Effects of processing depth on lexically guided perceptual learning

Abstract

Listeners use lexical information to modify the mapping to representations for individual speech sounds. This mechanism, termed lexically guided perceptual learning (LGPL), results in long-lasting changes to speech sound categories and may be modulated by attention mechanisms. The literature on LGPL has demonstrated that learning may be influenced by explicit or implicit attention towards anomalous aspects of the input and may be affected by individual factors, such as cognitive abilities. The current study used three experiments to examine the degree to which graded lexical recruitment, indexed by explicit attention to the lexicon compared to other stimulus features, influenced the magnitude of LGPL. Listeners completed an exposure phase, where they heard an ambiguous phoneme, midway between /s/ and /ʃ/. Attention was manipulated across experiments through task instructions during exposure such that attention was shifted either towards lexical information (lexical decision task), surface variation (amplitude judgment task), or syntactic knowledge (syntactic decision task). Following exposure, all participants completed a phoneme identification task for members of an /s/-/ʃ/ continuum. Preliminary results indicate that LGPL occurred in each experiment; however, the magnitude of learning differed as a function of attention. The final results will be discussed in terms of constraints of the LGPL mechanism.