The Gap Theory
The missing evolutionary period between early hominins and civilization. Exploring the five-to-eight-million-year journey that shaped modern human nature.
The Missing Chapter in Human Development
Paleontologists tell us that humans and our closest biological relatives belong to the Great Ape line. The line leading to gorillas split off roughly 8 million years ago, while the lines leading to chimpanzees and humans split sometime between 5 and 8 million years ago.
Robert L. Hays calls the poorly understood period between that split and the rise of civilization “The Gap.” It is during this long evolutionary interval that modern human bodies, minds, language, culture, and social organization began to take form.
Core Idea
- The Gap lasted about 5 to 8 million years.
- Fossils reveal only part of what changed.
- Modern human nature developed before civilization.
- Culture became increasingly important to human success.
- The Gap connects biology, behavior, and civilization.
A Journey Through Deep Time
The Gap Theory places modern human nature inside a long evolutionary period that begins with our split from the chimpanzee line and ends with civilization.
Gorilla Line Splits
The Great Ape line divided more than once, with the gorilla lineage becoming independent first.
Human & Chimpanzee Split
The ancestral line divided into the path leading to modern chimpanzees and the path leading to humans.
Modern Humanity Develops
During this poorly known period, humans developed key physical, mental, cultural, and social traits.
Modern Humans Appear
By the time civilization emerged, people depicted in our oldest stories already seem modern to us.
What Changed?
Some evolutionary changes are visible in fossils. Others — perhaps the most important — were changes in mind, language, culture, and social organization.
Bipedalism
Humans developed upright posture and the ability to walk efficiently on two legs.
Opposable Thumb
Physical changes improved tool use, dexterity, and interaction with the environment.
Language
Changes in throat anatomy helped make complex speech and communication possible.
Most Instincts Were Lost
Many instincts were lost, allowing humans to rely more on learning, reasoning, and cultural knowledge.
Programmable Mind Developed
The programmable mind developed, allowing individuals to choose goals and actions.
Modern Human Mind
Humans developed the modern human mind with subconscious and conscious portions.
Understanding the Origin of Modern Human Nature
The Gap Theory matters because it provides a way to connect evolution with the behavior of modern humans. It suggests that many of the traits we consider uniquely human were shaped before civilization began.
If modern human nature developed during The Gap, then civilization did not create human nature — it was built upon it. This makes The Gap essential for understanding culture, cooperation, competition, ethics, family, and society.
The Importance of the Gap
Definition
The Gap is the period between the split and the rise of civilization, which really means the cessation of genetic evolution caused by the growth and spread of humanoid species.
This was the period starting with the split between the lines leading to humans and the line leading to chimpanzees. The period ended when human genetic evolution slowed because the human population grew large and spread over most of the world. This poorly known period was a gap in our knowledge. It was a period of only about 5 to 8 million years (the difference reflects uncertainty in determining the dates of fossils).
Its importance is that during the Gap the characteristics of human nature that separate us from our chimpanzee relatives evolved.
Why a Small Population Mattered
For genetic evolution to have progressed to produce the dramatic differences that developed, the human population had to be small. Evolution could progress faster if the population were divided into small sub-groups that competed with one another, like the hunter-gatherer bands Hays believes were dominant then.
What Are the Important Differences Between Humans and Chimpanzees?
The biggest difference is in the mind. The modern human mind and the modern chimpanzee mind are very different. The chimpanzee mind is dominated by instincts (gene-based automatic behaviors). The human mind has these innovations:
- Humans think in concepts. A word is a concept.
- Humans have lost almost all of their instincts. To replace them they have a programmable mind that can work with beliefs, purpose, goals, priorities, manners, and fashions.
- The human mind has conscious and subconscious portions, and these work together. The conscious mind programs the subconscious one with intentions. The subconscious mind causes behaviors consistent with those intentions, which can be overridden by new intentions issued by the conscious mind.
The chimpanzee mind runs on instinct. The human mind runs on concepts, beliefs, and purposes that can be programmed and reprogrammed.
