Axelsson Emma L, Britton Tayla, Gulhati Gurmeher K, Kelly Chloe, Copeland Helen, McNamara Luca, Covell Hester, Quinn Alyssa A
School of Psychological Sciences, College of Engineering, Science and Environment, University of Newcastle Australia, Callaghan, NSW 2308, Australia.
School of Medicine and Psychology, College of Science and Medicine, Australian National University, Canberra, ACT 2601, Australia.
Behav Sci (Basel). 2025 Jul 28;15(8):1021. doi: 10.3390/bs15081021.
Infants discriminate faces early in the first year, but research on infants' discrimination of bodies is plagued by mixed findings. Using a familiarisation novelty preference method, we investigated 7- and 9-month-old infants' discrimination of body postures presented in upright and inverted orientations, and with and without heads, along with relationships with gross and fine motor development. In our initial studies, 7-month-old infants discriminated upright headless postures with forward-facing and about-facing images. Eye tracking revealed that infants looked at the bodies of the upright headless postures the longest and at the heads of upright whole figures for 60-70% of the time regardless of the presence of faces, suggesting that heads detract attention from bodies. In a more stringent test, with similarly complex limb positions between test items, infants could not discriminate postures. With longer trials, the 7-month-olds demonstrated a familiarity preference for the upright whole figures, and the 9-month-olds demonstrated a novelty preference, albeit with a less robust effect. Unlike previous studies, we found that better gross motor skills were related to the 7-month-olds' better discrimination of upright headless postures compared to inverted postures. The 9-month-old infants' lower gross and fine motor skills were associated with a stronger preference for inverted compared to upright whole figures. This is further evidence of a configural representation of bodies in infancy, but it is constrained by an upper bias (heads in upright figures, feet in inverted), the test item similarity, and the trial duration. The measure and type of motor development reveals differential relationships with infants' representations of bodies.
婴儿在出生后的第一年早期就能辨别面孔，但关于婴儿对身体的辨别研究结果却参差不齐。我们采用熟悉-新颖偏好法，研究了7个月和9个月大的婴儿对以直立和倒置方向呈现、有头和无头的身体姿势的辨别能力，以及与大肌肉和精细运动发展的关系。在我们最初的研究中，7个月大的婴儿能够辨别直立无头姿势的正面和背面图像。眼动追踪显示，无论有无面孔，婴儿看直立无头姿势身体的时间最长，看直立完整身体头部的时间占60%-70%，这表明头部会分散对身体的注意力。在一个更严格的测试中，测试项目之间的肢体位置同样复杂，婴儿无法辨别姿势。经过更长时间的试验，7个月大的婴儿对直立完整身体表现出熟悉偏好，9个月大的婴儿表现出新颖偏好，尽管效果不太明显。与以往研究不同的是，我们发现，与倒置姿势相比，更好的大肌肉运动技能与7个月大的婴儿对直立无头姿势的更好辨别能力有关。9个月大婴儿较低的大肌肉和精细运动技能与对倒置完整身体的更强偏好有关。这进一步证明了婴儿期身体的构型表征，但它受到上偏（直立身体中的头部，倒置身体中的脚部）、测试项目相似性和试验持续时间的限制。运动发展的测量方法和类型揭示了与婴儿身体表征的不同关系。
