High levels of testosterone in our ancient human ancestors may have prevented them from producing art, according to a new study in Current Anthropology reported upon by the Telegraph. The study found that culture and technology began to develop around 50,000 years ago and was spurred by a relatively sudden reduction of testosterone-related traits in human skeletal remains.

The drop in humans’ levels of the hormone caused them to become less aggressive, according to the study. They were thus more readily able to live together in larger groups. That increased collectivity seems to have marked the start of artistic expression and the development of tools and increasingly complex methods of food collection and fire maintenance.

As the study’s lead author, Robert Cieri from the University of Utah told the Telegraph, “The modern human behaviors of technological innovation, making art and rapid cultural exchange probably came at the same time that we developed a more cooperative temperament.”

He added, “If prehistoric people began living closer together and passing down new technologies, they’d have to be tolerant of each other. […] The key to our success is the ability to cooperate and get along and learn from one another.”

The study’s time line and findings match up to the previous, groundbreaking discovery of cave paintings dating back to approximately 42,000 years ago, which were found near Málaga, Spain. Scientists had previously believed that artistic expression first presented itself only in our modern human species, Homo sapiens sapiens. However, the Spanish paintings could only have been made by Homo sapiens neanderthalensis, more commonly known as Neanderthals.

This latest testosterone-linked theory was landed upon by researchers after comparing the skulls of over 1,400 ancient and modern humans. They found a sharp reduction in the thickness of the skull’s brow lines and rounder faces become prominent approximately 50,000 years ago. Both characteristics are associated with lower levels of testosterone.

For years, scientists have been looking for an explanation for the sharp rise in human technological and artistic development that took place at that time, following 150,000 years of comparably low levels of development.