'Humanlike' Ways of Thinking Evolved 1.8 Million Years Ago, Study Concludes

Scientists agreed that prehistoric humans obtained a small degree of intelligence 3.3 million years ago when the earliest stone tools were made. But their level of smartness was just a few stages ahead of primates and limited only to surviving. However, when did humans graduate from being ape-like to being rational?

Researchers from Indiana University have set forth to study the evolution of human intelligence to find out when cognition and language abilities began to evolve in people. They did this by scanning the brains of modern humans while working on a certain task.

The task involved making stone tools which Archeologists categorize into two. The first is the Oldowan industry consisting of small flakes with sharp cutting edges that were chipped from larger stones. These were made by small-bodied and small-brained human ancestors 2.6 million years ago, according to Science Daily.

The other set is the Acheulian industry. These are more complex tools skillfully made by removing the flakes from stones, leading to a flat hand ax with sharp edges. This toolkit was created in East Africa 1.8 million years ago by humans with larger bodies and brains.

In the experiment, 15 volunteers were divided into two groups: verbal and non-verbal. Both groups were made to watch a training video on making stone tools. The only difference was that the verbal group heard the voiced instructions while the non-verbal group watched the video's muted version.

Each of them was made to craft their stone tools while wearing a brain imaging device. The non-verbal group was able to complete the task without activating the language-related brain circuits. Because of this, the experiment didn't determine when language among humans began to exist.

On the other hand, it was learned that making Acheulian tools required a higher level motor planning and multi-sensory information. It tapped regions of the brain that are activated by modern activities like playing musical instruments. The experiment concluded that modern thinking in humans began 1.8 million years ago at the start of the Acheulian industry.