Figure 3.
Speech and macaque monkey calls have similar rhythmic structure in their acoustic envelopes. (A) Modulation spectra for human speech and long-duration (>400 msec) macaque monkey calls. (B) Modulation spectra for coo calls and an exemplar of a coo call, respectively. The x axes depict power deviations from a 1/f trend; the y axes represent frequency in log Hz.