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The Psychologies of Structure, Function, and Development A. CHARLES CATANIA New York University The nineteenth century closed with the promise of an integrated science of psychology (Titchener, 1898). In the twentieth century, that promise has yet to be fulfilled. Students of psychology still are asked to choose theoretical sides. They see functional accounts of operant behavior pitted against ethological accounts of behavioral structure, analyses of reinforcement contingencies pitted against theories of cognitive processing, and descriptions of language as verbal behavior pitted against psycholinguistic formulations of language competence. Behaviorism continues to clash with phenomenology, and empiricism with nativism. Psychologists are not yet even agreed on whether theirs is a science of behavior or a science of mental life. The development of these controversies has been described in terms of paradigm clash (e.g., Katahn & Koplin, 1968; Neisser, 1972; Segal & Lachman, 1972), as if psychology were in the midst of the kind of scientific revolution described by Kuhn (1962). The student, whether his mentor be cognitive psychologist or behaviorist, is led to believe that one or the other paradigm will emerge victorious from the confrontation of incompatible intellectual positions. But this characterization may be misleading, because it is not clear that the controversies have grown out of incompatible treatments of common problems. The present account argues that the important dimensions of psychology are different from those ordinarily considered when the history of psychology is interpreted in terms of paradigm clashes, and that these dimensions have 1 Preparation of this article was supported in part by National Institutes of Health Grant MH-18506 to New York University. Requests for reprints should be sent to A. Charles Catania, who is now at Department of Psychology, University of Maryland—Baltimore County, 5401 Wilkens Avenue, Baltimore, Maryland 21228. 434 • MAY 1973 • AMERICAN PSYCHOLOGIST 1 been emerging through evolution over the past century rather than through revolution in the past decade. Titchener's Psychologies Let us return to Titchener's position at the turn of the century (Titchener, 1898, 1899a, 1899b): Psychology was a single science that, like biology, contained lines of division. Biology included a science of structure called morphology or anatomy, a science of function called physiology, and a science of growth or development called embryology or morphogenesis. By analogy, Titchener saw psychology divided into structural, functional, and developmental components. (He also noted a similar division at the level of the analysis of species, which included the sciences of taxonomy, bionomics or ecology, and paleontology or evolutionism, and even suggested the possibility that this type of classification could be extended to the study of cultures.) Titchener (1899a) described the divisions of psychology in the following way: we see at once that the psychology of our definition is (1) a structural psychology, an anatomy or morphology of mind. Mind is a mass of tangled processes. Our problem is to dissect this complex, and to discover, if we can, its plan of arrangement. But we may also regard mind . . . as a system of functions. The mind "does" things for us, or enables us to "do" things. We shall then have (2) a functional psychology. And we may, further, discuss the makeup and working of the child's mind, and the way in which it passes over into the adult mind. We shall then have a mental embryology. Our psychology has become (3) the study of psychogenesis [pp. 21-22]. The present argument, simply, is that Titchener's classification of psychological problems, appropriate in his time, remains appropriate today. The critical point is that Titchener recognized the three psychologies as complementary, not incompatible. Titchener (1899a) went on to say: "No one of these three psychologies is 'better' psychology— psychology in a more real sense of the word—than any other [p. 22]." Psychologists, however, perhaps including Titchener, seem not to have taken sufficient note of the statement. The present account will take it as a point of departure. In elaborating on it, we will first concentrate on the distinction between structural and functional psychologies, because this distinction seems to lie at the root of the conflict between cognitive and behavioral psychologies. We will later have occasion to consider the place of psychogenesis. Structure and Function In biology, the distinction between structure and function was so well established that it supported a division of the field into such separate departments as anatomy and physiology. The line between anatomical research and physiological research was sometimes difficult to draw, and it remains so today. But it is at least clearly recognized that studies of biological structure and studies of biological function are concerned with different empirical questions. To say what an organ does, it may help to know how it is constructed; yet its function is not studied in the same way as its structure. While the analogous distinction is made in psychology, it is sometimes difficult, as in biology, to draw the line. Nevertheless, there exist some bodies of research predominantly concerned with analyzing stimulus structure or response structure, and other bodies of research predominantly concerned with analyzing behavioral function. An analysis of the distinctive features of a stimulus, for example, is concerned with a different problem than the analysis of the conditions that motivate the organism's continued attention to those distinctive features. The relation between these different kinds of psychological problems has typically been obscured by different languages