Chaotic dimensionality of hand movements define processing capacity by relational complexity

1998 ◽  
Vol 21 (6) ◽  
pp. 842-843
Author(s):  
Danko Nikolic
Keyword(s):  
Task Complexity ◽  
Behavioral Data ◽  
Hand Movements ◽  
Chaotic Attractors ◽  
Processing Capacity ◽  
Neural Firing ◽  
Experimental Conditions ◽  
Relational Complexity

Measurements of the dimensionality of chaotic attractors obtained on behavioral data represent the task complexity and also could be hypothesized to reflect the number of synchronized neural groups involved in the generation of the data. The changes in dimensionality for different experimental conditions suggest that limited processing capacity, task complexity, demand, and synchrony in neural firing might be closely related.

Relational complexity metric is effective when assessments are based on actual cognitive processes

1998 ◽  
Vol 21 (6) ◽  
pp. 848-860 ◽  
Author(s):  
Graeme S. Halford ◽  
William H. Wilson ◽  
Steven Phillips
Keyword(s):  
Complexity Theory ◽  
Cognitive Processes ◽  
Task Complexity ◽  
Developmental Differences ◽  
Connectionist Models ◽  
The Core ◽  
Target Article ◽  
Research Findings ◽  
Core Issue ◽  
Relational Complexity

The core issue of our target article concerns how relational complexity should be assessed. We propose that assessments must be based on actual cognitive processes used in performing each step of a task. Complexity comparisons are important for the orderly interpretation of research findings. The links between relational complexity theory and several other formulations, as well as its implications for neural functioning, connectionist models, the roles of knowledge, and individual and developmental differences, are considered.

Processing capacity defined by relational complexity: Implications for comparative, developmental, and cognitive psychology

1998 ◽  
Vol 21 (6) ◽  
pp. 803-831 ◽  
Author(s):  
Graeme S. Halford ◽  
William H. Wilson ◽  
Steven Phillips
Keyword(s):  
Working Memory ◽  
Sentence Comprehension ◽  
Computational Cost ◽  
Processing Capacity ◽  
Neural Net ◽  
Processing Load ◽  
Unary Relation ◽  
Sources Of Variation ◽  
Experimental Findings ◽  
Relational Complexity

Working memory limits are best defined in terms of the complexity of the relations that can be processed in parallel. Complexity is defined as the number of related dimensions or sources of variation. A unary relation has one argument and one source of variation; its argument can be instantiated in only one way at a time. A binary relation has two arguments, two sources of variation, and two instantiations, and so on. Dimensionality is related to the number of chunks, because both attributes on dimensions and chunks are independent units of information of arbitrary size. Studies of working memory limits suggest that there is a soft limit corresponding to the parallel processing of one quaternary relation. More complex concepts are processed by “segmentation” or “conceptual chunking.” In segmentation, tasks are broken into components that do not exceed processing capacity and can be processed serially. In conceptual chunking, representations are “collapsed” to reduce their dimensionality and hence their processing load, but at the cost of making some relational information inaccessible. Neural net models of relational representations show that relations with more arguments have a higher computational cost that coincides with experimental findings on higher processing loads in humans. Relational complexity is related to processing load in reasoning and sentence comprehension and can distinguish between the capacities of higher species. The complexity of relations processed by children increases with age. Implications for neural net models and theories of cognition and cognitive development are discussed.

Ipsilateral Motor Cortex Activity During Unimanual Hand Movements Relates to Task Complexity

2005 ◽  
Vol 93 (3) ◽  
pp. 1209-1222 ◽  
Author(s):  
Timothy Verstynen ◽  
Jörn Diedrichsen ◽  
Neil Albert ◽  
Paul Aparicio ◽  
Richard B. Ivry
Keyword(s):  
Motor Cortex ◽  
Left Hemisphere ◽  
Time Course ◽  
Right Hemisphere ◽  
Task Complexity ◽  
Hand Movements ◽  
Left Hand ◽  
Sequential Structure ◽  
Single Finger ◽  
The Right

