Trehub S E, Bull D, Schneider B A
J Speech Hear Res. 1981 Jun;24(2):202-6. doi: 10.1044/jshr.2402.202.
Localization responses to a speech phrase masked by white noise were obtained from infants 6, 12, 18, and 24 months of age and from adults. The masking noise was presented continuously from two loudspeakers located 45 degrees to each side of the infant. During a trial the speech phrase was presented through one of the loudspeakers. A head turn to the signal (correct response) was rewarded by activating an animated toy on top of the speaker. The intensity of the signal was varied over trials (method of constant stimuli) to determine thresholds (defined as the intensity corresponding to 65% correct head turns) at each of two levels of masking noise, 42 and 60 dBC. Thresholds for the speech signal were comparable across all infant groups for both levels of masking noise. Increasing the masking noise from 42 to 60 dBC resulted in a threshold shift of comparable magnitude for infants and adults. However, adult thresholds were approximately 10-12 dB lower than those of infants at both masking levels.
从6个月、12个月、18个月和24个月大的婴儿以及成年人那里获得了对被白噪声掩盖的语音短语的定位反应。掩蔽噪声由位于婴儿两侧各45度的两个扬声器持续发出。在一次试验中，语音短语通过其中一个扬声器发出。转向信号（正确反应）会通过激活扬声器顶部的动画玩具得到奖励。信号强度在各次试验中变化（恒定刺激法），以确定在42和60 dBC这两种掩蔽噪声水平下的阈值（定义为对应65%正确转头的强度）。在两种掩蔽噪声水平下，所有婴儿组的语音信号阈值相当。将掩蔽噪声从42 dBC增加到60 dBC，婴儿和成年人的阈值偏移幅度相当。然而，在两种掩蔽水平下，成年人的阈值比婴儿的阈值大约低10 - 12 dB。
