The ability to successfully discriminate between multiple potentially relevant source analogs when solving new problems is crucial to proficiency in a mathematics domain. Experimental findings in two different mathematical contexts demonstrate that providing cues to support comparative reasoning during an initial instructional analogy, relative to teaching the same analogs and solution strategies without such cues, led to increased ability to discriminate between relevant analogs at a later test. Specifically, providing comparative gestures and visibly aligned source and target problems during initial learning led to higher rates of positive extension of learning to new contexts, and lower rates of susceptibility to misleading contextual features, both immediately and after a week delay. (Contains 4 figures and 2 tables.)