SEPARATION OF CO-OCCURRING SYLLABLES: SEQUENTIAL AND SIMULTANEOUS GROUPING or CAN SCHEMATA OVERRULE PRIMITIVE GROUPING CUES IN SPEECH PERCEPTION? William J. Barry*, Georg Meyer** & Jacques Koreman* * Institute of Phonetics, University of the Saarland, Saarbrücken, Germany ** Dept. of Communication and Neuroscience, Keele University, Keele, UK 29 th European Mathematical Psychologists Group meeting (Keele, UK) 28 August - 2 September 1998

OVERVIEW Introduction Primitives and schemata in ASA Double-vowel experiments Utterances Linguistic primitives and schemata Experiment 1 Experiment 2 Conclusions

PRIMITIVES AND SCHEMATA SCHEMATA PRIMITIVES

PRIMITIVES AND SCHEMATA SCHEMATA PRIMITIVES On- and offset(time domain) F 0 and harmonicity(frequency domain)

DOUBLE VOWELS SCHEMATA PRIMITIVES On- and offset(time domain) STYLISED SPECTROGRAM

DOUBLE VOWELS SCHEMATA PRIMITIVES F 0 and harmonicity(frequency domain) STYLISED SPECTROGRAM

UTTERANCES SCHEMATA? PRIMITIVES?

LINGUISTIC PRIMITIVES SCHEMATA ACOUSTIC CUES

LINGUISTIC SCHEMATA SYLLABLES ACOUSTIC CUES

LINGUISTIC SCHEMATA PHONOLOGICAL FEATURES ACOUSTIC CUES

LINGUISTIC SCHEMATA (1) /a:l/ PRIMITIVES [alveolar][nasal] /e:n/ synthesised [a:l]synthesised [e:n]

LINGUISTIC SCHEMATA /a:l/ PRIMITIVES /e:n/ LINGUISTIC SCHEMATA (2) /a:l/ PRIMITIVES /e:n/ synthesised [a:l]synthesised [e:n]

EXPERIMENT 1 Stimuli:pairs of simultaneous synthetic VC syllables /e:/ /a:/ /o:/ /l/ /n/ Subjects:10 German listeners who were able to identify more than 95% of the individual synthetic VC syllables correctly

EXPERIMENT 1 Task:identify the pair of synthetic VC syllables /e:/ /a:/ /o:/ /l/ /n/ Primitives available to the listeners: 40-ms VC place transition with formants going from vowel to consonant target nasality cue starting early in vowel

EXPERIMENT 1 Phonetic background to the acoustic cues: The place cue in the vowel transition has been shown to be more important for the perception of the consonant’s place of articulation than cues available in the consonant itself. Nasality cues are very variable in speech production, varying strongly between languages and speakers, and should therefore be expected to play a less important role in perception. place nasality

EXPERIMENT 1 Task:identify the pair of synthetic VC syllables pre-nas. V non-nas. V n l n l consistent stimuliinconsistent stimuli trans Inconsistent stimuli were also presented in which the nasalised vowel was linked with /l/ Non-nasalised vowel was linked with /n/ leading to conflicting nasality and place cues BUT pre-nas. cues no pre-nas. cues

EXPERIMENT 1 Task:identify the pair of synthetic VC syllables pre-nas. V non-nas. V n l n l consistent stimuliinconsistent stimuli correct incorrect trans We say a VC pair is identified correctly if the place transitions are used for the decision. In the case of inconsistent stimuli this means that the nasality cue must be ignored! NOTE pre-nas. cues no pre-nas. cues

EXPERIMENT 1 Question 1:Do listeners use the nasality cue?

EXPERIMENT 1 Question 1:Do listeners use the nasality cue? Answer A:No. Predicted experimental result: No difference between consistent and inconsistent stimuli.

EXPERIMENT 1 Question 1:Do listeners use the nasality cue? Answer A:No. Predicted experimental result: Consistent stimuli better identified than inconsistent ones. Answer B:Yes.

EXPERIMENT 1 Question 1:Do listeners use the nasality cue? consistent inconsistent CONDITION % PAIRS CORRECT Significant difference between consistent and inconsistent condition (p<0.01)

EXPERIMENT 1 Question 1:Do listeners use the nasality cue? Answer A:No. Corresponding experimental result: Consistent stimuli better identified than inconsistent ones. Whether listeners use nasality as a primitive or schema is unclear. Answer B:Yes.

EXPERIMENT 1 Question 2:Do listeners map place cues onto phonetic feature schema?

