Fixed-ratio reinforcement of spaced responding.

Bigelow (1971) used pigeons on a fixed-ratio schedule that paid only for responses spaced in time.

The birds had to wait a set number of seconds between pecks, then finish the ratio to earn food.

The team changed ratio size across conditions to see which measure—rate, spacing, or accuracy—moved first.

Correct response rate rose as the ratio got smaller.

The spaced-response pattern stayed almost the same no matter the ratio.

This tells us ratio size mainly tweaks correct output, not the timing rule the bird already learned.

Byrd (1972) looks like a contradiction: that study said each stimulus controls its own response timing, so changing one contingency should not spill over.

Bigelow (1971) found the same independence—ratio size altered correct rate but left the spacing rule intact—so both papers agree that timing and accuracy are separate levers.

HENDRY et al. (1964) ran FR schedules earlier and saw slow, odd responding when reward size was tied to the ratio; Bigelow (1971) kept reward size flat and got clean rate changes, showing the critical variable is ratio size, not reward size.

Bennett et al. (1998) later showed ratio schedules produce less persistence than interval ones; G’s quick rate shifts preview that fragility.

When you shape spaced responding with an FR schedule, watch correct rate first. It is the fastest signal that the ratio is too big or just right. Timing patterns will lag behind, so do not wait for them to change before you adjust the schedule.