Fixed-interval performances with added stimuli in monkeys.
A simple clock wiped out FI lever pressing in monkeys, so species and stimulus type matter when you port schedule tactics to new learners.
01Research in Context
What this study did
Researchers put monkeys on a fixed-interval (FI) food schedule. They added a clock that ticked through the interval.
The team wanted to see if the extra visual cue would help the animals time their responses.
What they found
The clock did not help. It almost stopped the monkeys from pressing the lever.
Response rates fell far below the level needed to earn all available food.
How this fits with other research
Wanchisen et al. (1989) also worked with monkeys and saw orderly choice. Drug volume controlled how much the animals drank, so monkey behavior can be predictable.
Duker et al. (1991) used FI schedules too. Their monkeys learned to pick the schedule that gave fewer shocks, showing FI performance can improve when the payoff is clear.
Together the three studies say the same tool—monkeys on FI—can give very different outcomes. Added stimuli sometimes guide, sometimes suppress.
Why it matters
If you borrow timing cues from pigeon work, test them first. A clock that helps birds may shut down a monkey—or a child. Run a quick probe session before you build the cue into treatment.
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02At a glance
03Original abstract
The performance of two monkeys, on fixed-interval schedules, was examined with a visual, an auditory and a combined auditory-visual clock. The clock, a voltmeter and/or a variable frequency tone, produced performances different in many aspects from those recorded earlier with pigeons. Instead of the sustained high rates of responding at the optimal settings of the clock, the monkey's rates of responding were often extremely low even though a limited-hold contingency was utilized.
Journal of the experimental analysis of behavior, 1963 · doi:10.1901/jeab.1963.6-317