Much empirical work and theoretical discussion in the associative learning literature has focused on when and how a cue changes in its associability. A series of new findings in human learning preparations (collectively referred to as the "outcome predictability" effect) appear to show that outcomes vary in their capacity to enter into novel associations as a product of their associative history. This effect is reminiscent of how cues change in associability as a consequence of their reinforcement history. We review the new findings within a broader associative literature that has previously investigated how conditioning can modify the effectiveness of outcome events to motivate new learning. A variety of explanations arising from this review are then critically considered. The article concludes by identifying novel questions brought into focus by the outcome predictability effect. (PsycINFO Database Record (c) 2019 APA, all rights reserved).