A Brief History of Intelligence

Introduction: The Five Steps to Human Intelligence

In 1962, the cartoon The Jetsons predicted a future filled with video calls, smartwatches, and 3D printing. While most of these technologies eventually became reality, one remains missing: Rosey, the robotic housekeeper. Rosey was more than a machine that performed chores; she possessed human-like social finesse, empathy, and common sense. Today, even our most advanced artificial intelligence struggles with the simple physical task of loading a dishwasher, yet it can defeat world champions at complex games like chess or pass the bar exam with ease. This gap exists because we do not yet fully understand the nature of the biological intelligence we are trying to recreate.

To understand how to build a versatile mind, Max Solomon Bennett suggests we must look at the biological history of the human brain. The brain is the most complex object in the known universe, containing eighty-six billion neurons and a hundred trillion connections. Studying its current state is incredibly difficult because the sheer density of neural connections and constant chemical changes make reverse-engineering nearly impossible. However, nature provides a map through evolution. By looking at other animal brains and the fossil record, we can trace how intelligence was built one layer at a time over millions of years.

A popular but flawed way to view this history is the Triune Brain theory, which suggests the brain is like a three-layered cake with a primitive reptile brain for survival, a limbic system for emotions, and a neocortex for rational thought. Modern science has discredited this idea because evolution does not simply stack new parts on top of old ones without changing them. Instead, intelligence emerged through a series of integrated physical adaptations. By using artificial intelligence as a test to see which human tasks are easy for computers and which remain hard, we can better identify the specific algorithms that evolution discovered.

The story of human intelligence can be organized into five major evolutionary steps. Each milestone represents a period where our ancestors faced extreme environmental pressures that forced their brains to adapt, granting them new intellectual abilities. These steps are not a ladder of superiority over other animals, as every creature alive today is a success story in its own right. Rather, this framework allows us to see how the human lineage specifically acquired the capacity for things like memory, planning, and social cooperation. By understanding these five steps, we can bridge the gap between the narrow artificial intelligence of today and the versatile intelligence of the future.