A new eye on human evolution in our consortium with Paola Cerrito
As of this year, Paola Cerrito, PhD, took on the chair of human evolution at the University of Zurich, as well as a position of principal investigator within the NCCR Evolving Language. Her research work on human evolution focuses on life history, meaning a species-specific pattern of growth, survival and reproduction.
Humans have peculiar reproductive practices. “In humans, females live a long time after their reproductive period is over,” Paola Cerrito points out. “This is an odd behaviour among mammals, it’s usually not the case.” Humans also tend to have children with short intervals between births. Furthermore, human children are weaned earlier than most other species, before they are self-sufficient: they cannot walk, talk, or forage food…
So why is that? According to Paola Cerrito, humans rely heavily on alloparental care, meaning children are raised not only by their mothers, but also by other members of the community. In her previous research, thanks to the study of fossil teeth, she found that Neanderthals had children less frequently than Homo sapiens, hinting that they did not have an alloparental care system. On the other hand, other animals, such as marmosets or meerkats are cooperative breeders and rely on members of the group to raise children. “It’s interesting to investigate what were the selective pressures that favored this convergent evolution. Both the sociology and the biology involved in this behaviour is interesting to me,” says the researcher.
Within the NCCR Evolving Language, Paola Cerrito will study some preconditions for the evolution and development of language. Indeed, in humans, children are born pre-verbal: they can’t talk, but they still need to communicate their needs to their caretakers. In this, we observe the role of facial expressions in communication. “Previous studies have shown that there is more neural control of facial muscles in species that practice alloparental care,” Cerrito states. Cohort studies and comparative work will unravel the link between cooperative breeding and language development and evolution.