of psychology. These differences have developed as consequences of historical accident, the influence of everyday discourse on technical vocabulary, and the various research strategies that are appropriate to specific experimental issues. Structural research tends to be described in the cognitive or mentalist vocabulary, and functional research in the behaviorist vocabulary. But the correlation between these research concerns and these vocabularies is not a necessary one. A cognitive psychologist can be concerned with functional problems (e.g., in distinguishing between parallel and serial processes, cf. Sternberg, 1970) just as a behavioral psychologist can be concerned with structural ones (e.g., in analyzing the stimulus dimensions to which an organism responds in a color-matching task, cf. Wright & Gumming, 1971). In fact, a major argument of the present account is that psychological controversy has often originated because the dichotomy between structure and function has been confused with that between mentalism and behaviorism. (An instructive comparison is with the history of anatomy and physiology in biology, in which the respective concerns with structure and with function were not so highly correlated with vitalistic and mechanistic positions.) The point demands a concrete example, and one has been chosen that may at first seem frivolous: consider what a psychologist might do if he were interested in analyzing baseball pitching. He might begin by concerning himself with the coordination of the pitch. Through slow-motion photography or electromyographic recording, he could examine the sequential patterning of muscle movements, and he could analyze the relation between the early and the late parts of the performance. He might be able to specify the interaction between the ball's speed and trajectory as it leaves the pitcher's hand and the magnitude and form of the pitcher's follow-through. He might even venture a mathematical formulation in which fast balls and curves were distinguished by parameters of his equations, and his analysis could conceivably provide clues about what to emphasize in giving instruction to a novice pitcher. If he were reasonably successful, to the point, for example, that he could predict the properties of a given pitch from the early components of muscle activity, he might be tempted to claim that an exhaustive account of the critical features of pitching was realizable at least in principle if not attainable in practice. Yet no matter how exhaustive his analysis of the structure of the pitch, this psychologist would not be in a position to deal with the circumstances that determine when and at what the pitcher throws the ball. Such an account would require, instead, an analysis of the functional properties of the pitch: its relation to antecedent stimulus conditions and subsequent stimulus consequences. AMERICAN PSYCHOLOGIST • MAY 1973 • 43S The example may seem trivial. Yet it is precisely paralleled by contemporary developments in the psychology of language and illustrates the different strategies that have led to conflict between cognitive and behavioral formulations. Studies of both grammar and phonology (e.g., Chomsky & Miller, 1963; Liberman, 1970) have dealt specifically with the structure of language and speech. Transformational analyses have been concerned with the complex coordinations necessary to generate grammatical sentences or comprehensible phonetic utterances. Recognizing that the way a sentence or utterance ends interacts with characteristics of the earlier parts of the sentence or utterance is not so very different from recognizing that the followthrough interacts with the windup and the delivery even though it occurs after the ball has left the pitcher's hand. Such analyses can be elaborated at various levels of complexity; for example, the hierarchical organization of units such as phonemes, words, and grammatical forms is explicitly featured in accounts of grammatical structure. Structural analyses of grammar and speech, however, cannot tell us when a person will decide to speak, or what he will talk about. It is precisely these latter questions that are the concern of a functional analysis of language. This is illustrated even by some of those materials that are taken as critical examples of the primacy of a structural account. The written sentence "Dropping bombs can be dangerous" has one of two structures, depending on whether the speaker is concerned with the people in the air or those on the ground. There is no debate about whether these five words in this particular order can constitute two different sentences. But the structural account cannot help us to choose between the two structures. The choice must be based on functional considerations: the conditions under which the sentence is generated. But say instead that the words are spoken. Now the two sentences can be distinguished by different patterns of stress. Once both phonological and grammatical analyses are available, an account can be given of the relation between the two types of structure. The problem is not surmounted, however ; even at this point, the structural account cannot tell us about the circumstances under which a sentence with one or the other structure will be uttered. That issue is again functional. It is surprising that such relations are so often overlooked. Yet failures to note them can easily 436 • MAY 1973 • AMERICAN PSYCHOLOGIST be documented. The controversy over the psycholinguistic account of grammatical structure versus the functional analysis of verbal behavior has been both persistent and prominent in psychology. The chronology includes, among others, Skinner (1957), Chomsky (1959), Lenneberg (1967), Dixon and Horton (1968), MacCorquodale (1970), and Premack (1970). The two sides of the controversy were at most times simply