Abstract
Psychological intervention in aggressive and antisocial behavior with children. The objective of this research was to design a cooperative play program, in order to assess its effects on social behaviour. The design was pretest-intervention-posttest with control group. The sample included 86 participants aged 10 to 11 years, 54 experimental and 32 control. Before and after administering the program, two evaluation instruments were applied to measure social behaviours. The intervention consisted of a weekly two-hour play session throughout the school year. The program's activities stimulate communication, and prosocial behaviour. Results of the analysis of variance suggest significant impact of the intervention, since the experimental participants significantly increased their assertive behaviours, while showing a decrease in aggressive, antisocial and delinquent behaviours. Also confirmed was a greater effect of the intervention on participants who showed few assertive behaviours and many passive, aggressive, antisocial and delinquent behaviours in the pretest. Gender did not affect the results of the intervention.