Dichotic and monotic masking of CV's by CV second formants with different transition starting values

Listeners were asked to identify ambiguous and unambiguous stop-vowel targets placed in monotic and dichotic competition with second formants (bleats) from voiced consonant-vowel (CV) syllables lying along a place-of-articulation continuum. Target performance varied with bleat-continuum position as well as bleat intensities. In cases where target errors occurred, either dichotically or monotically, they reflected predominantly the place cue of the bleat. This result, like that of previous studies, suggests the dominance of target or bleat reflects the relative "salience" of the two signals' cues. Differences were seen between monotic and dichotic conditions in the rate of change in performance with bleat intensity and continuum position. The rate of monotic performance change was a more precipitous (higher slope) function of these variables than was dichotic performance. This difference was interpreted as suggesting that monotic interference includes a peripheral masking component which is sensitive to the relative spectral energies of target and bleat. Dichotic effects, in contrast, seem to primarily reflect the operation of (central) processes which grant different perceptual weights to signals' cues depending on their intensity-dependent saliences. The observation that ambiguity, per se, of the targets (or the CV's from which the bleats were extracted) played little role in predicting results, was interpreted as reflecting a primarily prephonetic (i.e., auditory) locus for both monotic and dichotic interactions.