Warmup in avoidance as a function of time since prior training.

Researchers trained rats to press a lever to avoid mild shock. They then varied the rest time between sessions from zero to 30 minutes. The goal was to see how long a break hurts performance when the animal returns.

Each rat served as its own control. The team tracked how many correct avoidance responses happened in the first minutes of every session.

Performance dropped as the break grew longer. The drop peaked once the gap reached 30 minutes. Longer breaks did not make the loss worse; the deficit simply stayed flat.

The pattern looked like the Kamin effect and punishment warm-up losses seen in older studies. The authors note the match but do not claim a shared cause.

Schroeder et al. (1969) seems to disagree. They saw pigeons lose steep generalization gradients after 24 hours, but a quick warm-up brought the skill right back. The key difference is time scale: 24-hour loss can be reversed, while the 30-minute loss in Hineline (1978) stays put.

Mulvaney et al. (1974) used the same rat avoidance prep. They showed that animals time their responses to the seconds within each cycle. Hineline (1978) adds the session-level rule: keep breaks under 30 minutes or expect a slump.

McIntire et al. (1987) push the idea further. They found that one aversive session can suppress appetitive behavior both before and after it. Together these papers warn that avoidance effects spill across time and across response types.

If you run avoidance or punishment protocols in the lab, schedule sessions closer than 30 minutes or plan for a warm-up period. For clinical work, the data hint that long breaks between aversive-based lessons could hurt fluency. Test shorter intervals or build quick fluency checks after any extended pause.