The Magical Number Seven, Plus or Minus Two: Some Limits on Our Capacity for Processing Information

First, the span of absolute judgment and the span of immediate memory impose severe limitations on the amount of information that we are able to receive, process, and remember. By organizing the stimulus input simultaneously into several dimensions and successively into a sequence or chunks, we manage to break (or at least stretch) this informational bottleneck. Second, the process of recoding is a very important one in human psychology and deserves much more explicit attention than it has received. In particular, the kind of linguistic recoding that people do seems to me to be the very lifeblood of the thought processes. Recoding procedures are a constant concern to clinicians, social psychologists, linguists, and anthropologists and yet, probably because recoding is less accessible to experimental manipulation than nonsense syllables or T mazes, the traditional experimental psychologist has contributed little or nothing to their analysis. Nevertheless, experimental techniques can be used, methods of recoding can be specified, behavioral indicants can be found. And I anticipate that we will find a very orderly set of relations describing what now seems an uncharted wilderness of individual differences. Third, the concepts and measures provided by the theory of information provide a quantitative way of getting at some of these questions. The theory provides us with a yardstick for calibrating our stimulus materials and for measuring the performance of our subjects. In the interests of communication I have suppressed the technical details of information measurement and have tried to express the ideas in more familiar terms; I hope this paraphrase will not lead you to think they are not useful in research. Informational concepts have already proved valuable in the study of discrimination and of language; they promise a great deal in the study of learning and memory; and it has even been proposed that they can be useful in the study of concept formation. A lot of questions that seemed fruitless twenty or thirty years ago may now be worth another look. In fact, I feel that my story here must stop just as it begins to get really interesting. And finally, what about the magical number seven? What about the seven wonders of the world, the seven seas, the seven deadly sins, the seven daughters of Atlas in the Pleiades, the seven ages of man, the seven levels of hell, the seven primary colors, the seven notes of the musical scale, and the seven days of the week? What about the seven-point rating scale, the seven categories for absolute judgment, the seven objects in the span of attention, and the seven digits in the span of immediate memory? For the present I propose to withhold judgment. Perhaps there is something deep and profound behind all these sevens, something just calling out for us to discover it. But I suspect that it is only a pernicious, Pythagorean coincidence

The operant conditioning of human motor behavior

A very large body of experimental results have accumulated in the field of operant, or instrumental, conditioning of the rat, the pigeon, and of other experimental animals. The application to human behavior of the laws generated by such research is most often done by the use of theory. An alternative method is to demonstrate that the manipulation of classes of empirically defined variables that produce specific and highly characteristic changes in the behavior of small experimental animals in Skinner boxes produce similar changes in the behavior of college students. This paper reports procedures for the direct application of the variables defining the paradigm for operant conditioning to human behavior and shows that human beings act very much indeed like experimental animals when they are subjected to the same experimental treatments. It suggests that direct application of conditioning principles to some categories of human behavior may be justified. The procedures are simple and they may be followed by anyone, with a minimum of equipment. That it is possible to condition human motor behavior will surprise few who are concerned with behavior theory. Nevertheless, it has not always been clear what behaviors will act as "responses," what events will prove to be "reinforcing stimuli," or exactly what procedures would most readily yield reproducible results. This paper describes methods that have been worded out for easy and rapid operant conditioning of motor behavior in humans, states characteristic findings, and reports sample results. Developed in a series of exploratory experiments in an elementary laboratory course in psychology, the methods may have a wider utility

The operant, from rat to man: an introduction to some recent experiments on human behavior.

