Probabilistically reinforced choice behavior in pigeons.
Animals often pick the option with the best immediate odds, not the best long-run ratio.
01Research in Context
What this study did
Pigeons pecked two keys. Each key paid off with grain on its own variable-interval clock.
The schedule changed every few minutes. Birds had to learn which key gave the better chance right now.
The researcher watched every peck to see if birds followed the overall payoff ratio or simply picked the key that was momentarily "hot."
What they found
Birds did not match the exact payoff ratio. They switched to whichever key had the higher chance of food at that instant.
This "momentary maximizing" meant short bursts on one key, then a quick jump when probabilities flipped.
How this fits with other research
Nevin (1969) saw the same birds pecking the same VI schedules yet declared "matching." The difference is lens size: 1966 looks peck-by-peck, 1969 averages whole sessions. Both data sets are real; the story depends on the ruler you use.
Yuwiler et al. (1992) later repeated the setup and found clean matching, not maximizing. They used longer, stable components, so birds had time to settle into the overall ratio. Method length, not bird brains, drives the clash.
Spanoudis et al. (2011) pushed the idea forward: pigeons in a perceptual task shifted choice criteria after tiny probability tweaks, proving the momentary rule can guide rapid, real-time shifts.
Why it matters
When clients hop between tasks, they may chase the momentary win, not the long-term payoff. Test this by shortening components and giving quick odds updates. If behavior flips fast, teach them to pause and scan the bigger picture before choosing.
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02At a glance
03Original abstract
A single principle, "momentary maximizing", may account for much of a pigeon's steady-state behavior in both probability learning and concurrent variable interval experiments. The principle states that a pigeon tends to choose the alternative that momentarily has the higher probability of reinforcement. A successive discrimination procedure, which produced matching in an earlier experiment, produced here a tendency to maximize if training were adequately extended. Maximizing was produced also by other procedures, in which no reinforcing event was presented on some trials: one procedure did and two did not provide a bird with information about the availability of reinforcement on a key after an unreinforced response on the other key. The latter two procedures were analogous to concurrent variable interval schedules in two respects: the reinforcement probability on one key increased while a bird responded on the other key; and they produced matching. But sequential statistics suggested that matching resulted from momentary maximizing. Depending on the procedure, the tendency to maximize produced different relative frequencies of pecking a key for a fixed relative frequency of reinforcement. Computer simulation of maximizing behavior in several concurrent variable interval schedules produced matching and sequential statistics similar to those produced by a real bird.
Journal of the experimental analysis of behavior, 1966 · doi:10.1901/jeab.1966.9-443