Hebb's Theory Research Articles

The Hebbian paradigm reintegrated: Local reverberations as internal representations

AbstractThe neurophysiological evidence from the Miyashita group's experiments on monkeys as well as cognitive experience common to us all suggests that local neuronal spike rate distributions might persist in the absence of their eliciting stimulus. In Hebb's cell-assembly theory, learning dynamics stabilize such self-maintaining reverberations. Quasi-quantitive modeling of the experimental data on internal representations in association-cortex modules identifies the reverberations (delay spike activity) as the internal code (representation). This leads to cognitive and neurophysiological predictions, many following directly from the language used to describe the activity in the experimental delay period, others from the details of how the model captures the properties of the internal representations.

Modelling Hebbian cell assemblies comprised of cortical neurons

A highly simplified network model of cortical associative memory, based on Hebb's theory of cell assemblies, has been developed and simulated. The network comprises realistically modelled pyramidal-type cells and inhibitory fast-spiking interneurons and its connectivity is adopted from a trained recurrent artificial neural network. After-activity, pattern completion and competition between cell assemblies is readily produced. If, instead of pyramidal cells, motor neuron type cells are used, network behaviour changes drastically. For instance, spike synchronization can be observed but after-activity is hard to produce. The authors results support the biological feasibility of Hebb's cell assembly theory. The analogy between this theory and recurrent artificial neural network models is discussed.

Modelling Hebbian cell assemblies comprised of cortical neurons

A highly simplified network model of cortical associative memory, based on Hebb's theory of cell assemblies, has been developed and simulated. The network comprises realistically modelled pyramidal...

Peripheral detection and central task complexity.

Subjects verbally tracked a central task that differed on a complexity dimension (subsets of two, four, or eight digits), while indicating their detection of small peripheral lights by pressing a hand–held switch. Teichner's stress theory would predict that the more complex the central task, the longer would be the reaction times to the peripheral lights, and that the differences would be most pronounced in the far periphery (the funneling effect). Hebb's arousal theory, applied to vigilance behavior, would predict the opposite effect, where increasing the complexity of the central task would heighten the subject's vigilance performance. The results supported an arousal interpretation, with faster reaction times to the peripheral lights as central task complexity increased.

Effects of prolonged low-frequency whole-body vibration on rats

Two cages of rats (N = 10) were subjected to continuous low-frequency vibration for 92 days. The vibrated Ss weighed less than control Ss in the later stages of vibration and were more active in an open-field test given 3 days after the vibration period. Necropsies of both groups did not reveal any permanent damage to the heart, kidneys, spleen, lungs, brain, testes, adrenals, thymus~ and liver as a consequence of the prolonged vibration. H~man Ss exposed to low-frequency whole-body vibration in buildings, vehicles, and aircraft often report discomfort. The experimental research regarding the effects of vibration upon animals has been reviewed by Schaefer & Ulmer (1959) and Nadel (1963). Schaefer, Link, Farrar, & Weins (1959) showed that lethality in confined rats was directly related to the frequency (10 to 45 Hz) of whole-body vibration when the amplitude was held constant at 0.25 in. In further studies, Schaefer, Ulmer, & Link (1959) found that vibrated rats weighted less, were less active in an open field, and that some . Ss had testicular atrophy and myocardial hemorrhages. The authors jrter~reted these findings as ... demonstrating a general decrement or debility in both behavioral and physiological functioning, similar to the usual stress pattern [po 25]. Hunt & Quay ( 1961) and Soskin (1963) employed whole-body vibration to test Hebb's discrepancy-arousal theory of motivation. While their results generally did not confirm Hebb's theory, vibration was shown to be an effective aversive stimulus-Hunt and Quay demonstrated that naive rats woul d leverpress to terminate vibration, and Soskin observed that rats preferred a nonvibrating goalbox to a vibrating one in U-maze tests. It may be noted that the Ss were vibrated for 53 and 21 days, respectively, in the two studies prior to tests. More recently, in a series of seven experiments, Wike & Wike (1972) in v est igated barpressing that

Visual scanning of triangles by the human newborn

Ten human newborns were shown a homogeneous black visual field and ten newborns were shown a large black triangle on a white field. Ocular orientation to within approximately ±5° of visual angle was measured by scoring infrared photographs of corneal reflections. The infants showed much less disperison of scanning in the presence of the triangle than in the presence of the homogeneous field. Moreover, ocular orientations were directed toward a vertex of the presented triangle. The results were related to Hebb's theory of perceptual development, to analyzer theories of discrimination, and to studies of complexity and preference in the human newborn.

A Quasineurological Model Elucidating the Causality of Freud's Topographic Formulation

Freud's topographic formulation is central to psychoanalytic theory. Nevertheless, there is little understanding of the causality underlying the topographic phenomena. This paper elaborates Hebb's theory, introducing more complex operations which are used as concrete explanation for the topographic formulation. A simplified six-step developmental outline of the unconscious process is employed to show how punishment may lead to fear and fear-avoidance, permanent anxiety and defense against anxiety, cognitive deficit and repression, and behavioral rigidification It becomes possible to see how the mental apparatus can give rise to the rational and irrational, how these two spheres of action may reside side by side and interpenetrate.

