Over the last 20 years, a big trend in psychology has been a focus on how the world helps you learn. A hundred years ago the behaviorists (like B. F. Skinner) assumed that everything was learned, from your knowledge of skills like riding a bicycle to your knowledge about how to use language. By the 1950s, though, psychologists assumed that many things like language were so complex that they probably could not be learned completely from scratch. Instead, linguists like Noam Chomsky suggested that a lot of the mechanisms for using language are built into the brain from birth.
More recently, the pendulum of research has begun to swing back toward learning. The idea is that the brain is able to pick up on information about how frequently you encounter things to learn. Jenny Saffran, Richard Aslin and their colleagues have demonstrated that babies learn a lot about the sounds of language that make up words by keeping track of the patterns of sounds that occur in sequence. Tom Landauer and Susan Dumais found that you can learn a lot about what words have similar meanings by using the patterns of words that occur together in the same conversations. Over time, you are much more likely to hear about doctors and nurses being talked about in the same conversation than to hear about doctors and lettuce.
One place where this kind of learning has an influence on your daily life is in affecting what you like. People are wired to be uncomfortable with objects that are completely new. Anything unfamiliar might not be safe, and so we are cautious on our first encounter.
Quickly, though, we become much more comfortable with things that are not dangerous. In the 1960s, psychologist Robert Zajonc observed that after seeing something just once, people like it much better than they did when they had never seen it before. He called this the mere exposure effect. You have probably noticed this with music. The first time you hear a new song on the radio, you may or may not like it, but you enjoy it better the second time. If the song plays often on the radio, you come to like it. By the time you see that band in concert, the songs that get the biggest cheers are the ones that have been on the radio. It isn't that only the songs on the radio are good ones. It is just that people like the songs they have heard before more than the ones that they have never heard.
So far, so good. You use a lot of information about how often things happen in the world to make judgments about what you like. And the things you like tend to be the things you buy.
Remember, though, that the brain evolved in an environment in which nature decided what you were going to see often. Thousands of years ago, the people, animals, plants and foods that you saw most often were the ones that were a part of your ecosystem. The number of times that you came into contact with things reflected how often you were likely to see them.
The statistics of the modern world are quite strange. Certainly, there are lots of things in your local neighborhood that become familiar because you see them all the time. You recognize the neighbor's car, a friend's dog, or a building you pass on your way to work.
But, you have also lost control of your information environment. In exchange for watching shows on television, listening to new music on the radio, and reading riveting blogs, you allow people to pay for the right to expose you to ads. The most significant effect of advertising is to change what is familiar to you. Products and services that you might never encounter in your neighborhood become familiar because they are being presented to you in ads.
Now, you might think that you're a savvy consumer. You know the ads are out there, so you try not to pay too much attention to them. You'd prefer to make your own choices.
And there's the rub.
These learning mechanisms that use information about how often you see things work particularly effectively when you are not really paying attention. Seeing a product in an ad gives your knowledge about that product a little boost of familiarity. If you're not really paying attention to the ad, though, then you don't necessarily realize why that product feels so familiar. When you see it later at the store, or a snack bar at the movies, that familiarity gets translated into liking that product and wanting it.
And there is a lot of research suggesting that ads are very effective at influencing what you want precisely because they make products feel more familiar. A clever study by Melanie Dempsey and Andrew Mitchell in the Journal of Consumer Research in 2010 found that people who saw an ad for a new product would choose that product later, even if the features of that product were a little worse than the features of another product that was unfamiliar.
So, what can you do?
First, when you are making important choices, you should slow down. The effects of familiarity on what you like are strongest when you act quickly. Familiarity still has an influence when you think for a long time, but at least you are giving yourself some time to consider other factors that might go into making a choice.
Second, be more deliberate about who you allow to feed information to you. For example, many websites, computer programs, and smart phone apps have both paid and ad-supported versions. Ask yourself whether it is worth a small amount of money to seize control of your own information environment. The more that you cede control of that environment to others, the more that you are allowing the things you like to be sold to the highest bidder.