The development of long-term lexical representations through Hebb repetition learning

► We clarify the role of memory in lexical learning. ► We propose that the Hebb repetition effect mimics lexical learning. ► Using the Hebb effect, we investigate the role of sleep in consolidation of lexical memories. ► Consolidation of lexical memories requires time, but the involvement of sleep is not crucial. This study clarifies the involvement of short- and long-term memory in novel word-form learning, using the Hebb repetition paradigm. In Experiment 1, participants recalled sequences of visually presented syllables (e.g., la-va-bu-sa-fa-ra-re-si-di), with one particular (Hebb) sequence repeated on every third trial. Crucially, these Hebb sequences contained three orthographic nonword neighbors of existing Dutch base-words (e.g., lavabu – lavabo [kitchen sink]). Twenty-four hours later, the same participants performed two auditory lexicalization tests involving the actual Dutch base-words (e.g., lavabo, safari, residu). Both tests yielded slower reaction times for these Dutch base-words compared with matched control words, which reflects lexical competition between the base-words and the Hebb sequences, therefore demonstrating lexical engagement of the Hebb sequences. In Experiment 2, we subsequently used the Hebb paradigm as an analogue of word-form learning, in order to investigate whether the creation of novel lexical memories requires sleep. Whereas earlier findings indicate that overnight sleep plays a crucial role in lexical consolidation, the current results show that Hebb learning of phonological sequences creates novel word-forms representations in the mental lexicon by the mere passage of time, with sleep playing no necessary role.