摘要：The purpose of this study was to investigate the effect of spontaneous play in nature on play behavior and happiness of the pre-school children. To this end, 45 children aged 4 to 6 were selected as a sample from Tabriz, in three groups of the outdoor, indoor space, and control. Play behavioral and children's happiness were measured respectively using the pre-school children's behavior in the play, oxford happiness questionnaire, pretest-posttest. Mix ANOVA showed that outdoor activity between pretest-posttest had a significant effect on play behavior and happiness of the children, so that 71% of changes in the play behavior and 98 %of changes in the happiness of the children were affected by their nature outdoor activities. It is while activity in indoors did not have a significant effect on children's play behavior and happiness. The results were discussed with respect to the external bronfenbrenner biomechanical and Piaget cognitive theory.
