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Updated: Aug 7, 2026

Progressive-ratio Responding for Palatable High-fat and High-sugar Food in Mice
Published on: May 3, 2012
Percentage reinforcement of fixed-ratio and variable-interval performances
Abstract:
Twenty to seventy per cent of the reinforcements scheduled for pigeons' fixed-ratio 80 performances were replaced by a 4-sec timeout. Pauses after reinforced ratios were unchanged at 80% reinforcement, but were lengthened at lower reinforcement percentages. Pauses after nonreinforced ratios were shorter than post-reinforcement pauses. When 50% of the reinforcements arranged by a variable-interval 60-sec schedule were replaced by a 4-sec timeout, pauses after reinforcement omission increased. Both frustrative nonreward and reinforcement aftereffects notions can explain the fixed-ratio results; neither easily explains the variable-interval data.
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