Grantee: University of Illinois at Urbana - Champaign, Champaign, IL, USA
Researcher: Kara D. Federmeier, Ph.D.
Grant Title: Cognitive and neural mechanisms of meaning comprehension
https://doi.org/10.37717/220020234
Program Area: Understanding Human Cognition
Grant Type: Scholar Award
Amount: $600,000
Year Awarded: 2010
Duration: 6 years
The human brain infuses its world with meaning. The senses provide the brain with pitch, volume, lines, curves, shading and color. The brain not only analyzes and categorizes these complex, often ambiguous inputs as spoken and written words, objects, and faces, but, remarkably, seems to immediately and effortlessly link them with a rich array of knowledge that is experienced as the "meaning" of those perceptual events. At the broadest level, my research program examines the cognitive and neural dynamics that make such rapid comprehension possible.
Studies using patient and imaging data to localize functions in the brain have catalogued a broad set of areas associated with subcomponent features of meaning - e.g., the shapes, textures, sounds, functions, and associations that make up the concept denoted by a word. Yet meaning is experienced as unified. How this distributed information comes to be bound together to yield a coherent, conceptual level representation remains a mystery at the very heart of an understanding of human language and thought. Our emerging data suggest that meaning is not "looked up" in memory, as traditionally thought, but is instead dynamically constructed - and that time serves as a critical binding force. What information becomes part of the meaning of an input critically depends on when information becomes available. Thus, as we have shown, meaning is context-dependent, colored by expectations, and subject to individual differences.
The critical role of processing dynamics in shaping meaning construction is strikingly attested by hemispheric differences. The left and right cerebral hemispheres share the same basic anatomy and physiology and perform most basic cognitive functions in parallel. Yet, we have argued, they differ in the efficacy of their feedback connections, and, as we have documented, this has critical consequences for how each recognizes and remembers words, comprehends the meaning and structure of sentences, and deals with ambiguity and errors. My research program thus goes beyond the study of individual cognitive subprocesses and the use of localization-biased cognitive neuroscience approaches. Instead, we investigate how processing unfolds over time as well as space, within and across the two hemispheres, and over a broad range of input types and tasks. To that end, we take advantage of the temporal and functional specificity of event-related brain potentials, which we are beginning to combine with techniques that allow perturbations of processing dynamics, such as transcranial magnetic stimulation (and computational modeling), as well as new techniques that provide concurrent temporal and spatial precision, such as event-related optical signal data, which has not yet been used extensively to study comprehension.
We also examine how those mechanisms and the dynamics of their interactions differ across individuals and change with age, with a focus on how factors such as timing, memory, recruitment of specialized neurocognitive resources, and anatomical and genetic variability affect the real-time construction and revision of meaning. In the long-term, we expect this approach will highlight novel kinds of factors and interventions that can protect against or alleviate functional decline across the lifespan.