concerned with two different kinds of problems: problems of structure and problems of function (or, equivalently, problems of competence and problems of performance, cf. McNeill, 1970, p. 146). But the accounts were couched in languages and contexts that were sufficiently different that the different problems each was addressing typically went unrecognized (cf. Catania, 1972). A Behavior Paradigm Although we are arguing that the development of contemporary psychology is not properly interpreted in terms of paradigm clashes, paradigms can be useful. We may recall that a paradigm is a model that exhibits essential relations among the phenomena that it represents. We should not be surprised if neither a cognitive nor a behavioral psychologist could come up with a paradigm on which his respective colleagues could universally agree. Nevertheless, we shall introduce a paradigm here to illustrate some of the properties of structural and functional accounts. The paradigm takes the form S'^RiS 0 ), where S represents a stimulus and R represents a response. The superscripts, in SD and S°, distinguish between two kinds of stimuli: a discriminative stimulus, SD, which is a stimulus denned in terms of the events that can occur in its presence, and a contingent stimulus, Sr, which is a stimulus defined in terms of its consequential relation to responses. The expression (R:S°) represents the relation of responses to consequences. This relation is called a contingency and can be translated, "the effect of response R on the probability of stimulus Sc." Thus, the paradigm as a whole represents a contingency that operates in the presence of a discriminative stimulus. The paradigm is not exhaustive; it does not include, for example, responses that may be elicited by the contingent stimulus. A more detailed account of the paradigm has been presented elsewhere (Catania, 1971); the point of using it here is not to argue the precedence of a behavioral terminology, but rather to illustrate some structural and functional dimensions of problems in psychology. Let us consider the scope of the paradigm. The contingency represents the way in which behavior can affect environmental events. If the contingent stimulus is a food pellet delivered to a hungry rat, for example, the rat's various responses may make the delivery of a pellet more likely or less likely, or might have no effect on pellet delivery. Let us say that the lever press makes the pellet delivery more likely, or, in other words, that the lever press produces a pellet; we call this an instance of positive reinforcement. But if the lever press makes the pellet delivery less likely, or, in other words, prevents the pellet delivery, we speak of the procedure as omission training. Finally, if the lever press has no effect on the likelihood of a pellet delivery, we speak of pellet deliveries as response independent. But each of these contingencies might operate only in the presence of some discriminative stimulus, such as a light. Such cases provide various examples of discrimination procedures. If, in the presence of a light, lever presses produce food pellets, we speak of an operant discrimination. If, in the presence of a light, lever presses prevent the delivery of food pellets, we speak of discriminated omission training. And if, in the presence of a light, food pellets are delivered independently of lever presses, we speak of a respondent or Pavlovian conditioning procedure: in the presence of a light, food pellets are delivered, just as food was delivered in the presence of various stimuli to Pavlov's dogs. The contingent stimulus, however, can be aversive instead of appetitive. If the contingent stimulus were electric shock, for example, the three cases would include punishment, when lever presses produce shock; avoidance or escape, when lever presses prevent or remove shock; and response-independent shock, when lever presses have no effect on the likelihood of shock delivery. These contingencies, too, can operate in the presence of a discriminative stimulus. In such cases, we classify the procedures as discriminated punishment, discriminated avoidance or escape, and respondent defensive conditioning, respectively. Finally, the contingent stimulus can be effectively neutral. If a rat's lever press produces or removes a stimulus such as a click or a light, we can ask about the extent to which the rat learned about the contingency relation between its lever press and this stimulus by later pairing the stimulus with some appetitive or aversive event. We speak of learning so demonstrated as latent learning. But relations between responses and such simple events typically occur in certain settings, and so it is appropriate to speak of discriminative stimuli for these contingencies also. In the presence of certain visual, tactile, and other stimuli, the rat moves about and encounters various parts of its environment: its movements are responses that have certain consequences, and these relations are also examples of contingencies. Thus, procedures in sensorimotor learning can be encompassed by such a paradigm. There may be, in addition, some neutral events that reliably occur independently of the rat's responses. Suppose, for example, that in the presence of a tone, a light consistently flashes; if we find, through later procedures in which we pair the tone or the light with other events, that the rat had learned something about the relation between these two stimuli, we refer to the initial procedure as an instance of sensory preconditioning. Thus, all of the basic learning procedures can be incorporated into this paradigm. The essential feature of the analysis of contingencies is in fact the description of the functional relations among stimuli and responses. Some stimuli, which we call discriminative, are stimuli denned in terms of the events