Subjects were selected from two different groups: the first group was composed by 48 high-school students with ages comprised between 14 and 18 years. The second group was composed by 17 subjects of a mixed sample of undergraduate and postgraduate university students with ages comprised between 22 and 32 years.

All the tests were passed in the same session. The times were, without including instructions, 10 min. for the prediction test, 5 min. for the abduction test, 5 min. of break, and 20 min. for the IQ test.