Heuristics are to make decisions quickly so that we don't have to stop and think about every step or the next course of action. 

By default, we try to use as little mental effort as possible, not because we are lazy, but that is how the brain has evolved. It needs to preserve energy for other activities:

To make sure we have reserves should we need to bolt - if confronted with danger.

To maintain and regulate the proper functioning of the rest of the body. 

We develop heuristics based on our past experiences or the frequency of information we are exposed to. It's not about making the perfect decision; it is merely about making one quickly. For instance, we might decide that the world is more violent today than ever before. Arriving at this conclusion might be based on the amount of violence we see on TV news. 

We create these mental shortcuts because it requires less effort. Tons of information surrounds us, but our brains have a limited capacity, and we can only process a limited amount of information at a time. We are not able to consider and analyze every aspect of every situation. If we did, we would not get very far.

Rules of thumb should be used in familiar situations where there is limited complexity involved. But we should be careful not to use these shortcuts when dealing with many unknown variables.

Heuristics lead to biases.

We need to be aware of this. These rules of thumb can speed up the problem solving and decision-making process, but they can easily lead to errors. Just because something worked in the past does not mean that it will work every time. The context is what we need to check.

Another problem with heuristics is that it can lead to stereotypes and prejudices. We have a natural tendency to categorize people and make poor judgments simply because of someone's race, accent, etc. For example, we might have a negative experience with someone from a particular country at some stage in the past. The brain will naturally be prone to believe that all people with that accent or from that country will behave the same way. We will instinctively use heuristics to respond. This is what we need to be aware of - the context. Heuristics do not work, nor are they always appropriate.

Our intuition is useful but dangerous. It is a practical method, not guaranteed to be optimal, but sufficient for making quick decisions. 

There are many different heuristics types, such as – representative, availability, recognition, base-rate, etc. We will explore these in a future post.