement of experimental trials (a). In Experiment 1, the tone was task-irrelevant. In Experiments 2–5, observers were required to produce a vowel sound, either /u/ or /i/, cued by the tone. In Experiment 3, observers also passively listened to a vowel (/i/) played through speakers after the tone. Illustration of bias (b). This observer is relatively sensitive to physical changes in the stimulus, but is prone to making “insincere” responses. Illustration of insensitivity (c). This observer exhibits no bias, but the responses vary less with physical changes in stimulus strength.