Virtually all psychologists accept the premise that human behavior is orderly. The order that they see, however, varies considerably from group to group, and the aspects of behavior in which these orders appear differ as well. The clinician and the personality psychologist observe their fellow men and see need-presses, repressions, and aggressive drives. The experimental psychologist finds his order in the rates at which nonsense syllables are learned, or at which conditioned eyelid reflexes are acquired. If he is physiologically oriented, he is apt to concern himself with muscle twitches and even with the secretion of saliva. It is in terms of such variables that psychologists have set their descriptions of, and their predictions about, the actions of people. All of us, whether psychologists or not, observe people acting. We learn rules of "practical psychology." Some of us, especially the novelists and playwrights, do a remarkably good job of giving plausible accounts of behavior, often in terms that seem pertinent. These writers, however, do not employ the language used by psychologists at either end of the spectrum. They describe ordinary, everyday behavior, and describe it well, but not by using the conceptualizations that psychologists seem to have found useful, nor even terms that can be readily translated into such conceptualizations. The psychologist's efforts tend to be limited in their usefulness to the description and prediction of the behavior of people whose behavior is awry, or of people who are engaged in the strange and unusual activities demanded of them in a laboratory of experimental psychology. Dale Carnegie, practical politicians, and, perhaps, everybody but psychologists, concern themselves with simple, ordinary, everyday behavior. One reason for this situation is, perhaps, the lack of methods of conceptualizing behavior, or of abstracting relevant aspects of behavior for study that are not clinic- or laboratory-bound. This lack of methods is due, perhaps, to a conviction that ordinary behavior is too complex and is determined by too many variables to make possible the discovery of any order except by the application of theory. What I desire to do here is to introduce some concepts, and to describe some experiments derived from them, that suggest that the orderliness of human behavior may be more accessible than has been hitherto assumed. These experiments may accordingly suggest new direction for research on human behavior

Burrhus F. Skinner

In dealing with Skinner, we are concerned with a theorist who now espouses no theory, a systematist whose system is still developing, and a constructive thinker some of whose most important contributions have been those of a critic. In the course of his writings, Skinner has presented the results of a comprehensive experimental program, and elaborated a theory of behavior based upon it. Since its publication in comprehensive form in The Behavior of Organisms, he has, one may infer from more recent writings, modified it greatly by eliminating several central concepts without substituting others. These publications are not sufficient to enable us to analyze the system in its current status, so that we will restrict ourselves to its earlier form. From an examination of this theory, we may learn something of the reasons for its alteration, and perhaps reveal some relationships between the adequacy of the theory as it was stated and the procedures which were followed in its construction. That portions of the theory as it was presented in 1938 no longer find complete acceptance is not relevant to our purpose; much may be learned from autopsies. The revision of Sinner's theoretical views has not extended downward to his basic assumptions with respect to the nature of psychological theory, nor to the elementary statements of much of his data language and of the basic laws of behavior. The systematic position is unchanged. It is largely at the level at which complex concepts are introduced that revisions have been made

Eating and drinking as a function of maintenance schedule

Animals without water do not eat as much food as usual, and hungry animals do not drink much water (4, 8, 13, 16, 17, 20). Animals drink more after meals than at other times. The dog and hen (13) and the rat (20) show a drop in food intake during water deprivation. Dogs (5, 11) and rats (20) similarly drop in water intake during food deprivation. Rats drink more after a period of water deprivation during which food is available than after a similar period with no food available (17). The corresponding case for food intake apparently has not been investigated. After protracted periods of food or water deprivation, rats exceed in both drinking and eating their average value before deprivation (4). No systematic sets of data are available on these phenomena as they are encountered in studies of learning, although their signifigance for theoretical formulations of "motivation" and learning has not escaped some investigators (9, p.234; 22). Recent studies on "drive interaction," "drive discrimination," and on "cognitions" have involved the control of the behavior of food-deprived and of water-deprived rats by food and water placed in goal boxes and alleys (21). These have not had uniform results, so that it is pertinent to examine the matter more closely. Today's learning theorists are in fair agreement on a definition of "drive." This concept is an intervening variable, explicitly involving two sets of operations and implicitly a third.2 The first operations establish drives; e.g., for hunger and thirst, the animal is deprived of food and water, respectively, for a stated number of hours. The second class of operations is the measurement of classes of behavior (running, bar pressing, eating) that vary with the duration of the preceding deprivation. The third, implicit, operation is that of satiation, usually giving the animal access to food and water long enough so that it neither eats nor drinks for a specified period. "Satiation" operations vary considerably. In this experiment, the operations are depriving the animal of food or water, or both, through stated intervals of time following free feeding and free drinking. The measure of behavior chosen is the total weight, in grams, of food and water ingested by the animal in the first hour following the period of deprivation. The adequacy of these measures has been established by others (1, p.128; 2, 7, 15, 18, 19). The general plan of the experiment and the values of the variables investigated have been chosen to provide data useful for the interpretation of experimental data in the field of learning

