From infancy onwards, EEG is widely used to measure face-categorization, i.e. differential brain activity to faces versus non-face stimuli. Four ERP components likely signal infants’ face-sensitivity but reflect different underlying mechanisms: the P1, N290, P400, Nc. We test whether these components reveal similar developmental patterns from early to late infancy, using a longitudinal dataset of 80 infants tested at 5 and 10 months. The P1, N290, and the Nc show face-categorization already in 5-months-olds, a pattern which did not change over time. Development is visible as increased amplitudes in all components, but similar for face and non-face stimuli. By using Markov models, we illustrate that there are differences in the distribution of individual trajectories of face-categorization components from 5 to 10 months. Whereas individual trajectories appear more varied for the Nc and the P1, the N290 reveals a more consistent pattern: a larger proportion of 5-month-olds shows the dominant group response; a larger proportion of 10-month-olds remains in this group, and larger proportions of the alternative trajectories from 5- to 10-month-olds move towards the dominant group. This is vital information when one wants to examine individual differences in infant ERPs related to face-categorization.

从婴儿期开始，脑电图已广泛用于测量面部分类，即面部与非面部刺激之间的差异性大脑活动。四个ERP组件可能表明婴儿的面部敏感性，但反映出不同的潜在机制：P1，N290，P400，Nc。我们使用80个在5个月和10个月进行测试的婴儿的纵向数据集，测试了这些成分从婴儿早期到晚期是否显示出相似的发育模式。P1，N290和Nc在5个月大时就已经显示了面部分类，这种模式不会随着时间而改变。在所有组件中振幅增加都可以看到发育，但是对于面部和非面部刺激却相似。通过使用马尔可夫模型，我们说明了从5到10个月的面部分类分量的各个轨迹的分布存在差异。Nc和P1的个体轨迹似乎变化较大，而N290则显示出更一致的模式：5个月大的人群显示出主要的群体反应。该组中仍然有较大比例的10个月大的孩子，从5个月到10个月大的孩子的替代轨迹中，有较大比例移向了优势群体。当要检查与面部分类相关的婴儿ERP中的个体差异时，这是至关重要的信息。