The left-cradling bias (LCB) refers to the (typically female) preference to hold an infant on the left side of one’s own body. Among the three main accounts proposed for such a phenomenon, namely the “handedness”, “heartbeat” and “hemispheric asymmetry” hypotheses, the latter has met with the greatest empirical success. Accordingly, the LCB would facilitate the communication of socio-emotional information through the right hemisphere of both the cradled and the cradling individual, and should emerge mainly in face-to-face interactions. In this regard, it should be noticed that when the infant’s body is oriented toward the cradler, the left or right side of their face is relatively more visible to left- and right-cradlers, respectively. Therefore, we hypothesized that the LCB might also be associated with a preference for left-facing profiles (i.e., those showing the left, and more expressive, hemiface/cheek) of human babies. In order to test our hypothesis, we assessed the cradling-side preferences of female participants, as well as their preference for the left- or right-facing profile of a human infant depicted in a drawing. Left-cradlers exhibited a significantly larger preference for the left-facing version of the drawing compared with right-cradlers, a finding further corroborating the right-hemisphere hypothesis.

中文翻译：

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保持左边的档案，宝贝！左摇篮偏差与对人类婴儿朝左轮廓的偏好有关

左摇篮偏差 (LCB) 是指（通常是女性）倾向于将婴儿抱在自己身体的左侧。在对这种现象提出的三个主要解释中，即“惯用手”、“心跳”和“半球不对称”假说，后者获得了最大的实证成功。因此，LCB 将促进社会情感信息通过受孕者和受孕者的右半球进行交流，并且应该主要出现在面对面的互动中。在这方面，应该注意的是，当婴儿的身体朝向摇篮时，左侧或右侧的摇篮分别相对更容易看到他们脸部的左侧或右侧。因此，我们假设 LCB 也可能与偏爱左侧轮廓有关（即，那些展示了人类婴儿的左侧和更具表现力的半脸/脸颊）。为了测试我们的假设，我们评估了女性参与者的摇篮侧偏好，以及她们对绘画中描绘的人类婴儿的左侧或右侧轮廓的偏好。与右侧摇篮者相比，左侧摇篮者对绘图的左侧版本表现出明显更大的偏好，这一发现进一步证实了右半球假设。