Binaural additivity of loudness in children and adults

Abstract

Thirty-six different binaural noises were formed by crossing six right-ear intensities of a broadband noise with the same six intensities in the left ear in a 6 X 6 factorial design. Children (6-7 years of age) and adults were presented with 2 of these 36 binaural noises on a trial and asked to indicate which noise was louder. In Experiment 1, the left-and right-ear noises were in phase and differed only in intensity. In Experiment 2, the left-and right-ear noises were in opposite phase. For both the children and adults in Experiments 1 and 2, the paired comparison judgments of binaural loudness were shown to satisfy the testable axioms of conjoint measurement (transitivity and double cancellation), permitting the determination of interval scales of loudness for the left ear, right ear, and the sum of the two ears. Power functions provided a good description of the relation between loudness and sound pressure for the left and right ears of both children and adults. For both adults and children, an examination of the pattern of differences in judgments between Experiments 1 and 2 indicated that, when the noises were in phase, the contribution of the right ear to fused loudness was greater than when the noises were presented in counterphase.

Empirical evaluation of axioms fundamental to Stevens’s ratio-scaling approach: I. Loudness production

“…It should be noted that the conclusions from the present axiomatic study mirror the scepticism toward subjects' use of numbers expressed in the scaling literature itself, which is reflected in the distinction of input and output functions in multistage models of psychophysical judgment (Attneave, 1962;Rule & Curtis, 1978) or in attempts to corroborate results from magnitude scaling experiments by validating them against nonmetric scaling techniques derived from paired comparisons (e.g., Parker & Schneider, 1994;Schneider, 1980;Schneider & Cohen, 1997;Schneider, Parker, & Stein, 1974). The encouraging conclusion from the present axiomatic treatment of magnitude scaling is that overt magnitude productions are consistent with the existence of an underlying ratio scale of loudness.…”

Directional loudness in an anechoic sound field, head-related transfer functions, and binaural summation

“…Starting from the observation that a sound appears louder when listened to with both ears ͑i.e., binaurally͒ than with only one ͑i.e., monaurally͒, a number of investigators conducted experiments using headphones, through which different combinations of left-and right-ear sound-pressure levels were presented in order to quantify this effect. The results are often summarized as providing evidence for a binaural-to-monaural loudness ratio of 2:1, or perfect loudness summation, corresponding to a binaural gain of approximately 10 decibels ͑e.g., Levelt et al, 1972;Marks, 1978;Schneider and Cohen, 1997͒, in accordance with the sone scale of loudness. The evidence is far from unequivocal, however, with many studies finding less-than-perfect summation ͑e.g., loudness ratios of approximately 1.5:1; Zwicker and Zwicker, 1991͒, and a level dependence of the binaural gain, which appears to increase from approximately 3 dB near threshold to 6 -10 dB at high sound-pressure levels ͑Shaw et al, 1947;Reynolds and Stevens, 1960;Hellman and Zwislocki, 1963͒. Interestingly, binaural loudness summation, as conceptualized in this paradigm, has not been investigated with sounds that are likely to reach the eardrums when emitted from a real source in space, i.e., with products of the first ͑HRTF͒ filtering stage.…”

Narrative Review of Loudness Perception Measures in Children

“…Existing literature overwhelmingly shows no significant developmental differences on measures of loudness growth (Dorfman & Megling 1966;Bond & Stevens 1969;O'Loughlin 1978;Teghtsoonian 1980;Collins & Gescheider 1989;Baruch et al 1993;Schneider & Cohen 1997;Fucci et al 1999;Serpanos & Gravel 2000, 2004Serpanos 2004;Scollie et al 2010;Schafer et al 2013). Note that the majority of studies comparing adults with children used magnitude estimation, magnitude production, or cross modality matching.…”