Why do we better remember items at the beginning or end of a list?
The Serial Position Effect, explained.
What is the Serial Position Effect?
The serial position effect describes how our memory is affected by the position of information in a sequence. It suggests that we best remember the first and last items in a series and find it hard to remember the middle items.
Where this bias occurs
The serial position effect impacts memory recall most obviously for lists. Imagine that your partner calls you to ask you to pick up some food at the grocery store on the way home. They ask you to get bananas, apples, bread, chicken, white rice, broccoli and crackers.
When you get to the grocery store, you can’t remember everything on your partner’s list. You only remember that they wanted you to get bananas, apples, broccoli and crackers.
Your memory has been impacted by the serial position effect, which suggests that the position of an item in a list impacts how well it will be remembered. You remember the first and last couple items on your partner’s list, but not the items in the middle.
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Not being able to remember all of the items on our grocery list may not be the end of the world, because we can easily write down what food we need to buy so that we can reference it again, instead of relying on our memory.
However, what happens when we need to remember information that we only briefly encounter? For example, imagine you are in a lecture, and your professor is explaining some important definitions. You want to write down the definitions, but he is speaking quite quickly. As you go to write down the last sentence he spoke, you realize you only remember the first few words and the last few words, but not the whole sentence.
The serial position effect means that your memory is hindered for information that is presented in the middle of a series. We need to be aware of how our memory works in order to organize information in a manner that is most optimal for recall. Without knowledge of how we best remember information, we may use tactics such as repeating a list in the same order again and again, believing that repetition is enough for information to be committed to memory.
Although individually, we can use tactics that try to counter the ways in which the serial position effect causes us to forget items in the middle of a series, we are often not able to control how information is presented to us. It is usually up to people in leadership positions to decide how to present important information. This begins all the way in childhood, when teachers plan their classes.
Teachers often have to try and squeeze large amounts of information in just a few classes and hope that their students are absorbing the information. This makes awareness of the serial position effect vital for effective teaching. Teachers need to plan learning sessions that take advantage of the primacy effect and the recency effect, because cognitive memory biases are hard to overcome even if students are aware of them. Important information should be presented at the beginning and end of a class, presentation or lesson, in order to give people the best chance at remembering the most important aspects.
Why it happens
The serial position effect is caused by two other memory recall biases called the primacy effect and the recency effect.
The primacy effect describes our tendency to better remember information at the beginning of a series. Items at the beginning of a series are stored in our long-term memory more easily because it takes less processing power for our brains to remember single items. As a series continues, our brains have to process groups of items, making the subsequent items harder to remember.1
The recency effect describes our tendency to better remember information that was most recently told to us. It means that it is easier to remember the items at the end of a series. It is believed that the recency effect occurs because those items are stored in our short-term memory, which is only able to hold a small amount of information at a time. It stores the information that was most recently told to us allowing us to quickly access it during recall.2
When combined, the primacy effect and the recency effect mean that our memory recall is better for both the items at the beginning and end of a series, but is poor for the items in the middle of a series. Items in the middle of a series are harder to remember because they are no longer in our short-term memory, but they haven’t been processed for long enough to be stored in our long-term memory.
The serial position effect therefore provides evidence for the multi-store model of memory which suggests that information passes from a sensory register, to our short-term memory, to our long-term memory.3
Why it is important
On a daily basis, we have to remember information that may be presented to us in series. Such instances can include remembering a grocery list, memorizing a phone number, or following instructions. Since we want to be able to remember important information, we need to be aware of how our memory works in order to improve recall.
Moreover, the serial position effect impacts more than day-to-day memory recall. It could also impact how we reflect on the past. When reflecting on a past event or experience, we may only remember the beginning and end of the event but be unsure about the details in the middle. This becomes an issue in situations like witness testimonies, where because we don’t have a complete picture of the sequence of events, we might be left to speculate how we got from the beginning of the incident to the end of the incident.
Since the serial position effect has both small and large implications on our lives, it is essential that we understand how it affects our memories in order to devise strategies to help counter the fact that it makes it harder to remember information in the middle of a series.
Awareness of the serial position effect can also help us organize information that we are presenting to people. Since we know that they are more likely to remember the information presented at the beginning and end, we can ensure that we organize the most important information in those positions and include less relevant details in the middle.
How to avoid it
The serial position effect negatively impacts our ability to remember information in the middle of a series. While writing down lists or series of information means that we don’t have to rely on memory for information recall, that is not always practical.
As mentioned, awareness of the serial position effect can also help us decide how to organize information. That can be information that we are presenting to others, to help them remember it, or it can be information that we are studying, to make us more likely to remember it when needed. One way to use the serial position effect is to put the most important information at the beginning and end of a series of information. Another technique could be to mix up the serial position of items in a series.
For example, imagine that you are trying to remember five facts about a particular phenomenon for an exam. Instead of studying the five facts in the same order repeatedly, you might want to write down the facts in a different order the second time you go through them. That means that different items will be at the beginning, middle and end of the series, which gives you a better chance of remembering more items since more of them will have held a place at the beginning and end.
