Words, thoughts, and brains

Representing the World in Language and Thought

Internal representations guide our navigation of the world, while language allows us to share some of what is encoded internally with others. I have been interested in the content of thought, the nature of word meanings and what they reveal about thought, and how thoughts are expressed in words. My work has combined evidence from laboratory experimentation with observation of word use in natural settings, including from people who speak different languages. Some of the ideas guiding the work are these: understanding entities in the world non-linguistically engages different representations and processes than talking about them; patterns of word use in a language reflect cultural and linguistic history, not only conceptual representations of current speakers; linguistic and non-linguistic knowledge is therefore at least partially independent, and so language and thought will not always closely parallel one another; the beliefs people express about their concepts and word meanings may not accurately reflect the implicit knowledge they draw on in interacting with and talking about the world; and only by carefully observing actual word use can we understand how word meanings come about and how linguistic knowledge is used to select words for communication.

Language Entails Linguistic Relativity

This commentary addresses the challenge of linking an individual-grounded theory of concepts to a phenomenon that assumes conceptual conventions at population level (linguistic relativity). We distinguish I-concepts (individual, interior, imagistic) from L-concepts (linguistic, labeled, local) and see that quite different causal processes are often conflated under the term "concepts." I argue that the Grounded Cognition Model (GCM) entails linguistic relativity only to the extent that it imports L-concepts into its scope, which it can hardly avoid doing given that practitioners require language to coordinate around their theory and findings. I conclude that what entails linguistic relativity is not the GCM but language itself.

Grounded Cognition Entails Linguistic Relativity: A Neglected Implication of a Major Semantic Theory

According to the popular Grounded Cognition Model (GCM), the sensory and motor features of concepts, including word meanings, are stored directly within neural systems for perception and action. More precisely, the core claim is that these concrete conceptual features reuse some of the same modality-specific representations that serve to categorize experiences involving the relevant kinds of objects and events. Research in semantic typology, however, has shown that word meanings vary significantly across the roughly 6500 languages in the world. I argue that this crosslinguistic semantic diversity has significant yet previously unrecognized theoretical consequences for the GCM. In particular, to accommodate the typological data, the GCM must assume that the concrete features of word meanings are not merely stored within sensory/motor brain systems, but are represented there in ways that are, to a nontrivial degree, language-specific. Moreover, it must assume that these conceptual representations are also activated during the nonlinguistic processing of the relevant kinds of objects and events (e.g., during visual perception and action planning); otherwise, they would not really be grounded, which is to say, embedded inside sensory/motor systems. Crucially, however, such activations would constitute what is traditionally called linguistic relativity-that is, the influence of language-specific semantic structures on other forms of cognition. The overarching aim of this paper is to elaborate this argument more fully and explore its repercussions. To that end, I discuss in greater detail the key aspects of the GCM, the evidence for crosslinguistic semantic diversity, pertinent work on linguistic relativity, the central claim that the GCM entails linguistic relativity, some initial supporting results, and some important limitations and future directions.

Semantic flow and its relation to controlled semantic retrieval deficits in the narrative production of people with aphasia

Aphasia has had a profound influence on our understanding of how language is instantiated within the human brain. Historically, aphasia has yielded an in vivo model for elucidating the effects of impaired lexical-semantic access on language comprehension and production. Aphasiology has focused intensively on single word dissociations. Yet, less is known about the integrity of combinatorial semantic processes required to construct well-formed narratives. Here we addressed the question of how controlled lexical-semantic retrieval deficits (a hallmark of aphasia) might compound over the course of longer narratives. We specifically examined word-by-word flow of taxonomic vs. thematic semantic distance in the storytelling narratives of individuals with chronic post-stroke aphasia (n = 259) relative to age-matched controls (n = 203). We first parsed raw transcribed narratives into content words and computed inter-word semantic distances for every running pair of words in each narrative (N = 232,490 word transitions). The narratives of people with aphasia showed significant reductions in taxonomic and thematic semantic distance relative to controls. Both distance metrics were strongly predictive of offline measures of semantic impairment and aphasia severity. Since individuals with aphasia often exhibit perseverative language output (i.e., repetitions), we performed additional analyses with repetitions excluded. When repetitions were excluded, group differences in semantic distances persisted and thematic distance was still predictive of semantic impairment, although some findings changed. These results demonstrate the cumulative impact of deficits in controlled word retrieval over the course of narrative production. We discuss the nature of semantic flow between words as a novel metric of characterizing discourse and elucidating the nature of lexical-semantic access impairment in aphasia at multiword levels.

