Julius Silver Professor of Psychology and Neural Science
My research examines the cognitive neuroscience of emotion, learning and memory. My primary focus has been to understand how human learning and memory are changed by emotion and to investigate the neural systems mediating their interactions. I have approached this topic from a number of different perspectives, with an aim of achieving a more global understanding of the complex relations between emotion and memory. As much as possible, I have tried to let the questions drive the research, not the techniques or traditional definitions of research areas. I have used a number of techniques (behavioral studies, physiological measurements, brain-lesion studies, fMRI) and have worked with a number of collaborators in other domains (social and clinical psychologists, psychiatrists, neuroscientists, economists, physicists). It is my belief that having focused questions and a broad approach to answering these questions has enhanced the overall quality of my research program and the cross-disciplinary relevance and appeal of my work.
Research projects in the lab can be characterized around four topics:
Extending animal models of emotional learning to human behavior. One technique we have used extensively is classical fear conditioning, which has been investigated as a model paradigm for emotional learning across species. Using this paradigm, we have been able to show that similar neural systems underlie the acquisition and extinction of fear conditioning across species. In humans, we have shown that social learning of fear (through instruction and observation) also engages these neural systems. Identifying these mechanisms in humans helps bridge the gap from animal models to normal human function. We are currently extending this work in two ways. First, we to starting to investigate the mechanisms of appetitive or reward processing. Second, we are exploring how learned emotional responses can be altered through extinction, emotion regulation and reconsolidation. These basic paradigms can be used to assess changes that may occur with psychopathology and/or the results of potential treatments.
Emotion's influence in episodic memory. Cognitive psychology research on emotion and memory has focused primarily on explicit or episodic memory. These studies have shown that episodic memory is enhanced with mild arousal. In addition, emotion may alter the characteristics of memory so that memories for emotional events seem more detailed and vivid, even when they are not more accurate. In a number of studies we are exploring the neural systems underlying emotion's influence on episodic memory accuracy and the subjective sense of remembering. We have extended these studies to behavioral and imaging studies of real-life emotional events, specifically memory for the terrorist attacks of 9/11.
The impact of emotion on perception, attention and expression. The first stage of memory processing is perception and attention. In order to have a complete understanding of emotion's influence on learning and memory, it is important to know how the initial stages of stimulus processing are influenced by emotion. Given this, we have explored the behavioral and neural mechanisms underlying emotion's influence on attention and perception. In addition, in order to assess emotion, it is important to have a thorough understanding of the different means emotion can be expressed. We have examined the differences in the behavioral and neural systems of emotion as it is expressed through explicit evaluation, psychophysiology, implicit reaction time tasks and choice behavior.
Extending the basic mechanisms of emotional learning to social behavior, decision making and economics. The ultimate goal of our research is to determine how an understanding of emotion's impact on learning and memory can influence our actions outside of the laboratory. This has led us to explore how emotion influences decision making (or choice), as well as social behavior. Along these lines, we have projects examining the acquisition, expression, and inhibition of social biases, particularly race bias. We are also exploring emotion's influence on decision making paradigms derived from economics, as well as more basic studies examining classical vs. instrumental conditioning. These studies extend our basic research on the behavioral and neural systems of emotion, learning and memory into the exciting new domains of Social Neuroscience and Neuroeconomics.