Martin Seligman is the founder of positive psychology, a field of study that examines healthy states, such as happiness, strength of character and optimism.

Shawn Achor is the CEO of Good Think Inc., where he researches and teaches about positive psychology.

Mihaly Csikszentmihalyi contributed pioneering work to our understanding of happiness, creativity, human fulfillment and the notion of "flow" -- a state of heightened focus and immersion in activities such as art, play and work.

In her book "The Power of Meaning," Emily Esfahani Smith rounds up the latest research -- and the stories of fascinating people she interviewed -- to argue that the search for meaning is far more fulfilling than the pursuit of personal happiness.

Aala El-Khani explores the needs of families affected by war and displacement and develops resources that support the mental health of children and their caregivers to promote current and future wellbeing.

Laurie Santos studies primate psychology and monkeynomics -- testing problems in human psychology on primates, who (not so surprisingly) have many of the same predictable irrationalities we do.

Per Espen Stoknes weaves together psychology and economics in imaginative ways, often revolving around our human relationships to the natural world and to each other.