Our ancestors predating Neanderthals might have been much smarter that we thought as researchers have found evidence that human-like ways of thinking may have emerged as early as 1.8 million years ago.
The researchers believe that the same areas of the brain engaged in modern activities like playing the piano were also used in making stone tools dating from 1.8 million to 100,000 years ago.
The results, published in the journal Nature Human Behaviour, place the appearance of human-like cognition at the emergence of Homo erectus, an early apelike species of human first found in Africa whose evolution predates Neanderthals by nearly 600,000 years.
"This is a significant result because it's commonly thought our most modern forms of cognition only appeared very recently in terms of human evolutionary history," said first author on the study Shelby Putt from Indiana University in the US.
"But these results suggest the transition from apelike to humanlike ways of thinking and behaving arose surprisingly early," Putt said.
The study's conclusions are based upon brain activity in modern individuals taught to create two types of ancient tools: simple Oldowan-era "flake tools" -- little more than broken rocks with a jagged edge -- and more complicated Acheulian-era hand axes, which resemble a large arrowhead.
Both are formed by smashing rocks together using a process known as "flintknapping."
Oldowan tools, which first appeared about 2.6 million years ago, are among the earliest used by humanity's ancestors. Acheulian-era tool use dates from 1.8 million to 100,000 years ago.
In the study, 15 volunteers were taught to craft both types of tools through verbal instruction via videotape.
An additional 16 volunteers were shown the same videos without sound to learn toolmaking through nonverbal observation.
Brain scans revealed that visual attention and motor control were required to create the simpler Oldowan tools.
A much larger portion of the brain was engaged in the creation of the more complex Acheulian tools, including regions of the brain associated with the integration of visual, auditory and sensorimotor information, the guidance of visual working memory, and higher-order action planning.
"The fact that these more advanced forms of cognition were required to create Acheulean hand axes -- but not simpler Oldowan tools -- means the date for this more humanlike type of cognition can be pushed back to at least 1.8 million years ago, the earliest these tools are found in the archaeological record," Putt said.
"Strikingly, these parts of the brain are the same areas engaged in modern activities like playing the piano," she said.