Is anybody there? JEFF PACHOUD/AFP/Getty

Stone Age Europe was a lonely place to live. An assessment of ancient population sizes suggests a vast swathe of western and central Europe may have been home to no more than 1500 people at any one time.

Our species, Homo sapiens, arrived in Europe about 43,000 years ago. Archaeological evidence, particularly the appearance of distinctive stone tools at multiple sites, suggests these humans rapidly spread across the continent. But it’s an open question exactly how many people lived in Europe at this time.

Now Isabell Schmidt and Andreas Zimmermann at …