Laughing and evolution
The first hoots of laughter from an ancient ancestor of humans could be heard at least 10 million years ago, according to the results of a new study.
Researchers used recordings of apes and babies being tickled A __________ to the last common ancestor that humans shared with the modern great apes, which include chimpanzees, gorillas and orangutans.
The finding challenges the opinion B __________, suggesting instead that it emerged long before humans split from the evolutionary path that led to our primate cousins, between 10m and 16m years ago.
“In humans, laughing can be the strongest way of expressing how much we are enjoying ourselves, but it can also be used in other contexts, like making fun of someone,” said Marina Davila Ross, a psychologist at Portsmouth University. “I was interested in C __________.”
Davila Ross travelled to seven zoos around Europe and visited a wildlife reserve in Sabah, Borneo, to record baby and juvenile apes D __________. Great apes are known to make noises that are similar to laughter when they are excited and while they are playing with each other.
Davila Ross collected recordings of laughter from 21 chimps, gorillas, orangutans and bonobos and added recordings of three babies that were tickled to make them laugh.
To analyze the recordings, the team put them into a computer program. “Our evolutionary tree based on these acoustic recordings alone showed E __________, but furthest from orangutans, with gorillas somewhere in the middle.” said Davila Ross. “What this shows is strong evidence to suggest F __________.”