Evidence for the less-is-more hypothesis in language acquisition using the Hebb repetition paradigm

Why children learn language more easily than adults is one of the most fundamental yet unresolved questions in human science. The less-is-more hypothesis proposes that children are better language learners than adults because they have less memory resources available. Although the less-is-more hypothesis is not new, the current study is one of the first that test it within a theoretical framework that explains the link between memory and language acquisition using the Hebb repetition paradigm. In this paradigm, sequences of stimuli are presented for immediate serial recall with one (Hebb) sequence repeated on every nth trial. Hebb repetition learning refers to improved recall for the repeated Hebb sequence compared to nonrepeated filler sequences. Using this paradigm, we conducted a one-year, multiple-session longitudinal study, in which we presented auditory sequences of syllables for immediate serial recall to a group of children (8-9 years old) and adults. Despite their lower memory capacity the children showed similar Hebb learning performance compared to the adults when asked to recall sequences of 9 syllables. After four hours, only the child groups showed evidence for offline learning gains. One week and one year later, the children eventually outperformed the adults by showing better long-term retention of the phonological sequences. Correlations with cognitive measures of explicit awareness, vocabulary knowledge and short-term memory capacity were explored, and suggest that children’s advantages for language learning are partly explained by fewer resources in explicit memory. The findings are discussed in the light of the less-is-more hypothesis of language acquisition