Laura L. Carstensen is the Fairleigh S. Dickinson Jr. Professor in Public Policy and professor of psychology at Stanford University, where she is founding director of the Stanford Center on Longevity and the principal investigator for the Stanford Life-span Development Laboratory. Carstensen is best known in academia for socioemotional selectivity theory, which has illuminated developmental changes in social preferences, emotional experience and cognitive processing from early adulthood to advanced old age. By examining postulates of socioemotional selectivity theory, Carstensen and her colleagues (most notably Mara Mather) identified and developed the conceptual basis of the positivity effect.