His research focuses on self-definition approached from three angles: (1) What information do people desire and select en route to self-definition? (2) How do people use their past to achieve self-definition? (3) How do people form a self-definition that feels real? These questions led to corresponding, and interrelated, research programmes on self-evaluation (self-enhancement/self-protection, narcissism), nostalgia, and authenticity. His research has culminated in over 500 publications and 17 books, and has been funded (among others) by the Economic and Social Research Council, Leverhulme Trust, and National Sciences Foundation. Constantine has received many awards including the Career Contribution Award, Daniel M. Wegner Theoretical Innovation Prize, and Nalini Ambady Award for Mentoring Excellence (all from the Society for Personality and Social Psychology), Life-Time Achievement Award (from the European Association of Personality Psychology), Distinguished Lifetime Career Award (from the International Society for Self and Identity), and Kurt Lewin Medal (from the European Association of Social Psychology). He is a Fellow of the British Academy.