During the first year of life, infants undergo a process known as perceptual narrowing, which reduces their sensitivity to classes of stimuli which the infants do not encounter in their environment. It has been proposed that perceptual narrowing for faces and speech may be driven by shared domain-general processes. To investigate this theory, our study longitudinally tested 50 German Caucasian infants with respect to these domains first at 6 months of age followed by a second testing at 9 months of age. We used an infant-controlled habituation-dishabituation paradigm to test the infants’ ability to discriminate among other-race Asian faces and non-native Cantonese speech tones, as well as same-race Caucasian faces as a control. We found that while at 6 months of age infants could discriminate among all stimuli, by 9 months of age they could no longer discriminate among other-race faces or non-native tones. However, infants could discriminate among same-race stimuli both at 6 and at 9 months of age. These results demonstrate that the same infants undergo perceptual narrowing for both other-race faces and non-native speech tones between the ages of 6 and 9 months. This parallel development of perceptual narrowing occurring in both the face and speech perception modalities over the same period of time lends support to the domain-general theory of perceptual narrowing in face and speech perception.

在生命的第一年，婴儿经历了一个称为知觉狭窄的过程，这降低了他们对婴儿在环境中不会遇到的刺激类别的敏感性。有人提出，面部和语音的感知缩小可能是由共享的领域通用过程驱动的。为了研究这一理论，我们的研究首先在 6 个月大时就这些领域对 50 名德国白人婴儿进行了纵向测试，然后在 9 个月大时进行了第二次测试。我们使用婴儿控制的习惯-去习惯范式来测试婴儿区分其他种族亚洲面孔和非本地粤语语音的能力，以及作为对照的同种族白人面孔。我们发现，虽然 6 个月大的婴儿可以区分所有刺激，到 9 个月大时，他们不再能够区分其他种族的面孔或非本地语气。然而，婴儿可以在 6 个月和 9 个月大时区分同种种族的刺激。这些结果表明，同样的婴儿在 6 到 9 个月大的时候，对其他种族的面孔和非母语语调的感知都会变窄。在同一时间段内，在面部和语音感知模式中发生的感知缩小的这种平行发展为面部和语音感知中的感知缩小的领域通用理论提供了支持。这些结果表明，同样的婴儿在 6 到 9 个月大的时候，对其他种族的面孔和非母语语调的感知都会变窄。在同一时间段内，在面部和语音感知模式中发生的感知缩小的这种平行发展为面部和语音感知中的感知缩小的领域通用理论提供了支持。这些结果表明，同样的婴儿在 6 到 9 个月大的时候，对其他种族的面孔和非母语语调的感知都会变窄。在同一时间段内，在面部和语音感知模式中发生的感知缩小的这种平行发展为面部和语音感知中的感知缩小的领域通用理论提供了支持。