Effects of chlordiazepoxide on pausing during rich‐to‐lean transitions

Pigeons pecked a key for food on a two-part schedule.

First part gave lots of food (rich). Then a tone said "lean coming."

After the tone, food was scarce (lean).

The birds got the anti-anxiety drug chlordiazepoxide before some sessions.

Researchers timed how long birds paused after the rich-to-lean switch.

The drug cut pausing only when the tone signaled less food ahead.

It did not change pecking when conditions stayed the same.

Result: the switch itself feels bad, like mild anxiety.

Deitz (1986) saw the opposite. Chlorpromazine slowed responding more when cues were big and clear.

Both labs used pigeons and drugs, but the drugs work differently. Chlorpromazine dulls all senses; chlordiazepoxide eases worry.

Yuwiler et al. (1992) showed that bigger past rewards make animals pause longer on progressive-ratio schedules.

Langford’s team adds a new layer: the drug tells us the pause is emotional, not just habit.

You can spot "lean warning" moments in your own sessions.

Think sudden jump from easy tasks to hard ones, or from high to low praise.

Those shifts may feel aversive and stall responding.

Buffer the change: give clearer signals, insert easier steps, or add calming items.

Less pause means more learning time.