Quantifier processing and semantic flexibility in patients with aphasia

Frontiers in Psychology, vol. 15, pp. 1328853

Abstract

Processing of quantifiers such as "many" and "few" relies on number knowledge, linguistic abilities, and working memory. Negative quantifiers (e.g., "few," "less than half") induce higher processing costs than their positive counterparts. Furthermore, the meaning of some quantifiers is flexible and thus adaptable. Importantly, in neurotypical individuals, changing the meaning of one quantifier also leads to a generalized change in meaning for its polar opposite (e.g., the change of the meaning of "many" leads to the change of that of "few"). Here, we extended this research to patients with fluent and non-fluent aphasia after stroke. In two experiments, participants heard sentences of the type "Many/few of the circles are yellow/blue," each followed by a picture with different quantities of blue and yellow circles. The participants judged whether the sentence adequately described the picture. Each experiment consisted of three blocks: a baseline block to assess the participants' criteria for both quantifiers, a training block to shift the criteria for "many," and a test block, identical to the baseline to capture any changes in quantifier semantics. In Experiment 1, the change of the meaning of "many" was induced by using adaptation to small numbers (20-50%) of circles of the named color. In Experiment 2, explicit feedback was given in the training block after each response to rate proportions of 40% (or higher) as "many," whereas 40% is normally rather rated as "few." The objective was to determine whether people with fluent or non-fluent aphasia were able to process quantifiers appropriately and whether generalized semantic flexibility was present after brain damage. Sixteen out of 21 patients were able to perform the task. People with fluent aphasia showed the expected polarity effect in the reaction times and shifted their criteria for "many" with generalization to the untrained quantifier "few." This effect, however, was only obtained after explicit feedback (Experiment 2) but not by mere adaptation (Experiment 1). In contrast, people with non-fluent aphasia did not change the quantifier semantics in either experiment. This study contributes to gaining new insights into quantifier processing and semantic flexibility in people with aphasia and general underlying processing mechanisms.

Authors 7

1. Birte Reißner Aachen Department of Neurology, Medical Faculty Department of Psychiatry, Psychotherapy and Psychosomatics Medical Faculty

   RWTH Aachen University

   Affiliation as printed

   Department of Neurology, Medical Faculty, RWTH Aachen University, Aachen, Germany

   Department of Psychiatry, Psychotherapy and Psychosomatics, Medical Faculty, RWTH Aachen University, Aachen, Germany

2. Wiebke Grohmann Aachen Department of Neurology, Medical Faculty

   RWTH Aachen University

   Affiliation as printed

   Department of Neurology, Medical Faculty, RWTH Aachen University, Aachen, Germany

3. Natalja Peiseler

   Heinrich Heine University Düsseldorf

   Affiliation as printed

   Department of Linguistics, Heinrich Heine University, Düsseldorf, Germany

4. João Pinho Aachen Department of Neurology, Medical Faculty

   RWTH Aachen University

   Affiliation as printed

   Department of Neurology, Medical Faculty, RWTH Aachen University, Aachen, Germany

5. Katja Hußmann Aachen Department of Neurology, Medical Faculty

   RWTH Aachen University

   Affiliation as printed

   Department of Neurology, Medical Faculty, RWTH Aachen University, Aachen, Germany

6. Cornelius Johannes Werner Aachen Department of Neurology, Medical Faculty

   Die Johanniter · RWTH Aachen University

   Affiliation as printed

   Department of Neurology, Medical Faculty, RWTH Aachen University, Aachen, Germany

   Johanniter Hospital Stendal, Stendal, Germany

7. Stefan Heim corresponding Aachen Department of Neurology, Medical Faculty Department of Psychiatry, Psychotherapy and Psychosomatics Medical Faculty

   Forschungszentrum Jülich · RWTH Aachen University

   Affiliation as printed

   Department of Neurology, Medical Faculty, RWTH Aachen University, Aachen, Germany

   Department of Psychiatry, Psychotherapy and Psychosomatics, Medical Faculty, RWTH Aachen University, Aachen, Germany

   Institute of Neuroscience and Medicine (INM-1), Forschungszentrum Jülich GmbH, Jülich, Germany