Structure from Stereo by Associative Learning of the Constraints

Perception ◽  
1989 ◽  
Vol 18 (6) ◽  
pp. 767-782 ◽  
Author(s):  
Alice J O'Toole
Keyword(s):  
Visual Field ◽  
Markov Process ◽  
Computational Model ◽  
Associative Learning ◽  
Input Data ◽  
Luminance Change ◽  
Depth Data ◽  
Graded Response ◽  
Left And Right ◽  
Spatial Locations

A computational model of structure from stereo that develops smoothness constraints naturally by associative learning of a large number of example mappings from disparity data to surface depth data is proposed. Banks of disparity-selective graded response units at all spatial locations in the visual field were the input data. These cells responded to matches of luminance change at convergent, divergent, or zero offsets in the left and right ‘retina’ samples. Surfaces were created by means of a pseudo-Markov process. From these surfaces, shaded marked and ummarked surfaces were created, along with random-dot versions of the same surfaces. Learning of these example shaded and shaded marked surfaces allowed the system to solve stereo mappings both for the surfaces it had learned and for surfaces it had not learned but which had been created by the same pseudo-Markov process. Further, the model was able to solve some random-dot versions of the surfaces when the surfaces had been learned as shaded marked surfaces.

Selectively Impaired Associative Learning in Older People with Cognitive Decline

2002 ◽  
Vol 14 (3) ◽  
pp. 484-492 ◽  
Author(s):  
Alexander Collie ◽  
Catherine Myers ◽  
Geoffrey Schnirman ◽  
Stephen Wood ◽  
Paul Maruff
Keyword(s):  
Cognitive Function ◽  
Older People ◽  
Cognitive Decline ◽  
Computational Model ◽  
Associative Learning ◽  
Declarative Memory ◽  
Hippocampal Formation ◽  
Impaired Performance ◽  
Experimental Protocols ◽  
Spatial Locations

Older people with declining cognitive function typically display deficits in declarative memory processes, often most evident on tests of associative learning (AL). The hippocampal formation (HF) is thought to be critically involved in the encoding and retrieval of such associations, consistent with neuroimaging findings that the HF is damaged in early stages of neurodegenerative disease and in older people with AL impairments. In the clinic, older people with cognitive decline commonly report difficulties associating names with faces. However, we have observed that such people are particularly impaired on tests requiring the association of novel stimuli. In Experiment 1, a series of AL tasks were administered to older people with cognitive decline to determine whether they were impaired at simply making associations, or at making associations between novel stimuli. In Experiment 2, we measured HF function in these subjects by administering an AL task designed to differentiate between HF-damaged and HF-intact individuals. Our experimental protocols were guided by a computational model of HF function in AL described by Gluck and Myers (1997). Older people with cognitive decline displayed impaired performance on tasks designed to be highly dependent upon intact HF function, including a task in which novel patterns and spatial locations were to be associated. These results suggest that the AL impairments observed in older people with cognitive decline may be due to HF dysfunction.

scholarly journals Left-right and upper-lower light sensitivity asymmetry in visual field defects caused by pituitary adenoma: a retrospective observational study

2019 ◽  
Author(s):  
Yumi Kotoda ◽  
Masakazu Kotoda ◽  
Masakazu Ogiwara ◽  
Hiroyuki Kinouchi ◽  
Hiroyuki Iijima
Keyword(s):  
Pituitary Adenoma ◽  
Visual Field ◽  
Light Sensitivity ◽  
Visual Field Defects ◽  
Lower Visual Field ◽  
Lower Quadrant ◽  
Lower Light ◽  
Left And Right ◽  
Left Right Asymmetry ◽  
Field Defects

Abstract Background While bitemporal visual field defects are characteristic in pituitary adenoma cases, it is rare to have complete bitemporal hemianopsia that is symmetrical in both eyes and has absolute scotoma throughout both temporal hemifields. Although several researches have investigated asymmetric visual field defects in patients with pituitary adenoma, no precise investigation with statistical analysis regarding the inter-eye and intra-eye symmetry of visual field defects has yet been reported. In this study, we conducted quantitative analysis to explore the asymmetric properties of visual field defects in pituitary adenoma patients. Methods Preoperative Humphrey 30-2 perimetry results were reviewed retrospectively using the charts of 28 pituitary adenoma patients who underwent surgery. Inter-eye light sensitivity comparisons of the temporal and nasal hemifields between the left and right eyes were conducted in each patient to study left-right asymmetry. Upper-lower asymmetry was investigated by comparing the frequency of severe scotoma (light sensitivity 5 dB or less) in the upper and lower visual field quadrants in the temporal and nasal hemifields. Results Left-right asymmetry was demonstrated in 61% of cases in the temporal hemifield and in 57% of cases in the nasal hemifield. Severe scotoma test points were investigated in the worse eye of each patient and were more frequent in the superotemporal quadrant of the visual field compared with the inferotemporal quadrant (P = 0.00029) and in the inferonasal quadrant compared to the superonasal quadrant (P = 0.00268). Conclusions Asymmetric visual field defects between left and right eyes are common in patients with pituitary adenoma. Severe scotoma is more frequent in the upper quadrant of the temporal hemifield and in the lower quadrant of the nasal hemifield.

