Design Psychology

The Serial Position Effect: Why ABC and XYZ stand out the most among all the alphabets.

We best remember the first and last items in a series.

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Experiments show that when participants are presented with a list of words, they tend to remember the first few and last few words, and are more likely to forget those in the middle of the list.

This is known as the serial position effect.

In the image above, you can see some examples from popular iOS applications. Each put the “Home” and “Profile” items all the way to the left and right, with serial position effect in mind.

The tendency to recall earlier words in a list is called the Primacy Effect; and the tendency to recall the later words is called the Recency Effect.

The Primacy Effect

The theory for the primacy effect is that the greater accuracy of recall is due to the relatively small amount of processing effort expended in rehearsing the item by itself.

This is in contrast to proceeding items (in the middle of a sequence) which must be rehearsed with all the other preceding information (in the beginning of a sequence); causing significant cognitive burden and affecting recall.

The Recency Effect

The theory for the recency effect is that recall is better for items appearing towards the end of a sequence due to their preservation in our working memory (the part of our short-term memory that processes conscious and immediate perceptual information.) Our working memory holds temporary information and acts as a buffer for new information while it absorbs into other memory systems.

How can designers use Serial Position Effect?

Knowing that the positioning of an item can affect user experience by causing information in the middle of a sequence to be harder to recall, designers can make conscious choices while placing items in a list, or arrange content in a webpage.

1. Placing the least important items in the middle of lists can be helpful because these items tend to be stored less frequently in long-term and working memory.
2. If the user has to take a decision some time after exposure (> 30 seconds), then placing the most important items first in a list can be of advantage. And, if the user has to take a decision immediately after reading the list, then placing the most important item last on the list can be of advantage. E.g., on a sales pages consider placing the main benefit of your product on top of the list, and your persuasive extras like “free shipping” and “5% cashback”, last. This way if the subject leaves the page they are more likely to remember the main benefit of your product.
3. When the user doesn’t set the pace of the presented items, such as in video and audio, it is usually better to present the most important items last.
4. Designers should also be aware of the primacy and recency effects while conducting surveys, especially while having people choose from a long list, as they often represent a margin of error. The right way to conduct the survey is to shuffle the list positions for each vote so as to nullify the error.

I write Sunday Wisdom where I discuss the principles of life, strategy, and antifragility. Subscribe here.