Foster, T. M., Temple, W., Robertson, B., Nair, V., & Poling, A. (1996).
Concurrent-schedule performance in dairy cows: Persistent undermatching.
Journal of the Experimental Analysis of Behavior,
65, 57-80.
Performance of dairy cows responding under concurrent
variable-interval variable-interval schedules of food delivery
was examined, with results analyzed in terms of the generalized
matching equation. In Experiment 1, bias measures indicated that
crushed barley was preferred over meatmeal when these foods were
available under the alternative schedules. For whole-session
data, substantial undermatching of response and time-allocation
ratios to obtained reinforcement ratios was evident.
Postreinforcement pause time ratios approximately matched
obtained reinforcement rates. Subtracting these times from total
time-allocation values yielded net time-allocation ratios that
undermatched obtained reinforcement ratios to a greater degree
than did whole-session time-allocation ratios. In Experiment 2,
substantial undermatching was evident when the same foods (hay
for 2 cows, crushed barley for 2 others) were available under the
alternative schedules. Food-related activities and other defined
behavior not related to food were quantified by direct
observation, and were found to occupy a substantial proportion
(roughly 40% to 80%) of experimental sessions. Subtracting the
time spent in these activities from the time allocated to each
component schedule did not reduce the degree of undermatching
obtained. Across all conditions in both experiments, slopes of
regression lines relating behavioral outputs to environmental
inputs characteristically were below 0.6, which agrees with prior
findings and suggests that, contrary to suggestions in the
literature, undermatching in dairy cows is not the result of
using different foods under alternative schedules or differential
pausing under those schedules.
Key words: matching equation, undermatching, food preference,
variable-interval schedule, nose-press response, dairy cows