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Last week, a team of scientists published a study in which they explained why humans are the only animals that have the facial feature known as chin.
However, a new study published by different researchers questions the previous explanations.
The first study claimed that the chin had developed after our earliest ancestors started eating softer food, while the new study claims that there is little evidence supporting the first theory.
Instead, the latest study suggests that chins started to develop as a “bony prominence” when the human ancestors started to be more sociable and stopped their fighting over territory.
In order to come to this conclusion, the researchers from Iowa analyzed scans of skulls as people grew from babies to adults.
According to the researchers, the human face changed its shape while we evolved from hunter gatherers to a more sociable group, which made the level of testosterone drop.
This evolution made the human skull to shrink and the chin to enlarge and be more prominent.
The human chin has intrigued scientists for a very long time, mainly because it cannot be found in any other species. Not even humans’ closest ancestor, the Neanderthal, has it.
Scientists originally thought that the reason why humans have chins was to help attract a mate, while other believed the chin appeared simply as a “genetic drift” and doesn’t really have an evolutionary purpose.
But a team of researchers from the University of Florida announced earliest this month that they have deciphered the purpose behind the human chin.
According to them, the human chin started to form approximately 2 million years ago, which coincided with the time when the human ancestors became more intelligent and figured out a way to make food softer by cooking it using fire.
James Pampush, one of the authors of the study, said that the fact that monkeys and apes are chinless proves that they must have evolved after the human ancestors moved away from other branches that belong to the primate family.
The latest study made by researchers from the University of Iowa suggests that chewing has nothing to do with the appearance of human chin.
According to the latest study, as the modern humans evolved, they changed from being isolated hunter gatherer groups to a more sociable and more cooperative creature, thus becoming calmer.
By being more sociable, the modern human fought less over territory, which led to a change in their behavior, mainly because the levels of hormones started to decrease.
Image Source: sextoninthecity
