Though early humans and Neanderthals are known to have co-existed and even mated with one another, scientists have so far uncovered few clues as to how the two species might have interacted socially. Based on certain anatomical differences, particularly regarding the shape of the skull, it has generally been assumed that the brains of these two hominids underwent contrasting development processes, causing a substantial intelligence gap that would have significantly shaped inter-species relations. However, a new study in Current Biology challenges this theory, suggesting that the brains of Neanderthal infants may have been remarkably similar to those of their human counterparts.
Such a finding instantly conjures up heart-warming images of human and Neanderthal children playing together, though much more research is needed in order to determine whether or not the two species were able to interact on a level cognitive playing field.
The researchers reached their conclusion after examining the skulls of 15 Neanderthals, and comparing these to 79 human samples. Among the Neanderthal specimens were six adults, six adolescents, and three infants, including one newborn and two children who died at around 18 months and 2 years old respectively. This allowed the team to observe how the Neanderthal skull changed in shape at different stages of the life cycle.
In doing so, they discovered that the Neanderthal skull grows in a remarkably similar pattern to the human skull during the first two years of life, with the cerebellar fossa and the temporal and frontal pole regions rapidly expanding immediately after birth, followed by extensive growth of the basal region.
The growth of the temporal lobes influences early skull development in humans – and possibly in Neanderthals too. decade3d – anatomy online/Shutterstock
These changes in skull shape are thought to reflect changes in the structure of the brain. In humans, for instance, brain regions like the cerebellum and the temporal and parietal lobes grow during early infancy, enhancing our capacity for language and social interaction.
The fact that Neanderthal infants display the same early skull growth suggests that they may also have developed these brain regions early on in life, supporting their ability to co-exist with human kids. Intriguingly, this finding contradicts most previous research, which has tended to assume that, because adult Neanderthals had much flatter skulls than humans, their brains probably developed in a different pattern, with the social cognition regions undergoing no such growth spurt.
Exactly how this new finding reshapes our understanding of human-Neanderthal relations is difficult to say. Since cognitive development is largely influenced by one’s environment, it is possible that humans and Neanderthals who grew up together acquired shared cognitive traits. This is likely to have shaped their social interactions and culture, which would subsequently have affected their mating practices, ultimately determining which Neanderthal genes crossed over to the human genome.