Binaural summation and lateralization of transients: A combined analysis

Complex sounds contain energy at a number of different frequencies. In a typical environment, several objects emit complex sounds overlapping in time. The inner ear performs a frequency analysis over time on the sum of these incoming sound waves, leaving it to higher stages of processing to appropriately recombine the various components into an accurate representation of the original environment. In order to do this, the auditory system must determine what the auditory objects are and where they are located in space.One of the first researchers to study the interaction between the auditory what and where pathways was Deutsch (1974), who demonstrated an interesting phenomenon that she termed the "octave illusion." When participants were presented with an alternating sequence of high (800-Hz) and low (400-Hz) pure tones (such that tones were presented to both ears simultaneously but out of phase, so the left ear was receiving the low tone while the right ear was receiving the high tone, and vice versa), most reported hearing a high tone in the right ear followed by a low tone in the left (see Figures 1A and 1B). When the headphones were reversed so that the left headphone now presented tones to the right ear and the right headphone presented tones to the left, most listeners reported the same percept: The high tone was still heard in the right ear. Most right-handed participants heard the illusion in this manner, but left-handed participants were just as likely to localize the high tone in the left ear as in the right. Deutsch (1983) suggested that this difference might be due to hemispheric dominance, with the high tones perceived as coming from the dominant ear.The octave illusion presents a paradox. Although each ear receives a sequence of high and low tones (see Figures 1A and 1B), Deutsch found that the most commonly reported percept was an alternating pattern with the high tones heard as though they were being presented solely to one ear and the low tones as though they were being presented solely to the other. Interestingly, the low tone is perceived as coming from the ear that is actually being presented with the high tone at that time. In the interpretations of the octave illusion offered by Deutsch and colleagues (e.g., Deutsch, 1975Deutsch, , 1983Deutsch & Roll, 1976), the location (where) information is determined solely by the higher pitched tone, and information from the lower tone is discarded. The pitch (what) information is determined solely by the input to the dominant ear, and information from the nondominant ear appears to be discarded (but see Chambers, Mattingley, & Moss, 2002, 2004, for an alternative, fusion-based model). However, research to date on the octave illusion has been based primarily on verbal reports or methods that do not attempt to quantify the percept across all acoustic dimensions, so it remains unclear whether information from one ear is completely suppressed or whether it makes some contribution to the perceived pitch, timbre, location, and/or intensity of what is heard. W...

Section: Resultssupporting

confidence: 54%

Perceived intensity effects in the octave illusion

Sonnadara

Trainor

2005

“…The results of Irvin (1965), Marks (1980), Reynolds and S. S. Stevens (1960), Scharf (1968), Scharf and Fishken (1970), and recently, of Algom et al (1988) showed a similar change with level for noise stimuli. At low levels, the monaural noise had to be about 4 dB greater than the binaural noise to be judged as loud, but this difference increased to about 9 dB, in the present set of short noise bursts, at levels around 70 dB.…”

Section: Resultsmentioning

confidence: 59%

“…For wide-band noise stimuli, on the other hand, the binaural-monaural ratio increases with increasing sound pressure (Algom et al, 1988;Irwin, 1965;Marks, 1980Marks, , 1987Reynolds & S. S. Stevens, 1960;Scharf, 1968;Scharf & Fishken, 1970). Although Reynolds and Stevens (1960) concluded that the loudness of both monaural and binaural noise stimuli grows as a power function of sound pressure (but that the exponents differ), Scharf and Fishken (1970) and Marks (1980), as well as the majority of other investigations (see Scharf, 1978, for a review), have reported psychophysical functions for noise that are not power functions of sound pressure.…”

