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John Milton said “Where there is much desire to learn, there will of necessity be much arguing, much writing, and many opinions, for opinion in good men is but knowledge in the making.” One of the most unsettled parts of the field of communication research and theory is the area of “ricochet” or “two‐step” information flow (briefly, the mass media tell the opinion leaders who tell others face‐to‐face). The assassination of President Kennedy provided an opportunity for a number of researchers to investigate the diffusion of information in a crisis situation. One of these studies, by Harold Mendelsohn, was published in the Spring 1964 issue of the Journal under the title “Broadcast vs. Personal Sources of Information in Emergent Public Crises: The Presidential Assassination.” In the present article, Stephen Spitzer compares the results of six different studies of information dissemination in connection with the presidential assassination. Because his conclusions directly contradicted Dr. Mendelsohn's study,...

Although language is our chief means of communication, there are a number of problems connected with its use. A writer must be aware of these problems and learn to overcome them if he is to be understood by his readers. Some of the problems are: 1. Our language system is not adequate to meet all needs. 2. Words themselves do not have “meaning”—people give them meaning. 3. “Meaning” has several dimensions including denotative, connotative, structural and contextual. The writer must give attention to all of these types of meaning. 4. There is a basic conflict between maximum accuracy in writing and maximum understanding in reading. One of the most valuable tools used in improving understanding is redundancy. A reader's understanding level must be low if the rate of information flow exceeds his capacity to deal with it.

Groups of scholars often behave in ways that are startlingly reminiscent of the behavior of groups of plants and animals in a biological ecosystem. I have tried to show that the parallel may have its basis in two fundamental considerations: (i) the similar properties of stable dissipative structures in a wide variety of contexts and (ii) the mathematical similarity of information to chemical (nutrient) free energy. A particularly intriguing problem is that of successional trends arising from the kinetic limitation of information flow through the intellectual and social structures created by scholars. The "strategy of ecosystem development" may have implications for the strategy of academic administration. In this connection, it is worth bearing in mind Marglef's dictum ( 6 , p. 77): "Probably the hypothesis holds everywhere that the less mature ecosystem feeds the more mature structures around it."

Such phrases as “information flow” may be purely metaphorical, or may refer to porterage and storage of physical documents, transmission of signals, power required for signaling, Shannon's Selective Information, changes in the state of one's personal knowledge, propagation of announcements concerning messages, social increase of awareness, propagation of or reaction to imperatives, and so on. These matters are distinct and must be distinguished. Then conditions must be stated under which one can validly speak of and measure the appropriate flow. In this paper it is shown that within the field of Notification (mention and delivery of recorded messages to users) there are twenty basic activities formed by choosing triads from the six variables, Message, Code, Channel, Source, Destination, and Designation. “Flow” has meaning only when two such triads have two variables in common, forming a tetrad. Then flow or correspondence between any pair of variables is inextricable from a conjugate flow or correspondence between the other pair. Between any pair of endpoints there are six possible distinct types of flow, according to which two of the remaining four variables are directly used to achieve the flow.

Summary.-The influence of visual distortions introduced by cylindrical lenses upon copying a geometric pattern of varying distortion was studied in 15 Ss. The experimental conditions specifically influenced shape bur nor size and regularity of drawings; the latter rather depend upon repetition of the task. The results are discussed as indicating some properties of a central selective mechanism for a visual sensorimotor model. The nature of visual perception and sitbsequent motor execution has often been explored by upsetting in some manner the natural interaction between the eye and the visual environment. Such experimentation in man has involved alteration of the visual field through illusions (Ames, 1949) or through lens or prism combinations introd~iced between the eye and the visual environment (Arnes, 1946; Burian, 1943; Helmholtz, 1866; Lippincott, 1917; Smith & Smith, 1962; Stratton, 1897; Wadsworth, 1876). Among the more recent experiments, the work of Held and Gottlieb (1958) and Held and Hein (1958) on human adaptation to visual re-arrangement induced by wedge-prisms has shown again the importance of re-afferent stimulation in perception. Of interest is the information flow model Held proposed to account for the effects of sensorimotor experience upon such adaptation (Held, 1961). Perception and perceptual phenomena are more often being framed in terms of such models (MacKay, 1962). By expanding the dimensions measured in visual sensorimotor experiments, such models may be made more adequate. Thus Held's model, which describes the long-term effects noted in his experiments, is a modification of a model originally proposed by Holst ( 1954) to describe an instantaneous process (see also Hein & Held, 1962). To uncover additional factors which might be of use in future information flow models of visual-motor coordination, we have attempted in this pilot study to examine other dimensions of visual perception. The problem initially was to find a task which was more complex than the target localization method of Held and which was at the same time quantifiable; this would make it unlike many of the earlier visual re-arrangement experiments. Such was the drawing test of Reed, et al. (1965) for testing motor execution; this task requires copying with pencil on paper a geometric pattern (Fig. 1, A) according to specific insuuc[ions; from each copy critical measurements are taken and, with the aid of a com

