Political scientists argue that people make the decision on whether to vote on the basis of a cost/benefit analysis. They weigh the costs of voting with the benefits that they expect to get. If the benefits outweigh the costs, they vote. In order to think about why some groups of people vote more than others, we need to think about the costs and benefits that various groups get.
Of course, no one has to pay to vote. The costs are, instead, costs in terms of time and effort. This means that there are two groups that will not have very high costs. One of the groups is people who are educated. These people are more likely to already know a great deal about the political system. When election time comes around, they do not have to spend a great deal of time and effort becoming familiar with issues and candidates. If they do have to spend some time, their ability to find and understand information makes it easier for them to learn the things they need to learn. This is in contrast to people with less education who will have to work harder to become informed.
A second group that will have low costs is elderly people. Such people are generally retired. Therefore, it does not matter as much to them if they have to spend time learning about issues or if they have to spend time standing in line to vote. They have less to do and therefore do not feel that spending time on voting is a major cost.
Since no gets paid to vote, the benefits of voting must be psychological or emotional. People will get the feeling that they have done their duty. They will feel that they have acted as good Americans should. They might also feel that they have done what they can for “their” side in the election.
This will typically mean that people who are happier with the American system will vote more. They will feel more as if they should be good Americans and they should do their civic duty. Richer people are more likely to feel this way. Whites are more likely to feel this way than minorities. Those groups typically feel that the system works for them and so they feel inclined to vote.
Thus, we can see why older people, more educated people, richer people, and white people tend to vote more than others.