In a run-on sentence, the reader's brain does not get a signal to dump the preceding main clause to Long-Term Memory. It therefore attempts to chunk the words in a new main clause to the words in the preceding clause. Since they do not connect, the process crashes and the reader must focus on the crash site.

      With a fragment, the brain meets a punctuation mark (period, question mark, exclamation mark, or semicolon) that signals a dump to Long-Term Memory. But the main Subject / Verb pattern that the brain has been expecting has not been completed. The reader's brain may therefore be momentarily confused.

     In relation to our model, the comma-splice is particularly interesting. Textbooks often state that comma-splices are acceptable if the main clauses are short. But they do not explain either why, or how short. Our model suggests that if the clauses can be easily and rapidly chunked in a seven-slot STM, the splice will not cause a crash. Otherwise, it will.

     The primary purpose of punctuation is to assist the reader in chunking. Punctuation should not be taught as "right" or "wrong," but as "effective" or "ineffective."

The theory of syntactic chunking has several other implications:

1. Traditional grammar fails because it teaches students how to identify simple constructions, but it never helps students develop their ability to chunk or inter-relate constructions. Rarely are students asked, for example, to analyze randomly selected passages from their own reading or writing.

2. Readability formulas, which are almost all limited syntactically to "words per sentence," may result in more harm than help. Chunking is not simply a matter of the number of words, it is a matter of the constructions used to convey those words. My research, for example, suggests that fourth-grade textbooks meet readability formulas by increasing the number of gerundives. But research shows that gerundives do not develop naturally until around tenth grade! The late development of the gerundive suggests that it involves a different chunking process. Shortening passages by increasing gerundives not only may make it more difficult for a fourth grader to read, but it may also interfere with natural syntactic development.

3. Instruction in syntax will improve a student's ability to read, to write, and to think, but only if that instruction is based on

a. an understanding of chunking,
b. natural syntactic development, and
c. a descriptive syntax such as the KISS Approach, which students can learn relatively easily and then apply on their own to their reading and writing.