scholarly journals Complex dynamics of choice during operant extinction and a “simple” associative learning account

2020 ◽  
Author(s):  
José R. Donoso ◽  
Julian Packheiser ◽  
Roland Pusch ◽  
Zhiyin Lederer ◽  
Thomas Walther ◽  
...  
Keyword(s):  
Computational Model ◽  
Associative Learning ◽  
Operant Conditioning ◽  
Complex Dynamics ◽  
Rule Learning ◽  
Learning Curves ◽  
Learning Mechanisms ◽  
Learning Session ◽  
Extinction Learning ◽  
Operant Extinction

AbstractExtinction learning, the process of ceasing an acquired behavior in response to altered reinforcement contingencies, is essential for survival in a changing environment. So far, research has mostly neglected the learning dynamics and variability of behavior during extinction learning and instead focused on a few response types that were studied by population averages. Here, we take a different approach by analyzing the trial-by-trial dynamics of operant extinction learning in both pigeons and a computational model. The task involved discriminant operant conditioning in context A, extinction in context B, and a return to context A to test the context-dependent return of the conditioned response (ABA renewal). By studying single learning curves across animals under repeated sessions of this paradigm, we uncovered a rich variability of behavior during extinction learning: (1) Pigeons prefer the unrewarded alternative choice in one-third of the sessions, predominantly during the very first extinction session an animal encountered. (2) In later sessions, abrupt transitions of behavior at the onset of context B emerge, and (3) the renewal effect decays as sessions progress. While these results could be interpreted in terms of rule learning mechanisms, we show that they can be parsimoniously accounted for by a computational model based only on associative learning between stimuli and actions. Our work thus demonstrates the critical importance of studying the trial-by-trial dynamics of learning in individual sessions, and the unexpected power of “simple” associative learning processes.Significance StatementOperant conditioning is essential for the discovery of purposeful actions, but once a stimulus-response association is acquired, the ability to extinguish it in response to altered reward contingencies is equally important. These processes also play a fundamental role in the development and treatment of pathological behaviors such as drug addiction, overeating and gambling. Here we show that extinction learning is not limited to the cessation of a previously reinforced response, but also drives the emergence of complex and variable choices that change from learning session to learning session. At first sight, these behavioral changes appear to reflect abstract rule learning, but we show in a computational model that they can emerge from “simple” associative learning.

Optimizational Model of Transit Line Chosen

2012 ◽  
Vol 178-181 ◽  
pp. 1887-1890
Author(s):  
Wen Bin Liu
Keyword(s):  
Graph Theory ◽  
Computational Model ◽  
Set Theory ◽  
Search Algorithm ◽  
Timing Function ◽  
Left And Right ◽  
Walking Time

In the paper,using graph theory,set theory and iteration,we give gradual search algorithm with number of transfer acting as parameter. Through dealing with data of traffic line, line is united in algorithm,and computational model is simplified. Through optimization of left and right in circuit site and same line repeating site, the shortest timing function in circuit is realized. We consider the subway and walking time of all sites furtherly.

Note on a Failure to Find Hemispheric Asymmetries for a Small Sample of Strongly Left- and Right-Handed Males and Females Using Verbal and Visuo-Spatial Recall

1980 ◽  
Vol 51 (1) ◽  
pp. 139-145 ◽  
Author(s):  
David K. Charman
Keyword(s):  
Visual Field ◽  
Small Sample ◽  
Hemispheric Asymmetries ◽  
Left Handed ◽  
Negative Findings ◽  
Left And Right ◽  
Males And Females ◽  
Spatial Positioning ◽  
Female Subjects

A column of letters was presented to the left, right, or center of the visual field of 10 male and 10 female subjects. 5 of each sex were either strongly left- or right-handed. The subjects' task was to position correctly the letters on a recall sheet. No significant hemispheric asymmetries emerged, a result that reflects other negative findings. The 10 females were significantly better at verbal identification; this was congruent with the literature. The 10 males and 10 females were equal in visuo-spatial (positioning) judgments; this did not support the literature. The 5 right-handed males were significantly inferior to the 5 left-handed males and the 10 females at positioning judgments, a result that remained unexplained. The findings were discussed in terms of other contradictory findings.

