You're planning a summer trip when you read about a shark attack off the very coast you meant to visit. Suddenly the beach feels like a gamble. Or a plane crash makes the evening news, and a long road trip starts to look like the sensible alternative. These shifts feel like caution. Often they're something else: your memory doing the math instead of the numbers.

Psychologists Amos Tversky and Daniel Kahneman called this the availability heuristic. It means judging how likely something is by how easily examples come to mind. Most of the time it's a useful shortcut. With danger, though, it quietly bends your choices. Here's how to spot it, check it, and respond in proportion.

Your brain doesn't keep a running tally of how often things happen. When you ask yourself how likely something is, it quietly answers an easier question: how easily can I picture it? If an example arrives quickly, the event feels common. If nothing comes to mind, it feels rare.

Most of the time, that swap works. Things that happen often are usually easy to recall. The trouble starts when something is memorable for reasons that have nothing to do with how often it happens. Dramatic events get replayed. Recent events are still fresh. Stories about people you know stick harder than statistics about strangers. A friend's burglary will shape your sense of neighbourhood safety more than years of quiet nights.

This is why plane crashes, shark attacks and violent crime tend to feel more threatening than heart disease, falls at home or ordinary car journeys, even though the quieter risks claim far more lives. Quiet risks don't make headlines, so they don't make memories. A useful habit is to pause when a fear feels urgent and ask: am I reacting to how often this happens, or to how vividly I remember it happening? That one question separates a feeling from an estimate.

Takeaway

Ease of recall is not evidence of frequency. When a risk feels big, first ask whether it's actually common or simply memorable.

Once you notice that memory is doing the estimating, the fix is to hand the job to something more reliable: the base rate. A base rate is simply how often something happens across a large group over a set period. It's the dull number that gets drowned out by the dramatic story.

You don't need a statistics degree to use it. Ask three questions. First, out of how many? One incident sounds alarming until you learn it happened among millions of similar situations. Second, over what period? A cluster of news stories in one week says little about the yearly pattern. Third, compared to what? Worldwide, unprovoked shark attacks typically cause fewer than ten deaths a year, while drowning claims hundreds of thousands. If you're worried about the ocean, the riptide deserves more attention than the fin.

Good sources for these numbers include government health and transport agencies, which publish yearly figures. Treat any single figure as a rough guide rather than gospel, and focus on rates rather than raw counts. The goal isn't precision. It's getting your estimate into the right neighbourhood, so you're not off by a factor of a thousand.

Takeaway

Every vivid story deserves a denominator. Before deciding how worried to be, ask: out of how many, over what period, and compared to what?

Misjudging risk wouldn't matter much if it stayed in your head. The problem is that it drives behaviour, and overreacting to one danger often pushes you towards another. After the September 2001 attacks, many Americans chose to drive rather than fly. Researcher Gerd Gigerenzer estimated that the extra road travel led to roughly 1,500 additional traffic deaths in the following year.

That's the hidden cost of misplaced caution: precautions aren't free. They use time, money and attention, and they can shift you towards risks you're not watching. So when deciding how to respond, weigh three things together: how likely the danger is, how severe it would be, and what the precaution itself costs or introduces.

A simple way to apply this is to rank your worries by actual likelihood and impact, then check where your effort is going. Many people anxiously avoid rare dangers while skipping cheap, effective protection against common ones: wearing a seatbelt on every trip, keeping a smoke alarm working, putting the phone away while driving. Proportional response means spending your caution where it buys the most safety, not where it soothes the loudest fear.

Takeaway

Caution is a budget, not a virtue. Spend it where the real risks are, and remember that avoiding one danger can quietly walk you into another.

The availability heuristic isn't a flaw to eliminate. It's a shortcut that sometimes takes a wrong turn, especially when fear is involved. You can't stop vivid stories from sticking, but you can stop them from making your decisions alone.

Next time a risk feels urgent, try a three-step check: notice whether recall is driving the feeling, find the base rate, and compare the cost of your precaution with the danger it prevents. Practise it on one worry this week.