Learning of monotonic and nonmonotonic sequences in domesticated horses (Equus callabus) and chickens (Gallus domesticus)

Hulse and Dorsky, 1977 and Hulse and Dorsky, 1979 found that rats, like humans, learn sequences following a simple rule-based structure more quickly than those lacking a rule-based structure. Through two experiments, we explored whether two additional species—domesticated horses (Equus callabus) and chickens (Gallus domesticus)—would show this same propensity. In both experiments, subjects encountered either a structured or unstructured sequence of food quantities in a runway paradigm. In both experiments, subjects exposed to structured patterns of food quantities learned to track sequences of food quantities more efficiently than those exposed to patterns lacking such structure by running fast for large food quantities and slowly for small food quantities. These results provide evidence that horses and chickens track simple sequences similarly to humans and rats.