Abstract: With material of artificial concept designed by Bruner et al (1956) we testedhypothesis--testing strategies in forming conjunctive and disjunctive concepts withundergraduate students. The results showed that undergraduates tended to usesingle-dimesion testing strategy (including single--dimesion --changing strategy andsingle--dimesion-positive strategy ), and the strategy facilitated tated conjuction task solvingand within--dimention disjunction task solving, but not inter--dimention disjunction tasksolving.

Key words: artificial concept, disjunctive concept, hypothesis, testing shategy