Why We Think What We Think summary

Imagine saying the word “twelfths” out loud across a windy field, trying to convey a message to your fellow farmer. You probably don’t have a field to try this, or a farmer at hand, but let me tell you, this task is quite a struggle – especially if you live in more northern latitudes.

The way humans talk is strongly influenced by the conditions where they live. Near the equator, where people spend much of their time outdoors, languages lean on big, booming vowels that carry across distances. Just think of the rolling sounds of Hausa, Arabic, or Italian. Now, head north toward the Arctic, where freezing weather drives conversation indoors, close to the fire. Those big vowels tighten into pinched umlauts and clattering consonants. In other words, climate sculpts the words in our mouths. And it also sculpts something far deeper: our beliefs.

Hot, humid places are paradises for bacteria, viruses, and parasites, where food rots and infections spread rapidly. To survive this, humans evolved two defenses. The first is biological, the immune system. The second is behavioral; it’s the customs and beliefs we adopt to avoid catching things, from not kissing strangers on the mouth to throwing out spoiled food. 

Many of those immune-protective behaviors take the form of attitudes. And those attitudes cluster into something resembling social conservatism. For example, societies in pathogen-rich environments tend to enforce strict rules around hygiene and sex. And they exhibit xenophobic tendencies – they distrust foreigners who might be carrying disease. 

Just compare the patriarchal, hierarchical Azande people who live in hot, humid Central Africa with the egalitarian, sexually relaxed !Kung of the bone-dry, low-pathogen Kalahari. Or the cold, dry Netherlands, which accepts drugs and prostitution, while tropical Singapore canes people for soliciting sex and outlawed homosexuality until 2022.

The same logic extends beyond disease to every kind of environmental threat. Places battered by extreme weather of any kind, such as Yemen, Russia, Turkey, and Somalia, tend to lean conservative and embrace strong, authoritarian leadership. Harsh conditions demand the kind of tight social order and cohesion that loose, egalitarian arrangements can’t provide. 

Surprisingly, our gods, too, seem to follow this map. In temperate places like Greece and Rome, we find spoiled, amoral gods who care little about human behavior. Then there’s the other kind –⁠ the all-seeing, all-judging, vengeful gods obsessed with how their followers behave. These ethical religions, with their commandments and threats of damnation, tend to emerge in harsh, disaster-prone regions, especially places gripped by drought –⁠ the deadliest climatic killer of all. It’s no accident that the parched Middle East gave birth to Judaism, Christianity, and Islam. When catastrophe threatens to shatter a community, strict moral codes that compel cooperation and solidarity become a kind of behavioral immunity against social collapse itself.