Effects of inducer continuity on auditory stream segregation: Comparison of physical and perceived continuity in different contexts

Abstract

The factors influencing the stream segregation of discrete tones and the perceived continuity of discrete tones as continuing through an interrupting masker are well understood as separate phenomena. Two experiments tested whether perceived continuity can influence the build-up of stream segregation by manipulating the perception of continuity during an induction sequence and measuring streaming in a subsequent test sequence comprising three triplets of low and high frequency tones (LHL-[ellipsis (horizontal)]). For experiment 1, a 1.2-s standard induction sequence comprising six 100-ms L-tones strongly promoted segregation, whereas a single extended L-inducer (1.1 s plus 100-ms silence) did not. Segregation was similar to that following the single extended inducer when perceived continuity was evoked by inserting noise bursts between the individual tones. Reported segregation increased when the noise level was reduced such that perceived continuity no longer occurred. Experiment 2 presented a 1.3-s continuous inducer created by bridging the 100-ms silence between an extended L-inducer and the first test-sequence tone. This configuration strongly promoted segregation. Segregation was also increased by filling the silence after the extended inducer with noise, such that it was perceived like a bridging inducer. Like physical continuity, perceived continuity can promote or reduce test-sequence streaming, depending on stimulus context.

Build-up of auditory stream segregation induced by tone sequences of constant or alternating frequency and the resetting effects of single deviants

“…Listeners' responses to the test sequences were consistent with the known effect of 11 frequency separation on stream segregation (e.g., van Noorden, 1975). As expected (Haywood & 12 Roberts, 2010, 2011b, the standard induction sequence had a strong segregation-promoting 13 effect, and the least streaming was observed for the no-induction condition. Also consistent with 14 the results of Haywood and Roberts (2010), reported segregation was significantly reduced 15 compared with the standard induction case when the 10 th (final) induction tone was replaced with 16 silence.…”

“…auditory streaming experiments (Haywood & Roberts, 2010;2011a;2011b). This experiment 10 included the standard-and no-induction conditions that were used in Experiment 1.…”

“…Continuous white 5 noise is known not to induce subsequent stream segregation (Bregman, 1978;Rogers & 6 Bregman, 1993, and a pilot study indicated that the same was true for the narrower noise 7 band used here. More generally, any long, continuous stimulus (even a pure tone) with only a 8 single onset and offset prior to the test sequence is ineffective at promoting subsequent stream 9 segregation (e.g., Rogers & Bregman, 1993;Roberts et al, 2008;Haywood & Roberts, 2011b).…”

“…Correspondence concerning this article should be addressed to Nicholas R. Haywood,9 UCL Ear Institute, 332 Grays Inn Road, London, WC1X 8EE, UK, Email: n.haywood@ucl.ac.uk 10 FOOTNOTE 11 (1) Note that these values do not correspond to the differences between the condition means 12 quoted above, because the data for the 4-and 14-ST cases have been excluded from these values 13 and the associated pairwise comparisons. Our previous studies in which the same measure of 14 streaming was used (Haywood & Roberts, 2010, 2011b) also excluded these cases from the 15 pairwise comparisons, but the mean differences reported in those studies did not. The only effect 16 of this discrepancy would have been a tendency to underestimate, in those studies, the magnitude 17 of the differences between conditions across the critical 6-to 12-ST cases.…”

Stable individual characteristics in the perception of multiple embedded patterns in multistable auditory stimuli

“…Previous work (Rogers and Bregman, 1993; Snyder et al, 2008, 2009b; Haywood and Roberts, 2011, 2013) has shown strong contextual effects of prior learning on auditory streaming. However, these studies of contextual influences on perception have typically involved within-session manipulations, and the perceptual effects have been probed using stimuli of rather short duration (generally <10 s).…”