Interaural time vs. interaural intensity in a lateralization paradigm

Abstract

In a two-interval lateralization procedure, observers judged whether a stimulus presented with an interaural intensive difference was right or left in lateral space of the same stimulus presented with only an.interaur~l te~poral difference. The stimuli were pure tones of 500 and 1,000 Hz and 1,000-Hzlow-pass noise. All stimuli were presented at both 65 and 55 dB SPL. For each of several values of interaural time (ranging from°to 1,000 microsec across all stimuli), a function was determined which related proportion of "right" re.lativ~p~sition judgments to th~value of the interaural intensive difference. The intercepts of these functions indicated that a progressively smaller amount of interaural intensive difference was required for the two stimuli to occupy a similar lateral location as the interaural temporal difference was increased. The slopes of the function suggested that the images associated with larger values of the interaural temporal differences are less distinct and blend together more than the images associated with sma~value~of the temporal diff~rence. Thu~, the procedu.re provided a means for comparing the lateral location of Images produced by interaural differences of time and intensity.Many investigators have studied how interaural temporal differences (lTD) and interaural intensive differences (110) alone mediate one's ability to lateralize a sound source. Except for investigations of the "binaural trading ratio," however, little research has been devoted to studying the interaction of the ITO and the lID in lateralization. The binaural trading ratio (Green & Henning, 1969) is the ratio of the lTD to the lID when an intensity-displaced image is brought back to midline with an interaural temporal difference. This procedure has been assumed capable of accurately determining the interaction of interaural time and intensity in lateralization.The results of the binaural trading ratio experiments are, however, not easily interpreted. Hafter and Ieffress (1968) showed that, for pure tones, observers often hear two lateral images in the binaural trading ratio experiment: one image associated with the lTD, the other with the lID. Furthermore, they suggested that the wide range of trading ratios reported in the literature are a result of the inability to obtain a "centered image." Hafter and Carrier (1972) and Hershkowitz and Durlach (l969b) demonstrated that, although an observer might report an image at midline, no combination of the lID and the ITO could be obtained which yielded an image indiscriminable from that produced by a tonal stimulus with no interaural differences. Thus, the difficulty in interpreting these binaural trading ratio experiments seems to lie in their procedure which required one "centered image."The purpose of the present experiment was to investigate the interaction of interaural time and intensity in a paradigm which avoids the "centered image" problem. Rather than cancelling the effects of the lID with the lTD, as was attempted in the binaural trading ratio experiments, we ...

The relation between auditory temporal interval processing and sequential stream segregation examined with stimulus laterality differences

“…Harris (1960) showed that the time-intensity trading relation for their broadest band of noise (7000-Hz bandwidth) was about 0.04 msec/dB; using this trading ratio, a 15-dB ILD corresponds to 600 μsec. Yost, Tanis, Nielsen, and Bergert (1975) provided psychophysical evidence suggesting that for noise stimuli, an ITD of 600 μsec was judged as roughly equivalent in lateral location to a stimulus with an ILD near 16 dB. The present choices of a 500-μsec ITD and a 15-dB ILD differ slightly from those used by Oxenham (2000; 640 μsec and 12 dB), but as will be seen, this was inconsequential to the pattern of results.…”

The impact of reference tones on the adjustment of interaural cues

“…Thus, the odd-one-out technique may be an appropriate alternative to the adjustment method in order to identify the amount of ITD resulting to the same sound perception as a specific IID. In contrast to setting the cues opposite to each other, Yost et al (1975) investigated the interaction of ITD and IID with a procedure in which the participants judged whether a stimulus with a preset IID appeared to the left or right of the perceived location of a previously presented stimulus with a preset ITD. However, the high variability in the data prohibited an exact investigation of the ITD-to-IID relation for lateral positions.…”

Binaural image position distributions for phase-shifted low frequency tone bursts

“…Note that only neighboring h i were presented within each block of 100 trials in this study. Other studies of lateralization of low frequency tones (Sayers, 1964;Yost et al, 1975;Yost, 1981;Kashino and Nishida, 1998;Lang and Buchner, 2009) had all IPDs presented within blocks of trials, and produced larger slopes for P(h), as would be expected from the foregoing hypothesis (three of these data sets are replotted in Fig. 5).…”

“…They include studies of high frequencies and variations in properties of stimulus waveforms Trahiotis, 2009, 2010), interactions between interaural time delays (ITDs) and interaural level differences (ILDs) (Domnitz and Colburn, 1977), onset versus ongoing interaural disparities (Freyman et al, 2010), auditory saltation (Getzmann, 2009), and aftereffects of adaptation (Phillips and Hall, 2005;Carlile et al, 2001;Vigneault-MacLean et al, 2007;Hafter, 1997). The study reported in this paper was somewhat similar to Yost (1981), which extended Sayers (1964) and Yost et al (1975). There, the listener was presented an eight unit train of tone bursts.…”