Researchers studying young bonobos in an African sanctuary
have discovered striking similarities between the emotional development of the
bonobos and that of children, suggesting these great apes regulate their
emotions in a human-like way.
This is important to
human evolutionary history because it shows the socio-emotional framework
commonly applied to children works equally well for apes. Using this framework,
researchers can test predictions of great ape behaviour and, as in the case of
this study, confirm humans and apes share many aspects of emotional
Zanna Clay, PhD, and Frans de Waal, PhD, of the Living Links
Centre at the Yerkes National Primate Research Centre, Emory University, conducted
the study at a bonobo sanctuary near Kinshasa, the capital of the Democratic
Republic of the Congo. The results are published in the current issue of the
Proceedings of the National Academy of Sciences.
Detailed video analysis of daily social life at the
sanctuary allowed Clay and de Waal to measure how bonobos handle their own
emotions as well as how they react to the emotions of others. They found the
two were related in that bonobos that recovered quickly and easily from their
own emotional upheavals, such as after losing a fight, showed more empathy for
their fellow great apes. Clay notes those bonobos more often gave body comfort
(kissing, embracing, touching) to those in distress.
The bonobo (Pan paniscus), one of our closest primate
relatives, is as genetically similar to humans, like the chimpanzee. The bonobo
is widely considered the most empathic great ape, a conclusion brain research
supports. "This makes the species an ideal candidate for psychological
comparisons," says de Waal. "Any fundamental similarity between
humans and bonobos probably traces back to their last common ancestor, which
lived around six million years ago," he continues.
If the way bonobos handle their own emotions predicts how
they react to those of others, this hints at emotion regulation, such as the
ability to temper strong emotions and avoid over-arousal. In children, emotion
regulation is crucial for healthy social development. Socially competent
children keep the ups and downs of their emotions within bounds. A stable parent-child
bond is essential for this, which is why human orphans typically have trouble
managing their emotions.
The bonobo sanctuary in this study includes many victims of
bushmeat hunting. Human substitute mothers care for the juvenile bonobos that
were forcefully removed at an early age from their bonobo mothers. This care
continues for years until the bonobos are transferred to a forested enclosure
with bonobos of all ages. "Compared to peers reared by their own mothers,
the orphans have difficulty managing emotional arousal," says Clay. She
observed how the orphans would take a long time recovering from distress:
"They would be very upset, screaming for minutes after a fight, compared to
mother-reared juveniles, who would snap out of it in seconds."
"Animal emotions have long been scientifically
taboo," says de Waal, but he stresses how such studies that zoom in on
emotions can provide valuable information about humans and our society.
"By measuring the expression of distress and arousal in great apes, and
how they cope, we were able to confirm that efficient emotion regulation is an
essential part of empathy.
Empathy allows great apes and humans to absorb the distress
of others without getting overly distressed themselves," continues de
Waal. He says this also explains why orphan bonobos, which have experienced
trauma that hampers emotional development, are less socially competent than
their mother-raised peers.