similarities across acquirers as to which structures tend to be acquired early and which tend to be acquired late (Brown, 1973; Dulay and Burt, 1975). Acquirers need not have a conscious awareness of the "rules" they possess, and may self-correct only on the basis of a "feel" for grammaticality.
Conscious language learning, on the other hand, is thought to be helped a great deal by error correction and the presentation of explicit rules (Krashen and Seliger, 1975). Error correction it is maintained, helps the learner come to the correct mental representation of the linguistic generalization. Whether such feedback has this effect to a significant degree remains an open question (Fanselow, 1977; Long, 1977). No invariant order of learning is claimed, although syllabi implicitly claim that learners proceed from simple to complex, a sequence that may not be identical to the acquisition sequence.
The fundamental claim of Monitor Theory is that conscious learning is available to the performer only as a Monitor. In general, utterances are initiated by the acquired system--our fluency in production is based on what we have "picked up" through active communication. Our "formal" knowledge of the second language, our conscious learning, may be used to alter the output of the acquired system, sometimes before and sometimes after the utterance is produced. We make these changes to improve accuracy, and the use of the Monitor often has this effect. Figure 1 illustrates the interaction of acquisition and learning in adult second language production.
Fig.1. Model for adult second language performance
The acquisition-learning distinction, as I have outlined it, is not new: Lawler and Selinker (1971) propose that for rule internalization one can "postulate two distinct types of cognitive structures: (1) those mechanisms that guide 'automatic' language performance... that is, performance... where speed and spontaneity are crucial and the learner has no time to consciously apply linguistic mechanisms... and (2) those mechanisms that guide puzzle- or problem-solving
performance..." (p.35). Corder (1967), citing an unpublished paper by Lambert, also discusses the acquisition-learning distinction and the possibility that acquisition is available to the adult second language performer.
The Monitor Theory differs somewhat from these points of view, in that it makes some very specific hypotheses about the inter-relation between acquisition and learning in the adult. In the papers that follow, I argue that this hypothesis sheds light on nearly every issue currently under discussion in second language theory and practice.
Conditions of Monitor Use
There are several important constraints on the use of the Monitor. The first condition is that in order to successfully monitor, the performer must have time. In normal conversation, both is speaking and in listening, performers do not generally have time to think about and apply conscious grammatical rules, and, as we shall see later, we see little or no effect on the Monitor in these situations. This condition, however, is necessary but not sufficient. Heidi Dulay and Marina Burt have pointed out to me that a performer may have time but may still not monitor, as he or she may be completely involved with the message. There is, thus, a second condition: the performer must be "focused on form", or correctness. As we shall see later, the second condition predicts some recent data nicely.
An important third condition for successful Monitor use is that the performer needs to know the rule, he or she needs to have a correct mental representation of the rule to apply it correctly. This may be a very formidable requirement. Syntacticians freely admit that they have only analyzed "fragments" of natural languages, applied linguists concede that they have mastered only part of the theoretical literature in grammar, language teachers usually do not have time to fully study the descriptive work of all applied linguists, and even the best language students do not usually master all the rules presented to them.
It is therefore very difficult to apply conscious learning to performance successfully. Situations in which all three conditions are satisfied are rare (the most obvious being a grammar test!).
Note that the model presented here allows us to self-correct using acquired knowledge of language, or our "feel" for grammaticality. That is what native speakers generally do in the case of speech errors. The point is not that we can only monitor using conscious rules. This is not the case. The point is that conscious learning is only available as a Monitor.
In the last few years, the acquisition-learning distinction has been shown to be useful in explaining a variety of phenomena in the field of second language acquisition. While many of these phenomena may have alternative explanations, the claim is that the Monitor Theory provides for all of them in a general, non ad hoc way that satisfies the intuitions as well as the data. The papers in this volume review this research, and include discussion of how the second language classroom may be utilized for both acquisition and learning.
Chapter 1, based on a paper written in 1976 and published in Ritchie (1978), describes how the learning-acquisition distinction captures one sort of individual variation in second language performance. Based on case histories, this section proposes that there are basically three types of performer:
Monitor "overusers" are performers who feel they must "know the rule" for everything and do not entirely trust their feel for grammaticality in the second language. One case, "S", described by Stafford and Covitt (1978), remarked: "I feel bad... when I put words together and I don't know nothing about the grammar." In Stevicks terms (Stevick, 1976, p. 78), overusers may suffer from "lathophobic aphasia", an "unwillingness to speak for fear of making a mistake".
At the other extreme is the underuser, who appears to be entirely dependent on what he can "pick up" of the second language. Underusers seem to be immune to error correction, and do not perform well on "grammar" test. They may acquire a great deal of the target language, however, and often use quite complex constructions.
The optimal user is the performer who uses learning as a real supplement to acquisition, monitoring when it is appropriate and
when it does not get in the way of communication (e.g. prepared speech and writing). Very good optimal users may, in fact, achieve the illusion of native speaker competence in written performance. They "keep grammar in its place", using it to fill gaps in acquired competence when such monitoring does not get in the way of communication.