that can occur in their presence. Other stimuli, which we call contingent, are stimuli defined in terms of their consequential relation to responses. Our interest in behavior encompasses both the circumstances under which responses can occur and the ways in which they can modify the likelihood of environmental events. Structural and Functional Research Strategies Consider how we proceed if we are interested in functional questions. We can study various contingencies, (R:S C ), by varying a response's effect on the probability of some contingent stimulus or by varying the nature of the contingent stimulus. For example, when we study the transition from reinforcement to extinction, we change from a contingency in which a response produces a reinforcing stimulus to one in which the response no longer produces that reinforcing stimulus; when we study AMERICAN PSYCHOLOGIST • MAY 1973 • 437 the effects of satiation, we change from a procedure in which the contingent stimulus is reinforcing to one in which the contingent stimulus is no longer reinforcing. Or we can study the stimulus control acquired by a discriminative stimulus, SD, by varying the contingencies on which the stimulus is superimposed or by changing the relation of the stimulus to a contingency. For example, when we compare the roles of stimuli in operant and respondent conditioning, we change the contingency that operates in the presence of a discriminative stimulus from one in which a response produces a contingent stimulus to one in which a response has no effect on presentations of a contingent stimulus; when we examine stimulus control in complex reinforcement schedules or in types of delay conditioning, we vary the temporal separation between the discriminative stimulus and the operation of a contingency. (We could now transfer this account to the baseball pitcher of our earlier example. We could argue that a given batter at a particular point in a game represents a discriminative stimulus, SD, in the presence of which a particular pitch, R, will be likely to have a particular consequence, S°. The translation is simple enough. To illustrate how the paradigm bears on structural and functional questions, however, we might better apply it to more traditional psychological materials.) Each of the functional questions in the preceding examples concerns relations among various terms in the paradigm. Let us now consider structural analyses, which deal with the distinguishing properties of individual terms when the relation among terms is held constant. For example, if a particular contingency operates in the presence of a particular discriminative stimulus, we can vary the stimulus and ask questions about its critical features. This is our strategy in psychophysical experiments with both human and animal subjects, but it is also applied when the stimulus features are more complex. Thus, in a study of how children learn to read, we can try to identify properties of the letters of the alphabet that are critical to learning, and we might find, among the features that we examine, that the child can be taught to distinguish between up-down reversals of letters more easily than between left-right reversals (cf. Gibson, 1965). The questions are about stimulus structure, or, as Pylyshyn (1972) put it, about "the structure of the percept": 438 • MAY 1973 • AMEKICAN PSYCHOLOGIST The question of the nature of a mental representation is really a question about which aspects of the pattern of incoming data are perceived, learned, and retained for potential future use. However, . . . these aspects that are distinguished and retained and that play a functional role in cognition need not be simple classes of physical properties of the stimulus pattern. They often are rather abstract properties whose relation to the physical features of the stimulus may be quite obscure . . . [p. 548]. The account is reminiscent of the distinction between sensation and perception, and we may recall the extent to which the field of perception has involved structural concerns. On the other hand, we might be interested in studying differences among the classes of responses that can be learned. Again, the relations among terms of the paradigm are held constant, but this time we vary the response rather than the discriminative stimulus. We could examine simple response properties, such as the force or topography of a rat's lever press, or we could study the differentiation of motor skills in human subjects. Similar questions, however, can be addressed to more complex modes of responding. In the four decades between Guilford's (1927) "The Role of Form in Learning" and Johnson's (1968) "The Influence of Grammatical Units on Learning," our experimental sophistication has changed, but the basic problem has remained the same: at issue is the structure of complex responses. A number of areas in the contemporary psychology of human verbal learning (e.g., subjective organization in free recall; Tulving, 1962) can be regarded as concerned with the structural properties of complex responses. (To extend the account to contingent stimuli, we might even argue that concern in motivation with the factors that influence the effectiveness of contingent stimuli, as in the analysis of incentives, is a structural problem in the present sense.) Hierarchical Organization of Stimuli and Responses Some might argue that this kind of an account misses the point, because an analysis of stimulus structure alone or of response structure alone will necessarily omit the complex interaction between organism and environment that must take place during cognitive processing (cf. Neisser, 1967). But each stage of such an interaction must involve the organism's responses to particular features of the environment. The resolution, therefore, may lie with an account of the hierarchical organization