The present study extends previous work from Lorenzi et al. ͓J. Acoust. Soc. Am. 110, 2470-2478 ͑2001͔͒ by investigating the respective contribution of two temporal cues ͑fast modulation sideband and slow envelope beat cues͒ to the detection and discrimination of "second-order" sinusoidal amplitude modulation ͑SAM͒. Second-order SAM detection and rate discrimination abilities were measured at low beat rates ( f m Ј р128 Hz͒ with a "carrier" modulation rate fixed at a high value ( f m ϭ256 Hz͒.

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... he second-order SAM data were compared with first-order SAM detection and rate discrimination thresholds measured in similar conditions at rates f m between 1 and 256 Hz. The results showed that ͑1͒ through 64 Hz, first-and second-order SAM detection thresholds increased similarly when stimulus duration decreased from 2 s to 250 ms, whereas first-order SAM detection thresholds remained unaffected by changes in duration when f m у128 Hz, and ͑2͒ through 32 Hz, first-and second-order SAM rate discrimination thresholds were similar and substantially lower than first-order SAM rate discrimination thresholds measured at f m у128 Hz. These data demonstrate that the perception of second-order SAM is mainly based on the slow envelope beat cues. They also suggest a substantial contribution of the slow envelope beat cues appearing at the output of modulation filters tuned to or near f m to the perception of second-order SAM.