Unattended exposure to components of speech sounds yields samebenefits as explicit auditory training

摘要

Learning a second language as an adult is particularly effortful when new phonetic repre-sentations must be formed. Therefore the processes that allow learning of speech soundsare of great theoretical and practical interest. Here we examined whether perception ofsingle formant transitions, that is, sound components critical in speech perception, canbe enhanced through an implicit task-irrelevant learning procedure that has been shownto produce visual perceptual learning. The single-formant sounds were paired at sub-threshold levels with the attended targets in an auditory identification task. Resultsshowed that task-irrelevant learning occurred for the unattended stimuli. Surprisingly,the magnitude of this learning effect was similar to that following explicit training on audi-tory formant transition detection using discriminable stimuli in an adaptive procedure,whereas explicit training on the subthreshold stimuli produced no learning. These resultssuggest that in adults learning of speech parts can occur at least partially through implicitmechanisms.