A Behavioristic Account of the Logical Function of Universals. I: Physical Signs and Social Signs
John M. Brewster
THE aim of this essay is to explain the universal reference relation which language symbols bear to their objects. The function of a symbol is to determine a reference to a referent distinct from itself, such that this reference becomes a control over subsequent overt behavior to the symbolized object. What constitutes the reference is a thought or idea of the referent. In calling ideas references I am adopting the terminology of Ogden and Richards. The relation between a symbol and its referent is the thought of the object as determined by the symbol.
It appears to us that most efforts to describe the kind of responses that may constitute ideas fail to state what are the functional properties of thoughts. This failure has led some to identify thoughts with symbols per se, and others to identify thoughts with any response to a referent initiated by a stimulus. The first can not account for the reference of an idea. The latter can not account for the stimulus function of thoughts.
I suggest; that functionally stated an idea is a reference from (1) a symbol, its cause, to (2) a referent, and (3) is a stimulus to the subsequent overt response of the organism to the object thought of such writers as Holt, Mursell, and Wells f, it to set 111) any criteria by which one may distinguish between ideas and non-conceptual responses. in like manner, it is this functional property of an idea which Ogden and Richards do not consider. The symbol observer's subsequent response to the symbol's referent is, then, a function, not of the symbol, but of the ideas or conceptual relation determined by the symbol. Mr. Holt, in making the overt response a "constant function" of the object itself, offers no function for ideas. Nowhere do these writers suggest that the problem of symbols is any other than that of pointing out that a part of a "context" comes to call out a response similar to that called out by the
(506) original context or object. What is obvious in their account is that if the response to the original object is not an idea, and if the response initiated by a sign or substitute stimulus is merely similar to the original response, then there is no differential trait which converts the response in the second case into a thought of the object for which the sign stands.
In holding that the function of communicative symbols is that of stimulating ideas and that ideas are substitute stimuli for the referents of symbols, I differ of course from Watson and Mursell, who identify ideas with lingual responses themselves. Mursell is quite specific. We "take knowledge to consist of speech reactions. . . . We do not have knowledge on the one hand and speech on the other. . .. We have nothing but speech." 
Hollingworth is more consistent in identifying ideas with signs. Watson and Mursell identify ideas with signs, but in order to hold that ideas are a species of behavior they restrict thoughts to lingual signs. However, if a thought of an object is the sign of an object, I see no reason for supposing that thoughts of objects are properties of an organism. We should say with Hollingworth that the bell sound is the idea of the food object "in so far as the bell sound leads to a salivary secretion appropriate to" the food object. A photograph of "a loved one" which "instigates words, acts, or feelings established in connection" with the loved one is a symbol and "hence an idea or thought of the absent person." A map is an idea of a road, in so far as it. is a symbol of a road. True, in order to be an idea, a sign must determine a response of its observer appropriate to a referent, but there is no necessity that such an idea must be constituted by the sign observer's reactions. It may seem quite strange that one's thought of a kiln may be constituted by a brickbat rather than by some unique behavior of one's own. But this conclusion is absolutely valid if ideas are identified with symbols of referents.
A sign, as Hollingworth suggests, does refer to a referent, an object distinct from and beyond the sign itself. But what constitutes this reference, the meaning relation between the sign and all object? What goes from the bell to the food beyond? Plainly it is the sign's function, i.e., the overt response which the sign initiates and its referent terminates. The only thing that transcends the sign is the response to something else which the sign initiates. Any overt response to an object as initiated by some phase of an object has then one property of thought, viz., that of being a reference to
( 507) an object distinct from immediate sensible stimuli. On the other hand the overt response to a referent is not functionally an idea-response, because it is not the stimulus to the sign-observer which may control his subsequent behavior to the sign's referent. Not until the response references to objects become delayed and function as controls over what the sign-observer will subsequently do, do the references of signs become ideas and signs become symbols.
Hence, to give a behavioristic interpretation of the reference relation of the language symbols, it is necessary to show how responses to objects intervene between the symbol and its referent so as to control the subsequent overt response to the symbolized object. Both the idea-responses and the subsequent overt behavior are directed toward the symbolized referent, but they are functionally different. A response functioning as a directing idea is not carried out.
I do not deny that communicative symbols are substitute stimuli. But I do contend that the responses to referents when evoked by symbols are themselves substitute stimuli for subsequent behavior to the objects symbolized. It is this double substitution which Watson seems to have overlooked.
The following pages will describe the manner in which symbols and idea-responses arise from those non-symbolic stimuli of gestures which lead directly to overt responses. In this I shall follow in general Mead's analysis of the social act.
