Risks are all around us. How we perceive and respond to them is pretty subjective: Our judgment calls on risk are just as complex and contradictory as human cognition — and the way most of us evaluate risk is far from rational, no matter how objective we claim to be. A mix of nature and nurture shape our perceptions and responses to risk in every area of life—sometimes with potentially dangerous consequences.

So how do we evaluate risk? We each filter data on how risky an action might be through our own belief and value systems — and those values are in turn shaped by the societal and cultural context in which we were raised.

The debate over vaccines is a prescient example: People with a pre-existing mistrust of government or big pharma perceive the risks associated with vaccines as greater — and the risks of contracting the diseases they prevent as lower — than the average person, studies (here and here) show.

Some of us just want to look on the bright side: Risk perception can be riddled with what researchers call optimism bias. Optimism bias isn’t just thinking good things are more likely to happen than bad things — it’s thinking that good things are more likely to happen *to you*, while bad things are more likely to happen to others. During the pandemic, most people surveyed judged themselves to be at a lower risk of getting covid than the average person — a dangerous risk assessment misstep born of optimism bias.

But the opposite is also true: Judgment calls on risk can also skew overly pessimistic, especially when people become hyper aware of dangers. Humans have a tendency to make decisions based on what jumps out to us in our minds, i.e. memorable events, things we see and read about a lot, or things that happened recently. This tendency — known as the availability heuristic — can cause people to over-exaggerate risk of a certain event if they have previous experience of it happening in their immediate surroundings or they’ve been exposed to heavy media coverage of it.

There are dozens of cognitive biases that inform our view of the world and the risks it holds: Exposure therapy has long been used by psychologists to help people confront their fears in small doses. But exposure to danger has also been found to reduce people’s perception of risk — for better or worse — in non-clinical settings. The more we do something, the less it worries us, leading risky behaviors to become normalized. This is also linked to other cognitive shortcuts like confirmation bias, which can see people downgrade their perception of risk based on a few incidents where they took a risk that turned out fine.

How to counter your irrational thinking on risk? Pay attention to the facts — but accept that how much risk you can handle is ultimately a personal call. Yes, you could do a rigorous assessment of all the available data on a given decision, weigh up the costs and benefits, and strategize for all the possible outcomes — and if you’re weighing up a major life or business decision, we recommend that you do. But the reality is that we make countless split-second risk assessments every day. It’s impossible to sort through the emotional, social, and neurochemical soup that informs that “gut feeling” for every single decision – and earth-shattering events are almost impossible to predict anyway. The best you can do is trust your own boundaries when it comes to risk and accept that in this life, there is no such thing as a sure thing.