Abilities of sequence learning and rule learning : experimental evidence in newborn chicks (Gallus gallus).

Sequence learning allows the encoding of the properties of event sequences, discriminating series composed of items presented in different order (e.g., ABA, MB), while rule learning allows the recognition of a familiar structure underlying a sequence, even when composed of perceptually unfamiliar items. Human infants are capable of rapidly encoding serial order in event sequences, recognizing and generalizing abstract algebraic-like patterns, a process that might be crucial for language development. These abilities seem to be not specific to language because they emerge using both auditory stimuli (sequences of speech and non-speech sounds) and visual stimuli (sequences of dogs/cats pictures) and they have been uncovered also in non-human animals (including some recent and highly debated reports of sophisticate rule learning in avian species). This evidence is consistent with an adaptive role of sequence and rule learning in a variety of sophisticate non-linguistic cognitive operations. ln the present study, we imprinted naiVe newborn chicks on a video-sequence of arbitrary visual elements (e.g., geometric shapes ordered according to an ABA rule, creating sequences such as cross-circle- cross). Afterward, we tested chicks' choice between this familiar sequence and a structurally different one, composed of the same elements in altered order (e.g., AAB, cross-cross-circle). We also tested chicks' ability to generalize the structure of the sequence they had learnt to sequences composed of novel elements (unfamiliar geometric shapes). Chicks successfully generalized, showing preferential approach of the perceptually-novel sequence whose structure resembled that of the imprinting stimulus. In further experiments we extended our initial results, investigating whether this same generalization ability can be revealed also in a non-social context, employing a learning paradigm in which chicks are trained to find food hidden behind screens depicting one type of sequence.