It is not possible to deny the existence of mind or consciousness or mental phenomena, nor is it desirable to do so; but it is possible to account for them or deal with them in behavioristic terms which are precisely similar to those which Watson employs in dealing with non-mental psychological phenomena (phenomena which, according to his definition of the field of psychology, are all the psychological phenomena there are). Mental behavior is not reducible to non-mental behavior. But mental behavior or phenomena can be explained in terms of non-mental behavior or phenomena, as arising out of, and as resulting from complications in, the latter.
I depart from dead on two basic points: He held that the relation of meaning exists only in an overt social act, whereas I find meaning present; even in non-social behavior. Secondly, he attempted to explain language on the basis of individual gestures whereas I am forced to conclude that, linguistic symbols are by , nature the common property of a group, and that it is for this reason that they can function as universals.
As already suggested, signs and symbols are functionally different kinds of stimuli. Hence, an analysis of signs and their re-
( 508) -lation to referents is necessary to the investigation of symbols. There are two kinds of signs, physical and social. Their difference rests upon the fact that there exist structurally two different kinds of acts. One is physical or non-social. The other is a social act. A social act will be discussed later. A physical response is one whose occurrence is in no wise determined by the response of another organism. For example, the rat's eating cheese is a non-social act because it is controlled by the cheese. Sitting is a physical act in so far as its execution is controlled by the chair and not by a social stimulus such as a host's invitation to be seated.
Wherever the complete response involves the serial functioning of different structures such as locomotion, manipulation, and consummation, the object can not be identified as any particular receptor quality. Instead, the whole physical act (including its objects) consists of a series of functionally different stimuli and responses. Thus, the distance receptor phases (visual, olfactory, etc.) of the cheese control the locomotor phase of the eating response with respect to the terminal, tactual, and gustatory phase of the act of getting food. That phase of an object which terminates a response may be called the referent of the distance phase. Any phase of an object (visual cheese) which initiates a response terminating at a referent phase of an object may be called a sign stimulus. The meaning relation or reference which a sign has to a referent is defined by the response which it initiates toward its referent. It is commonly recognized that though a response is produced by a stimulus it is not directed toward it. The response is not complete until it finds its object or objective. Thus Mr. Holt, after giving his definition of behavior, says rightly that the "immediate stimulus" need not be "the object of which the behavior is a constant function . . .; the development from reflex action to highly organized behavior is one in which the correlation between stimulus and organism becomes less and less direct, while that between the organism and the object. [here called the referent] of response becomes more and more prominent." Again, Wells says, "The response is released by a stimulus [sign] and is to an object [referent] removed from the stimulus, except in rare and simple cases where the stimulus and the object coincide, as in the case of the protozoa." Dewey expresses the same point when he says that the "response is not merely to the stimulus; it is, so to speak, into it." In his example,
( 509) seeing the light of the candle evokes a reaching response terminating in feeling the heat of the candle.
By a sign, then, is simply meant a stimulus controlling an overt response or terminal act affecting directly some other part of the environment. The response itself is the "objective reference" to a referent. There is nothing necessarily mental or conceptual about the relation of meaning. For a sign to exist it is only necessary that a stimulus call out a response directed to an object distinct from itself. For example, after association of a "dinner call" with the food object, the call will initiate the dog's going to the terminal food object just as did the original visual phase (sign) of the food object. But the meaning relation of the sign to its referent is still the response it initiates.
This account of signs and the relation of meaning has certain consequences. First, the fact that a sign determines a response that is an "objective reference" to another object gives no evidence that such a referential act is an idea, i.e., a thought. To be an idea or "a mental event" a sign's reference must be itself a stimulus to subsequent behavior to symbolized objects. A sign does not imply that an organism has an idea of the object. His response to the sign's referent constitutes his idea of the object only if, instead of being overtly executed, it functions indirectly as a stimulus to the kind of a response which he might carry out in the future. Even Russell, who interprets ideas in terms of images, asserts that signs may be of two sorts: those involving ideas and those which simply stimulate an immediate overt response to some object.
The operation of signs may or may not be accompanied by consciousness. lf a sensible stimulus A calls up an image of B and we act with reference to B, we have what may be called consciousness of B. But habit may enable us to act in a manner appropriate to B as soon as A appears, without having an image of B as soon as A appears. In that case, although A operates as a sign, it operates without the help of consciousness. Broadly speaking, a familiar sign tends to operate directly in this manner, and the intervention of consciousness marks an imperfectly established habit. 
We indicate this distinction of function by the terms "signs" and "symbols."
