Species differences in temporal control of behavior II: human performance.
People only scallop on FI schedules when they can see a clock; take the clock away and you get break-and-run.
01Research in Context
What this study did
Researchers asked adults to press a button on a fixed-interval schedule. The interval was always the same length. Sometimes a digital clock was on the wall. Sometimes it was off.
The team wanted to know if people would show the same scalloped response curve seen in rats and pigeons.
What they found
With the clock in view, people waited longer and longer as the interval passed. Their response curve looked like a scallop. Without the clock, they paused at the start, then burst. This break-and-run pattern is different from the classic scallop.
The result shows humans need an extra cue to track time like other animals do.
How this fits with other research
Lowe et al. (1977) found rats and pigeons already scallop without any added cues. The new study says humans only scallop when a clock is present. Together, the two papers show species matter.
Dove et al. (1974) saw the same latency scallop in rats under FI schedules. The human version only appears with a clock, so the rat data still hold.
Dews (1966) showed FI control stays strong even in darkness. That looks like a clash, but the older work used non-humans. The 1978 paper tells us people need light and a clock; animals do not.
Why it matters
When you run DRL or FI programs, give clients a visible timer. Without it, they may pause and then rush, missing the learning window. A simple wall clock or phone timer can shape the smooth wait-and-respond pattern you want.
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02At a glance
03Original abstract
Human subjects responded on two panels. A differential-reinforcement-of-low-rate schedule with a limited-hold contingency operated on Panel A. In Condition 1, responses on Panel B produced a stimulus on the panel that signalled whether reinforcement was available on Panel A. In Condition 2, responses on Panel B briefly illuminated a digital clock. In both conditions, performance on Panel A was very efficient; with few exceptions, Panel A was pressed only when reinforcement was available. Thus, in effect, a fixed-interval schedule operated on Panel B. In Condition 1, a "break-and-run" response pattern occurred on Panel B; with increasing temporal parameters, the duration of the postreinforcement pause on Panel B increased linearly while overall response rate and running rate (calculated by excluding the postreinforcement pauses) remained approximately constant. In Condition 2, the response pattern on Panel B was scalloped; the postreinforcement pause was a negatively accelerated increasing function of schedule value, while overall response rate and running rate were negatively accelerated decreasing functions of schedule value. The performance of subjects in Condition 2, but not in Condition 1, was highly sensitive to the contingencies in operation, and resembled that of other species on the fixed-interval schedule.
Journal of the experimental analysis of behavior, 1978 · doi:10.1901/jeab.1978.29-351