Method

Participants. Thirty-eight students from the University of Lyon participated in Experiment 2. Musical expertise, as measured by instrumental instruction, varied from 0 to 15 years (mean = 2.62  3.92 years; median = 0). None of them had participated in Experiment 1.

Material. Melodies were as described in Experiment 1.

Apparatus. Melodies were synthesized with the MATLAB software using sine waves with 20 ms fade-in and 20 ms fade-out. To create a timbre discrimination task for pure tones, target tones were synthesized either with the same sine wave as the context (Timbre A) or with a combination of the F0 sine wave with an additional sine wave one octave higher (i.e., frequency of 2*F0), thus creating an artificial “octave-doubled” timbre (Timbre B). The amplitude of Timbre B was adjusted to 35% of the amplitude of Timbre A, a factor that elicited similar subjective loudness levels for the three authors. To ensure that these tones remained pure tones when presented to the participants, we measured the harmonic distortion at the output of our equipment (Apple iBook computer and Sennheiser HD200 headphones) with an artificial ear (coupler: LD AEC101 IEC318; sound level meter: LD824) connected to a digital signal analyzer (HP 3561A). The signal-to-distortion ratio was over 70 dB. During the experiments, the stimuli were presented around 70-80 dB SPL (the volume could be slightly adjusted to match participants’ comfort level). Moreover, the experiment was conducted in a quiet but not soundproofed room and the background noise was then over 10 dB SPL. Altogether, this suggests that there was no audible distortion that could account for the behavioral results.

Procedure. The procedure was as described for Experiment 1 except that participants responded with keys on a computer keyboard.