Factors influencing inhibitory stimulus control: discrimination training and prior non-differential reinforcement.

Snapper et al. (1969) worked with pigeons to see how best to stop responding near the "no-go" cue.

Birds first pecked for food on one line tilt (S+) and then got two extinction layouts.

Group A kept the S+ vs S- alternation. Group B got massed extinction with no S+ at all.

After training the team tested how fast responding dropped as the line tilt moved toward S-.

Discrimination training gave a steep drop-off: birds almost never pecked near the S- line.

Massed extinction gave a flat line: birds kept pecking at angles close to the former S-.

In plain words, you need both the "go" and the "no-go" trials to build sharp inhibitory control.

Powell et al. (1968) from the same lab showed more sessions make the drop-off even steeper.

Rilling et al. (1969) found the same edge in goldfish: mixing reinforced trials into extinction sharpens control.

Together the papers say the active ingredient is contrast, not simply withholding food.

HOFFMAN et al. (1964) used tone instead of line tilt and got the same asymmetrical gradient, proving the rule works across stimuli and species.

When you want a client to stop in the presence of a red card or a stop sign, do not just ignore errors.

Run brief S+ trials that pay off, then present S- and withhold reinforcement.

This quick alternation builds a sharp "stop" boundary and cuts guessing.

Try five go/no-go swaps next session and watch the edge appear.