of stimuli and responses. Estes (1971) stated the issue as follows: If one who is attempting to describe and predict the behavior of an adult human learner fails to take account of these behavioral organizations, and attempts to construct an account in terms only of individual stimulusresponse units, the principles of operation of rewards and punishments may appear to be quite different from those revealed in simpler experiments with animals or immature human learners. Actually, it may be that the principles of operation of these factors are the same in all cases and that the difference lies in the nature of the behavioral units whose probabilities are being modified as a result of the experiments with various types of outcomes [p. 23]. The tendency to select one response strategy rather than another in a given situation must itself be modified by past experience with rewarding or punishing outcomes. A strategic question which must be fundamental to the further development of theory in this area is that of whether the laws and mechanisms of reinforcement are the same for these higher-order behavioral units as for the more elementary responses studied in most laboratory experiments [p. 31]. We may too often think of responses as single and discrete events, failing to regard their structural properties as also included among their defining features. (We have similar problems when we talk about stimuli when we mean to talk about stimulus properties.) Not simply the closure of a switch by a lever press, but perhaps also the grammaticality of a sentence that is uttered or the appropriateness of a strategy that is applied can be regarded as denning properties of those response classes that can enter into functional relations. Take Harlow's (1949) learning set experiment as an example. At one level of analysis, the choice of one or another stimulus is the response of interest. But at a hierarchically more complex level, the acquisition of learning set is denned in terms of the substitution, for many separate choices in different problems, of a single, more general response class that can be described in the following terms: if the stimulus choice produced food this time, continue to choose it; if it did not, choose the other stimulus; more economically, we may speak of "win-stay, lose-shift." It is fruitless to debate whether this performance should be spoken of in terms of a complex response class or in terms of a strategy; in either case, the point is that the analysis concerns behavioral structure. Questions about the nature of this structure are orthogonal to functional questions, such as that of whether rein- forcement was a learning or a performance variable in these procedures. (This does not imply that an analysis of structure will necessarily be irrelevant to an analysis of function, or vice versa; if structure and function interact in learning, for example, it is all the more important to be clear about the difference between structural and functional questions.) The following account (Fischer, 1972) of maze learning provides another illustration: After . . . familiarizing yourself with one of the more complete structural systems—perhaps Chomsky's grammar —you might even be able to begin to write that structural analysis of children's maze performance. While other psychologists were explaining the performance by reducing it to some lowest common factor like reinforcement or attention, you would be searching for key patterns and for rules that would relate those patterns to each other. In a way, it would be like writing a grammar for maze performance. You would need a set of grammatical categories to describe the "phrase structure" of the children's behavior in the maze and a set of transformation rules for relating different types of phrase structures. With this kind of structural description, you could account for the particulars of maze performance to an extent that is probably impossible for explanations that merely reduce behavior to factors like reinforcement and attention [pp. 330-3311. According to this account, Krechevsky (1932) was writing a preliminary grammar of maze learning when he carried out his experiments on hypotheses in rats. And this formulation is reasonable, because Krechevsky's concern, like Fischer's, was with the structure of the maze performance. Yet neither the child nor the rat will necessarily move through the maze, even if the maze has been thoroughly mastered, on the basis of a maze grammar alone. We may recall Tolman's (1948) rat, said to be lost in thought at the choice point. The cognitive map provided a way of describing the effective stimulus structure of the rat's world. But a rat with a cognitive map must have occasion to use it, and procedures that get the rat to perform and thereby demonstrate its map are functional. In psycholinguistics, we can similarly imagine Chomsky's speaker lost in thought, capable of grammatical speech but with nothing to say: In the case of linguistic concepts, such as grammaticality, such procedures are called generative grammars. Such grammars do not describe how people go about understanding or generating sentences, but they do describe the abstract relation that holds between strings of words and such concepts as "grammatical sentence" [Pylyshyn, 1972, p. 550]. AMERICAN PSYCHOLOGIST • MAY 1973 • 439 If we wish to understand how the thinker comes to speak, we must be able to provide a functional as well as a structural account of language. Explanation and Description Let us suppose, however, that we had provided both a structural and a functional account of language or of maze learning. To what extent would we have explained the performance? In his quotation above, Fischer contrasted functional factors like reinforcement and attention with structural factors like transformation rules as ways of explaining