Brain lateralization is commonly interpreted as crucial for human brain function and cognition. However, as comparative studies among primates are rare, it is not known which aspects of lateralization are really uniquely human. Here, we quantify both pattern and magnitude of brain shape asymmetry based on endocranial imprints of the braincase in humans, chimpanzees, gorillas, and orangutans. Like previous studies, we found that humans were more asymmetric than chimpanzees, however so were gorillas and orangutans, highlighting the need to broaden the comparative framework for interpretation. We found that the average spatial asymmetry pattern, previously considered to be uniquely human, was shared among humans and apes. In humans, however, it was less directed, and different local asymmetries were less correlated. We, thus, found human asymmetry to be much more variable compared with that of apes. These findings likely reflect increased functional and developmental modularization of the human brain.

中文翻译：

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脑外侧化的进化：人类的共享颅内不对称原始人型比大猿猴的多得多。

大脑偏侧化通常被解释为对人类大脑功能和认知至关重要。但是，由于灵长类动物之间的比较研究很少，因此尚不清楚侧枝化的哪些方面确实是人类独特的。在这里，我们根据人，黑猩猩，大猩猩和猩猩的大脑箱的颅内压印量化大脑形状不对称的模式和大小。像以前的研究一样，我们发现人类比黑猩猩更不对称，但大猩猩和猩猩也是如此，这突出了扩大解释的比较框架的必要性。我们发现，以前被认为是人类唯一的平均空间不对称模式在人类和猿类之间共享。然而，在人类中，它的指向性较小，并且不同的局部不对称性相关性较小。因此，我们 发现与猿相比，人类的不对称性变化更大。这些发现可能反映了人脑功能和发育模块化的增强。