Do you surprise yourself, reacting emotionally to a colleague or family member more strongly than seems rational? Do you occasionally observe your own behavior and wonder why you just did what you did, even though you’ve tried many times to avoid that behavior? Or do you not do things that you’d repeatedly sworn to yourself you would do?

If your answer is “yes,” welcome to the human race. At one time or another, we all observe our emotions, thoughts, and behaviors and go, “Huh?”

There are multiple reasons why it occasionally seems that we are passive spectators of our own feelings and behaviors, rather than active drivers of them. One is that a particular behavior may require ultra-fast pre-conscious or unconscious processing. For example, a golf swing or the production of speech, where we lack the time to think about what each muscle should be doing while swinging a club or to consciously form individual words in every sentence.

Another reason we surprise ourselves is that we store away so many experiences in our lifetimes that shape our perceptions and reactions that we can’t remember all of them. But an unconscious part of our brain aggregates and stores the meanings of those experiences, especially those that are emotionally charged. Thus, when a new situation arises, such as meeting a new co-worker, we are apt to feel drawn to or repelled by that person for reasons we can’t pinpoint based on many previous experiences with other people. One such mechanism is implicit learning [1] where we learn without being aware that we’re learning, like knowing that someone has suddenly come up behind us on a busy street by the sound shadow their nearby body casts.

But fast, unconscious responses and those arising from implicit learning aren’t the only sources of emotions and behaviors that catch us by surprise. Whereas highly repetitive tasks and implicit knowledge are acquired after birth, our brains have knowledge acquired millions of years before our birth. And it is precisely because we weren’t present when that ancient learning occurred, that behaviors and emotions emerging from those ancestral experiences can seem to come out of nowhere.

How ancient probabilities shaped modern brains to respond in strange ways

Evolutionary biologists and psychologists assert that perception, emotion, and behavior are heritable traits on the same level as body parts. For instance, our bodies evolved vocal cords that would be useless without parallel evolution of the mental ability to comprehend and produce speech.[2]

And all heritable traits survive or disappear based upon the remorseless math of survival and reproduction: perceptions, emotions and behaviors that, on average, favored survival and reproduction of healthy offspring persisted; those that didn’t vanished. Social bonding, sexual attraction, jealousy, disgust at human waste, and affinity for high-calorie food are just a few examples of emotions and behaviors evolution hard-wired into us because, statistically, they helped our ancestors survive and reproduce.[2]

The problem is, our brains evolved into their current form 50,000 years ago, when our ancestors were hunter-gatherers struggling to survive in ultra-dangerous environments, while most modern people do not face daily life-or-death struggles. This creates a mismatch between hard-wired programs in our brains and modern reality. So we sometimes act like stone-aged hunter-gatherers that have been time-warped into the present… and surprise ourselves when we observe a stone-aged persona controlling our life in ways that make little sense [2].

Here are examples of reactions arising from evolution, not lived experience

• We want to mate with attractive partners, even though we have never observed the correlation between the physical attractiveness of individuals and the health of their offspring; a historic correlation that drove modern mate preference.
• We feel extreme anxiety—as if our lives were at stake—about humiliation and rejection, even though losing status in a group or even being expelled is not a death sentence, as it was in primitive times when survival and reproduction required membership in a clan.
• Negativity bias and loss-aversion bias that make us unconsciously amplify perception of risk, reflecting the brutal math of our ancestors that we never experienced, where misidentifying a lethal threat as safe had a far higher cost than misidentifying an opportunity as a threat.
• We naturally are repelled at the prospect of mating a sibling, even though we have never personally witnessed unhealthy offspring of incest.
• We feel disgust at obnoxious odors, even though we have never consumed bacteria-laced substances (such as waste) that made us sick.
• We experience apprehension upon meeting people who are unlike us (xenophobia) even though we have never experienced the ancient reason for that aversion—infection from unfamiliar pathogens from strangers.

Why being aware that we have unlearned “knowledge” can make us happier

Some of the ancient mental adaptations, such as feelings of disgust to noxious odors just mentioned, still make sense. But due to the mismatch between the stone-aged environment that shaped these adaptations and modern life, many of the mental adaptations have not only outlived their usefulness but have become counterproductive. Being aware of that can make us happier.

Here are three examples, using the analogy of animals in our environment to speak to the ancient, but immensely powerful part of our brain that thinks in terms of lethal predators vs. bothersome pests vs. tasty prey animals.

• Negativity bias, loss aversion, and social fears can incorrectly signal life or death choices that drive unnecessarily intense anxiety. For instance, moderate anxiety at being humiliated is justified because we all crave acceptance, but intense, prolonged, crippling anxiety is not warranted. The humiliation we fear is more like a skunk around the corner than a tiger, but our threat-vigilant brains are hard-wired to imagine tigers, not skunks. Knowing this when extreme anxiety grips us, we can say to ourselves, “It’s a bothersome skunk, not a lethal tiger.”
• Xenophobia and the tribalism it fuels can lead us to be overly political and turf conscious in our jobs, increasing conflicts and stress at work, while damaging communication and productivity. This insight can prevent or dial down the intensity of a turf war if we say to ourselves, “The heads of rival departments are harmless gopher snakes, around which I should tread carefully, not vipers that I must stomp.”
• Over-reliance on physical appearance when choosing a romantic partner, can make us select mates who might be exciting in the short term, but are a very bad fit in the long term due to incompatibility in values, temperament, life goals, emotional intelligence, flexibility and other attributes crucial to lasting relationships. When meeting a potential mate, we can say to ourselves, “This person appears to be a prize show dog but don’t rush because they might end up being a mongrel … or even, a wolf.”

Attaining happiness with a stone-aged brain in a digital world

The voices of a thousand distant ancestors constantly whisper in our heads: our happiness can depend upon knowing when to listen to those voices and when to ignore them.