Random interval schedules of reinforcement.

Long (1963) built a brand-new schedule. He called it random-interval, or RI.

Pigeons pecked a key for grain. Reinforcement became available at random moments.

He then compared the birds’ response rates to those on a regular variable-interval schedule.

The birds pecked at about the same speed on RI as on VI.

The pattern of pauses and bursts looked almost identical.

Math formulas showed the two schedules could be made equivalent.

Mechner (1958) had already sketched ratio theory. R used those ideas to shape the new interval plan.

Bell et al. (2017) later showed that when VI and VR alternate quickly, pigeons still treat the mix like simple VI. This supports R’s claim that RI can stand in for VI.

Clarke et al. (1998) flipped the question into a classroom. They found fixed-ratio tokens beat VI tokens at cutting stereotypy. That seems to clash with R’s VI love, but the kids worked for tokens, not grain, and the goal was behavior reduction, not steady response rate. Different purpose, different winner.

You now have a backup for VI. If your software or staff can’t run true VI, set an RI schedule instead. The learner’s response rate should stay the same. Test it during baseline next week.