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Tag: Monahan

Categories
Auditory Perception Auditory Speech Processing EEG / MEG Evoked Activity Linguistics Papers Place of Articulation Features Publications Speech

New paper out in Jour­nal of Speech, Lan­guage, & Hear­ing Research [Update]

We are hap­py to announce that our paper “Asym­me­tries in the pro­cess­ing of vow­el height” will be appear­ing in the Jour­nal of Speech, Lan­guage, & Hear­ing Research, authored by Philip Mon­a­han, William Idsar­di and Math­ias Scharinger. A short sum­ma­ry is giv­en below:

Pur­pose: Speech per­cep­tion can be described as the trans­for­ma­tion of con­tin­u­ous acoustic infor­ma­tion into dis­crete mem­o­ry rep­re­sen­ta­tions. There­fore, research on neur­al rep­re­sen­ta­tions of speech sounds is par­tic­u­lar­ly impor­tant for a bet­ter under­stand­ing of this trans­for­ma­tion. Speech per­cep­tion mod­els make spe­cif­ic assump­tions regard­ing the rep­re­sen­ta­tion of mid vow­els (e.g., [{varepsilon}]) that are artic­u­lat­ed with a neu­tral posi­tion in regard to height. One hypoth­e­sis is that their rep­re­sen­ta­tion is less spe­cif­ic than the rep­re­sen­ta­tion of vow­els with a more spe­cif­ic posi­tion (e.g., [æ]).

Method: In a mag­ne­toen­cephalog­ra­phy study, we test­ed the under­spec­i­fi­ca­tion of mid vow­el in Amer­i­can Eng­lish. Using a mis­match neg­a­tiv­i­ty (MMN) par­a­digm, mid and low lax vow­els ([{varepsilon}]/[æ]), and high and low lax vow­els ([I]/[æ]), were opposed, and M100/N1 dipole source para­me­ters as well as MMN laten­cy and ampli­tude were examined.

Results: Larg­er MMNs occurred when the mid vow­el [{varepsilon}] was a deviant to the stan­dard [æ], a result con­sis­tent with less spe­cif­ic rep­re­sen­ta­tions for mid vow­els. MMNs of equal mag­ni­tude were elicit­ed in the high–low com­par­i­son, con­sis­tent with more spe­cif­ic rep­re­sen­ta­tions for both high and low vow­els. M100 dipole loca­tions sup­port ear­ly vow­el cat­e­go­riza­tion on the basis of lin­guis­ti­cal­ly rel­e­vant acoustic–phonetic features.

Con­clu­sion: We take our results to reflect an abstract long-term rep­re­sen­ta­tion of vow­els that do not include redun­dant spec­i­fi­ca­tions at very ear­ly stages of pro­cess­ing the speech sig­nal. More­over, the dipole loca­tions indi­cate extrac­tion of dis­tinc­tive fea­tures and their map­ping onto rep­re­sen­ta­tion­al­ly faith­ful cor­ti­cal loca­tions (i.e., a fea­ture map).

[Update]

The paper is avail­able here.

Ref­er­ences

  • Scharinger M, Mon­a­han PJ, Idsar­di WJ. Asym­me­tries in the pro­cess­ing of vow­el height. J Speech Lang Hear Res. 2012 Jun;55(3):903–18. PMID: 22232394. [Open with Read]
Categories
Auditory Cortex EEG / MEG Evoked Activity Linguistics Papers Publications

New Paper out: HELLO? in press (Neu­roIm­age)

Pho­net­ic cues instan­ta­neous­ly mapped onto dialec­tal cat­e­gories appear to be extract­ed at ear­ly moments in audi­to­ry speech per­cep­tion, as we try to show in our paper

You had me at “Hel­lo”: Rapid extrac­tion of dialect infor­ma­tion from spo­ken words

to appear in Neu­roIm­age (Math­ias Scharinger, Philip Mon­a­han, William Idsardi).

In a mod­i­fied pas­sive odd­ball design, we com­pare the Mis­match Neg­a­tiv­i­ty (MMN) to deviants in one Amer­i­can Eng­lish dialect (Stan­dard Amer­i­can Eng­lish or African-Amer­i­can Ver­nac­u­lar Eng­lish) to the stan­dards of the respec­tive oth­er dialect. In a con­trol con­di­tion, deviants with­in the same dialects have the same aver­aged acoustic dis­tance to their stan­dards than the cross-dialec­tal aver­aged acoustic dis­tance. Stan­dards and deviants were always spo­ken exem­plars of ‘Hel­lo’ in both dialects (ca. 500 ms). MMN effects are sig­nif­i­cant in the cross-dialec­tal con­di­tion only, imply­ing that a pure acoustic stan­dard-deviant dis­tance is not suf­fi­cient to elic­it sub­stan­tial mis­match effects. We inter­pret these find­ings, togeth­er with N1m source local­iza­tion data, as evi­dence for a rapid extrac­tion of dialect infor­ma­tion via salient acoustic-pho­net­ic cues. From the loca­tion and ori­en­ta­tion of the N1m source activ­i­ty, we can infer that dialect switch­es from stan­dards to deviants engage areas in supe­ri­or tem­po­ral sulcus/gyrus.

Ref­er­ences

  • Scharinger M, Mon­a­han PJ, Idsar­di WJ. You had me at “Hel­lo”: Rapid extrac­tion of dialect infor­ma­tion from spo­ken words. Neu­roim­age. 2011 Jun 15;56(4):2329–38. PMID: 21511041. [Open with Read]