Conflict during sentence comprehension: What hurts more, executive function or short-term memory deficits?
-
1
The George Washington University, United States
Sentence comprehension is a complex task that involves the short-term storage and integration of multiple linguistic representations. Comprehension can be especially challenging if there is conflict, for example, when different cues lead to different interpretations. Recent studies have suggested that executive functions used for behavior regulation are also used for resolving conflict during sentence comprehension. In neurotypical adults, frontal regions implicated in executive function are also activated during the comprehension of sentences containing conflict (e.g., Thothathiri, Kim, Trueswell, & Thompson-Schill, 2012a). Patients with frontal cortex damage show correlated deficits in executive function and the comprehension of garden-path and non-canonical sentences thought to induce conflict (e.g., Novick, Kan, Trueswell, & Thompson-Schill, 2009). However, contradictory evidence suggests no necessary relation between the two domains. For example, a lesion-symptom-mapping study found that deficits in understanding non-canonical sentences correlated with damage to posterior and not frontal regions (Thothathiri, Kimberg, & Schwartz, 2012b). To clarify the cognitive components necessary for resolving conflict during sentence comprehension, we conducted contrastive case studies in two patients with aphasia, one with posterior (non-frontal) and the other with frontal damage.
Each patient completed a task battery that tested three domains: short-term memory (STM), executive function (EF), and sentence comprehension. For STM, we used rhyme probe, category probe, digit and word span tasks to measure phonological and semantic retention (Allen, Martin, & Martin, 2012). For EF, two tasks (Stroop, MultiArrow) tested conflict resolution and two other tasks (1-back, Keep-track) tested a different function (updating of working memory content). For sentence comprehension, the critical task involved sentences containing syntactic-semantic conflict (e.g., The doctor was treated by the patient. Thothathiri et al., 2012a). For these sentences, the syntactic structure led to an interpretation that conflicted with semantic expectations (doctors usually treat patients rather than vice versa). Two other tasks tested the comprehension of reversible canonical and non-canonical sentences, and sentences that were semantically sensible or anomalous (Martin & He, 2004; Thothathiri et al., 2012b).
See Figure 1 for results. Patient 1 had frontal cortex damage. Consistent with the established link between this region and conflict resolution, she showed an exaggerated Stroop and MultiArrow effect. Her STM and updating performance appeared unimpaired. Notably, her sentence comprehension was also unimpaired, even for syntactic-semantic conflict and non-canonical sentences. Patient 2 showed a contrasting pattern. He had damage to posterior brain regions and showed a much smaller Stroop and MultiArrow effect. His span scores indicated an STM deficit, particularly for phonological STM (rhyme probe and digit spans). Finally, his scores on the syntactic-semantic task indicated difficulty with conflict sentences. Additionally, his performance on the reversible and anomalous sentences suggested that he failed to understand sentences accurately whenever semantics did not aid in interpretation.
These results suggest that intact STM, including phonological STM, might be important for sentence comprehension when semantic and non-semantic information must be integrated. Conversely, they cast doubt on the necessity of EF for sentence comprehension (Thothathiri et al., 2012b) and corroborate previous reports of dissociation between STM and EF (Allen et al., 2012).
Acknowledgements
We thank Michelle Rattinger and Hilary Gray for assistance with recruitment and data collection.
References
Allen, C. M., Martin, R. C., & Martin, N. (2012). Relations between short-term memory deficits, semantic processing, and executive function. Aphasiology, 26(3-4), 428-461.
Martin, R. C., & He, T. (2004). Semantic short-term memory and its role in sentence processing: A replication. Brain and language, 89(1), 76-82.
Novick, J.M., Kan, I.P., Trueswell, J.C., & Thompson-Schill, S.L. (2009). A case for conflict across multiple domains: Memory and language impairments following damage to ventrolateral prefrontal cortex. Cognitive Neuropsychology, 26(6), 527-567.
Thothathiri, M., Kim, A., Trueswell, J. C., & Thompson-Schill, S. L. (2012a). Parametric effects of syntactic–semantic conflict in Broca’s area during sentence processing. Brain and Language, 120(3), 259-264.
Thothathiri, M., Kimberg, D. Y., & Schwartz, M. F. (2012b). The neural basis of reversible sentence comprehension: Evidence from voxel-based lesion symptom mapping in aphasia. Journal of Cognitive Neuroscience, 24(1), 212-222.
Keywords:
syntactic-semantic conflict,
Aphasia,
cognitive control,
Language,
STM
Conference:
54th Annual Academy of Aphasia Meeting, Llandudno, United Kingdom, 16 Oct - 18 Oct, 2016.
Presentation Type:
Poster Sessions
Topic:
Academy of Aphasia
Citation:
Thothathiri
M and
Mauro
KL
(2016). Conflict during sentence comprehension: What hurts more, executive function or short-term memory deficits?.
Front. Psychol.
Conference Abstract:
54th Annual Academy of Aphasia Meeting.
doi: 10.3389/conf.fpsyg.2016.68.00120
Copyright:
The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers.
They are made available through the Frontiers publishing platform as a service to conference organizers and presenters.
The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated.
Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed.
For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions.
Received:
30 Apr 2016;
Published Online:
15 Aug 2016.
*
Correspondence:
Dr. Malathi Thothathiri, The George Washington University, Washington, DC, United States, malathi@email.gwu.edu