Figure 5.

Nine seconds with light from below are enough for the animal to detect the CS-offset. (Upper diagram) Crabs were trained on Day 1 and re-exposed to the training context for 2 h on Day 2. Before test trial, crabs underwent a period of either 9 sec with light from below (first pair) or 9 sec with light from below plus 36 sec with light from above (second pair). Test trials with light from above. (Lower panel) Mean responses and S.E.M. at test, normalized with respect to the UN group. Other symbols and indications as in Figure 1.