The 'mere exposure effect' is a psychological phenomenon that occurs when people develop a positive preference for something simply because they have been exposed to it more often. This can happen even when people are not consciously aware of the increased exposure, and it can lead to a preference for things that have been encountered more frequently, even if they may not necessarily be the best or most desirable options.

One reason for the mere exposure effect is that familiarity breeds liking. When we are exposed to something more often, it becomes more familiar to us and we may feel more comfortable with it. This can lead to a preference for things that have been advertised more or that have been around for a longer period of time.

Another factor that can contribute to the mere exposure effect is the psychological principle of fluency. This is the idea that things that are easier to process and understand are typically preferred over things that are more difficult to process. When we are exposed to something more often, it becomes easier for our brains to process and understand, which can lead to a preference for that thing.

The mere exposure effect can have a number of consequences, including influencing consumer behavior and shaping public opinion. It can also lead to a lack of diversity and innovation, as people may be more likely to prefer familiar things over new or unfamiliar options.