Heuristic facts for kids

A heuristic is a practical way to solve a problem. Think of it as a smart guess or a "rule of thumb." It helps you find a good answer quickly, even if it's not always the perfect one. People use heuristics all the time, based on their experience and common sense.

One simple heuristic is trial and error. This means trying different things until something works. While it's easy, it's not always the best method. Other names for simple heuristics include "educated guesses." Since a heuristic doesn't guarantee a perfect result, there can always be exceptions.

Sometimes, heuristics are a bit general, like "look before you leap." This means you should think before you act. Other times, a heuristic can be a series of steps. For example, when doctors examine a patient, they follow a set of tests and observations. This process helps them figure out what's wrong, even if they don't always find the exact answer right away. This is called a diagnosis.

In computer science, a 'heuristic' is a type of algorithm. Algorithms are like step-by-step instructions for computers to solve problems. A heuristic algorithm often finds good solutions, but there's no guarantee that the answer is perfectly correct. The speed at which the algorithm runs is also important.

What are Heuristics?

Heuristics help us find a good solution to a problem when we have limited information or not much time. They are based on past experiences and can speed up the search for an answer using simple rules. Sometimes, finding the absolute perfect solution would take too long or be too difficult.

In simpler terms, heuristics are strategies that use information that's easy to get, even if it's not super precise. They help both people and machines solve problems.

Heuristics can be useful in some areas of science but not in others. For example, in economics, an answer that's slightly off might be okay. But if a telescope is off by just one degree, it might be useless for looking at faraway stars. However, if you're using the same telescope to look at a window across the street, being off by one degree might not matter much.

Heuristics can also help us estimate an answer. Then, we can find a more exact solution on a smaller scale. This can save time, money, or effort on a project. For instance, a quick guess about how much weight a bridge needs to hold can help decide if it should be made of wood, stone, or steel. This way, you can buy the right materials while the exact design is still being worked out.

However, using heuristics in very technical fields can sometimes cause problems. For example, in computer programming, telling a computer to do "more or less" what you want can lead to big errors. So, computer tasks usually need to be very exact. But there are some areas where computers can safely use heuristic solutions. For example, Google's search engine uses a lot of heuristics. If it can't find an exact match for your search, it will suggest "near-miss" results. This allows you to decide if a suggested result, like "Pete Smith" instead of "Peter Smith," is what you were looking for.

Examples of Heuristics

Polya's Problem-Solving Tips

Here are some helpful heuristics from George Polya's 1945 book, How to Solve It:

• If you're having trouble understanding a problem, try drawing a picture. This can help you see things more clearly.
• If you can't find a solution, try pretending you already have the answer. Then, work backward to see what steps would lead to that solution.
• If a problem seems too abstract or confusing, try looking at a real-life example. This can make it easier to understand.
• Sometimes, solving a bigger or more general problem first can actually be easier. This is called the "inventor's paradox." A more ambitious plan might have a better chance of success.

The Packing Problem

Example of a packing problem. This is a one-dimensional (constraint) Knapsack problem: which boxes should be chosen to maximize the amount of money and keep the overall weight under 15 kg? A multi dimensional problem could consider the density or dimensions of the boxes, the latter a typical packing problem.
(The solution in this case is to choose all of the boxes besides the green one.)

A good example where heuristics are useful is a "packing problem." Imagine you have many items, and you need to fit them into a limited space, like the trunk of a car or a backpack. There are rules to follow. For instance, each item might have a value and a weight, and you want to pack the most valuable items without going over a certain weight.

To find the absolute perfect solution, you would have to try every single possible way to pack the items. This often takes a very long time, especially if there are many items. So, what most people do is use a heuristic. They might start by putting the biggest item in first, and then try to arrange the other items around it. This usually gives a good solution most of the time.

However, there are some situations where this simple method might not be the best. In those cases, you might need a different technique. Because this method usually works well but isn't always perfect, it's a great example of a heuristic solution.

See also

In Spanish: Heurística para niños