How Chunking Helps Content Processing

How Chunking Helps Content Processing, NN Group 1

How Chunking Helps Content Processing KATE MEYER, March 20, 2016, https://www.nngroup.com/articles/chunking/

Summary: Chunking is a concept that originates from the field of cognitive psychology. UX

professionals can break their text and multimedia content into smaller chunks to help users

process, understand, and remember it better.

Chunks and Chunking

Definition: In general usage, a ‘chunk’ means a piece or part of something larger. In

the field of cognitive psychology, a chunk is an organizational unit in memory.

Chunks can have varying levels of activation — meaning they can be easier or more difficult

to recall. When information enters memory, it can be recoded so that related concepts are

grouped together into one such chunk. This process is called chunking, and is often used as a

memorization technique. For example, a chunked phone number (+1-919-555-2743) is easier

to remember (and scan) than a long string of unchunked digits (19195552743).

UX-Definition: In the field of user-experience design, ‘chunking’ usually refers to

breaking up content into small, distinct units of information (or ‘chunks’), as opposed

to presenting an undifferentiated mess of atomic information items.

Presenting content in chunks makes scanning easier for users and can improve their ability to

comprehend and remember it. In practice, chunking is about creating meaningful, visually

distinct content units that make sense in the context of the larger whole.


Chunking Text Content Users appreciate chunked text content. It helps avoid walls of text, which can appear

intimidating or time-consuming. Chunking enables easy skimming — users’ preferred method

of reading online.

Some of the most commonly used methods of chunking text content are:

• Short paragraphs, with white space to separate them

• Short text lines of text (around 50–75 characters)

• Clear visual hierarchies with related items grouped together

• Distinct groupings in strings of letters or numbers such as passwords, license keys,

credit-card or account numbers, phone numbers, and dates (for example, 14487324534

vs 1 (448) 732 4534)

Chunked strings should use the most conventional format for each data type to minimize user

slips. For example, credit card numbers are usually presented in 4 chunks of 4 digits each (e.g.,

4111 1111 1111 1111 instead of 4111111111111111). Be aware that the standard format for

some strings will vary by country.

+65-5555-5555 (01) 55 1234 5678 (919)-555-5555

Singapore Mexico United States

Sample chunking formats for telephone numbers in three countries.

Although formatting improves scannability, it does make typing more difficult. Users should

not have to type in formatting characters; instead, forms should use autoformattting — input

fields should automatically chunk your users’ input.


Apartments.com: This contact form for a real-estate website appropriately chunks the agency’s

phone number at the top. The phone-number input is chunked automatically as the user types

a string of digits. (Note, however, that we recommend against displaying the field labels within

the input boxes.)

Simply chunking your text isn’t enough — you also need to support scanning by making it

easy to quickly identify the main points of the chunks. You can do this by including:

• Headings and subheadings that clearly contrast with the rest of the text (bolder, larger,

etc.)

• Highlighted keywords (bold, italic, etc.)

• Bulleted or numbered lists

• A short summary paragraph for longer sections of text, such as articles


ApartmentGuide.com: This wall of text on the homepage of a real-estate search engine has

long lines of text, no highlighting, and no subheadings. One user saw this unchunked wall of

text and said, “There’s a lot of writing down here. I’m not interested in this. It makes it look

messy.” The three words she used to describe this page were: “Busy,” “wordy,” and

“unwelcoming.”


BBC uses short paragraphs, lots of white space, subheadings, and a short summary to chunk

this article. Each topic subheading also has a subtle horizontal rule and a related photograph

to help further delineate between sections. One user took a few seconds to look over the page

and said, “I feel that this is very nicely split up. I’m positive that it’s an easy read. It said what

were the five [topics covered in the article], and then split them up.” She then proceeded to

actually read the entire article — which perhaps says more about the success of their chunking

than her comment.


Chunking Multimedia Content The key to effectively chunking multimedia content (text as well as images, graphics, videos,

buttons, and other elements) is to keep related things close together and aligned (in accordance

with the Law of Proximity in Gestalt psychology). Using background colors, horizontal rules,

and white space can help users visually distinguish between what’s related and what isn’t.

