What Is The Mere Exposure Effect?

Medically reviewed by Julie Dodson, MA
Updated April 24, 2024by BetterHelp Editorial Team

The mere exposure effect, sometimes referred to as the familiarity principle, is an effect that can happen due to repeated exposure to any stimuli. According to the American Psychological Association (APA), the mere exposure effect is "the finding that individuals show an increased preference (or liking) for a stimulus as a consequence of repeated exposure to that stimulus. This effect is likely when no preexisting negative attitude toward the stimulus object exists. It tends to be strongest when the person is unaware of the stimulus presentations." 

To better understand why the mere exposure effect exists, it may be helpful to consider its impact. One example that shows the psychological science behind this phenomenon involves how we interact with music. When you hear a song on the radio for the first time, you may dislike it. However, after you have listened to it many times, you may experience a shift in conscious cognition towards that song and actually enjoy it more. After a while, you might prefer the song or think of it as your favorite. Despite an initial aversion, you became exposed to the music enough to associate it with positive feelings. This can apply to many other forms of stimuli, with the mere exposure effect often reducing negative affect and increasing positive affect towards a specific source of stimulus.

Anxiety can make us question our judgment

Discovery of the mere exposure effect 

Polish-American social psychologist Robert Zajonc initially coined the mere exposure effect, with the first appearance of the term likely appearing in 1968 in the Journal of Personality and Social Psychology. Zajonc experimented with this social psychology concept by showing various representations of foreign words (or in some experiments, nonsense words), faces of strangers, and Chinese characters to participants in a study. Some participants had seen the stimuli once before, while others had seen them many times or had never seen them. 

After the participants were presented with the stimuli, Zajonc asked them to rate the images' levels of pleasantness. Across the board, the participants most enjoyed the familiar images. The studies showed that people tend to experience the mere exposure effect when they are stimulated by images, colors, people, and other stimuli and have a higher favorability toward the item when it has previously enabled them positively. 

Why is the mere exposure effect important?

The mere exposure effect in psychology can be significant based on the context it is seen in. It can be seen in personality and social psychology, and is often used in clinical settings to help people with phobias become more comfortable with stimuli they are irrationally afraid of. It can also help individuals get along with others when they are accustomed to being around them more often. In addition, it can help people become accustomed to new cultures, languages, foods, and other stimuli. 

In some cases, the mere exposure effect can even bring together groups with different goals or levels of tolerance. This is the basic theory behind the contact hypothesis, which states that exposure can lead to a change in opinion or acceptance of an outgroup. While previously published research claimed that this only worked in certain conditions, more recent research showed that contact alone could be effective

It’s worth noting that the mere exposure effect is still being researched, with some scientists disputing whether existing findings accurately describe the effect. A meta-analysis published in Psychological Bulletin found that the models they studied did not adequately account for the findings, and provided a framework they hoped would guide future research. Other findings in the field of experimental psychology claim that not only have decades of research supported these ideas, but more recent experiments have proven the effect’s existence. 

Mere exposure in advertising

One of the most powerful functions of the mere exposure effect is in advertising and consumer research. By bombarding consumers with advertisements in which a company's logo is presented, buyers begin to trust the brand. This trust may occur even if they have learned nothing new or substantive about the brand. Instead, they become accustomed to hearing the name often, which instills the idea that the brand is trustworthy or liked by the general public. While studies show this to be accurate, there is also a belief that too much exposure to advertising leads to ambivalence among customers.

Many researchers (including those conducting financial studies) agree that exposure in advertising is most effective when a product or brand is new. However, once people are mildly familiar with it, increasing exposure may not increase favorability. However, the mere exposure effect is still present, as getting to a level of favorability creates trust in the consumer.

Mere exposure in decision making

According to the mere exposure effect, people make a range of decisions because they are more familiar with one of the choices, despite evidence that an alternative might be better. This exposure can, in some cases, lead to perceptual fluency, which may make certain tasks or decisions easier to complete after being exposed to a stimulus. It also may lead someone to make the “incorrect” decision simply because they are more familiar with one of the options. 

For example, on Wall Street, many traders invest more in domestic companies due to more exposure, even if certain international companies offer far higher numbers. When deciding what movie to watch, many will try to interpret things about the movie through summaries or reviews. They may even find a film that sounds excellent but still choose the one they are not as interested in but have heard the name of more often.

There can be thousands of examples of how people choose the option they feel more comfortable with due to feeling it is the “path of least resistance”, or due to the false sense of understanding that comes from a baseline level of awareness.


Mere exposure in interpersonal attraction and relationships

Because the mere exposure effect means that individuals like what they see most often, they may be more likely to get along with people they see regularly. This effect could explain why many individuals feel most comfortable with people they see at work or school or why being around family can be comforting. In this way familiarity breeds investment, so it's not uncommon for individuals to emotionally “invest” in those they see on a regular basis. 

If you walk by someone every single day, you may begin to feel as if you know them and can trust them. This phenomenon may be due to your frequent exposure to them alone, not because you know anything about them that would substantiate these beliefs. Some might also feel shocked if they hear someone they are familiar with has done something wrong, although they know nothing about the person. The person is still a stranger, but their frequent exposure leads them to create a sense of trust or a temporary bond with that person. 

In familial relationships, people often begin to trust those who are "around" more often than those who aren't, despite their intrinsic character. When people enter potential romantic situations, they may also prefer those they have seen more often, even if there is a prospective partner who is funnier, more physically attractive, and more likable. This effect may also be the case when they have not directly spent time together but pass each other in the halls or are in the same classes at school. 

Subliminal exposure

While the mere exposure effect can be powerful, it may be more powerful when administered subliminally. For example, someone may still favor a specific presented stimulus even if they have not been exposed to it consciously. This subconscious exposure can range from images that flash on a computer screen to product placement found in popular films and TV shows. 

In a 1980 study published in Science Magazine, William Raft Kunst-Wilson and R.B. Zajonc found that "Animal and human subjects readily develop strong preferences for objects that they have been repeatedly exposed to. Experimental evidence is presented that these preferences can develop even when the exposures are so degraded that recognition is precluded."

Research also suggests that due to the link between mere exposure and repetition priming, humans are also impressionable to the effects of this cognitive bias while sleeping.

Anxiety can make us question our judgment

Counseling options 

The mere exposure effect can answer why you might prefer things that you frequently see or experience in your life. However, suppose you feel insecure in your judgment or ability to make decisions because of forces beyond everyday outside influences. In that case, it may be a symptom of a more significant psychological concern. If you suspect you're struggling with a mental health condition or find that a particular stimulus increases your sense of unease, speaking with a therapist can help you develop a plan to address it. In addition, you can take part in therapy online if you're struggling to find a provider that meets your needs. 

Online therapy platforms like BetterHelp have grown in popularity over the past few years, pairing people with vetted, experienced therapists who can treat mental health conditions like anxiety, depression, and post-traumatic stress disorder (PTSD). In addition, studies have backed up the claims that online therapy is cost-effective and as practical as in-person therapy, showing positive results in studies about anxiety and depression, and many other challenges.  

If you are experiencing trauma, support is available. Please see our Get Help Now page for more resources.

You can choose between phone, video, and live chat sessions with your therapist in online therapy. This flexibility may be helpful if you are unsure about seeing someone in person or if such resources are not available where you are. Additionally, you can schedule sessions around your availability. 

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The mere exposure effect explains how humans make unconscious and conscious decisions to prefer the stimuli they are exposed to most often. If you are experiencing this effect or want to try exposure therapy to cope with anxiety or a phobia, you're not alone. Consider reaching out to a therapist to get started.
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