The Seven Laws of Interaction: 7 Plus and Subtract 2 Laws

First appreciate a Q-version cartoon about the "7±2 Rule" drawn by Yahoo ued, and get a preliminary understanding of the 7±2 Rule:

About the "7±2 Rule" Q version of the comic strip

The 7±2 rule

1. One-sentence description:

The average person’s short-term memory capacity is about 7 digits plus or minus 2 digits. , that is, between 5 and 9. It can be understood as 7 plus or minus 2 blocks.

2. Understanding:

In order to better understand this rule, let’s play a small game first:

Please read the following line of random numbers:

71863421945284

Then remove your eyes and recall, see how many you still remember.

Now read the following random letters again:

HJMROSFLBTW

Then test your memory using the same method as above.

Let’s see if the conclusion is like this: If your short-term memory is like that of ordinary people, you may recall 5 to 9 units, that is, 7±2. This interesting phenomenon is the magical 7± 2 effect.

3. Background knowledge:

This law was first observed by the Irish philosopher William Hamilton in the mid-19th century. He found that if a handful of bullets were scattered on the floor, it would be difficult for people to observe more than seven bullets at once. In 1887, Jacobs discovered through experiments that the maximum number of disordered numbers that subjects could recall was about seven. Ebbinghaus, who discovered the forgetting curve, also found that people can remember about 7 letters after reading it once. This magical "7" has aroused the research interest of many psychologists. Since the 1950s, psychologists have conducted similar experiments using various materials such as letters, syllables, words, etc., and the results obtained are all about "7" ". In 1956, American psychologist Professor George A. Miller published an important paper "The Magic Number 7 Plus and Subtracted 2: Certain Limits on Our Ability to Process Information", which clearly stated that the capacity of short-term memory is 7±2, which is generally 7 and fluctuates between 5 and 9. This is the magical 7±2 effect.

However, the materials used in the experiment are all disordered and random. If they are familiar words or numbers, can the short-term memory only hold "7"? For example, "c-o-o-p-e-r-a-t-i-o-n", this letter sequence already has 11 letters. If people who have learned English hear this sequence, they will quickly understand that this is a word, which means "cooperation", and can recall it well. This is not a violation of Have you discovered the “7±2” effect of short-term memory? No, this is exactly another peculiar phenomenon of the magical "7±2". Because the information unit "chunk" in short-term memory itself has magical elasticity, a letter is a chunk, and a word composed of multiple letters is also a chunk. Smaller units can even be combined through some methods. It becomes a familiar, larger unit, and familiarity with the knowledge also affects it. For example, the five words "cognitive psychology" are five chunks for people who don't understand psychology; they are two chunks for people who know a little bit about psychology; and for professional psychology students and psychologists, In other words, there is only one chunk of these 5 words. But no matter what chunks people store, short-term memory has a capacity of 7±2 chunks.

4. Design case:

Number display in iPhone address book

The mobile phone number in iPhone address book is divided into "xxx-xxx-xxxx- xxxx" form, using the 7±2 rule for small detail design, reducing the user's memory burden

5. Related design applications

1) Try not to exceed web navigation or tabs 9. In mobile application interaction design, there will be no more than 5 tabs.

Web navigation:

App navigation:

The navigation of an e-commerce website is shown below. Do you think the navigation below is a bit confusing and you don’t know which one to choose? Woolen cloth?

The picture below is the current navigation of Apple’s official website. Does it feel much more refreshing?

Users use navigation to find the content they need. This need is often very urgent. Please do not think that every user will work tirelessly like digging for treasure. If they cannot quickly find what they want to see, , then they will close the browser and run away. Simplifying your navigation to fewer than nine elements will help users understand your site's content at a glance, making it faster and more effective.

2) If there is a lot of navigation or tab content, you can use a hierarchical structure to display each paragraph and its sub-paragraphs, and pay attention to the balance of depth and breadth.

As shown in the example above, navigation is divided into multiple levels. If there is too much navigation content to fit in, we can integrate and classify it to store it hierarchically. This is not difficult to understand, but what is depth and breadth?

In the information architecture of the website, there is an organizational structure called a tree structure: the homepage of the website is regarded as the first level in the link hierarchy, and the pages affiliated with it are regarded as the second level in the link hierarchy. Generally called secondary pages. Through the second-level page, you can continue to get the third-level page, and so on to get a complete tree link structure. Such a complete link structure is called a tree structure.

In the entire tree structure, the number of link levels is called the depth of the web page link. In the tree structure, the total number of pages contained in the bottom page is called the breadth of web links.

It is best to have a proper balanced relationship between the link depth and breadth of a website. A website that is too deep is not conducive to users quickly obtaining information, while a website that is too broad makes it easier for users to navigate through countless parallel hyperlinks. At a loss what to do. In grading schemes that are too deep and too broad, the response time required by users is relatively long. Therefore, when we organize website information, we need to carefully balance the relationship between depth and breadth.

3) Divide large chunks of entire paragraphs of information into small segments, and clearly mark each information segment and sub-segment to clearly confirm their respective contents.

Just like the picture above. No matter how much information there is, it can be structured and simplified into short information chunks that comply with the 7±2 rule. This way, when users view information, they can more easily focus on the information they care about and find it faster. What they are looking for is easier to understand and easier to remember.