Also see “Differences Between Humans and Other Species Mostly Ignored by Biologists,” posted to grandpahays.substack.com on May 5, 2023.
Important Questions
Why is it called “The Gap”?
Hays uses the term because this period is poorly known. We have some fossils and stone tools, but many important changes in mind, language, and culture did not fossilize.
Did fossils explain everything?
No. Fossils show physical changes such as upright posture, bipedalism, and anatomy related to speech, but they do not directly show consciousness, culture, language, or complex social behavior.
What happened to genetic evolution?
Hays argues that genetic evolution slowed greatly as humans spread across the Earth and population size increased, while cultural evolution continued to develop through competition.
How does culture fit into the theory?
Culture became a major factor in human success. Groups with better organization, leadership, practices, and values were more likely to survive, grow, and compete successfully.
What is the biggest difference between humans and chimpanzees?
The mind. The chimpanzee mind is dominated by instincts, while the human mind thinks in concepts and has a programmable mind with conscious and subconscious portions.
Continue Exploring Human Nature
The Gap Theory is only one part of Robert Hays’ larger framework. Continue with Natural Life Purpose, Culture, and Western Civilization.
The Gap Theory
Exploring the five-million-year evolutionary journey between our earliest ancestors and the rise of civilization — a period that shaped modern human nature.
The Missing Chapter in Human Development
Paleontologists tell us that humans and our closest biological relatives belong to the Great Ape line. The line leading to gorillas split off roughly 8 million years ago, while the lines leading to chimpanzees and humans split sometime between 5 and 8 million years ago.
Robert L. Hays calls the poorly understood period between that split and the rise of civilization “The Gap.” It is during this long evolutionary interval that modern human bodies, minds, language, culture, and social organization began to take form.
Core Idea
- The Gap lasted at least five million years.
- Fossils reveal only part of what changed.
- Modern human nature developed before civilization.
- Culture became increasingly important to human success.
- The Gap connects biology, behavior, and civilization.
A Journey Through Deep Time
The Gap Theory places modern human nature inside a long evolutionary period that begins with our split from the chimpanzee line and ends with civilization.
Gorilla Line Splits
The Great Ape line divided more than once, with the gorilla lineage becoming independent first.
Human & Chimpanzee Split
The ancestral line divided into the path leading to modern chimpanzees and the path leading to humans.
Modern Humanity Develops
During this poorly known period, humans developed key physical, mental, cultural, and social traits.
Modern Humans Appear
By the time civilization emerged, people depicted in our oldest stories already seem modern to us.
What Changed?
Some evolutionary changes are visible in fossils. Others — perhaps the most important — were changes in mind, language, culture, and social organization.
Bipedalism
Humans developed upright posture and the ability to walk efficiently on two legs.
Opposable Thumb
Physical changes improved tool use, dexterity, and interaction with the environment.
Language
Changes in throat anatomy helped make complex speech and communication possible.
Understanding the Origin of Modern Human Nature
The Gap Theory matters because it provides a way to connect evolution with the behavior of modern humans. It suggests that many of the traits we consider uniquely human were shaped before civilization began.
If modern human nature developed during The Gap, then civilization did not create human nature — it was built upon it. This makes The Gap essential for understanding culture, cooperation, competition, ethics, family, and society.
Important Questions
Why is it called “The Gap”?
Hays uses the term because this period is poorly known. We have some fossils and stone tools, but many important changes in mind, language, and culture did not fossilize.
Did fossils explain everything?
No. Fossils show physical changes such as upright posture, bipedalism, and anatomy related to speech, but they do not directly show consciousness, culture, language, or complex social behavior.
What happened to genetic evolution?
Hays argues that genetic evolution slowed greatly as humans spread across the Earth and population size increased, while cultural evolution continued to develop through competition.
How does culture fit into the theory?
Culture became a major factor in human success. Groups with better organization, leadership, practices, and values were more likely to survive, grow, and compete successfully.
Continue Exploring Human Nature
The Gap Theory is only one part of Robert Hays’ larger framework. Continue with Natural Life Purpose, Culture, and Western Civilization.