THE EFFECT OF AGE AND RELATIVE BRIGHTNESS ON ASSOCIATIVE LEARNING IN CHILDREN

Developmental theorists and child psychologists have placed considerable emphasis on the influence of processes on psychological and behavioral development. However, during recent years there have been relatively few systematic investigations concerned with this problem. A major difficulty, of course, has been the lack of clear theoretical formulations that specify the way in which maturational and environmental factors combine to produce effects on psychological development. Hebb's theory (2) is a step in the direction of developing such a structure. Previous investigations of age changes, as well as age differences, in learning have yielded conflicting results. Munn (5) and Razran (6), in the light of these disagreements, have pointed out, however, that these studies differ on a number of important variables other than age. Practice, motivational conditions, and type and difficulty level of tasks vary so widely that generalizations concerning the age variable are difficult to make. Nevertheless, there is abundant evi-

Conflict and choice time.

Four variables have been suggested as determinants of degree of conflict: (1) number, (2) nearness to equality in strength, (3) absolute strength, and (4) degree of incompatibility, of competing response tendencies. first two, but not others, have figured in investigations relating reaction time to information theory. Three experiments were carried out to test effects of all these variables on choice time. Two types of choice RT were recorded: first, forced‐choice RT (i.e. traditional choice RT), for which one stimulus was presented at a time, each stimulus having its appropriate response; and second, free‐choice RT, for which two or more stimuli were presented together, S having to respond to any one of them.principal findings were as follows. (1) Both types of choice RT were longer when number of alternative responses was increased. (2) Free‐choice RT's were invariably longer than forced‐choice RT's, confirming influence of equality of strength. (3) Forced‐choice RT's were inversely related to stimulus intensity, which was regarded as a factor influencing absolute strength of response tendencies. Free‐choice RT's were shortest at intermediate of three intensity levels studied and significantly longer at highest and lowest levels. proportion by which free‐choice RT's exceeded forced‐choice RT's increased with stimulus intensity. (4) Degree of physiological incompatibility did not affect free‐choice RT's, although physiologically incompatible responses produced longer forced‐choice RT's. (5) There were no significant differences between RT's of S's with high and low neuroticism scores.expediency of continuing to include degree of physiological incompatibility among determinants of degree of conflict is called in question by results. Otherwise, choice time, apart from time taken up by eye movements, etc., which may be shorter with more intense stimuli, appears to increase with degree of conflict. results are discussed in light of various theoretical models, derived from Hull's principle of behavioural oscillation, Miller's theory of conflict, information theory, and Hebb's theory of cortical disruption.

Recall and Organization of Aggressive Words under Varied Conditions of Emphasis

As generations of underlining, note-taking students testify, material emphasized in any fashion becomes more memorable. Within experimental confines this seems demonstrable whether the emphasis stems from differential reinforcement (9 ) , configural isolation ( 11 ) , or personal motivational import ( 10, 13 ) . In a series of studies, Bousfield and his associates have explored one variety of differential reinforcement dependent on intrinsic organizational habits (1, 2, 3 ) . These studies have shown that when all che words of a given list may be subsumed under a few superordinate concepts, when for example the list consists of 10 animals plus 10 names plus 10 professions plus 10 vegetables, presented in randomized order with instructions to recall as many as possible just as they come to mind, two main phenomena occur. First, words embodying the same superordinate tend to be listed successively during recall, to a degree significantly above chance; this means they receive organization not initially present in the randomized stimulus list ( 1 ) . Second, word lists so designed are more memorable than lists equated for ThorndikeLorge frequency count but more heterogeneous with respect to number of built-in superordinates ( 2 ) . Deriving his explanation from Hebb's cognicive theory, Bousfield ( 2 ) suggests' that any perceived word, e. g., cat, may activate super~rdinate l~ related cognitive systems, e. g., those corresponding to 'feline,' 'pet,' 'animal,' but that recurrence of related subordinates, e.g., cat-shortly-followed-by-fox, differentially reinforces the shared superordinate, in this case, animal. The aroused superordinate in turn confers added response-readiness on all subordinate members; not only are related words apt to be evoked one after the other during recall, but the emphasizing action of the facilitated superordinate lends memorability. Up to a limiting point, the more often the superordinate is stimulated by recurring subordinates, the stronger its reciprocal facilitating action. Thus it has been found that the larger the number of cues to the meaning of each item on the list, the better the recall, e.g., word-plus-coloredline-drawing > word-pius-line-drawing > word-alone ( 3 ) . Sakoda ( 15) has demonstrated that the correlation between clustering and recall is very high when individual differences in readiness to make use of