or accounting for the maze performance. But we may question whether either a structural or a functional account, or even both in combination, can ever have the power of explanation. The present view is that both structural and functional analyses are descriptive rather than explanatory. Consider the following commentary by Black (1970) on the psycholinguistic account of language in terms of deep structures and generative grammars: Whatever their value, Kepler's laws do not explain the planetary motions, in any useful sense of "explain": they replace a crude and unsystematic description ("those orbits out there", or "the orbits conforming to these readings") by another description concisely presenting some mathematical properties of the orbits. The same applies, mutatis mutandis, to the rules constituting a specific generative grammar. Our initial crude "intuitions" as to what should count as grammatical or the reverse are replaced by a set of precise and explicit rules that (approximately and with idealization) generate a corresponding classification. This provides valuable insight into structural connections: it may be said to provide intelligible reasons for what we previously seemed to be doing by a kind of instinct. But "explanation" hardly seems the right tag [pp. 454—455]. Functional terms like reinforcement, too, have typically been regarded as explanatory. Yet reinforcement is simply a name for a certain set of functional relations. If a response in a given class produces a stimulus, and responses in that class are strengthened by virtue of its production of that stimulus, we say that we have observed an instance of the process of reinforcement. We may wish to relate this process to other behavioral processes, or to characterize the properties of stimuli that can have this reinforcing effect, but that does not change the nature of the term. It remains a name, to be applied when it is appropriate like any other name (Catania, 1973). Thus, we can talk about 440 • MAY 1973 • AMERICAN PSYCHOLOGIST stimulus properties and about response properties at various hierarchical levels of complexity, and we can outline the kinds of functional relations that can exist among them. At each level, our concern is descriptive, and the question of what kinds of functional relations different stimuli or responses can enter into is an empirical one. Much emphasis has recently been given to the limits of learning (e.g., Breland & Breland, 1961; Revusky & Garcia, 1970; Rozin & Kalat, 1971; Seligman, 1970): limits on the kinds of responses that can be learned, on the kinds of stimuli that can act effectively on an organism, and on the kinds of relations that can be established between particular stimuli and particular responses. But analyses of the structure of effective stimuli, or of the different structures of those responses that can be more or less easily learned, are different from analyses of how stimuli and responses function in behavior. And if some functional relations turn out to be less general than was once believed, it does not follow that their names should be changed or that they no longer have the status of functional relations. Distinguishing the Structure-Function Dimension from the BehaviorCognition Dimension According to the present view, questions of stimulus structure and response structure are orthogonally related to questions of behavioral function. This is not to say that information about structure will never bear on the analysis of function, or vice versa. But to the extent that these relations can be clarified to show that various research areas in psychology complement rather than conflict with each other, controversy may give way to more productive interaction. For example, applications of psychology to education are often divided between those concerned with the cognitive organization of the subject matter and those concerned with behavioral methodology in classroom management. Yet to teach effectively, it is essential to know both how a subject matter is structured, as stimulus in the teacher's presentation and as response in the student's mastery, and how the teacher and the student can function in a classroom. We must give attention to cognition in both structural and functional senses: structurally in the extent to which cognitive strategies can be regarded as ways of describing the structural properties of complex stimuli, and functionally in the analysis of both the circumstances under which strategies are applied and the consequences of these strategies. At issue is the question of whether cognitive and behavioral approaches are inappropriately interpreted, respectively, as structural and functional psychologies. The evolution of psychology over the past century has included the successive elaboration of various structural and functional psychologies. The properties of these different psychologies have changed in detail over the years. Gestalt psychology was clearly structural, just as the analysis of contingencies in schedules of reinforcement was clearly functional. But structural and functional psychologies complement each other; they need not stand in opposition. Some of the differences have been differences in language. The clash between the vocabulary of mentalism and the vocabulary of behaviorism is readily evident. It is not unfashionable these days to be a mentalist; only dualism is reprehen'sible. But the debate between mentalism and behaviorism has been along different dimensions than those of structure and function. The major behaviorist argument has been against causal, not descriptive, mentalism, and to argue that mental events are not causes of behavior is not to argue that private events do not exist. In fact, the possibility of an internally consistent mentalism is implicit in the notion that a behavioral translation of mental or