Abstract: | The experimental group (Group HA-TA) received food (F) and water (W) rewarded trials in an alternating sequence under hunger in Phase 1 and under thirst in Phase 2. Group HA-TA ran faster on F than on W trials in Phase 1, and faster on W than on F trials in Phase 2. Early in Phase 2 the difference between speeds on W and F trials was larger for Group HA-TA than for a group which received no runway training in Phase 1 (Group HO-TA), but later in Phase 2 this difference was larger for Group HO-TA than for Group HA-TA. Also in Phase 2 the difference between speeds on W and F trials was larger for Group HA-TA than for a group which received a random sequence of F and W trials under hunger in Phase 1, and smaller for Group HA-TA than for a group which received alternating F and W trials under thirst in both phases. To interpret these results it was assumed that for Group HA-TA the expectancies of reward formed in Phase 1 facilitated development of alternation performance in Phase 2, but that the S-R associative connections formed in Phase 1 inhibited ultimate development of alternation performance in Phase 2. |