Fig 1.

Schematic of reinforcement protocol. Panel (a) illustrates baseline data, where the boundaries between peaks (denoted by red rectangles) and valleys (denoted by green rectangles) are identified. A green, encircled number denotes each of the six distinct valleys. Panel (b) illustrates the distribution of valley lengths and the calculation of the 65th percentile (180 min), which serves as the valley duration threshold in the post-baseline phase. Panel (c) illustrates the post-baseline phase. Peaks and valleys are colored as in Panel (a), but now valleys that exceed the valley duration threshold for reinforcement are shown in blue, which mirrors the blue light conditioned reinforcer that was presented during these times to indicate that gift card value was being accrued. Encircled numbers denote each distinct valley and are colored by whether the valley duration threshold was reached.