cognitive vocabularies is feasible. The choice of vocabularies will rest with the effectiveness with which their proponents apply them. On the side of the mental or cognitive vocabulary, it might be argued that it lies closer to everyday talk than some behaviorist languages, but on examination, the language of information storage and retrieval, for example, is no less esoteric than the language of reinforcement contingencies. On the side of the behaviorist vocabulary, it might be argued that it provides greater precision and less risk of contamination by everyday preconceptions, but behaviorists have yet to discount the possibility of an internally consistent and effective mentalist vocabulary (cf. Bolles, 1967). As the arguments are marshaled on both sides, the tide shifts: epistemological difficulties in behaviorism are balanced by accounts of its relevance to phenomenology (Day, 1969), while the expanding front of cognitive research is tempered by its philosophical limitations (Malcolm, 1971). These clashes, in any case, may be mere epiphenomena; the distinction between structure and function is critical to either viewpoint, and progress will depend more on results than on discussion. The Place of Psychogenesis Let us now turn back to Titchener's formulation. We have seen how various problems of psychology can be interpreted as problems of structure or of function. It remains to relate these two subdivisions to problems of development: what Titchener called psychogenesis. Superficially, it is tempting to equate this area with developmental psychology, and in one sense such an equation would be correct. Yet to place the area in its proper perspective, we must be clear about the kind of development that is to be studied. Certainly, we may be interested in the development, through maturation, of the capacity to respond to various complexes of stimuli or to engage in new responses and apply different strategies. But whether we say we are concerned with the development of behavior or with that of the mind, our psychogenesis must include the psychology of learning. If embryology deals with the development of the organism, and evolution with the development of a species, then psychogenesis must deal with the development of the organism's behavioral or mental capacities; this is what the psychology of learning is supposed to be about. The view resolves some paradoxes. In the analysis of behavior, the functional analysis of contingencies, as in the study of reinforcement schedules (Ferster & Skinner, 1957), created conflict. The operant analysis of steady-state performances was not seen as relevant to some problems in the psychology of learning. This was as it should have been: on the one hand, the analysis was more concerned with functional relations in the steady-state maintenance of behavior than with developmental relations in its acquisition; on the other, it might have been anticipated that the study of development, too, would divide into functional and structural components (e.g., respectively, Bijou & Baer, 1966; Piaget & Inhelder, 1969). According to the present view, it was appropriate for these various parts of psychology to proceed in different ways. It is only unfortunate that they AMERICAN PSYCHOLOGIST • MAY 1973 • 441 have often been seen as incompatible. Progress in these areas—structure, function, and development —has constituted the evolution in psychology over the past century. It has typically been uncoordinated, and there is much left to be settled. The detailed character of each area changes from time to time. The areas may variously merge and separate again, but they are at least as independently viable as are divisions of the biological sciences. Hopefully, they will not become totally isolated from each other. Paradigms and Clashes We have argued here that psychology is not in the midst of a paradigm clash. True paradigm clashes require points of contact. In the clash between the astronomies of Kepler and of Ptolemy, the subject matter stayed the same while the point of view changed; literally, as well as figuratively, the center did not hold. Different schools of psychology, however, have been concerned with different problems. This is not to say that the evolution of psychological concepts has never involved conflict. Rather, it is to say that the clashes have not been along any simple dimension of psychological problems. The multiplicity of issues may generally distinguish clashes in the life sciences from those in the physical sciences. A strong case for this view has been made in Mayr's (1972) analysis of the Darwinian revolution: It is now evident that the Darwinian revolution does not conform to the simple model of a scientific revolution as described, for instance, by T. S. Kuhn. . . . It is actually a complex movement that started nearly 250 years ago; its many major components were proposed at different times, and became victorious independently of each other. Even though a revolutionary climax occurred unquestionably in 1859, the gradual acceptance of evolutionism, with all of its ramifications, covered a period of nearly 250 years . . . [p. 988]. Neither is the revolution in psychology a revolution of a decade. We have argued that Titchener's insight into the organization of psychology is relevant today. Yet we may wonder why Titchener, in his structural account, contributed to an opposition between structuralism and functionalism that has persisted for most of this century. Part of the answer probably lies in what it was possible to do in each of these separate areas in Titchener's time. As Titchener 442 • MAY 1973 • AMERICAN PSYCHOLOGIST (1899a, p. 22) noted, structural psychology had made more progress in his day than either of the other two psychologies, But it is the progress in structural, functional, and developmental accounts that constitutes