An experimental analysis of the cost of food in a closed economy.
Delay, not effort, is the brake on reinforced behavior.
01Research in Context
What this study did
Pigeons lived in a closed economy. They had to peck a lever for every bit of food.
The researchers made the birds work on bigger and bigger fixed-ratio schedules. They also tested what happened when only the delay changed.
What they found
When the ratio got larger, the birds ate less. But if the delay stayed the same, intake stayed the same.
The lever presses did not matter. The wait time did.
How this fits with other research
Vos et al. (2013) ran the same FR-plus-delay setup and saw the same drop in responding. They called their work a direct replication of Bauman (1991).
Eisenmajer et al. (1998) added a twist: the 3-s delay came without a signal. The birds’ preference and resistance to change crashed even harder. That extends the 1991 finding to unsignaled delays.
Buriticá et al. (2017) moved the test to fixed-interval schedules. Delay still cut response rates, showing the rule holds across schedule types.
Why it matters
If you use token boards, DRO, or FR schedules with kids, keep the delay tiny or make it crystal clear. A three-second wait that feels “empty” can slash the value of your reinforcer no matter how many stars or checks the child just earned. Signal the wait or, better, deliver on the spot.
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Join Free →Count the seconds between the last response and the next reinforcer; if it ever tops two, add a signal or cut the wait.
02At a glance
03Original abstract
Rats lived in individual chambers in which the only food available was delivered for lever pressing. During Stage I, a fixed number of presses was required for each food pellet. As this fixed ratio of presses per food pellet was increased daily, a rat's daily intake of food was reduced. During Stage II, the cost of a food pellet was increased by replacing each fixed ratio with its interval equivalent. Each interval was a rat's mean time between the first press of a ratio and the delivery of a pellet during Stage I. During Stage II, only two presses were every required for a food pellet: The first press initiated a delay and the second activated the pellet dispenser after that delay elapsed. Food intakes for the series of fixed ratios and a rat's series of delay equivalents were very similar when plotted as a function of delay, but not when plotted as a function of presses per pellet. Consequently, the fixed ratio reduced food intake because larger ratios increased delay to food from the first press of a ratio. Observations and an analysis of interresponse times further revealed that as the fixed ratio increased, and local as well as overall rate of food intake decreased, lever pressing became more stereotyped. Because this increased stereotypy resulted in greatly increased rates of lever pressing, delay to food was minimized, and perhaps more importantly, so too was the reduction of a rat's baseline daily intake.
Journal of the experimental analysis of behavior, 1991 · doi:10.1901/jeab.1991.56-33