MailChimp’s minimalist design relies on subtle methods of indicating chunks. The paragraphs

and subheadings are clearly related by their proximity. Their shared width creates invisible

alignment (the subheading and paragraph text both sit in a 500px-wide HTML container). At

a glance, it’s harder to distinguish which chunk of text describes the screenshot in the middle.

When looking more carefully you may notice that the image is closer to the top paragraph.


Other types of content (such as videos or graphics) can also be chunked. Just remember that

the main idea of chunking is to divide information into clearly distinct groups of related

content. For example, you can chunk video content into individually accessible chapters or

topics, to allow users to easily navigate inside the video. Or you can group related tools in a

crowded application toolbar to help users remember where to find them.

TED.com: An interactive video transcript chunks a long video into individual, navigable

segments. Users can scan the text and jump to different points in the video. This transcript

misses an opportunity, however—subheadings and highlighted text would help call out the

main ideas of each chunk and better support navigation.

The Mythical Number Seven You’ve probably heard of the ‘magical number seven,’ made famous by cognitive psychologist

George Miller. In 1956, Miller found that most people can remember about 7 chunks of

information in their short-term memory. What Miller found interesting, however, was not the

number 7 itself. Instead, he was fascinated by the fact that the size of the chunks did not seem

to matter — people could remember 7 individual letters, or 28 letters if they were grouped into

7 four-letter words. (In the former case, each unrelated letter counts as a chunk, whereas in the

latter case, each word is a chunk.)

In the field of user experience, Miller’s magical number seven is often misunderstood to mean

that humans can only process seven chunks at any given time. As a consequence, confused

designers will sometimes misuse this finding to justify unnecessary design limitations.


For example, a designer may refuse to add more than seven options in a global navigation bar

for fear of violating the magical number seven. However, the point of menus is reliance on

recognition rather than recall: users don’t need to keep all of the menu items in their short-term

memory, because all the available options are continuously displayed on the screen. So there

are no usability gains to be made by limiting the number of menu items to seven. Menus can

still be easy to use with more than seven choices, as long as the options are structured in a

meaningful way.

The main takeaway from Miller’s research for UX professionals should be this: Human short-

term memory is limited, so if you want your users to retain more, pack information into

meaningful chunks. Don’t ask your users to hold more than a few pieces of information in

their short-term memory at once. And don’t get hung up on the number seven — Miller himself

titled his paper “The Magical Number Seven, Plus or Minus Two: Some Limits on Our

Capacity for Processing Information.” Other researchers have suggested that the right number

could be anywhere from three to six.

Whatever the average capacity of short-term memory may be, the specific capacity for

individual humans will vary (it's one of the many causes for the huge variability in user

performance). You could be one of the “plus-one” or “plus-two” people, especially if you’re a

developer who makes a living from keeping lots of information in memory at once. (No, it's

not that programming computers makes your brain grow until it strains against your skull.

Rather, it's only people born with high-capacity brains who are attracted to a career that requires

them to retain a lot of items in memory.) In contrast, many of your customers could easily be

“minus-one” or “minus-two” people, which means that they will have great difficulty

remembering things that you might find easy. The short-term–memory limits will additionally

be impacted by users’ context: where they are and what else is happening around them while

they use your interface. This point is discussed further in our UX Basic Training course and is

one of the key reasons you can’t judge ease of use purely on the basis on whether you

personally feel a design is easy to use.


hp.com: This e-commerce site uses a subtle background color and negative space to help users

visually distinguish between each chunk (each laptop), but displays 21 options on a single

page. This decision works fine, because users will probably browse or search on this page, and

they won’t need to remember each individual laptop.


Conclusion Chunking is critical for presenting content that users can comprehend and remember easily.

Use chunking for text and multimedia content alike to help users understand underlying

relationships and information hierarchy.

(Learn more about the relationship between cognition and UX design in our full-day course

The Human Mind and Usability.)

Reference George A. Miller, 1956. The Magical Number Seven, Plus or Minus Two: Some Limits on Our

Capacity for Processing Information. Psychological Review 63 (2): 81–97.

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How Chunking Helps Content Processing