According to a BBC program Animal Einstein (Builder), the intelligence of orangutans was tested before and after they were given human bedding materials.
Orangutans normally build beds in trees using branches and leaves. Their intelligence was tested using images on a touchscreen.
They were then given sheets, pillows, blankets, and other materials. Their quality of sleep was measured through brain waves.
With the given materials, the orangutans were able to achieve a more restful sleep than before and they immediately showed improvements in their intelligence tests.
How does sleep improve intelligence?
Why is sleep needed? Probably many reasons, as eerily stated before.
The BBC program proposes that better sleep led to higher intelligence. Monkey, chimps, orangutans built hammocks or beds in trees and slept better. They learned to build better beds and hammocks, some with roofs to protect from rain. Got more intelligent.
