Changing behavior within session: cyclicity and perseverance produced by varying the minimum ratio of a variable-ratio schedule.
Dropping the minimum ratio within a VR schedule pulls choice and speed, and the effect lingers even after the ratio rises again.
01Research in Context
What this study did
Meuret et al. (2001) worked with pigeons in a lab chamber.
The birds pecked two keys. Each key paid off on a variable-ratio schedule.
The twist: within every session the smallest ratio cycled up and down.
Researchers watched how the birds’ preference and speed changed minute to minute.
What they found
Choice and response rate followed the cycle.
When the minimum ratio dropped, birds pecked more on that side.
The falling part of the cycle pulled the strongest control.
Even after the cycle moved on, the birds kept the old bias for a while.
How this fits with other research
Burgess et al. (1971) saw heavy switching when concurrent VR schedules were linked.
E et al. add the idea that the recent VR minimum, not just overall rate, steers the next choice.
Wanchisen et al. (1989) showed a brief VR history can warp later fixed-interval performance.
The new study widens that history effect: within-session VR cycles also leave a sticky footprint.
Bell et al. (2017) used fast-changing VI VR schedules and found time allocation, not rate, drove preference.
E et al. differ: they held average payoff steady and still saw rate shifts, showing the minimum ratio alone can push behavior.
Why it matters
Your client’s reinforcement history inside the session can swing later responses.
If you thin a VR schedule quickly, expect brief but strong momentum toward the leaner side right after.
Watch for carry-over when you shift from easy to hard tasks; the descending path may lock in preference longer than you think.
Track minute-by-minute data to spot these mini-histories before they skew your main target.
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Join Free →Graph response rate each minute during VR thinning; if you see a jump that outlasts the easy ratio, pause and re-stabilize before thinning further.
02At a glance
03Original abstract
Four pigeons repeatedly chose between a fixed-ratio (FR) 20 and a variable-ratio (VR) 40 schedule of reinforcement, in which the minimum ratio of the VR cycled within each session. The minimum ratio ascended and descended (ASCDESC), descended and ascended (DESCASC), or remained constant (unchanging). In Phase 1, 2 birds (Group 1) were exposed to ASCDESC series and 2 birds (Group 2) were exposed to the DESCASC series. Choice proportions changed with the cycling minimum ratio for Group 2 but not for Group 1. In Phase 2, Group 1 subjects were exposed to the DESCASC series and Group 2 subjects were exposed to the unchanging condition. Although Group 1's choice proportions appeared to be undifferentiated in Phase 2, Group 2's choice proportions continued to cycle for more than 100 sessions. Group 2 subjects were then moved to the ASCDESC series in the third phase, and choice proportions cycled with the minimum ratio as in the first phase. The descending portion of the series was the more powerful determinant of cyclicity. Response rates also changed with the minimum component ratio, a finding that goes against the claim of universality of a rise-and-fall within-session pattern of responding. That preference varied despite the constancy of the average ratio requirement suggests nonlinear averaging in quantitatively representing a variable schedule's value. The strong perseverance observed also lends support to a growing body of literature on history effects.
Journal of the experimental analysis of behavior, 2001 · doi:10.1901/jeab.2001.75-235