Fig. 1.

Tone stimuli used in the experiments. All stimuli were sine-wave tones spaced along a logarithmic (musical) scale; their frequencies corresponded to the pitches of piano keys. In each trial, the mean frequency of the sequence was chosen from the range of frequencies highlighted here with darker shading, and the individual tones composing the sequence were drawn from a wider range that spanned both the dark- and light-shaded regions. Black dots represent the frequencies of the full range of tones from which the individual tones in each sequence were drawn. Adjacent dots are separated by 1 logarithmic (semitone) unit.