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January 2020

The Bowlby Conjecture—how we humans were designed to thrive and why we struggle in modern civilization

John Bowlby developed the concept of the environment of evolutionary adaptedness (EEA). It is the set of environmental factors that constrained and directed the evolution of a particular species. For example one aspect of the the EEA for polar bears is a cold environment of snow and ice. That led to polar bears having thicker fur and fat for insulation, and a white coat for blending in with their surroundings to better stalk their prey.

We humans had our own EEA: the area in South and East Africa during the Pleistocene epoch. The environment wasn’t just the landscape, climate, and biosphere. It also included the social structure of pre-human primates and humans. Our ancestors lived in nomadic hunter/gatherer bands of 30–45 individuals, comprising a multi-generational extended family primarily. They spent the vast majority of their time outside in nature, moving their bodies (walking, running, grasping, squatting… and using their hands for fine motor activities). They ate a diet of both raw and cooked whole foods, primarily fruits, vegetables, nuts, roots, and some meat. They had shared stories and experiences that they told and retold which helped maintain group cohesion.

Genetically modern humans appeared at the latest 50,000 years ago. This was when our DNA—which is the source code to Human OS version 1—had its last major update (which was very likely the ability to speak). The environment that our modern ancestors lived in between 50k–12k years ago was the one for which our DNA has been optimized.

From the agricultural revolution through the industrial revolution into the information revolution today, slowly but surely some of our ancestors started making decisions to live in ways that they felt were more convenient. But that whole time our genes stayed essentially the same. There were some minor variants—skin, hair and eyes to be better suited to different climates, lactose tolerance, and even sickle cell anemia (to protect against malaria). But on the whole the core Human OS was—and is—still running, optimized for a much different environment than we have today.

In modern civilization today (at least for the people who are likely to be reading this), most of us spend a large portion of our days inside, sedentary, staring at screens, eating processed foods, and spending far more time alone more often than any point in history. We now have a society that is orders of magnitude bigger than the 150 or so individual relationships Dunbar determined we were optimized to have. We have created a world in which it is possible to satisfy our Physiological and Safely needs (the bottom two levels of Maslow’s Hierarchy) without needing to truly invest in Love and Belonging. Anyone without that foundation is also left deficient on the two levels above (Esteem and Self-Actualization). This has led to increasing rates of depression, anxiety and suicide, which were already high to begin with.

I’m not saying we need to go back to bands of hunter/gatherers in order to have healthy and fulfilling lives. But we do need to look at the core daily aspects of that lifestyle and make a point of incorporating them into the foundations of our lives. Yes diet, yes exercise, yes being out in nature. But of critical importance are good relationships and social connections. The closer we can live our lives adhering to those aspects of our ancestors, the happier and healthier we will be.


There many diverse data sources that support the consilience of this conjecture:

I would appreciate any other references that either support or refute this conjecture. 🙏🏼


Tangential but also key to this conjecture is the fact that we humans have excellent deception skills. In fact we are so good at it, the only way we can really deceive others is to also deceive ourselves. Why else would we—individually and as a collective—continue to make choices that are not ultimately in our long-term best interest?