Section: Binaural Summation Of Tones and Noisesmentioning

confidence: 96%

Binaural and temporal integration of the loudness of tones and noises

Algom

Rubin

Cohen-Raz

1989

Self Cite

Subjects judged the loudness of tones (Experiment 1) and of bursts of noise (Experiment 2) that varied in intensity and duration as well as in mode of presentation (monaural vs. binaural). Both monaural and binaural loudness, for both types of signals, obeyed the bilinear-interaction prediction of the classic temporal integration model. The loudness of short tones grows as a power function of both intensity and duration with different exponents for the two factors (.2 and .3, respectively). The loudness of wide-band noises grows as a power function of duration (with an exponent of approximately .6) but not of sound pressure. For tones, binaural summation was constant but fell short offull additivity. For noises, summation changed across level and duration. Temporal summation followed the same course for monaural and binaural tonal stimuli but not for noise stimuli. Notwithstanding these differences between tone and noise, we concluded that binaural and temporal summation are independently operating integrative networks within the auditory system. The usefulness of establishing the underlying metric structure for temporal summation is emphasized.The integration of acoustic stimulation over time and the integration of stimulation over the two ears depict two widely documented auditory processes that display energy-dependent properties, at least for threshold. For both types of summation, loudness depends on the total amount of energy in the stimulus and is independent of how the energy is distributed over time or across the two ears (e.g., Babkoff & Algom, 1976;Hughes, 1938). Moreover, both temporal and binaural summation vary with the type (tone vs. noise) and level (threshold vs. suprathreshold) of the stimulus (e.g

“…The basic features characterizing binaural, dichotic, subcritical, and supercritical loudness integration have been documented (e.g., by Algom, Adam, & Cohen-Raz, 1988;Algom & Marks, 1984;Marks, 1978aMarks, , 1978bMarks, , 1979aMarks, , 1979bMarks, , 1980Scharf, 1970Scharf, , 1978. Loudness shows (1) a superiority of binaural to monaural listening, (2) invariance within a critical band, but (3) dependence on frequency separation beyond the critical band (diotic stimulation).…”

Section: Mode Of Presentationmentioning

confidence: 99%

Dichotic, diotic, and monaural summation of loudness: A comprehensive analysis of composition and psychophysical functions

Algom

Ben-Aharon

Cohen-Raz

1989

Self Cite

In a series of six experiments, the method of magnitude estimation, constrained by a multivariate model, was used to assess the rules that govern the summation of the loudness of two-tone complexes. This methodology enabled us to specify the amounts of summation and simultaneously to construct the corresponding loudness scales.\The components had different frequency separations and in the different experiments were presented (1) dichotically, a different frequency to each ear; (2) diotically, to both ears; and (3) monaurally. Results replicated and in some condi· tions extended known features of multiple signal processing by the auditory system. Thus, qualitatively different rules of loudness integration appeared. For monaural and diotic modes of stimulation, overall loudness depended on total sound energy within the critical band, but on the simple sum of component loudnesses beyond the critical band. For dichotic presentations, a fully additive rule of loudness summation appeared, regardless of frequency spacing. For the latter (but not the former), loudness summation was perfect, with the underlying loudness scales closely approximating Stevens's sone scale.In the present set of experiments, we measured the loudness of two tones as a function of (1) their frequency separation (narrow spacing within a critical band vs. wide spacing across a critical band) and (2) their mode of presentation (dichotic, diotic, or monaural). Although the various conditions thus generated have all come under the name of auditory summation, there are substantial differences among them in both the nature of the subjective experience and the objective, measurable outcome. For one, they can be classified as analytic or synthetic, depending on whether or not the components of stimulus mixtures are perceptually separable. More importantly, the rules of integration may differ across conditions. Indeed, the major purpose of this study is to uncover systematically the rules that govern summation under specific conditions of stimulation. Both of the variables tested within the framework of the present investigation are shown to affect the way the auditory system deals with the effects of concurrent multiple stimulation.Preparation of this paper was supported by Nlli Grant NS21326 to Lawrence Marks. His support and suggestions are gratefully acknowledged, as is Robert Melara's useful criticism. We also thank Edward Carterette and two anonymous reviewers for helpful comments on an earlier version of this manuscript. Barbara Faulkner and Elise Low provided skillful assistance at various stages of the completion of the manuscript. Address correspondence to Daniel Algom, Department of Psychology, Bar nan University, Ramat Gan 52100, Israel.Many of the basic findings on loudness summation have been reported by earlier researchers (e.g., Algom & Marks, 1984;Irwin, 1965;Marks, 1978a Marks, , 1978b Marks, , 1979a Marks, , 1979bMarks, , 1980Porsolt & Irwin, 1967;Reynolds & Stevens, 1960;Scharf, 1969Scharf, , 1970Scharf, , 1978Scharf & Fishken, 19...