Yettili-d ɣef teɣzi n ukala n ulmud, segmi ara yebdu ukala n ulmud, aselmad ad yettnadi ɣef yilɣiten n yinelmaden i wakken ad ten-yerr d tignatin n usejji. Aktazal amsilɣan d awal idyessudef Scriven Crouba di 1967 deg yiwen n umagrad id-yewwin ɣef uktazal n wallalen n uselmad. Ad t-naf daɣen deg yimuhal i yexdem Bloom di 1971 id-yewwin ɣef uktazal n ulemud unelmad. Awal-agi aktazal amsilɣan yessexdam-it uselmad deg ukala i wakken ad yefren tasnedwelt ara yeḍfer akken ddan yifaraten (progrés) d wuguren id-yettilin deg ulemud sɣur yinelmaden. Ihi aktazal amsilɣan yettwaḥsab d lsas deg uṣeḍru (réalisation) n tsuddest n 3 tesnedwelt (pédagogie) .