Dr. Peter Gray, an evolutionary biologist who took an interest in Sudbury schools, has contributed to the founding of Play Theory through extensive meta-research of hunter-gatherer cultures over the past several decades. He has provided empirical data showing a strong correlation between the decline in free play and a major increase in clinical mental illness [Journal of Comparative Psychology, American Journal of Education, Physiology and Behavior, etc.]. This research is compelling in its implications for how we educate our kids.
Gray relates his anthropological research to education as follows: Children are born curious and learn naturally through play. The more we restrict “play” and mandate “learning,” the more we kill children’s innate curiosity and contribute to various pathologies such as depression, anxiety, and narcissism. Hunter-gatherer children -- who are relatively free of these maladies -- learn the lessons of their societies through self-directed play; Gray has observed in his research that children in democratic schools develop the skills necessary for lifelong learning and active citizenship in the same way.
Gray’s research includes a survey of graduates of the Sudbury Valley School in Massachusetts, which found that 85% of these democratic school alumni had gone on to earn college degrees, and 40% had become successful entrepreneurs.
"To a considerable degree they maintain, in adulthood, the playful (and that means focused and intense as well as joyful) attitude to careers and life that they developed and refined while at the school." -Peter Gray in Psychology Today, August 2008