The visual discrimination shift learning task has been used to assess the attentional set-shifting deficits instead of Wisconsin Card Sorting Test (WCST). From a developmental psychological point of view, the discrimination shift learning tasks has been used to investigate developmental changes of learning on the basis of various developmental studies. Kendler (1995) has been proposed the level theory to explain cognitive process that governs discrimination shift learning. This theory suggests that the discrimination shift learning paradigm can be used as a modus operandi for the more wide study of cognitive dysfunctions since the precise analysis of the learning process in discrimination shift learning can give us various information about the cognitive deficits after brain damage more than attentional deficits. This paper discusses the assessable range of cognitive dysfunctions by means of the discrimination learning paradigm based on Kendler's level theory.