Sensitivity of conditional-discrimination performance to within-session variation of reinforcer frequency.
Tell learners when the payoff odds change and you’ll see true ratio control right away.
01Research in Context
What this study did
The team ran a matching-to-sample task with adults.
They changed the reinforcer ratio inside the same session.
Some blocks had 3:1 ratio, others 1:3.
Half the time a colored border told the learner which ratio was active.
Half the time no cue was given.
They tracked how fast choice shifted when the ratio flipped.
What they found
When the ratio change was signaled, choice tracked it almost perfectly.
Sensitivity scores matched the old way of running whole sessions at one ratio.
When the shift was not signaled, choice stayed stuck near the first ratio.
In plain words: a quick cue lets you see ratio control without extra days of testing.
How this fits with other research
Iwata et al. (1990) showed toddlers already work faster under ratio than interval schedules.
McLennan et al. (2008) now shows adults can feel that ratio shift inside minutes if you tell them it changed.
Winterling et al. (1992) used a changing-criterion VR to boost kids’ bike riding.
They had to run many days to see change.
D’s cue method could speed that up.
WERTHEIWENZEL et al. (1964) hunted for a clean rate-vs-probability curve under random ratio and never found it.
D’s result hints the hunt failed because pigeons were never told when the odds changed.
Why it matters
You can test reinforcer control in one sitting.
Just add a color, shape, or word that marks each new ratio.
This saves hours of separate sessions and gives clearer data for treatment decisions.
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02At a glance
03Original abstract
The present experiment developed a methodology for assessing sensitivity of conditional-discrimination performance to within-session variation of reinforcer frequency. Four pigeons responded under a multiple schedule of matching-to-sample components in which the ratio of reinforcers for correct S1 and S2 responses was varied across components within session. Initially, five components, each arranging a different reinforcer-frequency ratio (from 1:9 to 9:1), were presented randomly within a session. Under this condition, sensitivity to reinforcer frequency was low. Sensitivity failed to improve after extended exposure to this condition, and under a condition in which only three reinforcer-frequency ratios were varied within session. In a later condition, three reinforcer-frequency ratios were varied within session, but the reinforcer-frequency ratio in effect was differentially signaled within each component. Under this condition, values of sensitivity were similar to those traditionally obtained when reinforcer-frequency ratios for correct responses are varied across conditions. The effects of signaled vs. unsignaled reinforcer-frequency ratios were replicated in two subsequent conditions. The present procedure could provide a practical alternative to parametric variation of reinforcer frequency across conditions and may be useful in characterizing the effects of a variety of manipulations on steady-state sensitivity to reinforcer frequency.
Journal of the experimental analysis of behavior, 2008 · doi:10.1901/jeab.2008.90-301