We investigate the psychological and neural mechanisms that underlie attention and cognitive control. These include the mechanisms that enable minimizing distraction from irrelevant stimuli, cross-modal attention, memory-attention interactions, attentional capture, and multi-tasking (e.g., task switching). We use methods from cognitive psychology and cognitive neuroscience to investigate these mechanisms.
One of our main interests concerns the mechanisms that enable adaptive control: the ability to change behavior in response to recent events. For example, people are often less distracted by irrelevant stimuli just after they overcome distraction from such stimuli. This sequential effect suggests that minimizing distraction from irrelevant stimuli involves adaptive control mechanisms that promote a “distraction-resistant” attentional state.
People respond more slowly to relevant stimuli when they experience high levels of distraction (top line) than when they experience low levels of distraction (bottom line). But such distraction effects are smaller after people experience high levels of distraction (right side of the figure) than after people experience low levels of distraction (left side of the figure). This sequential effect suggests the existence of adaptive control processes that bring about a “distraction-resistant” attentional state right after people experience high levels of distraction.
One of our core research goals is to understand the role of memory in engendering this sequential effect. We have found that memories of recent distraction produce this sequential effect by biasing attentional systems to inhibit responses associated with irrelevant stimuli (Weissman et al., 2015). We have also found that this sequential effect is context-specific, meaning that it occurs only if the task context repeats (Grant et al., 2020).
More broadly, we have found that adaptive control mechanisms operate even in the absence of irrelevant stimuli (Weissman et al., 2017; Grant & Weissman, 2019). For example, using novel force-sensitive keyboards, we have found that these mechanisms operate by predicting (and preparing in advance) responses to upcoming stimuli (Weissman, 2019). Playing the video below (by pressing the arrow on the bottom left) illustrates how our novel keyboards register very small changes in finger pressure that index predicting an upcoming response.
We are also exploring the neural bases of adaptive control in epilepsy and brain tumor patients who have electrodes temporarily implanted in their brains. In particular, we are using electrocorticography, or eCog, to determine the spatial location and timing of neural events that are associated with distraction. Our preliminary findings indicate distraction-related effects in (a) middle frontal regions that have been linked to cognitive control, (b) temporal regions that have been implicated in processing auditory distractors, and (c) various other regions. In the figure below, significant differences in high-frequency gamma activity (time-locked to stimulus presentation) are indicated by the dark bars under each figure. This work is conducted in collaboration with Dr. David Brang.
We are also working on larger interdisciplinary projects to identify (1) effects of concussion on attention using functional near-infrared spectroscopy (with Dr. Ioulia Kovelman and Dr. Steven Broglio), (2) sources of age-related reductions of functional specialization using magnetic resonance spectroscopy and functional magnetic resonance imaging (with Dr. Thad Polk), and (3) brain regions that are critical for cognition in patients undergoing tumor resection (with Dr. Shawn Hervey-Jumper and Dr. David Brang).