In Mathematics it is often said that the order of the factors does not alter the product. However, in psychology, the slightest change can have unimaginable repercussions, giving rise to phenomena such as the primacy effect, which affects the way we perceive and process information and, therefore, influences our decisions and behaviors.
Primacy Effect: definition and practical examples
The primacy effect, also known as the primacy principle or primacy law, is a cognitive bias that refers to our tendency to better remember or learn facts, impressions, or items that occur first or later in a sequence. Thus, the same occurs in formal learning situations as in everyday social contexts.
When we must memorize a phone number, for example, it is easier to remember the first few numbers. If we are in a supermarket, the first products we see will generate a greater impact. The first few words of a web page are also often the most memorable, as is the first ad in an ad block. In fact, the primacy effect is even at the base of the first impression we form of a person.
This phenomenon is due to the fact that the elements that appear first in a list are stored in long-term memory more easily than those that appear later. The brain must work less hard to remember the first elements than the later ones, so that these are fixed in memory more easily.
It is also known that when we read a series of statements, the amount of time we spend on each item decreases with each new piece of information. Therefore, we pay more attention to the first elements than to those that appear later, which also contributes to their memorization.
The origin of the principle of primacy in the Asch experiment
In 1946, psychologist Solomon Asch conducted an experiment in which he explored the primacy effect on people and the impressions they formed on others. In that study, Asch first presented participants with an initial list of character traits, but generated two different types of lists, one beginning with positive traits and one beginning with negative ones.
The first “positive” list referred to an intelligent, hard-working, impulsive, stubborn, and envious person, and the second “negative” list contained those same characteristics, but in reverse.
Asch asked the participants to write down their impressions of the person describing the list. He found that participants who read the list with positive traits first formed more favorable impressions than those who read the list with negative traits first.
The difference in the order of the list led to a completely different description of the person. After reading the first list, the participants described the person as someone “who had certain shortcomings but these did not overshadow his merits”. Instead, impressions from the second list resulted in characterizations that described the person as “troubled as his severe difficulties hamper his abilities.”
The consequences of the primacy effect in our decisions
The primacy effect influences the perception of information and its recall, in such a way that it ends up affecting decision-making, since the way in which we receive information is a critical factor in this process. Research conducted at Harvard University, for example, confirmed that we tend to prefer things that are shown to us first.
In one of the experiments, the researchers asked a group of volunteers to evaluate the photos of alleged sellers. Each photo was presented in pairs, one first and one later. Then those people had to quickly choose, without thinking too much, which vendor they preferred. In this way their subconscious preferences could come to light. The researchers found that there was a predilection for the images that were shown first.
This experiment was repeated but using different brands of chewing gum. Once again, the researchers presented first one chewing gum and then the other. They then asked the participants to choose one. In this case, both the first and second marks had identical odds, so there was no clear winner.
However, everything changed when people were asked to choose a chewing gum without thinking too much. In this case, only 38% chose the gum presented to them second. That means we have an unconscious predilection for what we see first.
The primacy effect even holds when things have different characteristics, as another study conducted at the University of Klagenfurt found. In this case, the investigators asked the participants to choose a camping tent from a large number of options. The images were shown as a slideshow, one after another. Obviously, the psychologists made sure that each model changed position.
Surprisingly, although the tents differed in size, colour, configuration and extra accessories, the participants showed a preference for the first tent presented, a decision that could not be explained on logical grounds. In other words, regardless of the model and its features, most people preferred the first product they had seen.
However, the primacy effect is not limited to the items we buy but extends to many other decisions we make in our day to day lives. In 1998 psychologists Miller and Krosnick discovered that when we lack enough information to vote, our choices are influenced by the order in which the candidates’ names appear on the ballot.
According to that study, in the 1992 Ohio election results, the first-place candidates advanced at an average rate of 2.5%. In practice, the candidates who appeared first on the list obtained more votes than when they appeared in any other position. Thus, if the same candidate appeared at the top of the ballot in all electoral districts, he could tip the election in his favor.
How to avoid the primacy effect in everyday life?
The primacy effect is common and infiltrates our cognitive processes when we try to make decisions. It is a kind of mental shortcut for us to choose the first thing we see or hear, although it is not always the best solution. However, the simple fact of being aware of its existence helps us avoid this bias.
It is also important that before deciding, we stop to collect as much information as possible, paying more attention to the central elements that may go unnoticed. Being aware of the primacy effect when we go shopping or choose something can help us not to make hasty decisions based on our first impressions of products, rationally weighing their pros and cons.
Likewise, when we read something, we should take a few minutes to reflect on what we have learned and, if we have overlooked any detail, review the central information. Doing this we can avoid the bias generated by the primacy effect.
Carney, D. R. & Banaji, M. R. (2012) First Is Best. PLoS ONE; 7(6).
Felfemig, A. et. Al. (2007) Persuasive Recommendation: Serial Position Effects in Knowledge-Based Recommender Systems. Persuasive Technology. Lecture Notes in Computer Science; 4744: 283-294.
Miller, J. M., & Krosnick, J. A. (1998) The Impact of Candidate Name Order on Election Outcomes. Public Opinion Quarterly; 62(3): 291.
Asch, S. E. (1946) Forming impressions of personality. The Journal of Abnormal and Social Psychology; 41(3): 258-290.