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Jan2712:00pmMetcalf Research BuildingMichael S. Goodman ’74 Memorial Seminar Series. Speaker: Andrew Lynn, Brown University. Title: On the developmental relationship between visual processing and visual attention: Examining behavior and functional brain connectivity. Abstract: Both visual function and visual attention improve dramatically across the first decade of life. However, the developmental relationship between these two related processes remains unclear. We aimed to test whether visual function development is a catalyst for visual attention development and whether this relationship may be driven by developmental change in functional brain connectivity (Amso & Scerif, 2015). Across multiple studies, we measured children’s contrast sensitivity and performance on a feature search and conjunction search task that manipulates feature integration demands within and across the dorsal & ventral visual pathways. In a separate group of children, we also measured the functional architecture of the dorsal and ventral visual streams during rest, using a Graph Theoretical Approach. We predicted that 1) developmental change in contrast sensitivity may influence feature search performance and 2) developmental change in feature integration may influence conjunction search performance and 3) functional integration between the dorsal and ventral visual streams would increase across childhood. We found that across childhood, higher contrast sensitivity was associated with faster feature search and that age mediated this relationship. We also found that developmental improvements in visual feature integration across the dorsal and ventral stream, but not within the ventral stream, were associated with slower conjunction visual search. Despite these behavioral findings, preliminary functional connectivity analyses suggest that functional integration between the dorsal and ventral stream is stable across childhood. We suggest that, while increases in visual contrast sensitivity may facilitate bottom-up visual attention across childhood, improvements in visual feature integration may influence selective attention development by increasing competition among targets and distractors, and increase visual search cost. Our functional connectivity results lead us to speculate that functional integration across the dorsal and ventral visual stream may be task-dependent.
Jan293:00pmMetcalf Research Building
Speaker: Brian Nosek, University of Virginia. Title: What is replication?
Jan3012:00pmMetcalf Research Building
Michael S. Goodman ’74 Memorial Seminar Series. Speaker: Dagmar Sternad, Northeastern University. Title: Stability, Variability and Predictability: Dynamic Primitives in the Control of Complex Actions. Abstract: Everyday behavior is a complex flow of actions, combining rhythmic and discrete movement elements and flexibly interacting with objects in the environment. In contrast to real-life behavior, research in human motor control has studied isolated, highly controlled experimental tasks, resulting in focused models that may not scale up to actions with full complexity. The premise of our research is that complex functional behaviors should be understood as the manifestation of a hierarchy of dynamic primitives, robust modules that overcome delays and noise in the neuromotor system and thereby simplify control. Discrete and rhythmic movements are generated by fixed-point and limit-cycle dynamics, attractors that are stable in the face of perturbations and that grant predictability, required for fast and complex actions; impedance is necessary to enable physical interactions. To test this framework, our research pursues both analytic and synthetic approaches using a suite of interactive skills as testbeds: from throwing and bouncing a ball to a target, to transporting a cup of coffee and cracking a whip. Starting with a model of the task that is implemented in a virtual environment, mathematical analyses of the task’s solution space create hypotheses for the experimental studies. Key concepts in our analysis are stability, variability, and predictability. Results show that humans develop skill by: 1) finding error-tolerant strategies that permit variability, 2) exploiting solutions with dynamic stability, 3) optimizing predictability of object dynamics. Simulations based on dynamic primitives generate critical features of these experimental findings. This framework can guide our understanding of pathological behaviors in clinical populations.
Apr83:00pmMetcalf Research Building
Speaker: Daniel Jurafsky, Stanford University. Title: TBA
Apr293:00pmMetcalf Research Building
Speaker: Anna Papafragou, University of Delaware. Title: TBA