Psychology explains why first impressions are so powerful - and so difficult to change

First impressions happen in seconds, yet they can shape our opinions for months or even years. Whether we are meeting a new coworker, a neighbor, or someone on a first date, our brains quickly decide whether that person seems trustworthy, friendly, or confident. The surprising part is that these early judgments often remain in place even after we receive new information that contradicts them. This is why someone who made a poor first impression may struggle to change how others see them, while a person who impressed us right away may continue to receive the benefit of the doubt. Psychologists say this tendency is not simply stubbornness. Instead, it is the result of several mental shortcuts that help our brains process information quickly. While these shortcuts save time, they can also lead us to hold on to inaccurate beliefs. Research shows that understanding these biases can help us make fairer and more balanced decisions.

YOUR BRAIN MAKES SNAP JUDGMENTS TO SAVE TIME

The human brain is constantly processing enormous amounts of information. To avoid becoming overwhelmed, it relies on mental shortcuts, known as 'Heuristics', to make quick decisions. One of the first impressions we form is whether someone appears trustworthy or competent. A 2006 research, published in Psychological Science, by psychologists Alexander Todorov and Janine Willis at Princeton University found that people form impressions of a stranger's face in as little as 100 milliseconds. Their study showed that these rapid judgments often remain stable even after longer exposure. Although these first impressions are not always accurate, they become the foundation for how we interpret future behavior.


CONFIRMATION BIAS KEEPS FIRST IMPRESSIONS ALIVE

Once we form an opinion about someone, our brains naturally look for information that supports it while overlooking evidence that challenges it. This psychological pattern is known as 'Confirmation Bias'. The concept was extensively studied by British psychologist Peter Wason, whose experiments showed that people tend to search for evidence confirming what they already believe instead of testing whether their beliefs are wrong. In everyday life, this means if you initially think someone is rude, you are more likely to notice moments that reinforce that idea while ignoring examples of kindness or generosity. This bias explains why changing someone's opinion can take much longer than creating it in the first place.

THE HALO EFFECT SHAPES EVERYTHING THAT FOLLOWS

Another reason first impressions are so powerful is the 'Halo Effect', a cognitive bias first identified by psychologist Edward Thorndike in 1920. Thorndike discovered that when people notice one positive quality - such as attractiveness, confidence, or friendliness - they often assume the person possesses many other positive traits as well. The opposite, also known as 'Horn Effect' or 'Reverse Halo Effect', is also true. One negative characteristic can unfairly influence how we judge someone's intelligence, honesty, or ability. Modern research has repeatedly confirmed the halo effect across workplaces, schools, and social relationships. It affects hiring decisions, classroom evaluations, and even courtroom judgments, showing just how deeply first impressions influence human thinking.

CHANGING YOUR MIND REQUIRES CONSCIOUS EFFORT

Fortunately, psychologists say first impressions are not permanent. Changing them simply requires more effort because the brain prefers consistency over constant revision. Research by Nobel Prize-winning psychologist Daniel Kahneman, author of 'Thinking, Fast and Slow', explains this through two modes of thinking. System 1 operates quickly and automatically, producing instant first impressions. System 2 is slower and more analytical, allowing us to question our initial assumptions and consider new evidence. Studies suggest that spending more time with people, asking questions, and remaining open to new experiences can reduce the influence of first impressions. Instead of relying on quick judgments, consciously evaluating someone's actions over time leads to more accurate and fair assessments.

The next time you meet someone, remember that your first impression is only the beginning of the story - not necessarily the whole truth. Giving people the opportunity to change your mind may not only improve your relationships but also help you make wiser decisions in everyday life.