4aSC43 Patterns in the perception of VC(C)V Nearey and Smits - PowerPoint PPT Presentation

4aSC43 Patterns in the perception of VC(C)V Nearey and Smits Nearey & Smits: Perception of VCCV 1

Patterns in the perception of VC(C)V strings Terrance M. Nearey University of Alberta Roel Smits Max Planck Institute for Psycholinguistics (Work supported by SSHRC & MPI )

Experiment based on Repp 1983 • Our study like Repp [1] expt. 1 with synthetic VC(C)V where C = [+stop] – Repp ran 3 sub experiments 1a, 1b and 1c – Our experiment had smaller total gap duration range than Repp, but larger than any single sub experiment – Our experiment had more spectral patterns than Repp Nearey & Smits: Perception of VCCV 3

Challenge to modeling • Our models of perception of fixed string length have been quite successful – e.g. CV or /hVC/ syllables [3,4] • Repp’s 1983 abda experiments – Variable length strings in one stimulus set – VCV: aba, ada; VCCV : abda, abda, abba, adda – Apparently very complex perceptual results [1, 2] • We take complexity as a challenge to our models – Can we extend the simple architecture of our models to handle variable string-length case? Nearey & Smits: Perception of VCCV 4

5000 Stimulus # 78 of 144. Most extreme [abda] place cues /abda/ Stimulus #78 (of 144) 4000 3000 2000 1000 0 0 100 200 300 400 500 600 Nearey & Smits: Perception of VCCV 5

Experiment details • Stimuli arrayed in fully crossed design – F2 (F3) VC offset: 1060 (2180) to 1450 (2539) Hz in 6 steps – F2 (F3) CV onset: 1099 (2262) to 1635 (2500) Hz in 6 steps] • F2 and F3 correlated (r = +1.0) in both offsets and onsets – Gap Duration: 80, 120, 190 and 300 ms; – Total 144 = 6 x 6 x 4 stimuli • Subjects and responses – Each responded to10 repetitions of each of 144 stimuli – 13 native speakers of Canadian English – Response button layout: [b] [bb] [bd] [d] [dd] [db] Nearey & Smits: Perception of VCCV 6

Phonetic cover terms • Canonical “duration” classes – Singletons /aba/ or /ada/ – Clusters (heterorganic) /abda/ or /adba/ – Geminates /ab#ba/ or /ad#da/ • Place of articulation classes (closing and opening) – Closing place class (place of first or only stop) • Labial closers: / b / / b b/ / b d/; Dental closers: / d /, / d d/, / d b/ – Opening place class (place of second or only stop) • Labial openers : / b / / b b/ /d b /; Dental openers: / d /, / d d/, /b d / Nearey & Smits: Perception of VCCV 7

General results I: Primary duration class patterns • Duration class patterns – Short duration gaps favor singletons – Intermediate gaps favor heterorganic clusters – Very long gaps favor geminates – But single-place singleton and geminates always less likely when transition patterns clash see below. Nearey & Smits: Perception of VCCV 8

General Results II: Primary place patterns • Closing place class affected by VC- F2 F3 offset – Low F2 F3 offset favors labial closers / b b b b d/ – High F2 F3 offset favors dental closers / d d d d b/ • Opening place affected by -CV F2 F3 onset – Low F2 F3 offset favors labial openers / b b b d b / – High F2 F3 offset favors dental closers / d d d b d / Nearey & Smits: Perception of VCCV 9

General Pattern III: Apparent complications Definition: Clash of transition patterns – Closing VC_ transitions near the low /_b/ end but opening _CV near the high /_d/ end – or vice versa • At longer gap durations – even fairly small clash tends favor clusters [bd], [db] over singletons or geminates • At short gap durations, – singletons favored unless clash is quite large – singleton responses dominated by opening _CV cues Nearey & Smits: Perception of VCCV 10

Apparent time-dependent assimilation/dissimilation effects • Repp 1983 summarized key results in by • Time course – Proactive (left to right): preceding VC 1 _ stimulus affects judgment of following _C 2 V – Retroactive (right to left); following _C 2 V stimulus affects judgment of preceding VC 1 _ • Phonetic cross-gap agreement of responses – Assimilation (more one place responses: /d, dd, b, bb/) – Dissimilation (more two place: /db, bd/) Nearey & Smits: Perception of VCCV 11

General trends in apparent assimilation • For Repp 1983 experiment 1 – Retroactive effects larger than proactive – Strong assimilation prevalent for shorter gap durations – Some dissimilation present for longer gap duration – Longest gap duration shows little effect • Our experiment – Trends (using Repp’s measure) are similar [see notes]. Nearey & Smits: Perception of VCCV 12

