Effects of instructions and reinforcement-feedback on human operant behavior maintained by fixed-interval reinforcement.
Instructions paired with feedback create clean FI patterns in adults, but only if you start before bad timing habits form.
01Research in Context
What this study did
Sachs et al. (1969) tested how instructions change adult behavior on a fixed-interval schedule. They split neurotypical adults into two groups. One group got clear instructions plus feedback after each reinforcer. The other group got no instructions at all.
All participants earned money for pressing a button. The schedule paid only after a set time had passed. The researchers tracked how fast each person pressed and when they paused.
What they found
Adults who heard instructions and got feedback showed the classic FI scallop. They paused right after pay-off, then speeded up as the next pay-off time neared. Their pattern looked like textbook pigeon data.
Adults without instructions never shaped up the scallop. They pressed at a steady, slow rate. Once this flat pattern set in, adding instructions later could not fix it.
How this fits with other research
Britwum et al. (2025) extends the same combo—instructions plus feedback—into a real clinic. They gave staff brief directions and a quiet beep each time they praised. Praise rates shot up and stayed high for weeks. The lab finding travels to the workplace.
WALLETHOMAS et al. (1963) seems to disagree. Monkeys given a clock stimulus on an FI schedule stopped responding almost completely. The 1969 humans, given instructions, thrived. The clash is about species and stimulus type: a clock scared monkeys, but clear rules helped people.
REYNOLDS (1964) shows how fast recovery can be. Two reinforcers brought DRL responding right back after extinction. Sachs et al. (1969) shows the opposite edge: once poor FI differentiation forms, later instructions cannot rescue it. Together they warn—get the prompt in early.
Why it matters
If you want staff or clients to show schedule-appropriate patterns, give directions before the first trial and keep feedback coming. Waiting until you see flat responding is too late—the habit already locked in. Use plain words plus immediate feedback, whether it is a beep, points, or a smile, to build the rhythm you want from day one.
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02At a glance
03Original abstract
In three experiments, human subjects were trained on a five-component multiple schedule with different fixed intervals of monetary reinforcement scheduled in the different components. Subjects uninstructed about the fixed-interval schedules manifested high and generally equivalent rates regardless of the particular component. By comparison, subjects given instructions about the schedules showed orderly progressions of rates and temporal patterning as a function of the interreinforcement intervals, particularly when feedback about reinforcement was delivered but also when reinforcement-feedback was withheld. Administration of the instructions-reinforcement combination to subjects who had already developed poorly differentiated behavior, however, did not make their behavior substantially better differentiated. When cost was imposed for responding, both instructed and uninstructed subjects showed low and differentiated rates regardless of their prior histories. It was concluded that instructions can have major influences on the establishment and maintenance of human operant behavior.
Journal of the experimental analysis of behavior, 1969 · doi:10.1901/jeab.1969.12-701