Eli5: what causes and how does it work? Innate natural traits and preferences.


Ask any parent, even from the youngest ages, children show innate preferences especially towards being tidy or shy or determined.

What causes this, but more so, how does it work?

Maybe a gene makes me more likely to be super organized and tidy. Ok. But how is that gene functioning inside me to encourage that behavior?

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We don’t know. The way behavior is driven by physical processes in the body is not very well understood, and what we do understand is usually by observation and experimentation around observations, not derived from any general theories about how behavior works in some grand sense.

There are multiple mechanisms by which genes could affect personality, but here’s one that’s gotten a fair amount of discussion in the psychogenetics literature:

Emotions involve chemical activities in your brain. For example, there’s a part of the brain called the “reticular activating system” that responds to certain blood chemicals by making you feel alert and attentive: when it’s active, you’re excited (but maybe also anxious); when it’s inactive, you’re relaxed (but maybe also bored).

The RAS has receptors for various chemicals, such as dopamine and adrenaline: you feel more relaxed when there’s not much adrenaline in your bloodstream than when there’s lots of adrenaline in your bloodstream.

Instructions for building these receptors, as well as the blueprints to use *while* building them, are found in your genes and can vary from person to person. One person’s genes might instruct their RAS to build a relatively-large number of relatively-sensitive receptors; that person will be highly excitable. Another person’s genes might instruct their RAS to build a relatively-small number of relatively-insensitive receptors; that person will be relatively inexcitable.

A highly-excitable person might find novel situations to be overwhelming and prefer to hang out in calm environments while following personal routines. A relatively-inexcitable person might find familiar situations to be boring, so be more prone to seek out stimulation and adventure.