External theories of learning emphasize the necessity of overt response to a stimulus. On the other hand, internal theories support the position that learning can take place through the process of covert responses, even in the absence of overt responses. Cognitive theorists are not opposed to practice, but they maintain that understanding should precede practice. Psychological studies concerning the role of repetition, imitation, and practice are relevant to this problem and to the selection of appropriate teaching/learning activities in the classroom.
Rock (1957, p. 193) precipitated a great deal of research on the subject when he concluded that "repetition plays no role in the formation (as distinct from strengthening) of associations, other than that of providing the occasion for new ones to be formed, each in a single trial." Estes (1960) stated that Kimble and associates found that only the first few trials were effective in strengthening stimulus-response bonds. Murdock and Babick (1961) concluded that repetition had no discernible effect on recall. Although unwilling to accept Rock's conclusion, Clark et ai. (1960, p. 23), after having obtained similar results, called for further studies and stated: "If, therefore, his results are confirmed, if they are not artifacts of his method, which still has to be proved, then all of the modern-day theories of learning that are based on repetition, or some form of it, will have to be abandoned or very radically modified."
Associated with a great deal of repetition is the phenomenon of verbal satiation. Some research shows that constant repetition tends to weaken or actually cause a total lapse of meaning of the repeated word on the part of the subject. One article reported a dissipation of meaning within three or four seconds. The theoretical explanation of this loss through repetition is that after a period of continually activating the environmental referent associated with the word, an inhibiting factor develops causing a loss of the mediators involved (Lambert & Jakobovits, 1960). Hull's reactive inhibition postulate states: "As a word is repeated, the trace associated with it, and with its meaning, as well as the connection between the two, are repeatedly activated, and should lead to their own inhibition. Repeated activation of the traces and bonds limits their further activation" (Wertheimer & Gillis, 1958, p. 79).
A great deal of research has been done in the area of observational learning and imitation. On the basis of their work, Bandura and Walters concluded that "new behavior units, or chunks of behavior, are learned initially through observing and imitating a model, rather than being shaped through successive
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approximations involving differential reinforcement" (Klausmeier & Ripple, 1971, p. 50). Although this line of research dealt originally with the learning of social behavior, the basic procedures have been expanded to other areas of learning. In one study, Rosenthal and Zimmerman (1973) found that practice in which the student was required to perform without error was far less effective than observation of a model. In a later study, Zimmerman and Rosenthal (1974) reported that a physical, overt response interfered with vicarious learning. After reviewing the research on imitative behavior, Flanders (1968) concluded that the acquisition of complex, unfamiliar behavior, whether it be verbal or nonverbal, is possible, even by very young children, without any overt response having actually occurred.
One purpose of practice is to refine initial learning to the skill level. In a review of skill learning, Posner and Keele (1973, p. 805) point out that the term skill refers to "those processes producing expert, rapid, and accurate performance" and that this definition can be applied to internal mental processes as well as physical actions. Even though they limit their review to a consideration of skilled motor movement, Posner and Keele indicate that an information processing approach is supported by the research being done in the field. The data indicate that central systems of control underlie physical movement. This internal control of movement may be explained on the basis of S-R chains acquired through kinesthetic reinforcement or on the basis of a "central motor program control." Studies support the thesis that movement is guided by an internalized mental model, which the learner tries to achieve. The existence of such an internalized model means that at some stages in the development of a skill, especially in the initial stages during which the model is established, overt, physical practice may be unnecessary. Instead, mental practice involving observation of models and verbal guidance may be more beneficial.
An examination of six reviews surveying sixty-one studies comparing overt and covert responding revealed thirty-three with no significant difference, eighteen favoring overt responding, four favoring covert, and six containing interactions. 2 These reviews lead to the conclusion that in many situations and with many types of learning overt responses are not necessary. In cases involving psychomotor skills, some practice is obviously necessary. Too, covert response is not synonymous with no response. The learner is still actively involved in the teaching-learning process (Levie & Dickie, 1973).
Ausubel (1968, p. 291) asserted that, "Research findings . . . indicate that subjects who respond covertly not only learn and retain verbal material as well as or better than subjects who construct their responses, but also do so more efficiently in terms of learning time." At the same time, however, Ausubel
(1968, p. 276) maintained that, "On theoretical grounds there are many reasons for believing that repetition is typically required not only for the retention of adequately clear, stable, and valid meanings (and often for their acquisition as well), but also for the degree of consolidation of antecedent portions of sequentially organized subject matter that is necessary for efficient learning of subsequent portions."
Mouly (1973) also defends practice as an important variable in the learning process. In his opinion, practice (1) assists in overcoming those factors that cause the student to forget, (2) provides opportunities to modify the existing cognitive structure associated with the information being learned, and (3) gives students a chance to determine their comprehension of the material presented. However, he warns that practice does not necessarily produce improvement and that practice will in all likelihood be of little benefit unless the student understands the purpose of the practice. The best type of practice activity is that involving previously learned material being employed in the acquisition of more advanced work.