Sensitivity to second-order relations in faces - i.e., the spacing among features - has been identified as one of the most relevant aspects of face-processing skills that improve during development. However, there is still debate as to when this sensitivity first emerges, and when it becomes face-specific. The ability to use variations in the spacing of features to discriminate between faces and between cars was tested in 4-year-old children using a delayed matching two-alternative forced-choice task. Four-year-olds performed above change in both face and car discrimination even when differences in spacing were smaller than previously shown (within ± 1.6 SD). Better discrimination of faces than cars was found only when spacing cues were made more readily available (± 2.5 SD).