PhD - Psychology, Johns Hopkins University, October 2010
MA - Psychology, Johns Hopkins University, May 2007
BA - Psychology, the University of Pennsylvania, May 2003
Research Area: Cognition and Cognitive Neuroscience
attention, working memory, information processing, capacity limits, multitasking, perception, visual short term memory (VSTM), functional magnetic resonance imaging (fMRI)
How does the human brain allow us to react adaptively to widely varying situations and tasks? And why does this extremely flexible system fail in seemingly simple situations? My research aims to understand the cognitive and neural bases of the paradoxical, flexible-yet-limited nature of human cognition. I use a variety of methods to pursue two primary research directions:
1. How are cognitive processes implemented in the human brain? Humans are very good at arbitrarily processing information to perform novel tasks. But this flexible information processing may come at a cost: if we use general-purpose mechanisms to select, represent, and transform information, we may be stuck using identical mechanisms to process even unrelated tasks, leading to bottlenecks on our ability to perform multiple tasks at once. A wealth of research has shown that our brains are not wholly general-purpose information processors, but neither do we depend on "grandmother cells"--completely specialized neural machinery for every situation and percept. I use behavioral measures, fMRI, and brain stimulation (tDCS) to determine the architecture of information processing in the human brain, with the goal of understanding how general-purpose and specialized neural mechanisms implement cognition. Furthermore, I ask how these neural mechanisms--particularly those underlying attention and response selection--explain capacity limits in human behavior.
2. How do we represent the world we see now, and the world we saw in the past? A fundamental limit on human behavior is the accuracy with which we represent the world around us, both as we perceive it and as we maintain this information in memory. My research on perceptual representations has ranged from low-level mechanisms such as cortical magnification in primary visual cortex to high-level mechanisms such as the neural basis of individual differences in perception of items of expertise (e.g., what makes perception of cars different in car experts compared to novices?). In the domain of memory, I recently showed that visual working memory (VWM) representations have similar spatial resolution to perceptual representations, but encode information in a different format. The connecting theme of these studies is that the way we represent information enables our behavior but also places limitations on it. This means that to understand our flexible-yet-limited information processing, we need to understand the way we represent information as well as the way we process and transform it.
In order to carry out the above research aims, I use methods such as:
- functional magnetic resonance imaging (fMRI)
- multivariate/multivoxel pattern analysis (MVPA)
- transcranial direct current stimulation (tDCS) of the brain
- computational modeling (quantitative mixture modeling)
- behavioral measures of response time and accuracy