Department of Allied Health Sciences, CB 7190, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
Ear Hear. 2013 Jan-Feb;34(1):3-14. doi: 10.1097/AUD.0b013e31825e2841.
The purpose of this study was to test the hypothesis that a carrier phrase can improve word recognition performance for both children and adults by providing an auditory grouping cue. It was hypothesized that the carrier phrase would benefit listeners under conditions in which they have difficulty in perceptually separating the target word from the competing background. To test this hypothesis, word recognition was examined for maskers that were believed to vary in their ability to create perceptual masking. In addition to determining the conditions under which a carrier-phrase benefit is obtained, age-related differences in both susceptibility to masking and carrier-phrase benefit were examined.
Two experiments were conducted to characterize developmental effects in the ability to benefit from a carrier phrase (i.e., "say the word") before the target word. Using an open-set task, word recognition performance was measured for three listener age groups: 5- to 7-year-old children, 8- to 10-year-old children, and adults (18-30 years). For all experiments, target words were presented in each of two carrier-phrase conditions: (1) carrier-present and (2) carrier-absent. Across experiments, word recognition performance was assessed in the presence of multi-talker babble (Experiment 1), two-talker speech (Experiment 2), or speech-shaped noise (Experiment 2).
Children's word recognition performance was generally poorer than that of adults for all three masker conditions. Differences between the two age groups of children were seen for both speech-shaped noise and multi-talker babble, with 5- to 7-year-olds performing more poorly than 8- to 10-year-olds. However, 5- to 7-year-olds and 8- to 10-year-olds performed similarly for the two-talker masker. Despite developmental effects in susceptibility to masking, both groups of children and adults showed a carrier-phrase benefit in multi-talker babble (Experiment 1) and in the two-talker masker (Experiment 2). The magnitude of the carrier-phrase benefit was similar for a given masker type across age groups, but the carrier-phrase benefit was greater in the presence of the two-talker masker than in multi-talker babble. Specifically, the children's average carrier-phrase benefit was 7.1% for multi-talker and 16.8% for the two-talker masker condition. No carrier-phrase benefit was observed for any age group in the presence of speech-shaped noise.
Effects of auditory masking on word recognition performance were greater for children than for adults. The time course of development for susceptibility to masking seems to be more prolonged for a two-talker speech masker than for multi-talker babble or speech-shaped noise. Unique to the present study, this work suggests that a carrier phrase can provide an effective auditory grouping cue for both children and adults under conditions expected to produce substantial perceptual masking.
本研究旨在验证一个假设，即通过提供听觉分组提示，承载短语可以提高儿童和成人的单词识别性能。假设承载短语将有益于在从竞争背景中感知分离目标词有困难的情况下的听众。为了检验这一假设，检查了掩蔽物的单词识别情况，这些掩蔽物被认为在产生感知掩蔽的能力方面有所不同。除了确定获得承载短语益处的条件外，还研究了年龄相关的掩蔽易感性和承载短语益处的差异。
进行了两项实验，以描述在目标词之前使用承载短语（即“说出这个词”）受益的能力的发展效应。使用开放式任务，测量了三个听众年龄组的单词识别性能：5 至 7 岁的儿童、8 至 10 岁的儿童和成年人（18 至 30 岁）。对于所有实验，在两种承载短语条件下呈现目标词：（1）承载短语存在和（2）承载短语不存在。在两项实验中，均在多说话人噪声（实验 1）、双说话人语音（实验 2）或语音噪声（实验 2）下评估单词识别性能。
对于所有三种掩蔽条件，儿童的单词识别性能普遍比成人差。在语音噪声和多说话人噪声两种情况下，两个年龄组的儿童之间存在差异，5 至 7 岁的儿童表现不如 8 至 10 岁的儿童。然而，5 至 7 岁的儿童和 8 至 10 岁的儿童在双说话人掩蔽下表现相似。尽管在掩蔽易感性方面存在发育差异，但儿童和成人在多说话人噪声（实验 1）和双说话人掩蔽（实验 2）中均表现出承载短语益处。在给定的掩蔽类型下，各年龄组的承载短语益处的幅度相似，但在双说话人掩蔽下的承载短语益处大于多说话人噪声。具体而言，儿童在多说话人噪声和双说话人掩蔽条件下的平均承载短语益处分别为 7.1%和 16.8%。在语音噪声存在的情况下，任何年龄组都没有观察到承载短语益处。
听觉掩蔽对单词识别性能的影响对儿童比对成人更大。对于双说话人语音掩蔽，易感性的发展过程似乎比多说话人噪声或语音噪声更持久。与目前的研究不同，这项工作表明，在预期产生大量感知掩蔽的情况下，承载短语可以为儿童和成人提供有效的听觉分组提示。
