David E. Sandman

Magnitude estimates of loudness adaption at 60 dB SPL.

Previous reports indicate that adaptation measured by the technique of successive magnitude estimations is not found above 30 dB SL (Fishken et al., 1977; and others). Although the present study confirmed this finding at 60 dB SPL for the original procedure, it was found that a modification of the magnitude estimation procedure resulted in significant loudness adaptation at this intensity. Introduction of a 20-dB increment for 5 s, every 30 s, resulted in a marked and statistically significant decline in successive loudness judgements of the 60-dB tone. In addition, the decline in reported loudness magnitude was cumulative and progressive throughout the 7-min duration of the monaural stimulus. This is typical of classical results found with simultaneous dichotic loudness balances.

Loudness adaptation: fact or artifact?

Abstract In the present study, the authors tested the hypothesis that contrast effects confound the Ipsilateral Comparison Paradigm (ICP). Bidirectional referents were used in which base tones of 50 or 70 dB alternated with referents of greater or lesser intensity in a 3.5-min listening period. The contrast hypothesis leads to the expectation that the bidirectional referents would produce opposing effects that should nullify time-based loudness changes in the common base tone. Contrary to that expectation, base-tone loudness declined significantly over time in the context of the bidirectional referents, and the loudness of the referents also declined significantly over time. Thus, the results of the study testified to the validity of the ICP as a contrast-free measure of broad-based loudness adaptation.

Four triggering factors in loudness adaptation

A factor analysis was used to determine whether induced loudness adaptation (Botte, Canevet, & Scharf, 1982; Scharf, 1983) and adaptation measured by Hoods (1950) classic Simultaneous Dichotic Loudness Balance technique (SDLB) would cluster on the same factors. The two phenomena did not cluster on the same factors; thus, induced adaptation cannot replace SDLB adaptation. Four independent factors that trigger auditory adaptation were identified in the factor analysis.

Ipsilateral loudness adaptation over multiple intensity levels.

Abstract Could monaural loudness adaptation be a simple artifact of psychophysical contrast? From adaptation data based on the Ipsilateral Comparison Paradigm (ICP), A. J. Dange, J. S. Warm, E. M. Weiler, and W. N. Dember (1993) concluded that loudness adaptation was not an artifact of psychophysical contrast, but their conclusion was dependent on results from one intensity. This study, involving multiple intensities, re-examined the issue of contrast versus adaptation and generally supported the conclusions of Dange et al. The results also showed an unexpected asymmetry of adaptation based on the direction of the referent modulation used with the ICP technique. Some implications are discussed.

Puzzles of loudness constancy, loudness adaptation, and speech frequencies

Loudness constancy is suggested as a term for the failure to observe simple adaptation above 30 dB, noting however that Miskiewicz et al. [J. Acoust. Soc. Am. 94, 1281–1286 (1993)] indicated that simple adaptation is found at higher intensities above 4 kHz. Conversely, using the ipsilateral comparison paradigm (ICP), Dange et al. [J. Gen. Psychol. 120, 217–243 (1993)] found adaptation at 1000 Hz, from 45 to 75 dB. They saw this as revealing underlying neural adaptation, normally concealed by processes of loudness constancy. As a further test, Hellman [personal communication (1996)] urged that ICP adaptation be attempted without the usual designated modulus. In the present study (N=20), strong ICP loudness adaptation was indeed found with and without the designated modulus. Recently, Janson et al. [Br. J. Audiol. 29, 288–297 (1996)] found that ICP adaptation at 1 kHz was much less consistent for subjects with higher frequency loss than for nonimpaired listeners. Discussion of the possible value of loudness...

Ipsilateral comparison paradigm loudness adaptation: Is contrast hidden in complexity?

