Mothers usually cradle their infants to the left of their body midline, an asymmetry that seems to be a typically female lateral preference. This bias is deemed to be an evolutionary facilitator of communication between cradling and cradled individuals and is believed to be strongly related to hemispheric specialization for complex socio-affective behaviors. Thus, left cradling might facilitate affective interactions in females with typical brain organization, probably due to a right-hemisphere dominance for social attachment. In this study, we investigated cradling-side preferences in 288 young females as a function of their attachment styles to parents and partners. A left-cradling bias was more frequent in participants experiencing positive relationships with their mother and romantic partners. These findings indicate that the left-cradling bias may be associated with high-quality social attachment behaviors in females and, therefore, can be considered as a natural index of socio-emotional attunement between the cradling and cradled individuals.

中文翻译：

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左摇篮偏见与对父母和伴侣的依恋之间的关系。

母亲通常将婴儿抱在身体中线的左侧，这种不对称似乎是女性典型的侧向偏好。这种偏见被认为是摇篮和被摇篮个体之间交流的进化促进者，并且被认为与复杂社会情感行为的半球专业化密切相关。因此，左摇篮可能会促进具有典型大脑组织的女性的情感互动，这可能是由于右半球在社会依恋方面占主导地位。在这项研究中，我们调查了 288 名年轻女性对摇篮侧的偏好，作为她们对父母和伴侣的依恋风格的函数。在与母亲和浪漫伴侣建立积极关系的参与者中，左摇篮偏见更为常见。这些发现表明，左摇篮偏差可能与女性的高质量社会依恋行为有关，因此，可以被认为是摇篮和被摇篮个体之间社会情感协调的自然指标。