As part of his efforts to develop empirical tests to examine personality and to understand the mechanisms that enable self-control, Walter Mischel conducted a series of experiments known as the Stanford Marshmallow Tests. In the experiment, Mischel gave a child a choice between a single marshmallow, obtainable immediately, or two marshmallows obtainable by waiting for them. He found that children who were able to delay gratification and waited longer to get more marshmallows (or other treats), were later in life better adjusted, more dependable and able to tolerate frustration, and as high school students scored much higher on the collegiate Scholastic Aptitude Test. Follow-ups with these participants 40 years later are also revealing important differences in cognitive and neural mechanisms (e.g. revealed by brain scans) linked to their self-control behavior over the life course. Mischel’s research looks at the psycho-social and physiological mechanisms that underlie adaptive self and emotional regulation in hopes of further understanding how these factors impact consequential real-world behaviors including mental and physical health. His theory that personality cannot be separated from the contexts and the specific situations with which the person interacts revolutionized the field of personality psychology and sparked the development of new methods and models to study individual differences in social behavior. Mischel is a member of the National Academy of Sciences and a Fellow of the American Academy of Arts and Sciences. He is a Past President of the Association for Psychological Science (APS) and is the recipient of the field’s highest honors in areas ranging from clinical to social to personality psychology, including more than 50 years of continuous research support from the National Institutes of Health, two consecutive National Institute of Mental Health MERIT Awards, and the 2011 Grawemeyer Award.