psychology's evolution and revolution. It is reassuring to note that Boring (1969) detected signs that Titchener, near the end of his career, was gradually moving toward behaviorism; Boring's grounds were simply that Titchener's theory of meaning was changing into a functional account. And from that development, too, both structuralists and functionalists can learn. REFERENCES BIJOU, S. W., & BAER, D. M. Operant methods in child behavior and development. In W. K. Honig (Ed.), Operant behavior: Areas of research and application. New York: Appleton-Century-Crofts, 1966. BLACK, M. Comment. In R. Borger & F. Cioffi (Eds.), Explanation in the behavioural sciences. Cambridge: Cambridge University Press, 1970. BOLLES, R. C. The syntax of the mind. Psychological Reports, 1967, 21, 493^99. BORING, E. G. Titchener, meaning and behaviorism. In D. L. Krantz (Ed.), Schools of psychology: A symposium. New York: Appleton-Century-Crofts, 1969. BRELAND, K., & BRELAND, M. The misbehavior of organisms. American Psychologist, 1961, 16, 681-684. CATANIA, A. C. Elicitation, reinforcement, and stimulus control. In R. Glaser (Ed.), The nature of learning. New York: Academic Press, 1971. CATANIA, A. C. Chomsky's formal analysis of natural languages: A behavioral translation. Behaviorism, 1972, 1, 1-15. CATANIA, A. C. The nature of learning. In J. A. Nevin & G. S. Reynolds (Eds.), The study of behavior: Learning, motivation, emotion, and instinct. Glenview, 111.: Scott, Foresman, 1973. CHOMSKY, N. Review of B. F. Skinner's Verbal behavior. Language, 1959, 35, 26-58. CHOMSKY, N., & MILLER, G. A. Introduction to the formal analysis of natural languages. In R. D. Luce, R. R. Bush, & E. Galanter (Eds.), Handbook of mathematical psychology. Vol. 2. New York: Wiley, 1963. DAY, W. F. Radical behaviorism in reconciliation with phenomenology. Journal of the Experimental Analysis of Behavior, 1969, 12, 315-329. DIXOM, T. R., & MORTON, D. L. (Eds.) Verbal behavior and general behavior theory. Englewood Cliffs, N.J.: Prentice-Hall, 1968. ESTES, W. K. Reward in human learning: Theoretical issues and strategic choice points. In R. Glaser (Ed.), The nature of reinforcement. New York: Academic Press, 1971. FERSTER, C. B., & SKINNER, B. F. Schedules of reinforcement. New York: Appleton-Century-Crofts, 1957. FISCHER, K. W. Structuralism for psychologists. Review of M. Lane (Ed.), Introduction to structuralism. Contemporary Psychology, 1972, 17, 329-331. GIBSON, E. J. Learning to read. Science, 1965, 148, 10661072. GUILFORD, J. P. The role of form in learning. Journal of Experimental Psychology, 1927, 10, 415-423. HARLOW, H. F. The formation of learning sets. Psychological Review, 1949, 56, S1-6S. JOHNSON, N. F. The influence of grammatical units on learning. Journal of Verbal Learning and Verbal Behavior, 1968, 7, 236-240. KATAHN, M., & KOPLIN, J. H. Paradigm clash: Comment on "Some recent criticisms of behaviorism and learning theory with special reference to Breger and McGaugh and to Chomsky." Psychological Bulletin, 1968, 69, 147-148. KRECHEVSKY, I. "Hypotheses" in rats. Psychological Review, 1932, 39, 516-532. KUHN, T. S. The structure of scientific revolutions. Chicago: University of Chicago Press, 1962. LENNEBERG, E. H. Biological foundations of language. New York: Wiley, 1967. LIBERMAN, A. M. The grammars of speech and language. Cognitive Psychology, 1970, 1, 301-323. MACCORQUODALE, K. On Chomsky's review of Skinner's Verbal behavior. Journal of the Experimental Analysis of Behavior, 1970, 13, 83-99. MALCOLM, N. The myth of cognitive processes and structures. In T. Mischel (Ed.), Cognitive development and epistemology. New York: Academic Press, 1971. MAYR, E. The nature of the Darwinian revolution. Science, 1972, 176, 981-989. McNEiLL, D. The acquisition of language. New York: Harper & Row, 1970. NEISSER, U. Cognitive psychology. New York: AppletonCentury-Crofts, 1967. NEISSER, U. A paradigm shift in psychology. Review of A. Richardson, Mental imagery; S. J. Segal (Ed.), Imagery: Current cognitive approaches; and A. Paivio, Imagery and verbal processes. Science, 1972, 176, 628630. PIAGET, J., & INHELDER, B. The psychology of the child. (Trans, by H. Weaver) New York: Basic Books, 1969. PREMACK, D. A functional analysis of language. Journal of the Experimental Analysis of Behavior, 1970, 14, 107125. PYLYSHYN, Z. W. Competence and psychological reality. American Psychologist, 1972, 27, 546-552. REVUSKY, S., & GARCIA, J. Learned associations over long delays. In G. H. Bower (Ed.), The psychology of learning and motivation. Vol. 4. New York: Academic Press, 1970. ROZIN, P., & KALAT, J. W. Specific hungers and poison avoidance as adaptive specializations in learning. Psychological Review, 1971, 78, 459-486. SEGAL, E. M., & LACHMAN, R. Complex behavior or higher mental process: Is there a paradigm shift? American Psychologist, 1972, 27, 46-55. SELIGMAN, M. E. P. On the generality of the laws of learning. Psychological Review, 1970, 77, 406-418. SKINNER, B. F, Verbal behavior. New York: AppletonCentury-Crofts, 1957. STERNBERG, S. Memory-scanning: Mental processes revealed by reaction-time experiments. In J. S. Antrobus (Ed.), Cognition and affect. Boston: Little, Brown, 1970. TITCHENER, E. B. The postulates of a structural psychology. Philosophical Review, 1898, 7, 449-465. TITCHENER, E. B. An outline of psychology. New York: Macmillan, 1899. (a) TITCHENER, E. B. Structural and functional psychology. Philosophical Review, 1899, 8, 290-299. (b) TOLMAN, E. C. Cognitive maps in rats and men. Psychological Review, 1948, 55, 189-208. TULVING, E. Subjective organization in free recall of "unrelated" words. Psychological Review, 1962, 69, 344-354. WRIGHT, A. A., & CUMMING, W. W. Color-naming functions for the pigeon. Journal of the Experimental Analysis of Behavior, 1971, 15, 7-17. AMERICAN PSYCHOLOGIST • MAY 1973 • 443