Words in sentences that are more predictable are read more quickly and processed more easily. Many lines of research suggest readers are able to activate features of upcoming words before they appear (known as "pre-activation"); however, lots of research has focused on the consequences of predictions being confirmed or violated, rather than how this pre-activation process works. We are interested in identifying and examining neural activity prior to a word's occurrence that is indicative of word pre-activation, and use multiple analysis methods (e.g., time-frequency analyses, multivariate decoding) to pursue this line of research.
Open Questions:
What features (orthographic, semantic, etc.) of words are pre-activated, and when?
How does neural pre-activation vary based on how predictable a particular word is?
How does pre-activation differ between individuals? What factors (e.g., reading experience, world knowledge) contribute to these individual differences?
Which systems in the brain are involved in pre-activation of upcoming words?
Several lines of research have identified changes in behavior or neural activity at the time of a prediction being confirmed or violated, but little work has investigated how cognitive processing or behavior changes following a prediction confirmation or violation. Work in our lab has identified that our memories for words and sentences that we previously read are impacted by the degree to which those words violated our expectations. Additionally, individuals have a tendency to falsely remembering seeing words that they predicted, but never actually read - a "false memory" for predicted words. We are interested in further investigating the factors that contribute to false memories for predicted stimuli, other cognitive or behavioral processes that are impacted by prediction, and the neural mechanisms involved in changing or updating representations based on outcomes of predictions.
Open Questions:
What are other consequences of prediction on cognition, potentially even outside of the domain of language and memory (e.g., sensory processing, attention, salience, etc.)?
How does pre-activation of stimuli at the time of prediction relate to the downstream consequences of that prediction on cognition?
Which brain responses following prediction confirmations or violations (e.g., ERPs, oscillatory power changes) are related to downstream changes in behavior?
What other cognitive systems or abilities (e.g., inhibitory control, attention) might impact the relationship between prediction and later behavior?
How does pre-activation of features of upcoming stimuli change as we age? Previous psycholinguistic work with older adult participants suggests that older readers may not engage anticipatory mechanisms to the same degree as younger readers; however, this work primarily focused on consequences of prediction. In our lab, we have examined neural signals of pre-activation before upcoming words, and found that younger and older readers' brain activity doesn't look all that different. This suggests pre-activation might be relatively preserved with age, but processing of expectation violations is what really changes with age. We are interested in understanding what might be changing with age that leads to this difference between age groups.
Open Questions:
What cognitive changes (e.g., semantic memory, language experience) might be associated with age-related changes in processing expectation violations?
What neurophysiological changes, either structural or functional, might be associated with these age-related changes?
Do older adults show similar downstream consequences of prediction on memory or other cognitive processes as younger adults?
How might predictive processing differ in children or developing adults?
A primary mission of cognitive neuroscience is to "map" particular neural responses, or activity in certain brain areas, to cognitive processes (e.g. memory, attention, etc). This is challenging in multiple ways - we must have well-defined cognitive processes to map brain responses onto, but we must also have a thorough understanding of the physiological signals that we measure. A long-standing interest in the lab more on the methodological side of cognitive research has been to better understand these physiological signals (e.g., ERPs, oscillations, pupil dilation) that we measure. We investigate this through the application of more advanced analytic techniques, such as multivariate decoding and source separation, to electrophysiological and pupillometric data.
Open Questions:
To what degree do different measures derived from EEG data (ERPs, oscillations, multivariate decoding) actually reflect different neural processes, or ultimately reflect the same process?
If brain responses appear similar in different tasks / domains, does this reflect engagement of the same underlying cognitive process? Or are there important subtle differences we can measure?
How can we better understand the topography and timing of electrophysiological responses without smearing / distorting the response through averaging across trials and individuals?
To what degree are physiological responses recorded by different tools (i.e., electrophysiology and pupillometry) capturing different or similar underlying processes?
One of the most rewarding aspects of a career in scientific research is also one of the most important for the integrity and success of the research process - collaboration with fellow researchers. Often times, scientists working in different labs are conducting research on the same mechanism or process without even realizing it, due to a lack of communication or usage of different terminology. Our understanding of this mechanism would likely increase if these scientists worked together! In this career, not only do we have the opportunity to meet and befriend like-minded individuals with similar goals and purposes, but also by working together we bring together novel ideas and scientific viewpoints, as well as ensure that everyone involved in the collaborative work is doing the best work they can and maintaining ethical and responsible research practices. At the HECL, we are ardent proponents of engaging in collaborative cognitive neuroscience, either by sharing data and code, meeting with others and giving talks or workshops, and even working together on research projects.
Interested in working with us?