Case Studies of Monitor Users

An interesting case study, illustrating some of the points mentioned above, is P, a fairly typical successful Monitor user studied by Krashen and Pon (1975). P was a native speaker of Chinese in her 40s, who had begun to learn English sometime in her 20s when she came to the United States. About 5 years before she was studied by Krashen and Pon, she had enrolled in college, and had graduated with an "A" average.

Krashen and Pon studied P's casual, everyday language production. Observers, native speakers of English (usually P's son), simply recorded her errors from utterances she produced in normal family living or in friendly conversational situations. Immediately after an utterance containing an error was recorded, it was presented to the subject. The data were gathered over a 3-week period and about 80 errors were tabulated.

Upon considering P's self-correction behaviour, the investigators came to what was then an unexpected conclusion:

We were quite surprised to note... that our subject was able to correct nearly every error in the corpus (about 95%) when the errors were presented to her after their commission. In addition, in nearly every case she was able to describe the grammatical principle involved and violated. Another interesting finding was that for the most part the rules involved were simple, "first level" rules (e.g. omission of the third person singular ending, incorrect irregular past tense form, failure to make the verb agree with the subject in number (is/are), use of "much" with countable nouns, etc.) (p.126).

The fact that the vast majority of P's errors were self-correctable suggested that "she had a conscious knowledge of the rules" but did not choose to apply this knowledge. Further evidence that this is the case "is our observation that the subject is able to write a virtually error-free English.... In writing, and in careful speech, she utilizes her conscious linguistic knowledge of English, while in casual speech she

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