Simplifying the Complex: Capacity Limits of Short-term Memory and Its Implications for Consumer Decision-Making

8-minute read

The Challenge of Short-term Memory: Understanding the Basics

The human brain is a fascinating and complex organ, capable of performing a wide range of tasks with incredible efficiency. However, there are certain limitations that can affect our ability to think and process information. One such limitation is the low capacity of short-term memory.

When we engage in everyday activities such as cooking meals or browsing online shopping sites, we are constantly taking in new information and retrieving information from our long-term memory. To process this information and make decisions, our brain uses short-term memory as a temporary buffer. Therefore it is often referred to as working memory, to emphasize its role in the processing of information.

While long-term memory is for the future, short-term memory is used in the present moment. Unfortunately, the capacity of this buffer is quite limited, which can have a significant impact on consumer behavior and decision-making. In this blog post, we will take a closer look at short-term memory and its impact on consumer behavior.

Revisiting the Magical Number: The Current State of Short-term Memory Research

When it comes to the capacity of short-term memory, "small" is a relative term. The classic number associated with the capacity of short-term memory is 7 ± 2, which was proposed by the psychologist George Miller in 1956. This number, known as the "magical number," suggests that the limit of human short-term memory is about seven chunks of information.

However, more recent research has challenged this number and suggested that the capacity of short-term memory may be even more limited. In 2001, psychologist Nelson Cowan published a paper entitled "Magical Number 4," which proposed that the capacity limit of short-term memory is around 4 (±1) chunks of information. This idea is becoming more widely accepted among scientists.

This means that the maximum amount of information that can be processed at one time is around four. This is quite a bit less than the classic number of 7 ± 2 and helps to explain why people have difficulty processing large numbers of options, as seen in the famous jam study by Iyengar and Lepper (2000), where 24 types of jam were presented on one side.

Simplifying for Short-term Memory: The Importance of Grouping and holistic configuration 

While there is ongoing debate in the academic community about the exact capacity of short-term memory, it is generally recommended to keep in mind that the limit is around four chunks of information (preferably no more than three). This number has been found to be useful in practice in a variety of situations.

It is important to note that this number is based on a unit called a "chunk." For example, a still image like the one below would probably be processed as three clusters (chunks) rather than 17 individual triangles.

It is interesting to note that this diagram might look somewhat like that if you dare to consciously try to see it as two groups. If you put the middle triangle in the right-hand group, then that triangle would appear to face toward right. Likewise, if you put it in the group on the left, it would look toward down left.

There are well-known principles/laws of human perception, called Gestalt principles, that describe how humans’ group similar elements, recognize patterns, and simplify complex images when we perceive objects. These principles include ‘proximity’, ‘similarity’, ‘closure’, ‘contiguity’, among others.

Designers use these principles to organize content on websites and other interfaces, as well as packaging and communication materials, so that it is aesthetically pleasing and easy to understand. When using such principles, it is important to try to keep the number of chunks down to 3-4. Grouping should also be considered in other forms of media such as video, where the number of chunks in each element should be limited, such as the number of segments in a composition, characters, functions, etc.

In the case of semantic information such as concepts and slogans, it is also important to control the number of chunks by creating groups using higher-level concepts and common terms. 

Putting it into Practice: Applying Short-term Memory Understanding to Marketing

In this blog post, we have discussed the limited capacity of human short-term memory and the importance of grouping information to make it as simple as possible. 

Short-term (or working) memory is the foundation of our thinking, and the limited capacity of this function makes it difficult for consumers to think deeply and critically. In fact, consumers often prefer to avoid thinking altogether if possible.

Therefore, it is critical to simplify information as much as possible and to avoid overwhelming consumers with too much information. Deliberating with a working memory is a cognitively demanding task and is often avoided by consumers.

Instead, it is recommended to appeal to emotions, allowing information to be processed intuitively and, if possible, leading to automation and habituation. When it is necessary to explain a function or make a logical comparison, try to present the information in a holistic and cohesive way, using no more than four chunks of information with making use of chunking.


Cowan N (2001) The magical number 4 in short-term memory: A reconsideration of mental storage capacity, Behavioral and Brain Sciences, 24: 87 – 114.

Iyengar S, Lepper M (2000) When choice is demotivating: Can one desire too much of a good thing? Journal of Personality and Social Psychology, 79: 995 – 1006.

Miller GA (1956) The magical number seven, plus or minus two: Some limits on our capacity for processing information, Psychological Review, 63: 81 – 97.

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