If it be true that sign stimuli may control responses to referents directly responded to in the past, then we can hardly accept the account of those who identify signs with symbols and sign references with ideas. Such, for example, is the view of Wells. "A word [symbol] is a stimulus that releases a response that is the function of the denotation [referent] of the word." For example,
( 510) a blow stimulates flight. If the word "blow" stimulates flight, then the original blow is the denotation of the word, and the flight is the reference of the word to its object. "It is the organic response which establishes the relation of reference of a word to its object." 
All that occurs here is that one sign has been substituted for another. There is no suggestion that the word stimulates a response that would become a blow if completed, but that, instead of being carried out, becomes a control over some subsequent overt response which might or might not be flight from the object for which the word "stands." Such a response, which involves an idea of what the sign stands for, is qualitatively and functionally different from a simple and direct response to a sign.
Ogden and Richards likewise assume that all acts of reference are thoughts of objects for which signs stand. "The peculiarity of all interpretation," they say, is "that when a context [object] has affected us in the past, the recurrence of merely a part of the context will cause us to re-act in the way in which we reacted before." The part of the "context" is called a sign. The "reaction" evoked by the sign to the old object is called a "thought" or "reference" to the object. But a reaction evoked by a sign is not functionally different from that caused by the object itself. A sign is simply a substitute stimulus, but there is no suggestion that a sign (symbol) is a unique substitute which in some way enables the reactions to past objects to function as stimuli to the beginning of some new type of response to the object symbolized. In other words, the overt behavior of the organism, in their view, can not itself be the function of the idea or reference relation. Their theory accounts for the causality of signs, but gives no function to ideas.
The meaning or reference relation between a sign and its referent is indeed the "specific response" called out by the sign. But there is no reason to suppose that the meaning relation is equivalent to a conceptual relation. To be an idea, a response must not only be a reference to an object, but must also be a stimulus redirecting subsequent behavior to the object thought about. Nor do the proponents of the views criticized suggest any method by which a sign may become a symbol and idea-responses arise from overt responses. Substitution simply describes how signs are multiplied. It provides no suggestion as to how a stimulus evoking ideas may arise.
In so far as the response is controlled by a physical object, no phase of the response itself can be a sign to an organism. In the
( 511) physical or non-social situation an organism's response to the physical object is never the function of the sign's reference to its referent. The visual ball may evoke a throwing response to the tangible ball. But the throwing itself in no way controls the organism's throwing behavior. In other words, the observer's receptors of a physical sign are never affected by the meaning relation determined by signs, but by the stimulating physical object. The response itself which a mere physical sign determines never becomes the stimulus object controlling the subsequent behavior of any organism.
But this is not true in the case of social acts. Here we find a sign's meaning relation to be functionally different from that of physical signs. It was Mead's chief contribution to this analysis to show that a social act is the type of conduct out of which symbols and ideas may arise.
What is the basic mechanism whereby the social process goes on? It is the mechanism of gesture, which makes possible the appropriate responses to one another's behavior of the different individual organisms involved in the social process. Within army given social act, an adjustment is effected, by means of gestures, of the actions of one organism involved to the actions of another; the gestures are movements of the first organism which act as specific stimuli calling forth the (socially) appropriate responses of the second organism. The field of the operation of gestures is the field within which the rise and development of human intelligence has taken place through the process of the symbolization of experience which gestures-especially vocal gestures-have made possible. The specialization of the human animal within this field of the gesture has been responsible, ultimately, for the origin and growth of present human society and knowledge, with all the control over nature and over the human environment which science makes possible.
An overt social act considered as a whole consists of the codetermining responses of two or more organisms. A dog fight, boxing bout, buying and selling, attack and defense, giving and taking, are examples of overt social acts. A social act does not consist of a summation of individual acts that might exist independently of each other. The unique feature of a social act is that the response of each organism can exist only as the directly determined occurrence of the response of another organism. The completion of the attack which one dog begins depends upon the type of defense offered by the other dog.
But what is the basic stimulus mechanism by which a social act goes on? According to Mead, this mechanism consists of gestures (language signs). A gesture is any early phase of the act of one organism which stimulates a response of another organism directed toward the later phase of the gesturing act and is a stimulus
( 512) to the subsequent response of the gesturer. Let us examine several examples. Let A and B be carrying out an act of throwing and catching ball, where A is catcher and B is pitcher. Suppose an early phase of A's catching is getting in position, such as cupping his hands. As a sign this gesture phase of catching stimulates the response of the pitcher directed to a subsequent phase of the catching, viz., A's grabbing the ball. Again, the bared teeth of dog A are the initial phase of A's biting dog B. But the bared teeth stimulate a response (vicious growl and snap) of dog B directed toward the later attack of A, such that B's response stimulates a retreat on the part of A. Since the reference or meaning relation which a sign bears to its referent is defined as the response it initiates toward this referent, the meaning, i.e., the reference, relation of a gesture to its referent, is the response of another; and what a gesture means to the other is the subsequent response of the gesturer. A gesture, then, has a referent, or meaning, where meaning is considered as what is referred to rather than the referential act itself, only for the other organism and not for the gesturer.