EXPERIMENT 1 Question 2:Do listeners map place cues onto phonetic feature schema? Answer A:No. Predicted experimental result: Given the identification rate of the vowel, the distinction in the identification of the consonant is above chance. Reason: the acoustically different place transitions are used to link the vowel with the correct consonant in VC schema.

EXPERIMENT 1 Question 2:Do listeners map place cues onto phonetic feature schema? Answer A:No. Answer B:Yes. Predicted experimental result: Given the identification rate of the vowel, the distinction in the identification of the consonant is at chance level. Reason: the acoustically different place transitions are mapped onto the same place schema (both cons. are alveolar) and cannot contribute to link the vowel with the correct consonant.

EXPERIMENT 1 Identification of VC pairs given correct vowel pair is at chance level Question 2:Do listeners map place cues onto phonetic feature schema? vowel pair correct consistent inconsistent CONDITION % PAIRS CORRECT vowel pair correct VC pair correct chance level VC pair correct, given correct vowel pair

EXPERIMENT 1 Question 2:Do listeners map place cues onto phonetic feature schema? Answer A:No. Answer B:Yes. Corresponding experimental result: Given the identification rate of the vowel, the distinction in the identification of the consonant is at chance level. Reason: the acoustically different place transitions are mapped onto the same place schema (both cons. are alveolar) and cannot contribute to link the vowel with the correct consonant.

EXPERIMENT 1 CONCLUSIONS Listeners use acoustic continuity cues to link speech sounds: lower VC identification rate for inconsistent than for consistent stimuli shows that the nasality cue is used. Nasality cue may be a primitive or a schema. Listeners map the place-of-articulation primitives onto a schema: linking of the vowel with /n/ or /l/ is at chance level despite acoustically different place transitions, because the (phonetically important) place transitions are mapped onto the same schema for the two consonants.

EXPERIMENT 2 Stimuli:the same pairs of simultaneous synthetic VC syllables, but this time also at different F 0 ’s Subjects:10 German listeners who were able to identify more than 95% of the individual synthetic VC syllables correctly

EXPERIMENT 2 Task:identify the pair of synthetic VC syllables Primitives available to the listeners: 40-ms VC place transition with formants going from vowel to consonant target nasality cue starting early in vowel F 0

EXPERIMENT 2 Note:  F 0 provides “primitive” melody and harmonicity link between V and C  F 0 cannot trigger a schema at the level of the stimulus offered for identification (VC syllable), although it may trigger a schema at higher levels of prosodic-phonological structuring, i.e. in intonation

EXPERIMENT 2 Question:Do listeners use the F 0 cue more than they do nasality?

EXPERIMENT 2 Question:Do listeners use the F 0 cue more than they do nasality? Answer A:No. Predicted experimental result: Consistent stimuli better identified in the different-F 0 condition, but distinction between consistent and inconsistent stimuli maintained or even enhanced.

EXPERIMENT 2 Question:Do listeners use the F 0 cue more than they do nasality? Answer A:No. Predicted experimental result: F 0 cue overrides the distinction between consistent and inconsistent stimuli in the different-F 0 condition. Answer B:Yes.

EXPERIMENT 2 Question:Do listeners use the F 0 cue more than they do nasality? conincon same F 0 different F 0 % PAIRS CORRECT conincon Significant difference consistent/inconstent only for same F 0 (p<0.01)

EXPERIMENT 2 Question:Do listeners use the F 0 cue more than they do nasality? Answer A:No. Corresponding experimental result: F 0 cue overrides the distinction between consistent and inconsistent stimuli in the different-F 0 condition. Answer B:Yes.

EXPERIMENT 2 CONCLUSIONS F 0 presents a strong continuation cue linking the V and C The F 0 primitive cue overrides the nasality cue

very tentative... HYPOTHESES Primitives trigger schemata if possible Place transitions in experiment 1 triggered same place schema and therefore could not override nasality cue. Problem: we have no proof that nasality triggers a schema.

very tentative... HYPOTHESES Primitives trigger schemata if possible Place transitions in experiment 1 triggered same place schema and therefore could not override nasality cue. Problem: we have no proof that nasality triggers a schema. Competing primitives are weighted In experiment 2, it is shown that the F 0 primitive is a stronger cue than the inconsistent nasality cue.

very tentative... HYPOTHESES Primitives trigger schemata if possible Place transitions in experiment 1 triggered same place schema and therefore could not override nasality cue. Problem: we have no proof that nasality triggers a schema. Competing primitives are weighted In experiment 2, it is shown that the F 0 primitive is a much stronger cue than the inconsistent nasality cue. Streams are preselected on the basis of F 0 In experiment 2, the inconsistent nasality cue cannot be used by the listener because the F 0 primitive has split the signal into two streams. or

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