Scanning faces is important for social interactions. Difficulty with the social use of eye contact constitutes one of the clinical symptoms of autism spectrum disorder (ASD). It has been suggested that individuals with ASD look less at the eyes and more at the mouth than typically developing (TD) individuals, possibly due to gaze aversion or gaze indifference. However, eye-tracking evidence for this hypothesis is mixed. While gaze patterns convey information about overt orienting processes, it is unclear how this is manifested at the neural level and how relative covert attention to the eyes and mouth of faces might be affected in ASD. We used frequency-tagging EEG in combination with eye tracking, while participants watched fast flickering faces for 1-min stimulation sequences. The upper and lower halves of the faces were presented at 6 Hz and 7.5 Hz or vice versa in different stimulation sequences, allowing to objectively disentangle the neural saliency of the eyes versus mouth region of a perceived face. We tested 21 boys with ASD (8–12 years old) and 21 TD control boys, matched for age and IQ. Both groups looked longer at the eyes than the mouth, without any group difference in relative fixation duration to these features. TD boys looked significantly more to the nose, while the ASD boys looked more outside the face. EEG neural saliency data partly followed this pattern: neural responses to the upper or lower face half were not different between groups, but in the TD group, neural responses to the lower face halves were larger than responses to the upper part. Face exploration dynamics showed that TD individuals mostly maintained fixations within the same facial region, whereas individuals with ASD switched more often between the face parts. Replication in large and independent samples may be needed to validate exploratory results. Combined eye-tracking and frequency-tagged neural responses show no support for the excess mouth/diminished eye gaze hypothesis in ASD. The more exploratory face scanning style observed in ASD might be related to their increased feature-based face processing style.

中文翻译：

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频率标记脑电图和眼动追踪测量相结合，并不能支持自闭症的“嘴巴过多/眼睛注意力减弱”假说


扫描面部对于社交互动很重要。眼神交流的社交使用困难是自闭症谱系障碍（ASD）的临床症状之一。有人认为，与典型发育中 (TD) 个体相比，自闭症谱系障碍 (ASD) 个体较少注视眼睛，较多注视嘴巴，这可能是由于凝视厌恶或凝视冷漠所致。然而，支持这一假设的眼球追踪证据好坏参半。虽然凝视模式传达了有关明显定向过程的信息，但尚不清楚这在神经水平上如何表现，以及自闭症谱系障碍中对眼睛和嘴巴的相对隐蔽注意力可能受到怎样的影响。我们将频率标记脑电图与眼动追踪结合使用，同时参与者观看快速闪烁的面孔以进行 1 分钟的刺激序列。在不同的刺激序列中，脸部的上半部和下半部以 6 Hz 和 7.5 Hz 的频率呈现，反之亦然，从而可以客观地区分所感知脸部的眼睛与嘴部区域的神经显着性。我们测试了 21 名患有自闭症谱系障碍 (ASD) 的男孩（8-12 岁）和 21 名 TD 对照男孩，他们的年龄和智商都匹配。两组人看眼睛的时间都比看嘴的时间长，在这些特征的相对注视持续时间上没有任何组间差异。 TD 男孩明显更多地关注鼻子，而 ASD 男孩则更多地关注脸部之外。 EEG神经显着性数据部分遵循这种模式：组间对上半部或下半部的神经反应没有差异，但在TD组中，对下半部的神经反应大于对上半部的反应。面部探索动态表明，TD 个体大多在同一面部区域内保持注视，而 ASD 个体则更频繁地在面部部位之间切换。 可能需要在大型独立样本中进行复制来验证探索性结果。结合眼动追踪和频率标记的神经反应显示，不支持自闭症谱系障碍中嘴巴过多/眼睛注视减少的假说。在 ASD 中观察到的更具探索性的面部扫描风格可能与其增加的基于特征的面部处理风格有关。