Bob Hughes developed different types of play for studying how adults learn and children develop. These play types include symbolic play, rough and tumble play, and socio-dramatic play which allow children to gradually explore, increase understanding, act out real experiences, and engage socially. Other play types are deep play, exploratory play, fantasy play, imaginative play, locomotor play, mastery play, object play, and recapitulative play which help children experience risk, gain new information, enhance imagination, develop physical skills, perfect skills, show curiosity, and display human evolution.