Andrzejewski, M. E., Field, D. P., & Hineline, P. N. (2001).
Changing behavior within session: Cyclicity and perseverance produced by varying the minimum ratio of a variable-ratio schedule.
Journal of the Experimental Analysis of Behavior,
75, 235-246.
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.
Key words: choice, within-session responding, cyclicity, history
effects, variable-ratio schedules, key peck, pigeons