Behavioral contrast: Pavlovian effects and anticipatory contrast.
Pavlovian contrast rules during extinction; anticipatory contrast can steal the show when brief components still deliver reinforcement.
01Research in Context
What this study did
Hassin-Herman et al. (1992) ran pigeons on two-key multiple schedules. One component stayed the same. The other changed: sometimes food never came, sometimes it came fast.
They kept components short or long. They watched which kind of contrast showed up—Pavlovian or anticipatory.
What they found
When the target component had zero food, only Pavlovian contrast appeared. Response rates rose in the other key.
When food was available and the component was short, anticipatory contrast took over. Birds pecked faster before the food came.
How this fits with other research
Hineline et al. (1969) first showed that what happens next controls contrast size. Hassin-Herman et al. (1992) zoom in and say ‘next’ matters only if food is there and time is tight.
de Rose (1986) proved longer extinction makes later FI rates jump. The new study agrees—long extinction gives pure Pavlovian contrast.
McSweeney et al. (1993) tested duration the next year. They found contrast peaks at 30–60 s. That lines up with D’s finding: short components let anticipatory contrast beat Pavlovian.
Whalen et al. (1979) got contrast in 3-month-old babies. The pigeon data now show the same rules apply across species.
Why it matters
You run mixed schedules every day—work, break, work, break. If the break has no reinforcement, expect Pavlovian contrast: the kid may work harder when you come back. If the break is short and has tiny reinforcement, watch for anticipatory contrast: the child may rush during the break itself. Plan component length and reinforcement presence to steer the effect you want.
Want CEUs on This Topic?
The ABA Clubhouse has 60+ free CEUs — live every Wednesday. Ethics, supervision & clinical topics.
Join Free →Make the non-preferred task 30–60 s long and withhold reinforcement; watch rates rise in the next preferred task.
02At a glance
03Original abstract
Two sources of behavioral contrast have been identified previously: Pavlovian stimulus-reinforcer relations and component sequence effects (anticipatory contrast). This study sought to isolate these sources of control procedurally in a four-ply multiple schedule composed of two fixed two-component sequences. Different cues were associated with the first component of each sequence, and contrast effects were studied in these target components. In Experiment 1, differential cuing of Component 2 between sequences and availability of reinforcement during target components were varied across three groups of pigeons; the stimulus-reinforcer relation between target-component cues and schedule of reinforcement in Component 2 was varied within subjects. Control by the Pavlovian relation was demonstrated under all conditions, and anticipatory contrast was not observed. In Experiment 2, target-component duration was systematically varied in the three groups of Experiment 1. Control by the Pavlovian relation was reliably obtained only when target-component behavior was unreinforced, and diminished with increases in component duration. Anticipatory contrast emerged in the two groups for which target-component reinforcement was available. These and other data indicate that Pavlovian effects in multiple schedules may be obscured when the requisite conditions for anticipatory contrast are present.
Journal of the experimental analysis of behavior, 1992 · doi:10.1901/jeab.1992.57-159