The structure and function of a gesture may now be more precisely defined. A gesture is a sign phase of the social response of one organism -which controls the response of a second organism to the subsequent response of the gesturer. The subsequent response of the gesturer is the referent or the meaning (in the sense of what is meant rather than of the act of meaning or referring) of the gesture, because it is the objective of the response of the second organism. The completed catch is the terminal object of the throw initiated by the gesture phase of the catch.
There is, therefore, a marked difference between the meaning relation of a physical sign and that of a gesture. The subsequent response of the gesturer is a constant function of his gesture's meaning which he immediately observes in the response of another organism. Thus, the catching is the constant function of the pitching initiated by early gesture phases of catching and directed to the terminal or referent phase of catching. The dog that bares his teeth finds himself observing his gesture's reference and this is a stimulus to his subsequent response. The gesture determines the object series of stimuli which controls the gesturer's subsequent behavior. It is therefore the characteristic of a gesture that its reference response controls the subsequent behavior of the gesturer.
But there is nothing necessarily common about a gesture sign. As a mechanism of a social act, a gesture need exist only with respect to the sensitivity of that organism whose response it controls. Thus, in the case of the dog-fight, 01's bared teeth are a gesture to 02 who side-steps. A great deal of human behavior functions as gesture
(513) signs which are meaningful only to other observers. Such, for instance, arc most of our "facial expressions," the clenched fist in combat, and even many shades of our speech. If a gesture were a common sign, it would also stimulate a response in the gesturing organism. Such a common sign is not essential to the performance of a social act. The existence of a social act only requires that each organism be sensitive to, i.e., an observer of, the gestures of others in order that these may control his own responses. Thus, what is the least essential, in fact ruinous, to carrying on a boxing bout is that each boxer observe his own gestures as these stimulate the appropriate phases of his opponent's blows. If one is constantly sensitive to one's own gesture signs, one's behavior, being conscious, will slow up, and will be ineffective where rapid social adjustments are necessary. Mead held that we have no evidence that the members of sub-human groups can, by means of their own gestures, stimulate in themselves the responses which they stimulate in others. Mead's own theory implied that the dog would have to be able to take the rôle of the other. Regardless of Mead's theory, evidence for the use of common gestures here would consist, for instance, in a dog's baring his teeth merely to frighten and not actually to fight another dog. Even children make gestures long before they "understand" them, that is, observe them as signs. They act socially before they use their gestures consciously as imitations of adults. The principle may be laid down, then, that each social organism is as such an observer of the gestures of others, but not necessarily of his own. The gesture response is the other's sign and not the gesturer's sign.
Lastly, a. gesture as such has no common referent and no common reference. The referent of any gesture is the subsequent response of the gesturer, and its reference to this referent is the response of the gesture-observer, which is another organism. The bared teeth of dog A refer to his subsequent bite, and this gesture's reference is constituted by the response of the second dog. The early windup of the pitcher refers to the pitcher's subsequent throw in so far as it controls the catcher's response to the subsequent throw. The catcher's getting in position refers to his subsequent catch. In this respect a gesture differs radically from a communicative symbol which has the same reference relation for every organism.
A gesture and its reference, i.e., the response it controls as found in another organism, are different from a symbol and its idea. But still there are striking similarities between a symbol and a gesture. First, a gesture is distinct from the referential response which it controls, just as an idea of an object is distinct from the symbol which determines the idea. Secondly, it is the gesture's reference
( 514) response which controls the subsequent response of the gesturer, just as an idea may control one's subsequent behavior to the thought of an object.
The question now arises as to how gestures may be transformed into symbols. In an overt social act controlled by mere gestures, it is the immediate response of another, B, as determined by the gesture of 11, which is the controlling object of A's subsequent response. A has no idea of the object of his response, viz., the behavior of another which functions as a control over his reaction to R when B is not sensibly present. Thus, the object of each organism's response is the response of another organism, and these constitute a common social act.
Our main problem now is to describe how a gesture would have to function in order to stimulate, in two or more organisms, responses which constitute, according to the above criteria, ideas of a common referent. The common referent in this case is, as we shall see, the overt social act as a whole, and the idea is a logical universal because its symbol is socially universal.
JOHN M. BREWSTER.