Avoiding Conflict: When Speaker Coordination Does Not Require Conceptual Agreement

In this paper we discuss the socialization hypothesis-the idea that speakers of the same (linguistic) community should share similar concepts given that they are exposed to similar environments and operate in highly-coordinated social contexts-and challenge the fact that it is assumed to constitute a prerequisite to successful communication. We do so using distributional semantic models of meaning (DSMs) which create lexical representations via latent aggregation of co-occurrence information between words and contexts. We argue that DSMs constitute particularly adequate tools for exploring the socialization hypothesis given that 1) they provide full control over the notion of background environment, formally characterized as the training corpus from which distributional information is aggregated; and 2) their geometric structure allows for exploiting alignment-based similarity metrics to measure inter-subject alignment over an entire semantic space, rather than a set of limited entries. We propose to model coordination between two different DSMs trained on two distinct corpora as dimensionality selection over a dense matrix obtained via Singular Value Decomposition This approximates an ad-hoc coordination scenario between two speakers as the attempt to align their similarity ratings on a set of word pairs. Our results underline the specific way in which linguistic information is spread across singular vectors, and highlight the need to distinguish agreement from mere compatibility in alignment-based notions of conceptual similarity. Indeed, we show that compatibility emerges from idiosyncrasy so that the unique and distinctive aspects of speakers' background experiences can actually facilitate-rather than impede-coordination and communication between them. We conclude that the socialization hypothesis may constitute an unnecessary prerequisite to successful communication and that, all things considered, communication is probably best formalized as the cooperative act of avoiding conflict, rather than maximizing agreement.

Interactions between language, thought, and perception: Cognitive and neural perspectives

ABSTRACT The role that language plays in shaping non-linguistic cognitive and perceptual systems has been the subject of much theoretical and experimental attention over the past half-century. Understanding how language interacts with non-linguistic systems can provide insight into broader constraints on cognitive and brain organization. The papers that form this volume investigate various ways in which linguistic structure can interact with and influence how speakers think about and perceive the world, and the related issue of the constraints that in turn shape linguistic representations. These theoretical and empirical contributions support deeper understanding of the interactions between language, thought, and perception, and motivate new approaches for developing directional predictions at both the neural and cognitive levels.

Naming and Knowing Revisited: Eyetracking Correlates of Anomia in Progressive Aphasia

Progressive naming impairment (i.e., anomia) is a core diagnostic symptom of numerous pathologies that impact anterior and inferior portions of the temporal lobe. For patients who experience such regional temporal lobe degeneration, patterns of language loss often parallel the degradation of semantic memory, an etiology of naming impairment known as semantic anomia. Previous studies of semantic anomia have focused extensively on the output of naming attempts by contrasting errors, omissions, and distortions as a function of item-level characteristics (e.g., prototypicality, semantic category). An alternative approach involves evaluating visual confrontation naming as the naming process unfolds. Techniques with high temporal resolution (e.g., eyetracking) offer a potentially sensitive mode of delineating the locus of impairment during naming. For example, a lexical retrieval disorder would hypothetically elicit normal gaze patterns associated with successful visual object recognition regardless of naming accuracy. In contrast, we hypothesize that semantic anomia would be distinguished by aberrant gaze patterns as a function of reduced top-down conceptually guided search. Here we examined visual object recognition during picture confrontation naming by contrasting gaze patterns time locked to stimulus onset. Patients included a cohort of patients with anomia associated with either primary progressive aphasia (N = 9) or Alzheimer’s disease (N = 1) who attempted to name 200 pictures over the course of 18–24 months. We retrospectively isolated correct and incorrect naming attempts and contrasted gaze patterns for accurate vs. inaccurate attempts to discern whether gaze patterns are predictive of language forgetting. Patients tended to show a lower fixation count, higher saccade count, and slower saccade velocity for items that were named incorrectly. These results hold promise for the utility of eyetracking as a diagnostic and therapeutic index of language functioning.