Risky choice as a function of amount and variance in food supply.

Researchers let rats pick between two levers. One lever always gave three food pellets. The other lever gave either 15 pellets or nothing.

They changed how long each session lasted and how much food the rats already had. Then they watched which lever the rats pressed more.

When sessions were short or when the rats already had plenty of food, they played it safe. They picked the sure-three lever more often.

In plain words: a bigger food budget makes animals avoid gambles.

Collier et al. (1986) showed the same rats worked harder when each pellet was smaller or cost more. Together the papers say amount and price drive choice.

Matson et al. (2009) swapped variance for delay and added nicotine. They found amount still ruled choice, proving the lever method works for new variables.

Méndez (2024) moved the setup to college students who followed rules. People, like rats, chased the richer schedule. The animal rule still holds in humans.

Your client also picks between sure and unsure pay-offs. When reinforcement is already plentiful, the safe option looks better. If you want novelty or variation, keep the overall rate lower. Watch session length too—short sessions push clients toward safe choices.