Buss Emily, Hall Joseph W, Grose John H
Department of Otolaryngology/Head and Neck Surgery, University of North Carolina School of Medicine, Chapel Hill, North Carolina 27599, USA.
J Acoust Soc Am. 2009 Feb;125(2):1050-8. doi: 10.1121/1.3050273.
Previous work on pure tone intensity discrimination in school-aged children concluded that children might have higher levels of internal noise than adults for this task [J. Acoust. Soc. Am. 120, 2777-2788 (2006)]. If true, this would imply that psychometric function slopes are shallower for children than adults, a prediction that was tested in the present experiment. Normal hearing children (5-9 yr) and adults were tested in a two-stage protocol. The first stage used a tracking procedure to estimate 71% correct for intensity discrimination with a gated 500 Hz pure tone and a 65 dB sound pressure level standard level. The mean and standard deviation of these tracks were used to identify a set of five signal levels for each observer. In the second stage of the experiment percent correct was estimated at these five levels. Psychometric functions fitted to these data were significantly shallower for children than adults, as predicted by the internal noise hypothesis. Data from both stages of testing are consistent with a model wherein performance is based on a stable psychometric function, with sensitivity limited by psychometric function slope. Across observers the relationship between slope and threshold conformed closely to predictions of a simple signal detection model.
先前关于学龄儿童纯音强度辨别能力的研究得出结论，在这项任务中，儿童可能比成年人具有更高水平的内部噪声[《美国声学学会杂志》120, 2777 - 2788 (2006)]。如果这是真的，这将意味着儿童的心理测量函数斜率比成年人更平缓，本实验对这一预测进行了检验。正常听力的儿童（5 - 9岁）和成年人按照两阶段方案进行测试。第一阶段采用跟踪程序，使用门控500赫兹纯音和65分贝声压级标准水平来估计强度辨别71%正确时的情况。这些跟踪的均值和标准差用于为每个观察者确定一组五个信号水平。在实验的第二阶段，在这五个水平上估计正确百分比。正如内部噪声假说所预测的，拟合这些数据的心理测量函数在儿童中比在成年人中显著更平缓。测试两个阶段的数据都与一个模型一致，在该模型中，表现基于稳定的心理测量函数，灵敏度受心理测量函数斜率限制。在所有观察者中，斜率与阈值之间的关系与一个简单信号检测模型的预测紧密相符。