Dange et al. [J. Gen. Psychol. 120, 217–244 (1993)] investigated Weiler’s ipsilateral comparison paradigm (ICP) and determined that the results could not be explained as a function of simple auditory contrast. This study introduces a mixed referent condition, wherein increasing and decreasing referents alternate in the same trial. Results from all conditions demonstrated that both base and referent tones adapt under both levels of intensity (50 and 70 dB). If contrast were the dominant influence, adaptation would not be expected in mixed or decreasing referent conditions, nor should the referents themselves adapt. Thus contrast would not explain the results. However, certain preliminary post hoc analyses may reveal an influence due to contrast. Alternately, the simple referent conditions show correspondence with a model for binaural adaptation [Weiler and Hood, Audiology 16, 499–506 (1977)]. This analysis shows that the average for simple referent ICP adaptation differs from binaural adaptation only by a power of 2.

Auditory adaptation: Some agreement between loudness effects

We have not yet found significant intercorrelations between binaural balances, monaural balances, monaural reaction time, and magnitude estimates of loudness adaptation. Despite this, the intracorrelations for each method have been significant and moderately high. Furthermore, for group averages, the characteristics of adaptation measured by the different techniques share similarities such as the progressive decline of loudness over time, even though individuals are not consistent across methods. Recently, using the modified method of magnitude estimates with short intensity increments, we found effects on loudness estimates consistent with the models proposed for binaural balances by Weiler, Loeb, and Alluisi (1972) and Hood and Weiler (1977). Noting that magnitude judgments of loudness should occur at the highest level of the auditory system, perhaps simple magnitude estimates as evolved by Scharfs group include more of the complexities of auditory function than reaction time or balance measures.

Primary speech frequencies: Adaptation inside versus outside—Inhibition or excitation?

Previously, loudness adaptation from the ipsilateral comparison paradigm (ICP) and the simple adaptation (SA) procedure were compared at primary speech‐ related frequencies (250 to 4000 Hz), with only the ICP showing significant loudness decline/adaptation [Tannen et al., J. Gen Psychol. 128, 385–399 (2001)]. Eighty naive undergraduates participated in any one of three subsequent studies of ICP versus SA adaptation. In agreement with Tannen et al., only the ICP showed significant loudness decline/adaptation from 250 to 6000 Hz. However, at 8000 Hz both the ICP and SA show significant adaptation, and correlate significantly. However, despite the lack of correlation between individual scores under 8000 Hz, a further analysis of group mean values from 250 to 8000 Hz showed a significant correlation (r=0.97, p<0.001). Perhaps the SA procedure shows a lack of adaptation at speech frequencies because the method is insensitive. Alternatively, it may be considered that a ‘‘stable platform’’ [i.e., no adaptation f...

Objective limits for four varieties of putative loudness adaptation

The four varieties included three monaural techniques: (1) tone decay (TD); (2) simple adaptation (SA); (3) ipsilateral comparison paradigm (ICP); and the binaural (4) simultaneous dichotic loudness balances (SDLB). ‘‘Loudness adaptation’’ indicates that over time, under some conditions, there is a perceived decrease in loudness, when the initial baseline stimulus is progressively assessed. The authors have found the following limits: (1) the classic TD occurred within about 30 dB of threshold for all values tested (250 to 8000 Hz). (2) Except near threshold, SA for the loudness of a continuous unmodulated tone was observed at or above 40 dB when the stimulus reached 6000 Hz, or more. (3) ICP adaptation, which depends on at least 5‐s intensity modulation, was found at all values tested from 40 to 80 dB, and from 250 to 8000 Hz. It correlates significantly with TD, with suppression of transient evoked otoacoustic emissions, and at 8000 Hz with SA adaptation. (4) Binaural SDLB adaptation has been repeatedly...

Further progress with loudness adaptation inside and outside the speech range

Measurement of loudness adaptation at 4000 Hz and below depends on the technique used [Weiler et al., J. Acoust. Soc. Am. 101, 3171(A) (1997); T. Maguire et al., J. Acoust. Soc. Am. 106, 2207 (1999)]. Further comparison of simple adaptation (SA) to the ipsilateral comparison paradigm (ICP) with repeated measures designs again shows adaptation for both techniques at 8000 Hz but stronger effects for the ICP now. At 6000 Hz only, violations of normal curve parameters were again observed but no SA. Observations at 250 Hz for the ICP and SA will be discussed. The difference in adaptation between the two techniques is extreme in the primary speech frequencies but intermediate at 8000 Hz for our repeated measures designs. Further investigation is planned.