First studied in 8-month-old human infant language learning (Saffran et al., 1996), statistical learning involves recognizing statistical regularities in stimuli. For example, infants must learn which phonemes occur together regularly (vs. randomly) in order to learn what syllables create different words (vs. nonwords). Statistical learning has also been found when learning non-linguistic information (e.g., music and visual stimuli), because of this statistical learning is thought to be a domain-general learning mechanism.
Saffran, J. R., Aslin, R. N., & Newport, E. L. (1996). Statistical learning by 8-month-old infants.