A latent consolidation phase in auditory identification learning: Time in the awake state is sufficient

TLDR

Large performance gains that emerge hours after practice have been reported in visual, motor, and auditory discrimination tasks, suggesting a latent consolidation phase in human skill learning. This study investigates whether delayed performance gains occur after training in an auditory verbal identification task. Young adults showed robust delayed gains beginning 4 h post‑training, most after 6 h, retained for over 6 months, and occurring during wakefulness, confirming a latent, hours‑long consolidation phase in auditory verbal learning.

Abstract

Large gains in performance, evolving hours after practice has terminated, were reported in a number of visual and some motor learning tasks, as well as recently in an auditory nonverbal discrimination task. It was proposed that these gains reflect a latent phase of experience-triggered memory consolidation in human skill learning. It is not clear, however, whether and when delayed gains in performance evolve following training in an auditory verbal identification task. Here we show that normal-hearing young adults trained to identify consonant–vowel stimuli in increasing levels of background noise showed significant, robust, delayed gains in performance that became effective not earlier than 4 h post-training, with most participants improving at more than 6 h post-training. These gains were retained for over 6 mo. Moreover, although it has been recently argued that time including sleep, rather than time per se, is necessary for the evolution of delayed gains in human perceptual learning, our results show that 12 h post-training in the waking state were as effective as 12 h, including no less than 6 h night's sleep. Altogether, the results indicate, for the first time, the existence of a latent, hours-long, consolidation phase in a human auditory verbal learning task, which occurs even during the awake state.