An experimental analysis of jackpot reinforcers
Surprise mega-rewards do not boost responding—stick to sized, paired, or scheduled reinforcers.
01Research in Context
What this study did
Kuroda et al. (2020) ran five lab tests with rats and pigeons.
They wanted to see if a surprise, oversized reinforcer—called a jackpot—made animals work harder or learn faster.
Each animal got the same task, but sometimes a huge food pellet or extra grain dropped in.
What they found
The big surprise did nothing.
Response rates stayed flat; no bird or rat sped up after a jackpot.
Across every test, the jackpot failed to beat normal-sized rewards.
How this fits with other research
Lattal (2020) looked at every jackpot paper and reached the same empty shelf.
That review folds the Kuroda data into a wider warning: there is still no proof that jackpots help.
McCormack et al. (2019) tell a different story for differential outcomes—where each correct response gets its own special reinforcer.
Their meta-analysis shows clear gains in speed and accuracy, proving that not all reinforcer tweaks are useless; the trick is pairing the right reward to the right response, not just making one reward huge.
Why it matters
If you are tempted to give a client a giant candy or big praise burst to "lock in" a skill, save it.
Keep your schedule steady and save the variety for differential outcomes instead.
Track data before and after any jackpot you still want to test; Kuroda’s animals say you will see no change.
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02At a glance
03Original abstract
Animal trainers and others often recommend the use of jackpot reinforcers, which are disproportionally large and come as a "surprise" to the animals. Because the actual behavioral effects of these jackpots remain uninvestigated, many basic questions about their use and even definition are unanswered. This series of experiments explored the definitions of jackpots using several different behavioral tests with both rats and pigeons. Because the original description of a jackpot resembled the reinstatement of previously reinforced and extinguished responding with response-independent deliveries of reinforcer, reinstatement effects of a jackpot, defined by its quality, were examined with rats in Experiment 1. In Experiment 2, response-potentiating effects of response-independent and -dependent deliveries of a jackpot, defined by its quantity, were assessed with pigeons when responding had nearly ceased. The response-potentiating effects of the frequency of jackpot-reinforcer delivery were investigated when responding of pigeons was maintained in single (Experiment 3) or concurrent (Experiment 4) schedules of reinforcement. Effects of jackpots on resistance to change were assessed with rats in Experiment 5. The effects of jackpots in each experiment were either absent or unsystematic across the subjects, casting doubt on their utility in animal training. Possible factors contributing to the negative results are discussed.
Journal of the Experimental Analysis of Behavior, 2020 · doi:10.1002/jeab.593