The Neuroscience of First Impressions

First impressions are made within 7 seconds, and they can change the course of history. It was 1960, September 26, John F. Kennedy and Richard Nixon were debating for the position of president. This debate was both heard on the radio and watched on TV. An interesting contrast between the radio listeners and the TV viewers arose though; those who listened to the debate on the radio considered Nixon’s performance to be better, while those who watched on television thought JFK’s performance was better. JFK appeared to be confident and composed on TV, while Nixon appeared pale and tired. The way in which our brain decides different qualities about people so quickly is actually very interesting and explains a lot about evolution and human psychology. In this blog I am going to speak about the neuroscience of first impressions and give some helpful tips in order to improve the impression that you radiate to others, and who knows, you might even win a presidential election:D.

§ The Psychology of First Impressions

In order to effectively understand first impressions, one has to understand what they judge and get judged upon when meeting someone for the first time. According to research, people form rapid opinions and impressions of other people within seven seconds of meeting them. Some factors that influence a first impression are appearance and grooming, body language, and the aura/energy/vibe that someone gives off. While these may seem abstract and random, there is actually an evolutionary reason for each of these assessments which we will discuss later.

Another interesting concept which is very prevalent in psychology is thin-slicing. Thin-slicing is the ability to make an accurate judgment of a person or situation based on limited information (key phrase here, “limited information”). Thin-slicing leads to increased efficiency when evaluating a person. Because only a few seconds of observation are needed, the necessity for a long, intensive evaluation is not essential. While thin slicing has been shown to be remarkably accurate in predicting future behavior, it is not always perfect. Because you are making your assessment based on a limited amount of information, the possibility of stereotyping or other negative consequences arises.

For example, let’s take a fictional job interview. The interviewer starts the line of questioning and hears a foreign accent. They then might subconsciously assume the interviewee is not a cultural fit or less competent. While this may not be the case, the spot in the company might go to another candidate because of thin-slicing. This illustrates one of the main concerns of thin-slicing: an individual is judged upon generalized beliefs, which could arise from implicit biases, cultural norms, and past experiences, instead of the individual qualifications of the person, reinforcing negative stereotypes.

§ The Neurology Behind It

During social interactions, many areas are involved in a variety of tasks. Arguably the most important is the amygdala. The amygdala is located in the temporal lobe and is responsible for processing emotions, social cognition, and emotional memory. The amygdala is the primary brain region associated with the fight-or-flight response, so when you meet someone for the first time, a rapid, subconscious assessment is made of the person, trying to decide if they are a threat and judging their trustworthiness. In other words, the amygdala reacts before you even realize.

Another region at work during an initial interaction with someone is the fusiform gyrus. The fusiform gyrus is crucial for processing faces, bodies, and words. The last vital region is the dorsomedial prefrontal cortex. Located in the frontal lobe, the dmPFC is also involved in social cognition and understanding social information. All these brain regions, in conjunction, allow the body to analyze people and store those emotional memories, forming an impression of people that is likely to stick.

Along with the brain regions, neurochemistry has an effect on first impressions. Remember the amygdala? When it perceives someone as a threat, or when someone makes you feel uneasy, the amygdala helps secrete cortisol, a stress response. In contrast, hormones such as dopamine and oxytocin exhibit feelings of trust and bonding.

§ Why First Impressions Stick

Now that we understand how a first impression is made, we have to explore why a first impression sticks; why the first encounter with someone holds so much more weight than the subsequent impressions. The brain relies on several cognitive biases to process initial social information, one of those being the primacy effect. The primacy effect is the brain’s tendency to weigh information received first more heavily than information received later.

In social contexts, this causes the first impression to have a disproportionately large influence on your opinion of someone. Once an initial perception of a person is formed, the brain looks to seek out information proving its assessment while disregarding contradictory evidence. This is called confirmation bias.

Another reason this happens is your brain simply being lazy. Your brain likes to be efficient in order to save energy. In trying to save energy, it prefers the first judgment. This can be attributed to neural efficiency, the brain’s tendency to be efficient.

To tie this all together, I think a story will be useful; this is something that happened in my own life and really exhibits first impressions and the power they have because they “stick.” I walk into class, it’s the first day. I don’t have any friends in that class. I walk in, quiet, and take a seat in the back. During the icebreakers I’m quiet, during the first lessons I don’t answer her questions, and overall I’m very shy. Days pass, and I notice something. People don’t approach me, the teacher doesn’t call on me; it’s like the version they saw on the first day has stuck. Even when one of my friends transfers in, and I become full of energy, even when they see me thrive in group projects, I’m still labeled as quiet, reserved, and distant. This is at no fault of the teachers or peers in that class—in fact, it is completely natural.

§ Can We Change First Impressions?

While the first impression may have a large impact on the way you are perceived by others, it’s not set in stone. The brain can make “second impressions.” Second impressions are a chance for the brain to revise its initial judgment. This can happen due to a variety of factors.

One example is when the prefrontal cortex reevaluates the first impression of someone when new behavior contradicts the initial prediction. The brain also stores new experiences alongside the first impression, leading to a more nuanced opinion of the person. Context can also play a role in perception. A different setting (formal versus casual, for example) can allow the brain to reinterpret someone’s traits.

§ Practical Takeaways

• Smile genuinely: Others mirror your emotion subconsciously.
• Use eye contact: Continued (but not intense) eye contact triggers oxytocin release, boosting trust and connection.
• Modulate your voice: A calm, confident tone engages the listener’s auditory cortex and signals emotional stability.
• Use open body language: Open body language can reduce perceived threat, activating the brain’s social reward circuits.
• Show curiosity/enthusiasm: Your energy can spark dopamine in others, making you more memorable.
• Stay relaxed: Your calm presence helps lower others’ stress hormones, making them feel safe around you.

So whether you’re meeting someone new, watching a presidential debate on TV in the 1960s, or giving a pitch in front of your company’s management, be mindful about the first impressions being made about you, and conversely the way in which you judge someone else. Be aware of the potential negative consequences of deciding too fast. Recognize the complexity of the brain and its systems, constantly working to protect you from danger and keep you safe. And lastly, while our brains may decide in seconds, we can always decide again.