Although a wealth of studies have evidenced successive negative contrast effects in instrumental or operant procedures, relatively few studies have determined if and how a sudden downshift in reward quality alters foraging behaviour. In light of research by ecologists and psychologists in the area of risk-sensitive foraging, this area would serve as an adequate framework to examine the effects of a sudden downshift in reward quality on foraging behaviour. Therefore, the purpose of the current experiment was to explore if and how a sudden downshift in reward quality altered risk-sensitive foraging in rats. Subjects chose between a variable and fixed option that returned the same mean amount of sugar pellets, but one group of subjects (i.e., contrast group) were downshifted from 100% to 20% sugar pellets, whereas an unshifted control group received 20% sugar pellets throughout the study. Consistent with past risk-sensitive foraging research where reward quality was manipulated, subjects in the contrast group displayed significantly more risk-prone choices when reward quality was decreased from 100% to 20% sugar. However, the change in choice was inconsistent with contrast effects observed in prior contrast experiments. In addition to choice behaviour, other behavioural measures (e.g., rejected food, latency to choice) were significantly different between the unshifted control and contrast group and across conditions in the contrast group (e.g., latency to choice and rejected food significantly increased when reward quality changed from 100% to 20% sugar). These findings revealed a contrast effect and were similar to past contrast studies where reward quality was downshifted. Thus, when foragers experience a sudden downshift in reward quality, they may display significant behavioural changes and, in turn, display a bias for patches that yield a greater reward quality despite potentially lower payoffs. (PsycInfo Database Record (c) 2020 APA, all rights reserved).