This paper is concerned with behaviour possible in an information-flow system intended explicitly as a hypothetical model for comparison with human information-handling system. A statistically self-organizing system is described in which not only normal homeostatic behaviour but also such activities as invention of fruitful hypotheses, imagination of fictitious situations, and like would find a natural place. Discussion is confined mainly to manner of concept-formation and concept-handling in such a system. It has been suggested that correlate of perception (as distinct from reception) is activity which organizes an outwardly directed internal matching response to signals from receptors. This organizing activity amounts logically to an internal representation of feature in incoming signals to which it is adaptive, i.e. feature which is thus ‘perceived’. A hierarchic structure is postulated wherein much of organizing activity is concerned with modifying probabilities of other activity. Abstract concepts and hypotheses are represented by ‘sub-routines’ of such organizing activity. These can in principle be evolved as a result of experience in a manner analogous to-or at least fruitfully comparable with-process of learning and discovery; and it is not necessary for designer to predetermine, nor possible for him to foresee, all conceptual categories in terms of which information received by system may be structured. Particular attention is directed to conditions under which such a process of concept-formation could take place with sufficient rapidity. Some of symptoms of psychopathology find apparent correlates in possible modes of malfunction of such a system. But in this, as in other respects, it is not intended to press resemblances; intention is rather to stimulate critical comparisons, in order that differences between information-flow model and real thing may continually lead to progressive refinement and enlarged understanding.

Teaching and education are processes of communication. Educational theory is concerned with the communication process itself as well as with the cognitive changes brought about by this process. By far the greatest part of this communication is conveyed through speech and writing. Here we take the term “written language” to include mathematical, technical and similar symbols, also drawings and diagrams. In this chapter, the measurement of the information in written language is emphasized for two reasons: A) The transmission of information via printed texts plays a large part in teaching, study and education. Textbooks, handbooks, sourcebooks and reference works are used for this purpose. Today, on an increasing scale, programmed teaching texts are being introduced with the aim of making teaching objective. Besides instruction in reading, the traditional cultural skill—and for our purposes reading is the ability to code phonetic symbols into written symbols and vice versa—there is also instruction in the symbolic languages of mathematics, the natural sciences, technology and other areas of life. The application of information theory to written language opens up a defined and bounded set of pedagogical problems. B) At present there are still difficulties in attempting a differentiated and direct analysis of the written language by information theory. However, it is feasible to transcribe into written language the verbal communications which occur in the course of educational processes. Compared with direct communication, transcribed speech represents a loss, since it cannot express that part of the information flow between teacher and student which is conveyed by intonation, emphasis, and dynamics, or by gestures and mime. Nevertheless, a large proportion of the information survives transcription. Thus, teaching protocols can be used in the science of education for the analysis of instructional strategies, processes, and situations. If we can apply information theory to the study of written language, we can also gain indirect access to spoken communication via transcription.

After analyzing the common attacks for some software systems, a dynamic software behavior verification model related with the unchecked input data based on software analysis and dynamic slicing technology is proposed. Regarding a statement as a basic analysis unit, and the information flow as the main behavior of the software, the direction of the information flow of each statement is defined as its behavior specification, the information flow verification problem is converted into the verification for assigning variable address's validation. During the execution, behavior of the statements that use untrusted variable is monitored to verify whether the address modified by the statements belongs to the specification or not. If it is consistent with the specification, the execution of the statement is permitted. Based on the behavior model proposed, a method of extracting of the behavior specification was researched and a method of dynamic verification was designed. In order to prove for efficiency and performance of the model, the input data related behavior acquiring framework was implemented, and a set of tests were conducted. Preliminary results show the validity of the software's behavior model.

In transcribing documents for machine entry, the font limitation of existing input devices becomes a barrier to full information flow. The printer's press has more than 3,000 symbols commonly available; a Flexowriter has less than 90, a card punch has less than 50. A satisfactory input language must significantly reduce this disparity and meet three additional requirements:1) It should require a minimum of intellection on the part of the input typist.2) The typed copy should be readable or readily translatable.3) The language must be machine interpretable by unequivocal and simple algorithmsA method is shown meeting these requirements, which uses pseudo-alphabets having mnemonic names, wherein the initials of these names are used in a manner analogous to single-address computer codes. The sequence of a transform signal followed by an alphabet initial specifies the operation or transformation, and simple format rules specify the extent of the operand. The most frequently used elements of these pseudo-alphabets have themselves a high degree of mnemonic correspondence to the keyboard symbols that represent them. The method is shown to be machinable and the logic of a simple interpreter-translator is presented.

In whatever language today's physicist converses, one topic that will always enter the conversation is the problem of information flow within the physics community. Many participants will say that no problem exists and quote the invisible 'colleges of knowledge' through which they receive their information.