Attack behavior as a function of minimum inter-food interval.
Reinforcement timing alone can dial aggression up or down, with middle delays being the riskiest.
01Research in Context
What this study did
Cohen (1969) looked at how long a pigeon has to wait between food deliveries.
The longer the wait, the more the birds pecked or attacked a nearby target.
Each bird worked alone in a small chamber. The feeder opened on a fixed schedule.
What they found
Attack jumps up at first, then drops again as the wait keeps getting longer.
Most strikes came right after the grain was delivered, not during the wait.
Middle-length waits produced the highest hit rates.
How this fits with other research
Kelly (1973) used the same lab setup and also showed that schedule design drives behavior.
AZRIN et al. (1963) found fixed-ratio escape responding stayed strong even when shocks almost stopped.
Together these papers show that schedule rules, not just the amount of food or shock, set the pace of responding.
Why it matters
You can turn aggression up or down by tweaking how often and when reinforcement lands.
If a client hits right after a treat, toy, or praise, try stretching the time before the next delivery.
Watch for the sweet spot where waits are long enough to calm the behavior but not so long that new problems start.
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02At a glance
03Original abstract
Pigeons were exposed to a procedure in which food was presented after a fixed period of time had elapsed, provided no attack against a nearby stuffed pigeon had occurred during the last 15 sec of the period. As the minimum inter-food interval was increased logarithmically through seven values from 15 sec to 960 sec, attack increased to a maximum and then decreased. For both pigeons, attack predominantly occurred after, rather than shortly before, food deliveries.
Journal of the experimental analysis of behavior, 1969 · doi:10.1901/jeab.1969.12-825