Open versus closed economies: performance of domestic hens under fixed ratio schedules.
Session length, not economy type, controls whether response rates rise or fall as fixed-ratio requirements increase.
01Research in Context
What this study did
The team worked with six hens in a small lab space.
Each bird pecked a key under fixed-ratio (FR) schedules.
Some sessions were short (15 min), others long (90 min).
Food was either always available (open economy) or only during the session (closed economy).
They watched how fast the birds pecked as the ratio grew from FR 5 to FR 80.
What they found
In short closed sessions the birds slowed down as the ratio got bigger.
That pattern looked just like an open economy.
In long closed sessions the birds sped up as the ratio got bigger.
Session length, not economy type, decided the direction of change.
How this fits with other research
Garcia et al. (1999) later saw the same twist with patch leaving: long sessions kept birds in a patch longer, not the closed economy itself.
The two papers together say "watch the clock" when you interpret choice data.
Sutphin et al. (1998) showed rats skipping costly patches by eating fewer, bigger meals.
That study changed cost; M et al. changed time.
Both prove the same point: small procedural details swing the results.
Why it matters
If you run reinforcement sessions longer than 20 minutes, expect different response patterns than in brief probes.
Close or open economy labels won’t help you predict the curve—timing will.
Next time you adjust a token board or DR schedule, track session length as closely as you track the ratio.
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02At a glance
03Original abstract
Domestic hens responded under fixed‐ratio schedules of food (wheat) reinforcement under several experimental conditions. Part 1 (open economy) investigated performance on fixed‐ratio schedules over both multisession steady‐state conditions and daily changes of the schedule, with hens maintained at 80% of free‐feeding weights by extraexperimental feeding. In Parts 2 and 3 (closed economy and short sessions) sessions were 40 min long, and the hens' weights were allowed to vary (Part 2) or sessions were conducted only when the hens were at approximately 80% of free‐feeding weights (Part 3). In Part 4 (closed economy and long sessions) sessions were 24 hr long and the fixed‐ratio requirement was changed either daily or after 7 consecutive days. In general, the daily changes of fixed‐ratio requirement in the open economy and short‐session closed economy gave much the same result as the steady‐state open‐economy sessions. Overall response and reinforcer rates decreased with increasing fixed‐ratio requirement (except at the shortest fixed ratios). Running response rates decreased, and postreinforcement pauses generally increased. In contrast, overall response rates in the long‐session closed economy generally increased with the fixed‐ratio requirement. Session length is suggested as a cause of the differences between the short‐ and long‐session closed‐economy results.
Journal of the experimental analysis of behavior, 1997 · doi:10.1901/jeab.1997.67-67