Data from: Rapid categorization of natural face images in the infant right hemisphere

Human performance at categorizing natural visual images surpasses automatic algorithms, but how and when this function arises and develops remain unanswered. We recorded scalp electrical brain activity in 4–6 months infants viewing images of objects in their natural background at a rapid rate of 6 images/second (6 Hz). Widely variable face images appearing every 5 stimuli generate an electrophysiological response over the right hemisphere exactly at 1.2 Hz (6 Hz/5). This face-selective response is absent for phase-scrambled images and therefore not due to low-level information. These findings indicate that right lateralized face-selective processes emerge well before reading acquisition in the infant brain, which can perform figure-ground segregation and generalize face-selective responses across changes in size, viewpoint, illumination as well as expression, age and gender. These observations made with a highly sensitive and objective approach open an avenue for clarifying the developmental course of natural image categorization in the human brain.

人类对自然视觉图像的分类表现优于自动算法，但该功能的产生机制与出现时机仍未明晰。我们以每秒6张图像（6赫兹(Hz)）的快速呈现速率，向4~6个月龄的婴儿展示带有自然背景的物体图像，并同步记录其头皮脑电活动。每间隔5个刺激呈现一张变化幅度极大的人脸图像时，会在右侧半球诱发出精准对应1.2赫兹（6Hz/5）的人脸选择性反应（face-selective response）。该反应在相位打乱图像（phase-scrambled images）刺激下并未出现，因此并非由低水平视觉信息所引发。上述研究结果表明，右侧偏侧化的人脸选择性加工过程早在婴儿大脑开始阅读习得之前就已出现；这类加工能够完成图形-背景分离（figure-ground segregation），并可针对图像的尺寸、视角、光照条件，以及表情、年龄与性别变化，实现人脸选择性反应的泛化。采用这种高灵敏度且客观的研究方法所获得的这些观测结果，为阐明人类大脑自然图像分类能力的发展轨迹开辟了新的研究路径。