Kristina Thiele

Children's syntactic-priming magnitude: lexical factors and participant characteristics

This study examines whether lexical repetition, syntactic skills, and working memory (WM) affect childrens syntactic-priming behavior, i.e. their tendency to adopt previously encountered syntactic structures. Children with Specific Language Impairment (SLI) and typically developing (TD) children were primed with prenominal (e.g., the yellow cup) or relative clause (RC; e.g., the cup that is yellow) structures with or without lexical overlap and performed additional tests of productive syntactic skills and WM capacity. Results revealed a reliable syntactic-priming effect without lexical boost in both groups: SLI and TD children produced more RCs following RC primes than following prenominal primes. Grammaticality requirements influenced RC productions in that SLI children produced fewer grammatical RCs than TD children. Of the additional measures, WM positively affected how frequently children produced dispreferred RC structures, but productive syntactic skills had no effect. The results support an implicit-learning account of syntactic priming and emphasize the importance of WM in syntactic priming tasks.

An evaluation of measures to dissociate language and communication disorders from healthy controls using machine learning techniques

Reliably distinguishing patients with verbal impairment due to brain damage, e.g. aphasia, cognitive communication disorder (CCD), from healthy subjects is an important challenge in clinical practice. A widely-used method is the application of word generation tasks, using the number of correct responses as a performance measure. Though clinically well-established, its analytical and explanatory power is limited. In this paper, we explore whether additional features extracted from task performance can be used to distinguish healthy subjects from aphasics or CCD patients. We considered temporal, lexical, and sublexical features and used machine learning techniques to obtain a model that minimizes the empirical risk of classifying participants incorrectly. Depending on the type of word generation task considered, the exploitation of features with state-of-the-art machine learning techniques outperformed the predictive accuracy of the clinical standard method (number of correct responses). Our analyses confirmed that number of correct responses is an adequate measure for distinguishing aphasics from healthy subjects. However, our additional features outperformed the traditional clinical measure in distinguishing patients with CCD from healthy subjects: The best classification performance was achieved by excluding number of correct responses. Overall, our work contributes to the challenging goal of distinguishing patients with verbal impairments from healthy subjects.

Lexical alignment in triadic communication

Lexical alignment refers to the adoption of one’s interlocutor’s lexical items. Accounts of the mechanisms underlying such lexical alignment differ (among other aspects) in the role assigned to addressee-centered behavior. In this study, we used a triadic communicative situation to test which factors may modulate the extent to which participants’ lexical alignment reflects addressee-centered behavior. Pairs of naïve participants played a picture matching game and received information about the order in which pictures were to be matched from a voice over headphones. On critical trials, participants did or did not hear a name for the picture to be matched next over headphones. Importantly, when the voice over headphones provided a name, it did not match the name that the interlocutor had previously used to describe the object. Participants overwhelmingly used the word that the voice over headphones provided. This result points to non-addressee-centered behavior and is discussed in terms of disrupting alignment with the interlocutor as well as in terms of establishing alignment with the voice over headphones. In addition, the type of picture (line drawing vs. tangram shape) independently modulated lexical alignment, such that participants showed more lexical alignment to their interlocutor for (more ambiguous) tangram shapes compared to line drawings. Overall, the results point to a rather large role for non-addressee-centered behavior during lexical alignment.

Temporal effects of alignment in text-based, task-oriented discourse

Communicative alignment refers to adaptation to ones communication partner. Temporal aspects of such alignment have been little explored. This article examines temporal aspects of lexical and syntactic alignment (i.e., tendencies to use the interlocutors lexical items and syntactic structures) in task-oriented discourse. In particular, we investigate whether lexical and syntactic alignment increases throughout the discourse and whether alignment contributes to speedy task completion. We present data from a text-based chat game in which participants instructed each other on where to place objects in a grid. Our methodological approach allows calculating a robust baseline and revealed reliable lexical and syntactic alignment. However, only lexical alignment, but not syntactic alignment, was sensitive to temporal aspects in that only lexical alignment increased throughout the discourse and positively affected task completion time. We discuss how these results relate to the communicative task and mention implications for models of alignment.

New ways to analyze word generation performance in brain injury: A systematic review and meta-analysis of additional performance measures

ABSTRACT Introduction. The investigation of word generation performance is an accepted, widely used, and well-established method for examining cognitive, language, or communication impairment due to brain damage. The performance measure traditionally applied in the investigation of word generation is the number of correct responses. Previous studies, however, have suggested that this measure does not capture all potentially relevant aspects of word generation performance and hence its underlying processes, so that its analytical and explanatory power of word generation performance might be rather limited. Therefore, additional qualitative or quantitative performance measures have been introduced to gain information that goes beyond the deficit and allows for therapeutic implications. Method. We undertook a systematic review and meta-analysis of original research that focused on the application of additional measures of word generation performance in adult clinical populations with acquired brain injury. Results. Word generation tasks are an integral part of many different tests, but only few use additional performance measures in addition to the number of correct responses in the analysis of word generation performance. Additional measures, which showed increased or similar diagnostic utility relative to the traditional performance measure, regarded clustering and switching, error types, and temporal characteristics. Conclusions. The potential of additional performance measures is not yet fully exhausted in patients with brain injury. The temporal measure of response latencies in particular is not adequately represented, though it may be a reliable measure especially for identifying subtle impairments. Unfortunately, there is no general consensus as of yet on which additional measures are best suited to characterizing word generation performance. Further research is needed to specify the additional parameters that are best qualified for identifying and characterizing impaired word generation performance.