Sample-specific ratio effects in matching to sample.

Paul (1983) worked with pigeons on a matching-to-sample task. The birds had to peck a sample key a set number of times before choosing a comparison key.

The twist: the number of required pecks changed with the sample. One sample needed 5 pecks. Another needed 20. The team watched whether the ratio itself guided later choices.

The pigeons' choices followed both the sample picture and the peck requirement. A high-ratio sample made the birds pick one comparison more often, even when the picture stayed the same.

In short, the ratio acted like a second cue, not just a hurdle to clear.

Brown et al. (1994) later added fixed-ratio observing to stimulus-equivalence training. Their pigeons formed new, untaught relations after matching with the same peck requirement, showing the idea holds across more complex tasks.

Ramer et al. (1977) had already shown that both stimulus-reinforcer and response-reinforcer links steer key pecking. Paul (1983) tightens the focus: the ratio itself becomes part of the stimulus package.

THOMAS et al. (1963) proved pigeons need solid simultaneous matching before they can handle delays. Paul (1983) keeps the early, error-free stage but swaps delay for ratio control, giving trainers another lever to pull.

For BCBAs, the ratio is more than busywork. It can function as a discriminative stimulus, so you can program different effort requirements to signal different tasks or reinforcers. Try alternating FR 5 and FR 20 within the same stimulus class and watch whether the learner starts responding faster to the easier ratio—then use that cue to speed up instruction.