Functional imaging studies have revealed recruitment of ipsilateral motor areas during the production of sequential unimanual finger movements. This phenomenon is more prominent in the left hemisphere during left-hand movements than in the right hemisphere during right-hand movements. Here we investigate whether this lateralization pattern is related specifically to the sequential structure of the unimanual action or generalizes to other complex movements. Using event-related fMRI, we measured activation changes in the motor cortex during three types of unimanual movements: repetitions of a sequence of movements with multiple fingers, repetitive “chords” composed of three simultaneous key presses, and simple repetitive tapping movements with a single finger. During sequence and chord movements, strong ipsilateral activation was observed and was especially pronounced in the left hemisphere during left-hand movements. This pattern was evident for both right-handed and, to a lesser degree, left-handed individuals. Ipsilateral activation was less pronounced in the tapping condition. The site of ipsilateral activation was shifted laterally, ventrally, and anteriorly with respect to that observed during contralateral movements and the time course of activation implied a role in the execution rather than planning of the movement. A control experiment revealed that strong ipsilateral activity in left motor cortex is specific to complex movements and does not depend on the number of required muscles. These findings indicate a prominent role of left hemisphere in the execution of complex movements independent of the sequential nature of the task.

ACT-R: A higher-level account of processing capacity

1998 ◽  
Vol 21 (6) ◽  
pp. 831-832 ◽  
Author(s):  
John R. Anderson ◽  
Christian Lebiere ◽  
Marsha Lovett ◽  
Lynne Reder
Keyword(s):  
Individual Differences ◽  
Processing Capacity ◽  
Spreading Activation ◽  
Relational Complexity

We present an account of processing capacity in the ACT-R theory. At the symbolic level, the number of chunks in the current goal provides a measure of relational complexity. At the subsymbolic level, limits on spreading activation, measured by the attentional parameter W, provide a theory of processing capacity, which has been applied to performance, learning, and individual differences data.

scholarly journals Task Aspects Triggering Observational Learning in Jackdaws (Corvus monedula)

2020 ◽  
Vol 7 (4) ◽  
pp. 567-588
Author(s):  
Berenika Mioduszewska ◽  
Xenia Schleuning ◽  
Anaïs Brunon ◽  
Mark O’Hara ◽  
Alice M. I. Auersperg ◽  
...  
Keyword(s):  
Observational Learning ◽  
Task Complexity ◽  
Animal Cognition ◽  
Learning Mechanisms ◽  
Experimental Conditions ◽  
Action Sequence ◽  
Future Studies ◽  
Informational Cues ◽  
Foraging Task ◽  
Corvus Monedula

Complex novel tasks are often used in animal cognition research to allow discrimination between various learning mechanisms. Successful performance relies on the capacity to identify informational cues from features in the environment. Additionally, observational learning is often considered more beneficial for survival than individual learning. Despite the importance of controlling task complexity, it can often be challenging to operationalize. This study investigated whether jackdaws, a highly social corvid species, can learn to drop stones inside a tube to release a reward after observing a trained conspecific. Additionally, it aimed to identify the underlying learning mechanisms and to detect the informational cues triggering learning. A research design was developed to highlight different aspects of the required action sequence. Experimental conditions included a conspecific model demonstrating the full sequence, parts of the sequence, consuming the reward without solving the task, and consuming the reward after the solution was demonstrated without a visible model. None of the 12 naïve jackdaws solved the task in pretests. Two subjects started solving in test sessions and they developed modified versions of the demonstrated action. Observing the full action sequence performed by a conspecific seemed to trigger learning. The majority of the subjects exhibited changes in their stone-oriented behavior, most likely due to stimulus and/or local enhancement. As predicted, jackdaws were influenced by conspecific model demonstrations when manipulating a complex novel foraging task. Factors contributing to the apparent task difficulty and directions for future studies are discussed within a tri-dimensional framework including the task, setup, and individuals.

