Local response-rate constancy on concurrent variable-interval schedules of reinforcement.
A two-second wait to switch keys keeps post-switch pecking high for three seconds, while a five-peck rule produces only a one-second burst.
01Research in Context
What this study did
Pigeons pecked two keys for food. Each key paid off on its own variable-interval schedule. The birds could switch keys any time.
To switch, they had to meet one of two rules: either wait two seconds (changeover delay) or peck five times (fixed-ratio requirement). The team measured how fast the birds pecked right after each switch.
What they found
After a two-second wait, birds kept pecking fast for about three seconds. After five pecks, they pecked fast for only one second, then slowed for two seconds.
The short wait rule kept the local response rate high longer than the work rule.
How this fits with other research
Harrison et al. (1975) showed that signalling a reinforcer on one key sped up pecking on the other key. The 1978 study adds a time lens: the speed-up lasts longer if the switch rule is a short wait, not extra work.
Blue et al. (1971) taught us to raise changeover delays in half-second steps to keep reinforcement rates steady. The new data say the delay length also shapes the very first seconds after each switch.
Emmelkamp et al. (1986) found local rates stay flat across conditions on multiple VI schedules. The 1978 paper agrees local rates can be steady, but shows the switch rule still tweaks the first few seconds.
Why it matters
When you run concurrent schedules in the lab or with clients, the switch rule is a hidden variable. A brief delay keeps responding strong right after the change; a work requirement gives a short burst then a lull. Pick the rule that matches the response pattern you want.
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02At a glance
03Original abstract
Concurrent variable-interval schedules were arranged with a main key that alternated in color and schedule assignment, along with a changeover key on which a small fixed ratio was required to changeover. Acceptable matching was observed with pigeons in two replications, but there was a tendency toward overmatching. Local response rates were found to differ for unequal schedules of a concurrent pair: local response rate was greater for the variable-interval schedule with the smaller average interreinforcement interval, but qualifications based on an interresponse-time analysis were discussed. In a second experiment, two 3-minute variable-interval schedules were arranged concurrently, and the experimental variable was the changeover procedure: either a changeover delay was incurred by each changeover or a small fixed ratio on a changeover key was required to complete a changeover. Changeover delays of 2 and 5 seconds were compared with a fixed-ratio changeover of five responses. The response output on the main key (associated with the variable-interval schedules) was greater when a changeover delay was arranged than when a fixed ratio was required to changeover. A detailed analysis of stripchart records showed that a 2-second delay generated an increased response rate for 3 seconds after a changeover, while the fixed-ratio requirement generated an increased rate during the first second only, followed by a depressed response rate for 2 seconds.
Journal of the experimental analysis of behavior, 1978 · doi:10.1901/jeab.1978.29-431