Data from: Infants prefer the faces of strangers or mothers to morphed faces: an uncanny valley between social novelty and familiarity

The “uncanny valley” response is a phenomenon involving the elicitation of a negative feeling and subsequent avoidant behaviour in human adults and infants as a result of viewing very realistic humanlike robots or computer avatars. It is hypothesised that this uncanny feeling occurs because the realistic synthetic characters elicit the concept of “human” but fail to satisfy it. Such violations of our normal expectations regarding social signals generate a feeling of unease. This conflict-induced uncanny valley between mutually exclusive categories (human and synthetic agent) raises a new question: could an uncanny feeling be elicited by other mutually exclusive categories, such as familiarity and novelty? Given that infants prefer both familiarity and novelty in social objects, we address this question as well as the associated developmental profile. Using the morphing technique and a preferential-looking paradigm, we demonstrated uncanny valley responses of infants to faces of mothers (i.e., familiarity) and strangers (i.e., novelty). Furthermore, this effect strengthened with the infant’s age. We excluded the possibility that infants detect and avoid traces of morphing. This conclusion follows from our finding that the infants equally preferred strangers’ faces and the morphed faces of two strangers. These results indicate that an uncanny valley between familiarity and novelty may accentuate the categorical perception of familiar and novel objects.“恐怖谷（uncanny valley）”效应是一种现象：人类成人与婴儿在目睹高度逼真的类人机器人或计算机虚拟化身（computer avatars）时，会产生负面情绪并随之出现回避行为。现有假说认为，此类恐怖感受的产生源于逼真的合成虚拟角色唤起了“人类”的概念，却又未能完全契合该概念。此类违背我们对社会信号的常规预期的情况，会引发不安感。这种存在于人类与合成智能体（synthetic agent）这两个互斥类别间的、由冲突引发的恐怖谷效应，引出了一个新问题：其他互斥类别（如熟悉性与新颖性）是否也能引发恐怖感受？鉴于婴儿在社交对象中对熟悉性与新颖性均存在偏好，我们不仅探讨了这一问题，还研究了相关的发展特征。借助变形技术（morphing technique）与优先注视范式（preferential-looking paradigm），我们证实了婴儿会对母亲面孔（即熟悉性刺激）与陌生人面孔（即新颖性刺激）产生恐怖谷效应。此外，该效应会随着婴儿年龄增长而增强。我们排除了婴儿因检测并回避变形痕迹而产生该效应的可能性，这一结论基于我们的发现：婴儿对陌生人面孔与两名陌生人的变形面孔的偏好程度并无差异。上述结果表明，熟悉性与新颖性之间的恐怖谷效应，可能会强化个体对熟悉与陌生对象的类别知觉（categorical perception）。