Interference with Olfactory Memory by Visual and Verbal Tasks

1995 ◽  
Vol 80 (3_suppl) ◽  
pp. 1307-1317 ◽  
Author(s):  
Judith M. Annett ◽  
Neil Mclaughlin Cook ◽  
Julian C. Leslie
Keyword(s):  
Free Recall ◽  
Task Complexity ◽  
Recall Performance ◽  
Verbal Task ◽  
Dual Coding ◽  
Olfactory Memory ◽  
Interference Task ◽  
Experimental Conditions ◽  
Verbal Tasks ◽  
Theoretical Issues

It has been claimed that olfactory memory is distinct from memory in other modalities. This study investigated the effectiveness of visual and verbal tasks in interfering with olfactory memory and included methodological changes from other recent studies. Subjects were allocated to one of four experimental conditions involving interference tasks [no interference task; visual task; verbal task; visual-plus-verbal task] and presented 15 target odours. Either recognition of the odours or free recall of the odour names was tested on one occasion, either within 15 minutes of presentation or one week later. Recognition and recall performance both showed effects of interference of visual and verbal tasks but there was no effect for time of testing. While the results may be accommodated within a dual coding framework, further work is indicated to resolve theoretical issues relating to task complexity.

scholarly journals Executive control mechanisms in bilingualism: Beyond speed of processing

2016 ◽  
Vol 20 (3) ◽  
pp. 613-631 ◽  
Author(s):  
KLARA MARTON ◽  
MIRA GORAL ◽  
LUCA CAMPANELLI ◽  
JUNGMEE YOON ◽  
LORAINE K. OBLER
Keyword(s):  
Young Adults ◽  
Implicit Learning ◽  
Executive Control ◽  
Processing Speed ◽  
Task Complexity ◽  
Task Demands ◽  
Control Mechanisms ◽  
Experimental Conditions ◽  
Bilingual Advantage ◽  
Baseline Response

The question of interest in this study was whether bilingual individuals show superior executive control compared to monolingual participants. Findings are mixed, with studies showing advantage, disadvantage, or no difference between bilingual and monolingual speakers. In this study, we used different experimental conditions to examine implicit learning, resistance to interference, monitoring, and switching, independently. In addition, we matched our monolingual and bilingual participants on baseline response time. Bilingual participants demonstrated faster implicit learning, greater resistance to interference, more efficient switching compared to monolingual participants. The groups did not differ in monitoring. In conclusion, depending on task complexity and on the target executive control component, there are different patterns of bilingual advantage, beyond the global faster processing speed documented in previous studies. Bilingual young adults showed more efficient adjustments of the cognitive system in response to changes in task demands.

Electrolytic Isolation of Twin-Type Shock Deformation Structures

1967 ◽  
Vol 25 ◽  
pp. 318-319
Author(s):  
F. I. Grace ◽  
L. E. Murr
Keyword(s):  
Grain Boundaries ◽  
Thin Foil ◽  
Electrolyte Composition ◽  
Experimental Conditions ◽  
Average Current Density ◽  
Electron Transmission ◽  
Deformation Structures ◽  
The Matrix ◽  
Average Current ◽  
Specimen Edge

During the course of electron transmission investigations of the deformation structures associated with shock-loaded thin foil specimens of 70/30 brass, it was observed that in a number of instances preferential etching occurred along grain boundaries; and that the degree of etching appeared to depend upon the various experimental conditions prevailing during electropolishing. These included the electrolyte composition, the average current density, and the temperature in the vicinity of the specimen. In the specific case of 70/30 brass shock-loaded at pressures in the range 200-400 kilobars, the predominant mode of deformation was observed to be twin-type faults which in several cases exhibited preferential etching similar to that observed along grain boundaries. A novel feature of this particular phenomenon was that in certain cases, especially for twins located in the vicinity of the specimen edge, the etching or preferential electropolishing literally isolated these structures from the matrix.

Site of Lysosome Production During Hepatic Injury

1969 ◽  
Vol 27 ◽  
pp. 348-349
Author(s):  
Nalin J. Unakar
Keyword(s):  
Electron Microscopy ◽  
Golgi Apparatus ◽  
Mouse Liver ◽  
Hepatic Injury ◽  
Close Approximation ◽  
Experimental Conditions ◽  
Toxic Injury

The increased number of lysosomes as well as the close approximation of lysosomes to the Golgi apparatus in tissue under variety of experimental conditions is commonly observed. These observations suggest Golgi involvement in lysosomal production. The role of the Golgi apparatus in the production of lysosomes in mouse liver was studied by electron microscopy of liver following toxic injury by CCI4.

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