TY  - JOUR
A1  - Roon, Kevin D.
A1  - Gafos, Adamantios I.
T1  - Perceiving while producing: Modeling the dynamics of phonological planning
JF  - Journal of memory and language
N2  - We offer a dynamical model of phonological planning that provides a formal instantiation of how the speech production and perception systems interact during online processing. The model is developed on the basis of evidence from an experimental task that requires concurrent use of both systems, the so-called response-distractor task in which speakers hear distractor syllables while they are preparing to produce required responses. The model formalizes how ongoing response planning is affected by perception and accounts for a range of results reported across previous studies. It does so by explicitly addressing the setting of parameter values in representations. The key unit of the model is that of the dynamic field, a distribution of activation over the range of values associated with each representational parameter. The setting of parameter values takes place by the attainment of a stable distribution of activation over the entire field, stable in the sense that it persists even after the response cue in the above experiments has been removed. This and other properties of representations that have been taken as axiomatic in previous work are derived by the dynamics of the proposed model. (C) 2016 Elsevier Inc. All rights reserved.
KW  - Speech perception
KW  - Speech production
KW  - Computational modeling
KW  - Response time modulation
KW  - Phonological planning
Y1  - 2016
U6  - https://doi.org/10.1016/j.jml.2016.01.005
SN  - 0749-596X
SN  - 1096-0821
VL  - 89
SP  - 222
EP  - 243
PB  - Elsevier
CY  - San Diego
ER  - 
TY  - JOUR
A1  - Patil, Umesh
A1  - Hanne, Sandra
A1  - Burchert, Frank
A1  - De Bleser, Ria
A1  - Vasishth, Shravan
T1  - A Computational Evaluation of Sentence Processing Deficits in Aphasia
JF  - Cognitive science : a multidisciplinary journal of anthropology, artificial intelligence, education, linguistics, neuroscience, philosophy, psychology ; journal of the Cognitive Science Society
N2  - Individuals with agrammatic Broca's aphasia experience difficulty when processing reversible non-canonical sentences. Different accounts have been proposed to explain this phenomenon. The Trace Deletion account (Grodzinsky, 1995, 2000, 2006) attributes this deficit to an impairment in syntactic representations, whereas others (e.g., Caplan, Waters, Dede, Michaud, & Reddy, 2007; Haarmann, Just, & Carpenter, 1997) propose that the underlying structural representations are unimpaired, but sentence comprehension is affected by processing deficits, such as slow lexical activation, reduction in memory resources, slowed processing and/or intermittent deficiency, among others. We test the claims of two processing accounts, slowed processing and intermittent deficiency, and two versions of the Trace Deletion Hypothesis (TDH), in a computational framework for sentence processing (Lewis & Vasishth, 2005) implemented in ACT-R (Anderson, Byrne, Douglass, Lebiere, & Qin, 2004). The assumption of slowed processing is operationalized as slow procedural memory, so that each processing action is performed slower than normal, and intermittent deficiency as extra noise in the procedural memory, so that the parsing steps are more noisy than normal. We operationalize the TDH as an absence of trace information in the parse tree. To test the predictions of the models implementing these theories, we use the data from a German sentence—picture matching study reported in Hanne, Sekerina, Vasishth, Burchert, and De Bleser (2011). The data consist of offline (sentence-picture matching accuracies and response times) and online (eye fixation proportions) measures. From among the models considered, the model assuming that both slowed processing and intermittent deficiency are present emerges as the best model of sentence processing difficulty in aphasia. The modeling of individual differences suggests that, if we assume that patients have both slowed processing and intermittent deficiency, they have them in differing degrees.
KW  - Aphasia
KW  - Non-canonical sentences
KW  - Sentence-picture matching
KW  - Eye movements
KW  - Computational modeling
KW  - Cognitive architecture
KW  - Individual differences
Y1  - 2016
U6  - https://doi.org/10.1111/cogs.12250
SN  - 0364-0213
SN  - 1551-6709
VL  - 40
SP  - 5
EP  - 50
PB  - Wiley-Blackwell
CY  - Hoboken
ER  -