Computing Machinery and Intelligence

I propose to consider the question, "Can machines think?" This should begin with definitions of the meaning of the terms "machine" and "think." The definitions might be framed so as to reflect so far as possible the normal use of the words, but this attitude is dangerous, If the meaning of the words "machine" and "think" are to be found by examining how they are commonly used it is difficult to escape the conclusion that the meaning and the answer to the question, "Can machines think?" is to be sought in a statistical survey such as a Gallup poll. But this is absurd. Instead of attempting such a definition I shall replace the question by another, which is closely related to it and is expressed in relatively unambiguous words. The new form of the problem can be described in terms of a game which we call the 'imitation game." It is played with three people, a man (A), a woman (B), and an interrogator (C) who may be of either sex. The interrogator stays in a room apart front the other two. The object of the game for the interrogator is to determine which of the other two is the man and which is the woman. He knows them by labels X and Y, and at the end of the game he says either "X is A and Y is B" or "X is B and Y is A." The interrogator is allowed to put questions to A and B. We now ask the question, "What will happen when a machine takes the part of A in this game?" Will the interrogator decide wrongly as often when the game is played like this as he does when the game is played between a man and a woman? These questions replace our original, "Can machines think?

Programma TFA Informatica di Base AA 2012-3

1. Che cos’è il software? La natura del software è un aspetto dell’informatica che viene raramente analizzato in tutti i suoi aspetti. Il software infatti ha almeno due livelli, il codice sorgente (leggibile dall’uomo) e il codice binario (leggibile dalla macchina). Ma questo primo livello di analisi lascia aperte una serie di domande importanti: quanto è importante l’implementazione? Perché usiamo diversi linguaggi di programmazione se in teoria sono tutti Turing-equivalenti? Che differenza c’è tra istruzioni, esecuzione, e dati? Vedremo il caso particolare della meta-\ud programmazione, e il ruolo del programmatore come (meta)autore del software.\ud \ud 2. Modelli di produzione del software. Attorno al software c’è tutto un ecosistema, formato da diverse figure, professionali e non solo: il designer, lo sviluppatore, il\ud committente, l’utente finale, ecc. A seconda della licenza scelta (proprietaria, a sorgente aperto, software libero) si configurano diversi modelli di produzione, con risvolti diversi anche da un punto di vista economico. Vedremo il modello di produzione industriale del software proprietario di tipo tayloristico, il modello Toyota (dall’eXtreme\ud Programming), il modello a bazar di Raymond, la strategia della doppia licenza, la legge della coda lunga di Anderson e altri modelli noti in letteratura.\ud \ud 3. Analisi di casi etici in informatica La pervasività dell’informatica nella società comporta una serie di dilemmi etici di difficile soluzione, che possono essere analizzati tramite il metodo dell’analisi dei casi etici. Dopo aver spiegato il metodo in tutti i suoi passaggi, verranno proposti alcuni casi etici noti in letteratura, quali: chi è responsabile del drone che in guerra uccide erroneamente un civile? È giusto mettere videocamere di sorveglianza ovunque o potrebbe essere usato per fini poco leciti e quindi andrebbe limitato