early childhood educators believe that play is primary way that young children develop and learn as well as a reflection of what they know and can do

Answer 1

Research has demonstrated that play is very important for school readiness because it enhances kids' physical, cognitive, social, emotional, language, and literacy skills; Moreover, it is essential to a child’s overall healthy development and enhances self-regulation. Play is how kids expand their vocabulary, learn to work cooperatively, and use their imaginations. Mildred Parten is well-known for her 6 stages of play, which are divided into 2 subsets of play: nonsocial play and social play. Essentially, nonsocial play decreases as children age and their peer interactions increase, which in turn improves their communication skills - thereby increasing social play.

(A) Nonsocial Play consists of unoccupied play, solitary play & onlooker play:

1. Unoccupied Play (ages 0-2) – not engaged in play (i.e., moves randomly without objective, remains stationary).
2. Solitary [Independent] Play (ages 2-3) – plays alone & is uninterested in/unaware of others' activity because their cognitive, physical and social skills are not yet fully developed; Solitary play teaches children how to entertain themselves.
3. Onlooker [Behavior] Play (ages 2.5-3.5, can occur at any age) – watches others play but does not join in - but may frequently engage in alternate forms of social interaction (i.e.,conversation about the game to learn more about it)

(B) Social Play consists of parallel play, associative play and cooperative play:

1. Parallel [Adjacent] Play (ages 2.5-3.5, can occur at any age) – plays separately from but next to others without verbal interaction & often mimic each other. This is a transitory stage from the socially immature (solitary, onlooker) play, to more socially mature (associative, cooperative) play. 
2. Associative Play (ages 3-4/preschool) – begin to play together with verbal interaction & few attempts to organize play. This stage is important to develop necessary skills of language development, cooperation, and problem solving.
3. Cooperative [Organized] Play (ages 4-6) – play is organized into groups, formalized with assigned roles (leader, etc), and structured to accomplish group goals or specific tasks. Cooperative play requires an evolved set of organizational skills and a higher degree of social maturity.

For more info, see: http://www.childaction.org/families/publications/docs/guidance/Handout13-The_Importance_of_Play.pdf

https://www.beststart.org/OnTrack_English/4-importanceofplay.html (link to pdf on webpage)