**7. Sample**

The sample consisted of 300 children, 150 of them belonging to the experimental group (75 boys and 75 girls), and 150 corresponding to the control group (75 boys and 75 girls) from two public schools in Guanajuato, Mexico. The ages of the children ranged from 8 years to 12 years; students had to meet the following selection criteria: (a) Children could not have repeated or failed courses, (b) they could not have taken art classes (like drawing or painting) or literature classes, in which parents or guardians in charge might have influenced them in one of these two areas by demonstrating precepts of imaginative instruction and interpretation. These aforementioned variables, namely those of art or literature, were considered to restrict any prior intervention of factors that could have either a ffected or strengthened children's awareness or employment of creative imagination in some way or the other. Children who had this prior stimulus may have had higher scores. To evade the intervention of these

variables, we had to make sure that the children population were equivalent in both the experimental and control groups.
