Why First Impressions Are Deceiving: Primacy and Recency Effects
Allow me (Rolf Dobelli) to introduce you to two men, Alan and Ben. Without thinking about it too long, decide whom you prefer. Alan is smart, hardworking, impulsive, critical, stubborn, and jealous. Ben, however, is jealous, stubborn, critical, impulsive, hardworking and smart. Who would you prefer to get stuck with in an elevator? Most people choose Alan, even though the descriptions are exactly the same. Your brain pays more attention to the first adjectives in the lists, causing you to identify two different personalities. Alan is smart and hardworking. Ben is jealous and stubborn. The first traits outshine the rest. This is called the primacy effect.
If it were not for the primacy effect, people would refrain from decking out their headquarters with luxuriously appointed entrance halls. Your lawyer would feel happy turning up to meet you in worn-out sneakers rather than beautifully polished designer oxfords.
The primacy effect triggers practical errors, too. Nobel laureate Daniel Kahneman describes how he used to grade examination papers at the beginning of his professorship. He did it as most teachers do—in order: student 1 followed by student 2 and so on. This meant that students who answered the first questions flawlessly endeared themselves to him, thus affecting how he graded the remaining parts of their exams. So, Kahneman switched methods and began to grade the individual questions in batches—all the answers to question one, then the answers to question two, and so forth. Thus, he canceled out the primacy effect.
Unfortunately, this trick is not always replicable. When recruiting a new employee, for example, you run the risk of hiring the person who makes the best first impression. Ideally, you would set up all the candidates in order and let them answer the same question one after the other.
Suppose you sit on the board of a company. A point of discussion is raised—a topic on which you have not yet passed judgment. The first opinion you hear will be crucial to your overall assessment. The same applies to the other participants, a fact that you can exploit: If you have an opinion, don’t hesitate airing it first. This way, you will influence your colleagues more and draw them over to your side. If, however, you are chairing the committee, always ask members’ opinions in random order so that no one has an unfair advantage.
The primacy effect is not always the culprit; the contrasting “recency effect” matters as well. The more recent the information, the better we remember it. This occurs because our short-term memory file drawer, as it were, contains very little extra space. When a new piece of information gets filed, an older piece of information is discarded to make room.
When does the primacy effect supersede the recency effect, or vice versa? If you have to make an immediate decision based on a series of “impressions” (such as characteristics, exam answers, etc.), the primacy effect weighs heavier. But if the series of impressions was formed some time ago, the recency effect dominates. For instance, if you listened to a speech a few weeks ago, you will remember the final point or punch line more clearly than your first impressions.
In conclusion: First and last impressions dominate, meaning the content sandwiched between has only a weak influence. Try to avoid evaluations based on first impressions. They will deceive you, guaranteed, in one way or another. Try to assess all aspects impartially. It’s not easy, but there are ways around it. For example, in interviews, I jot down a score every five minutes and calculate the average afterward. This way, I make sure that the “middle” counts just as much as hello and good-bye.
* Source: The Art of Thinking Clearly by Rolf Dobelli