Availability bias can be defines as: ”The more easily people can call some scenario to mind, the more available it is to them, the more probable they find it to be. Any fact or incident that is especially vivid, or recent, or common, or anything that happened to preoccupy the person, was likely to be recalled with special ease, and so be disproportionately weighed in any judgment.” This is what psychologists call availability bias.
Any available impulse can matter
Many impulses have an effect on you every day. Your senses receive inputs all the time. You are not reacting to all of them. It is just more probable that you react, when things are more available. You can get impulses from the media, friends, colleagues and even from your neighborhood, etc. Your brains are saving energy all the time. Using what is available takes less energy than putting missing pieces together. Sometimes you overestimate what is important, because some impulses are more available than others. These impulses can have an effect later on. You can retreive them from your memory. The more memorable some event has been, the more probable is it´s effect on you.
Events that have occurred to you are more easily available than events you have read from the paper or seen in TV. For example, if you have seen a traffic accident, you will retrieve it from your memory more easily compared to an accident you have read from the paper. Frequency of the event matters too. For example, when you are working in a company, some of your colleagues give you available clues of how to behave. The ways your closest colleagues behave, give the most available clues for your behavior.
Focusing too much on the present and recent events, instead of thinking about the future
It is easier to focus on the events that have happened recently or happening right now. For example, when the airplanes crashed into twin towers in 2001, people started to travel more by car. They overestimated a probability of terrorist attacks done with airplanes. This lead to more deaths in traffic after the 9/11, because going by car is more dangerous. Present events are available more easily than recent events.
You can also think that something has more value now than in the future. For example, most people would rather get 100$s today than wait six months to get 150$s. When you are making a decision, you are mostly thinking about the first order effects. They are more available in your mind than the second or third order effects. For example, buying something can feel like a no-brainer, because you only think about the price you pay now. Using a credit card can make you forget about the interests you have to pay later.
You have a tendency to anchor yourself too heavily on the first piece of offered information, when you are making decisions. Different starting points yield different estimates. These estimates are biased toward the initial values. For example, you are represented two different sentences before asking a question. First sentence says ”There are approximately two hundred members in United Nations.” Second sentence says ”There are two countries in north America.” Then you get a question: ”How many countries are in Africa?” Unless you know the right answer, the first sentence anchors your guess to a bigger number than the second sentence. In my own experience, anchoring can have an effect in almost anything. For example, after you buy some item first time, the properties of the first item are the anchors for buying same items in the future. This my own view and I don´t really know if it applies in reality or it is a result of my imagination. You should think about this yourself.
Using/avoiding availability bias
First and foremost available impulses work most often as triggers for some other psychological tendencies, or behavior. They are not so significant by themselves. You should design your environment in a way that available triggers are good for you. You should also avoid an environment in which available triggers are bad for you. Latter option is not always available, because you cannot control everything. For example, if you are on a diet and you have no forbidden foods at home, you cannot control what other people eat with you. Designing your environment in a way that bad triggers are not available is not always worth the effort. If the opportunity cost is bigger than the benefit, you should forget it. You should probably focus on getting the biggest benefits and avoiding biggest damages.