Performance of children under a multiple random-ratio random-interval schedule of reinforcement.
Toddlers already press faster when pay depends on number, not time—schedule control starts early.
01Research in Context
What this study did
Three toddlers sat on mom’s lap in front of a yellow box. When they pressed the big button, music played and M&M’s dropped. Some minutes the box paid only after many presses (random-ratio). Other minutes it paid only after time passed (random-interval). The order flipped each session so the kids felt both schedules every day.
The team watched response rates over the study period. They also doubled the ratio requirement halfway through to see if the kids still pressed faster under ratio rules.
What they found
Every child pressed faster under the random-ratio part. When the schedule flipped, their rate flipped with it. Even after the ratio got harder, ratio minutes still produced more presses than interval minutes.
Schedule control showed up early. Toddlers as young as two already work harder when pay depends on number, not time.
How this fits with other research
WERTHEIWENZEL et al. (1964) found no clear link between ratio size and rate in pigeons even over the study period. The new kid data seem opposite: rate rose with ratio. The gap is method. The pigeon study held ratio size steady for weeks; the child study flipped schedules every few minutes, letting the kids feel the contrast.
Winterling et al. (1992) later used a changing-criterion variable-ratio schedule to boost exercise in obese boys. They started easy and raised the pedal count a large share each week. The boys kept up, matching non-obese peers. The toddler finding—that ratio schedules push more work—scaled up to real-world fitness.
O'Leary et al. (1979) showed fixed-interval token schedules can make adults pace around. Together these papers show schedule control works across age, species, and response type.
Why it matters
If you want more responses, tie reinforcement to count, not time. Use VR instead of VI when shaping new skills with young learners. Start with low ratios and raise them slowly, just like V et al. did with exercise. Watch for contrast effects: switching from VR to VI can drop rate fast, so prepare extra prompts during the change.
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02At a glance
03Original abstract
Three children, aged 1.5, 2.5, and 4.5 years, pressed telegraph keys under a two-component multiple random-ratio random-interval schedule of reinforcement. In the first condition, responses on the left key were reinforced under a random-interval schedule and responses on the right key were reinforced under a random-ratio schedule. In the second condition, the schedule components were reversed. In the third condition, the original arrangement was reinstated. For all subjects, rates of responding were higher in the random-ratio component despite higher rates of reinforcement in the random-interval component. The average interreinforcement interval of the random-interval component was increased in the fourth condition, resulting in more similar rates of reinforcement for both schedule components, and then returned to its original value in the fifth condition. In both conditions, all subjects continued to exhibit higher rates of responding in the ratio component than in the interval component. Although these observations are consistent with results from studies with pigeons, it is argued that the response-rate differences between the interval and ratio schedule components are sufficient to demonstrate schedule sensitivity.
Journal of the experimental analysis of behavior, 1990 · doi:10.1901/jeab.1990.54-263