Left and Right Visual Field Superiority for Letter Classification

1979 ◽  
Vol 31 (3) ◽  
pp. 423-439 ◽  
Author(s):  
John Jonides
Keyword(s):  
Visual Field ◽  
Task Demands ◽  
Perceptual Processing ◽  
Right Visual Field ◽  
Left And Right ◽  
The Right ◽  
Visual Field Superiority

Two letter classification experiments examine the hypothesis that lateral asymmetries in perceptual processing are sensitive to subtle changes in task demands. The first experiment reports a right visual field superiority for an easy letter classification, but a left field superiority for a difficult classification using the same population of stimuli. Experiment II demonstrates that the right field superiority can be reversed if the easy classification trials are embedded among more difficult trials. The implications of these results for theories of hemispheric localization are discussed.

Effects of Stimulus and Field Size on the Accuracy of Orientation in the Homogeneous Environment

1965 ◽  
Vol 20 (1) ◽  
pp. 167-172
Author(s):  
Milton S. Katz ◽  
William Metlay ◽  
Paul A. Cirincione
Keyword(s):  
Visual Field ◽  
Small Error ◽  
Field Size ◽  
Homogeneous Field ◽  
Small Target ◽  
Systematic Fashion ◽  
Left And Right ◽  
Initial Starting ◽  
Initial Target ◽  
Homogeneous Environment

The effects of various size targets and the extent of the visual field on the accuracy of orientation in the homogeneous environment were investigated by requiring Ss to recenter four different targets, starting from 11 locations, in a 270° homogeneous field. The results showed that: (1) each S positioned all four targets in a preferred field, (2) small error scores and consistency in positioning around perceived centers were found with only three of the four targets, (3) in all cases the largest error and greatest variability was in centering the smallest target, (4) absolute errors were not related in any systematic fashion to the initial starting points, and (5) with respect to initial target presentations, i.e., left and right fields, S's errors tended to be smaller in the field containing that S's perceived center. It was suggested that the variability of the small target could be accounted for, in part, by the autokinetic effect.

Moral masters or moral apprentices? A connectionist account of sociomoral evaluation in preverbal infants

2021 ◽  
Author(s):  
Deon T. Benton ◽  
Candace Lapan
Keyword(s):  
Computational Model ◽  
Associative Learning ◽  
Computer Simulations ◽  
Learning Mechanism ◽  
Theoretical Account ◽  
Sociomoral Reasoning ◽  
Preverbal Infants

Numerous studies suggest that preverbal infants possess the ability to make sociomoral judgements and demonstrate a preference for prosocial agents. Some theorists argue that infants possess an “innate moral core” that guides their sociomoral reasoning. However, we propose that infants’ capacity for putative sociomoral evaluation and reasoning can just as likely be driven by a domain-general associative-learning mechanism that is sensitive to agent action. We implement this theoretical account in a connectionist computational model and show that it can account for the pattern of results in Hamlin et al. (2007) and Hamlin and Wynn (2011). These are pioneering studies in this area and were among the first studies to examine sociomoral evaluation in preverbal infants. Based on the results of 6 computer simulations, we suggest that a domain-general associative-learning mechanism can account for previous findings on preverbal infants’ capacity for sociomoral evaluation. These results suggest that an innate moral core may not be necessary to account for apparent sociomoral evaluation in infants.

Cerebral Lateralization of Global-Local Processing in Left- and Right-Handed People

2005 ◽  
Vol 100 (3) ◽  
pp. 734-742 ◽  
Author(s):  
Mohammad Ali Goodarzi ◽  
Mohammad Reza Taghavi ◽  
Mohammad Reza Zoughi
Keyword(s):  
Visual Field ◽  
Left Visual Field ◽  
Right Hemisphere ◽  
Local Processing ◽  
Cerebral Lateralization ◽  
Left Handed ◽  
Left And Right ◽  
The Right ◽  
Paradigm Analysis ◽  
Local Superiority

Cerebral lateralization of global-local processing of 70 left-handed and 70 right-handed students was compared using a computerized global-local task in a half-visual field paradigm. Analysis showed that left-handed individuals were slower than right-handed individuals in processing Globally Directed stimuli presented to the left visual field (right hemisphere). In addition, left-handed individuals showed smaller local superiority in the left hemisphere to the right-handed individuals. These findings are more consistent with Levy's prediction of spatial inferiority of left-handed individuals than Geschwind and Galaburda's or Annett's hypotheses.

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