Baseline logistic model • Define 6 ‘diphone’ consonant categories – Label them ‘CC’ CC 1 = b, CC 2 = d, CC 3 = bb, CC 4 = dd, CC 5 = bd, CC 6 = db/ * /d/ and /b/ are ‘degenerate’ diphones • Three stimulus properties 1) Xclose – VC (syl. 1) closure transition step 2) Xopen – CV (syl. 2) opening transition step 3) Xdur – gap duration [note: duration coded as sqrt(ms)] Nearey & Smits: Perception of VCCV 13

Results Baseline Model • Pretty good fit 1) RMS = 5.96% • Score response rate in percentage points • Calculate RMS error of (predicted – observed) 2) Percent modal agreement PMA = 93.75% • Number of cells in which observed response category with most votes corresponds to predicted response category with highest predicted score. • Agrees for 135 of 144 stimuli Nearey & Smits: Perception of VCCV 14

Analysis of regression weights • Fit baseline model to each subject’s data separately – Basis for simple repeated measures comparisons • Examine means and between subject variation in weight patterns for each cue • May give insight into how information is integrated Nearey & Smits: Perception of VCCV 15

Baseline Model: CC * Xclose Baseline model CC * Xclose t 1 n e i 0.5 c i f f 0 e o C -0.5 -1 d dd db b bb bd ResponseCategory Matlab Boxplots. “Belt” is median, notch width robust 95% confidence estimate. Nearey & Smits: Perception of VCCV 16

Coefficients of Xclose depend only on phonetic closer class • Coefficients for Xclose [ = closing (VC) F2 F3 transition patterns] show very strong clustering – Labial closers / b , b b, b d/ show low values – Dental closers / d , d d, d b/ show high high values [Statistics in appendix panels] • Key fact: the phonetic nature of the opener has negligible effect on how Xclose tunes likelihood of closer place. Only phonetic closer class matters. Nearey & Smits: Perception of VCCV 17

Baseline Model: CC * Xopen Baseline model CC * Xopen 1.5 t n e 1 i c 0.5 i f f 0 e o -0.5 C -1 -1.5 d dd db b bb bd ResponseCategory Matlab Boxplots. “Belt” is median, notch width robust 95% confidence estimate. Nearey & Smits: Perception of VCCV 18

Coefficients of Xopen depend on phonetic opener class • Coefficients for Xopen [= opening (VC) F2 F3 transition patterns] show very strong clustering – Labial openers / b , b b , d b / show low values – Dental openers / d , d d , b d / show high high values [Statistics in appendix panels] • Key fact: the phonetic nature of the closer has minimal effect on how Xopen tunes likelihood of opener place. Only phonetic opener class matters. Nearey & Smits: Perception of VCCV 19

Baseline Model: CC * Xdur Baseline model CC * Xdur 0.6 t n 0.4 e i c 0.2 i f 0 f e o -0.2 C -0.4 -0.6 d dd db b bb bd ResponseCategory Nearey & Smits: Perception of VCCV 20

Coefficients of Xdur depend only on phonetic duration class • Coefficients for Xdur (= silent gap duration) show strong clustering – Singletons /b, d/ show low coefficients for Xdur – Heterorganic clusters /db, bd/ show moderately high coefficients – Geminates /bb, dd/ show highest coefficients • There is negligible differentiation of members within duration class [See appendix panels for statistics] Nearey & Smits: Perception of VCCV 21

Summary of baseline model • Only the ‘obvious’, primary cues count • Results from Baseline model suggest extremely simple tuning of response by ‘local’ stimulus properties • This permits construction of a more restricted model • Fewer fitted parameters implementing a factored model – Extension of methods of Nearey 1990 Nearey & Smits: Perception of VCCV 22

Factored model Factoring characteristics of CC in baseline model – Pdur : tripartite category of phonological duration classes • 1-singleton, 2-geminate and 3-heterorganic cluster – Pclose : • 1- labial closer :[b, bb, bd] • 2- dental closer [d, dd, db] – Popen : • 1- labial opener :[b, bb, db] • 2- dental opener [d, dd,bd] Nearey & Smits: Perception of VCCV 23

Example Factoring of CC * Xdur • Example if contrasts among 6 CC can be factored for different stimuli – (e.g.) replace CC*Xdur with Pdur * Xdur – Reduces coefficients from 6 to 3, (and df from 5 to 2) • If gap duration affects CC judgments only through Duration Class, then this should give similar fit with fewer coefficients Nearey & Smits: Perception of VCCV 24