How it all started
The serial position effect was first coined by German psychologist Hermann Ebbinghaus in 1964, after he conducted a series of memory experiments on himself.4 Hermann Ebbinghaus was a pioneer for memory experiments, and is also responsible for discovering the spacing effect.5
In his book Memory: A Contribution to Experimental Psychology, Ebbinghaus outlines a series of free-recall experiments that he conducted on himself to examine whether the position of an item in a list affects how well it is remembered.5 He listened to recordings that he had previously taped of himself saying lists of random syllables like “DAX” and then tried to remember as many of those “words” as possible. Ebbinghaus found that he could more easily remember the words that were at the beginning and end of the list compared to the words in the middle of the list.
Ebbinghaus realized that the position of an item in a list did impact how well it was remembered and named this cognitive function the serial position effect. He was the first to suggest that the serial position effect occurs because of a combination of the primacy effect and the recency effect.5
Example 1 - Bilingualism
Most of the studies that provide evidence of the serial position effect are conducted on monolingual speakers. Jeewon Yoo and Margarita Kaushanskaya, PhD students with an interest in bilingualism and memory, wanted to examine whether bilingual individuals, were still impacted by the serial position effect in each language to the same degree.6 They were interested in bilingual individuals because they wanted to see if extensive linguistic knowledge countered the serial position effect.
Yoo and Kaushanskaya tested the serial position effect on 20 participants who were fluent in both Korean and English, with Korean being their native or primary language. Participants were presented with lists of 10, 15 and 20 items in both Korean and English and then were asked to recall as many words as possible, in no particular order.
Yoo and Kaushanskaya found that bilingual individuals are similarly impacted by the serial position effect in both their primary (Korean) and their secondary (English) language. However, participants were better able to remember words at the beginning and middle of the list in their native language than in their secondary language. This suggests that the primacy effect is stronger when there is greater linguistic knowledge. However, the recency effect was not stronger in either of the two languages.6
From these findings, Yoo and Kaushanskaya concluded that linguistic knowledge is not enough to overcome the serial position effect, however, that greater mastery over a language can help individuals remember more items at the beginning and middle of a list, suggesting it can expand the primacy effect. The serial position effect is reduced slightly because more items at the beginning of a list are remembered.
Example 2 - Designing user interfaces
The serial position effect describes the difficulty of remembering all of the pieces of information in a long list, because we find it harder to remember the middle items in a series. Since user interfaces are supposed to be designed in a way that is easiest for users to access and retain information, we should consider the serial position effect when designing applications and websites.
The Interaction Design Foundation (IDF) has suggested different ways that the serial effect position should be considered in user interface design. The first suggestion is to only include task-relevant information on applications, in order not to overload users with too much information that they find difficult to remember. Tools should be included that guide users, so only small bits of information need to be remembered at a time. Moreover, important information should be the first or last thing users are presented with on an interface.7
Another suggestion the IDF put forward is to limit the amount of information that users may need to recall, because the recency effect demonstrates that we can only retain a small amount of information in our short-term memory, and we often browse websites too quickly to commit information to our long-term memory. For example, when designing a clothing website, designers can allow users to create filters so that they are only presented with a small number of clothing items instead of the entire stock that the store has to offer. This will make users more likely to remember the items and allow them to more seamlessly decide what to purchase.7
What it is
The serial position effect describes our tendency to remember information that is at the beginning or end of a series, but find it harder to recall information in the middle of the series.
Why it happens
The serial position effect occurs because of a combination of the primacy effect and the recency effect. The primary effect makes it easier to remember items at the beginning of a list because it is easy to process and it gets stored in our long-term memory. The recency effect makes it easier to remember items at the end of a list because they get stored in a short-term memory.
Example 1 – Linguistic knowledge and the serial position effect
Bilingual speakers show the serial position effect in both their primary and their secondary language, suggesting that better linguistic knowledge does not help completely overcome the serial position effect. However, bilingual speakers show an expanded primacy effect in recall for their native language as they can remember more items at the beginning and middle of a list than in their secondary language. Linguistic knowledge helps expand the primacy effect, which in turn reduces the serial position effect.
Example 2 – User interfaces
When we browse the internet or applications, we often encounter a lot of information that we are supposed to remember. That can include video games and online shopping. By being aware of the serial position effect, user interface designers should organize information on their interface in a manner that makes it easiest for users to remember it. That includes limiting the amount of information users are presented with through guides and filters, and putting the most information at the beginning and end of the experience.
How to avoid it
It is difficult to avoid the serial position effect, because we would have to change how our memory works. Instead, we should try to be aware of the serial position effect in order to optimize how we ingest information. That can include position important information at the beginning and end of a list, or switching up the order of items in a list so that each item has a better chance of being remembered due to the primacy effect and the recency effect.
In this article, our writer Zoe Adams, who studies linguistics in relation to public health, examines the ways in which health and well-being technology is only useful if we learn how to best navigate and refine the large amounts of data. The quantified-self refers to self-knowledge, and Adams explores how we can make that self-knowledge positively impact behavior. Adams reminds readers of the serial position effect in designing applications for health and well-being, as such memory biases need to be taken into account for the most positive outcomes.