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People process and understand information in chunks. The maximum number of chunks of information that people can process at the same time is about 7 (Miller 1956). In other words, people can only hold about 7 pieces of information in their mind at any one time. We chunk information all the time in our daily lives, in all sorts of situations. Yet most of the time we are not even aware we are doing this. In order to process and understand complex information, we tend to segment that information into chunks.
Sentences are chunks of information. Imagine how hard it would be to read a text that was not segmented into sentences. The purpose of using sentences is therefore to break down complex information based on this principle of chunking. So does this mean that sentences should be only 7 words long? Does it mean that we can only read 7 sentences at a time? Not exactly. Read on.
The process of chunking information is best illustrated by looking at telephone numbers. How would you remember this telephone number?
0429138206
Most people would automatically break up the number into two chunks:
0429 138206
or three chunks:
0429 138 206
When most people say, or try to remember, a sequence of numbers (e.g., telephone numbers), they usually break up the sequence into chunks. They do this because the number is then easier to remember.
It does not matter how you chunk this number sequence! Some people may prefer to have three small chunks while others may prefer two larger chunks. What matters is that most people would probably chunk the number sequence in some way. This means that chunks can vary in size.
Chunking works not just for remembering strings of numbers. Readers break sentences into chunks when they read too.