Concurrent-schedule performance in dairy cows: persistent undermatching.
Undermatching is normal in cows and probably in other non-humans, even after you scrub pauses and side behavior.
01Research in Context
What this study did
Researchers put six dairy cows in a pen with two feed troughs.
Each trough paid grain on its own variable-interval schedule.
The cows could switch back and forth at any time.
Sessions lasted 45 minutes and ran for months.
The team recorded every nose-press and time stamp.
What they found
The cows did not match.
They pressed the lean side even less than the matching law says.
The slope stayed below 0.6 no matter what.
Cutting out pauses, chewing, or switching did not fix it.
Undermatching was baked in.
How this fits with other research
Macdonald et al. (1973) showed pigeons almost perfectly match on the same VI-VI layout.
That paper is the classic baseline; the cow data sit far below it.
Yuwiler et al. (1992) also found tight matching with pigeons, so the species gap is real.
Hall (2005) later proved that if earning rates differ, even pigeons undermatch.
The cow study may have had hidden earning-rate gaps, linking the two findings.
Why it matters
If you run concurrent schedules with non-human clients, expect undermatching.
Do not assume pausing or side activities are the culprit.
Check whether the two alternatives really deliver the same earned rate.
When in doubt, measure obtained—not just arranged—reinforcement.
This keeps your treatment analyses honest and your data pictures clean.
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Join Free →Plot obtained reinforcer rates against response rates; if the slope is under 0.6, adjust the schedules, not the subject.
02At a glance
03Original abstract
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.
Journal of the experimental analysis of behavior, 1996 · doi:10.1901/jeab.1996.65-57