Rats' lever-press durations as psychophysical judgements of time.

Researchers watched how long rats held down a lever. They changed the quiet time between food deliveries. The rats had to learn new time rules to get pellets.

The team wanted to see if lever-press length acts like a clock in the rat’s head.

When the between-trial pause grew or shrank, the rats adjusted how long they held the lever. The new press lengths fit a power-law curve, just like human time judgments.

The schedule structure, not the food itself, set the internal timer.

Fox et al. (2001) later showed that one hidden factor, response strength, links rate, latency, and how long animals keep responding. The 1973 duration data now sit inside that bigger picture.

Staddon et al. (2002) added math models saying these measures move together as random walks. Their models embrace the power-law finding instead of replacing it.

Storm (2000) looked at wheel-running and found that schedule order can shift rate parameters. Both papers warn that tiny setup details change the numbers you see.

If you shape a new response, the quiet gaps between reinforcers may already be teaching duration. Pick your inter-trial times on purpose, not by habit. A two-second gap could give you short taps; a ten-second gap could give you long holds. Test the length you want by adjusting the schedule first, then add extra cues if needed.