Abstract rule generalization for composing novel meaning recruits a frontoparietal control network

Imaging Neuroscience, vol. 3

Abstract

The ability to generalize previously learned knowledge to novel situations is crucial for adaptive behavior, representing a form of cognitive flexibility that is particularly relevant in language. Humans excel at combining linguistic building blocks to infer the meanings of novel compositional words, such as "un-reject-able-ish". The neural mechanisms and representations required for this ability remain unclear. To unravel these, we trained participants on a semi-artificial language in which the meanings of compositional words could be derived from known stems and unknown affixes, using abstract relational structure rules (e.g., "good-kla" which means "bad", where "-kla" reverses the meaning of the stem word "good"). According to these rules, word meaning depended on the sequential relation between the stem and the affix (i.e., pre- vs. post-stem). During fMRI, participants performed a semantic priming task, with novel compositional words as either sequential order congruent (e.g., "short-kla") or incongruent primes (e.g., "kla-short"), and real words serving as targets that were synonyms of the composed meaning of the congruent primes (e.g., "long"). Our results show that the compositional process engaged a broad temporoparietal network, while representations of composed word meaning were localized in a more circumscribed left-lateralized language network. Strikingly, newly composed meanings were decodable already at the time of the prime in a way that could not be accounted for representations of the prime words themselves. Finally, we found that the composition process recruited abstract rule representations in a bilateral frontoparietal network, in contrast to our preregistered prediction of a medial prefrontal-hippocampal network. These results support the hypothesis that people activate a bilateral frontoparietal circuitry for compositional inference and generalization in language.

Authors 6

1. Xiaochen Zheng Aachen Cognitive Psychology Unit Institute of Psychology, Leiden University

   Leiden University · Radboud University Nijmegen · Donders Centre for Cognitive Neuroimaging · Donders Institute for Brain, Cognition and Behaviour

   Affiliation as printed

   Cognitive Psychology Unit, Institute of Psychology, Leiden University, Leiden, the Netherlands

   Donders Center for Cognitive Neuroimaging, Radboud University, Nijmegen, the Netherlands

   Cognitive Psychology Unit, Institute of Psychology, Leiden University, Leiden, The Netherlands

   Radboud University, Donders Institute for Brain, Cognition and Behaviour, Nijmegen, the Netherlands

2. Mona M. Garvert

   University of Würzburg

   Affiliation as printed

   Julius-Maximilians-Universität Würzburg, Faculty of Human Sciences, Würzburg, Germany

3. Hanneke E.M. den Ouden

   Radboud University Nijmegen · Donders Institute for Brain, Cognition and Behaviour · Donders Centre for Cognition

   Affiliation as printed

   Donders Center for Cognition, Radboud University, Nijmegen, the Netherlands

   Radboud University, Donders Institute for Brain, Cognition and Behaviour, Nijmegen, the Netherlands

4. Lisa I. Horstman

   Radboud University Nijmegen · Radboud University Medical Center

   Affiliation as printed

   Radboud University Medical Center, Department of Psychiatry, Nijmegen, the Netherlands

5. David Richter

   Radboud University Nijmegen · Universidad de Granada · Donders Centre for Cognitive Neuroimaging · Donders Institute for Brain, Cognition and Behaviour · Centro de Investigación Mente, Cerebro y Comportamiento

   Affiliation as printed

   Donders Center for Cognitive Neuroimaging, Radboud University, Nijmegen, the Netherlands

   Mind, Brain and Behavior Research Center (CIMCYC), University of Granada, Granada, Spain

   Radboud University, Donders Institute for Brain, Cognition and Behaviour, Nijmegen, the Netherlands

6. Roshan Cools

   Radboud University Nijmegen · Radboud University Medical Center · Donders Centre for Cognitive Neuroimaging

   Affiliation as printed

   Donders Center for Cognitive Neuroimaging, Radboud University, Nijmegen, the Netherlands

   Radboud University Medical Center, Department of Psychiatry, Nijmegen, the Netherlands