Habituation To The Reinforcer May Contribute To Multiple-schedule Behavioral Contrast.

Delaney et al. (1998) wrote a theory paper. They asked why response rates jump in one part of a multiple schedule when conditions change in another part. They proposed a new answer: the animal gets used to the reinforcer. Less exposure to the reinforcer keeps it fresh and valuable. They built equations to show how this habituation idea explains classic contrast effects.

The paper does not give new data. Instead it links thirty years of pigeon data to one process: habituation. When reinforcement drops in one component, the animal meets the reinforcer less often. The reinforcer loses its boredom. The animal then works harder for the same reward in the next component. This single process, they argue, can replace older multi-process theories.

Hineline et al. (1969) showed that response rates rise when the next component is extinction. F et al. keep that finding but give it a new reason: fewer reinforcers mean less habituation, so the reward feels bigger. Thomas et al. (1974) proved contrast can come from cutting reinforcement frequency alone. The habituation model predicts exactly that—less frequency, less habituation, more value. Rogers-Warren et al. (1976) found no contrast when reinforcement rates were equal across components. F et al. embrace this null: equal rates yield equal habituation, so no value shift occurs. The old and new stories agree on the data; they differ on the engine driving them.

When you set up multiple schedules or mixed sessions, think about reinforcer exposure, not just rate. If you thin reinforcement in one activity, the next activity may suddenly look better to the client. Watch for spikes in manding or task engagement after lean components. You can use this: insert brief lean periods before key tasks to boost their value, then fade the contrast once the skill is strong.