Concurrent schedules of response-independent reinforcement: duration of a reinforcing stimulus.
Longer reinforcer time, even with no response needed, pulls learners toward that setting.
01Research in Context
What this study did
Macht (1971) worked with pigeons in a two-key box.
Grain dropped at random times no matter what the bird did.
One side gave short grain flashes. The other gave long grain flashes.
The bird could hop to either side at any moment.
What they found
Birds spent most of their time on the side with longer grain flashes.
Time matched the duration ratio almost perfectly.
No peck was ever required. Duration alone pulled the birds in.
How this fits with other research
Glynn (1970) showed the same rule works for rate. When rate-time product stayed equal, birds still matched. Macht (1971) took rate away and proved duration is enough.
Decasper et al. (1977) later added response rules. They saw response rates drop when contiguity weakened, but duration effects stayed. The two papers together say: duration sets attraction; contingency sets effort.
Fraley (1998) looked at stimulus duration, not grain duration. Longer stimuli weakened conditioned reinforcement. It seems opposite, yet the events differ: grain feeds the bird; a light only signals food.
Why it matters
You can bias a client’s location without any task demand. Just let the richer activity last longer. In free-play, make the preferred toy stay available twice as long. In group work, let the high-reinforcement center keep its payoff window open a few extra seconds. Duration becomes an easy, invisible prompt for time allocation.
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02At a glance
03Original abstract
Presentations of grain to three pigeons were determined by two response-independent schedules. Interpresentation intervals varied with a mean interval of 1.5 min for each schedule. Both were concurrently operative, but grain was presented by one only when the chamber was illuminated with blue light and by the other only during amber illumination. A response on a white key, the only key in the chamber, alternated the stimulus conditions and the effective schedule. Grain presentation durations associated with the illumination conditions were varied from 1.5 to 4.5 sec. The proportion of the total session time spent in an illumination condition closely approximated the relative grain presentation duration provided in that illumination. For two of the birds, the proportion of the total number of grain presentations obtained in an illumination condition was an increasng function of the presentation duration in that illumination.
Journal of the experimental analysis of behavior, 1971 · doi:10.1901/jeab.1971.15-211