Are there limits to binaural additivity of loudness?

Abstract

In recent years there has been notable interest in additive models of sensory integration. Binaural additivity has emerged as a main hypothesis in the loudness-scaling literature and has recently been asserted by authors using an axiomatic approach to psychophysics. Restrictions of the range of stimuli used in the majority of former experiments, and inherent weaknesses of the axiomatic study by Levelt, Riemersma, and Bunt (1972) are discussed as providing reasons for the present investigation. A limited binaural additivity (LBA) model is proposed that assumes contralateral binaural inhibition for interaural intensity differences that exceed a critical level. Experimental data are reported for 12 subjects in a loudness-matching task designed to test the axioms of cancellation and of commutativity, both necessary to the existence of strict binaural additivity. In a 2 X 2 design, frequencies of 200 Hz and 2 kHz were used, and mean intensity levels were 20 dB apart. Additivity was found violated in 33 out of 48 possible tests. The LBA model is shown to predict the systematic nonadditivity in the loudness judgments and to conform to results from other studies.

Empirical and Theoretical Studies of Psychophysical Phenomena

“…Therefore, in our empirical evaluation of the theory in loudness and brightness, we studied that property. However, although we found substantial support for the it, we observed certain problems in its empirical realization, as had some previous researchers before us (Gigerenzer & Strube, 1983). We concluded the trouble stemmed from unequal number of compound estimate involved in the estimated signals subjected to statistical evaluation (a major culprit is the phenomenon of NEM reported in item 5).…”

Evaluating a model of global psychophysical judgments for brightness: I. Behavioral properties of summations and productions

“…Also studied in psychophysics is how intensity summates when, for example, signals are administered independently to the two ears (Falmagne, 1976;Falmagne, Iverson, & Marcovici, 1979;Gigerenzer & Strube, 1983;Levelt et al, 1972;Schneider, 1988;Steingrimsson & Luce, 2005a, 2005b or the two eyes (Bolanowski, 1987;Bourassa & Rule, 1994;Cohn & Lasley, 1976;Curtis & Rule, 1978;de Silva & Bartley, 1930;de Weert & Levelt, 1974;Ding & Sperling, 2006;Engel, 1969;Grossberg & Kelly, 1999;Irtel, 1998;Levelt, 1965;J. C. Stevens, 1967) and how the two modalities compare (Lehky, 1983;Wade & Ono, 2005).…”

Binaural additivity of loudness in children and adults

“…Several studies (Algom & Marks, 1984;Levelt, Riemersma, & Bunt, 1972;Marks, 1978Marks, , 1979aMarks, , 1980 have shown that the judgments ofsubjects are, for the most part, consistent with this additive model (but see Gigerenzer & Strube, 1983). These studies also show that both leftand right-ear loudness is a power function of sound intensity; that is, LL(P) = kLPnL and LR(P) = kRpn R , (3) where kL,kR,nL' andnR are constants.…”