Profile analysis and level variation

Research on informational masking for nonspeech stimuli has focused on the effects of spectral uncertainty in the masker. In this letter, results are presented from some preliminary probe experiments in which the spectrum of the masker is held fixed but the spatial properties of the masker are randomized. In addition, in some tests, the overall level of the stimulus is randomized. These experiments differ from previous experiments that have measured the effect of spatial uncertainty on masking in that the only attributes ͑aside from level͒ that distinguish the target from the masker are the spatial attributes; in all of the tests, the target and masker were statistically identical, statistically independent, narrowband noise signals. In general, the results indicate that detection performance is degraded by spatial uncertainty in the masker but that compared both to the effects of spectral uncertainty and to the effects of overall-level uncertainty, the effects of spatial uncertainty are relatively small.

Section: Discussionmentioning

confidence: 99%

Effect of spatial uncertainty of masker on masked detection for nonspeech stimuli

Fan

Streeter

Durlach

2008

“…Commonly referred to as "rove", this variation was meant to ensure that the level difference created by the spectral-shape change did not provide a confounding cue ͑e.g., Speigel et al, 1981;Green et al, 1983;Mason et al, 1984; see Green, 1988 for a history͒. The few studies that have evaluated the effects of rove consistently have demonstrated better sensitivity in conditions that have no level randomization ͑Henn and Turner, 1990; Kidd et al, 1991;Drennan and Watson, 2001͒.…”

Section: Introductionmentioning

confidence: 95%

“…Roving levels might also lead to varied shapes of the internal spectrum ͑i.e., the excitation pattern͒ at different levels through nonlinear changes in auditory filter shape with level ͑Mason et al, 1984͒. Rather than the spectrally dense stimuli used by Mason et al ͑1984͒, the following experiment employs spectrally sparse stimuli to determine whether the inconstancy of the shape of the internal spectrum on a presentation-bypresentation basis contributes to the decrease in spectralshape sensitivity provided by level variation.…”

Section: Introductionmentioning

confidence: 99%

Profile analysis: The effects of rove on sparse spectra

Lentz

2005

Profile-analysis thresholds were measured in the presence and absence of overall level variation at different stimulus levels to determine whether nonlinear changes in the shape of the edges of excitation pattern peaks contribute to poorer spectral-shape sensitivity observed under roving levels. Roving levels decreased sensitivity for stimuli having few components separated widely in frequency to a greater extent than for stimuli having more densely spaced components. The stimulus level did not influence sensitivity when overall level variation was absent, suggesting that listeners rely on peaks in the excitation patterns and not the edges of the peaks (as would have been predicted by the near miss to Weber's law). Because the edges of the peaks were not used in the absence of roving levels, it follows that the larger rove effects for sparse stimuli were not likely due to excitation pattern inconstancy.

“…In the variable-level condition, F 0 amplitude was determined randomly and independently over a range of 20 dB for each of the three stimuli on a trial, thus precluding an effective use of the absolute level in performing the spectral slope discrimination task. This type of roving of intensity procedure has been used in profile analysis studies to eliminate responding to the absolute level (Green, 1988;Mason et al, 1984).…”

Section: Experiments Imentioning

confidence: 99%

Perceptual constancy of a global spectral property: Spectral slope discrimination

Pastore

1995

The current study investigated perceptual constancy for spectral slope discrimination when fundamental frequency (F0) and spectral shape were varied across three complex stimuli within a single trial. The three stimulus variables were global or emergent properties of a complex sound. The selection of the stimulus variables was in keeping with notions that perception may be organized in terms of a source-filter model of complex sound production; F0 and spectral slope represent properties of sound sources and spectral shape typically represents a filter property. According to the source-filter model, interaction between stimulus properties should depend upon whether the typical origin of the property was common to the source spectrum or the filter transfer function. The four experiments in the current study demonstrated a significant performance decrement in spectral slope discrimination when F0 (a second source property) varied. However, spectral slope discrimination was minimally altered when spectral shape (a filter property) was varied. The study supported claims that listeners treat source properties as a unit which, in perception, is relatively independent of filter properties.