One factor that affects your judgments about these future events is how specifically you think about them. However, the influences of being specific are complicated.

Sometimes, thinking specifically about things will make you think the events are more likely than thinking about them abstractly. This happens when it is easier to think about an example of a specific event than an abstract one. It may be difficult to think about a car breaking down, but a few specific examples might make it easier to remember similar situations that happened to you or a friend in the past.

In this case, someone selling you an extended warranty would do well to remind you about the many things that can go wrong with a car as it gets older. As you hear about worn belts, slipping transmissions, and broken ball joints will make you remember other times this has happened. In this case, specific thinking makes you feel that an event is more likely, and so you are more likely to purchase insurance. This idea is consistent with a number of studies done by Derek Koehler, Amos Tversky, and their colleagues.

At other times, thinking specifically can actually make a set of outcomes harder to think about. This possibility was explored in a paper in the May, 2011 issue of the Journal of Experimental Psychology: General by Joseph Redden and Shane Frederick. They pointed out that sometimes thinking specifically requires keeping track of many different possible outcomes. In this case, it may feel harder to think about the specific cases than about the general one. When that happens, your belief that the specific events will happen may actually go down.

In one study, they had people judge whether they were interested in playing a number of bets on an upcoming Dallas Cowboys football game. Participants also made judgments about many other bets unrelated to the game. In each case, participants had the choice between receiving $15 for certain or receiving $35 if a particular outcome occurred. Some outcomes were fairly general. The participants rated how interested they were in gambling that Dallas would kick a field goal some time during the game. They also rated how interested they were in gambling that the opposing team would kick a field goal some time during the game. In each case, people were reasonably interested in the bet and thought that there was about a 65% chance they would win.

Other outcomes were specific, though together they were equivalent to the general bets. For example, one involved betting that Dallas would kick a field goal in the first half OR the opponent would kick a field goal in the second half. The second involved betting that the opponent would kick a field goal in the first half OR Dallas would kick a field goal in the second half.

If you think that there is about a 65% chance that each team will kick a field goal some time during the game, then across these two other bets, you ought to think that there is about a 65% chance that you will win the more specific bets as well. Yet people were much less interested in playing these specific bets and overall judged that there was only a 53% chance that they would win these bets.

These specific bets are more difficult to think about than the general ones. You have to focus just on the first half for one team and just the second half for the other team. This increase in difficulty makes the bets seem less attractive.

What binds these examples together is the importance of ease of thinking in evaluating the future. If an abstract event does not call much to mind, but a specific event does call past events to mind, then you tend to judge the specific event as more likely than the abstract one. If a specific event has lots of sub-events that are difficult to track, then the specific event is seen as less likely than the general one.

So, the next time you are deciding whether to buy insurance, don't rely on your . Try to get some actual data about how likely it is that a bad event will happen and compare that probability against the price. For these kinds of long-term decisions, your feeling about the choice is not a reliable indicator of the actual chances that a bad outcome will occur.

Follow me on Twitter.