1992 — 2000 |
Carpenter, Patricia A |
K05Activity Code Description: For the support of a research scientist qualified to pursue independent research which would extend the research program of the sponsoring institution, or to direct an essential part of this research program. |
Working Memory in Visual Reasoning and Language @ Carnegie-Mellon University
This proposal constitutes an application for an ADAMHA Research Scientist Award (RSA). The research activity consists of new experimental investigations focusing on working memory constraints and individual differences in visual reasoning, as well as new theory development. The PI also intends to extend her familiarity with the experimental methodologies and theories in the neuropsychology of language, as well as connectionist simulation techniques. The proposed research examines how the limited capacity of working memory constrains problem solving and visualization in visual reasoning tasks. One series of experiments investigates a problem-solving task whose solution requires that subjects mentally generate a series of goals and subgoals and then retrieve them appropriately. The hypothesis is that experimental manipulations that increase the goal management load should cause selective decrements in performance, partly at times when the load is high and particularly for individuals who have a low capacity for mental goal management. A second series examines the working memory demands of spatial and non- spatial strategies that can be used in a deductive reasoning task (linear syllogisms). The experiments examine what aspect of working memory resources determines the shift from one strategy to the other, and what the processing consequences are of each strategy. Other studies investigate complex visual tasks that require the visualization of mechanical motion. The process of understanding a mechanical device involves both the goal management that is found in ordinary reasoning, as well as the visualization of constrained motion. These experiments examine the contribution of goal management ability and spatial ability to performance in complex visualization tasks. The dependent measures to be used include both response latencies (the time to choose a next move in a problem or to mentally generate a constrained spatial transformation) and error patterns. In addition, pupil dilation measures will be used to index the consumption of cognitive resources. The obtained results will be integrated within a capacity-constrained computational model of working memory. Within this model, a production- system architecture with graded activations propagated by productions, both the processing and storage functions of working memory are fueled by activation. The total amount of activation available to the system has an upperbound that corresponds to the maximum capacity of an individual. The goal of the theory is to explain how performance and strategy selection in visual reasoning are influenced by working memory capacity. This research can indicate how the availability of cognitive resources affects visual thinking in different individuals, from the most gifted to those with neurological impairments.
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1 |
1997 — 2001 |
Carpenter, Patricia A |
P01Activity Code Description: For the support of a broadly based, multidisciplinary, often long-term research program which has a specific major objective or a basic theme. A program project generally involves the organized efforts of relatively large groups, members of which are conducting research projects designed to elucidate the various aspects or components of this objective. Each research project is usually under the leadership of an established investigator. The grant can provide support for certain basic resources used by these groups in the program, including clinical components, the sharing of which facilitates the total research effort. A program project is directed toward a range of problems having a central research focus, in contrast to the usually narrower thrust of the traditional research project. Each project supported through this mechanism should contribute or be directly related to the common theme of the total research effort. These scientifically meritorious projects should demonstrate an essential element of unity and interdependence, i.e., a system of research activities and projects directed toward a well-defined research program goal. |
Behavioral and Fmri Studies of Cognition in Autism @ Mellon Pitts Corporation (Mpc Corp)
The braod objective of the proposed research is to provide an integrated account of the cognition of autism that applies to both the cognitive and neural levels. The general approach is to determine how the cognitive system and the underlying neural systems are modulated by variations in the size and type of the processing demand that a task imposes. The brain imaging studies will use fMRI (functional Magnetic Resonance Imaging) in conjunction with previously tested functional neuroimaging paradigms for studing cognitive processes. The studies test the theory that the cognitive deficits that autistic individuals exhibit in higher level abstraction are due in considerable part to difficulties with executive processes that require extensive involvement of the prefrontal cortex. The studies will compare the cognitive performance and brain activity of individuals with autism to corresponding measures in age and IQ matched control subjects. In addition, key facets of language development and executive processing will be examined longitudinally (over a 3 to 5 year interval) in autistic children and adolescents and in control subjects, in both behavioral and brain imaging studies. The research will focus on three cognitive systems: the language comprehension system, the visuo-spatial processing system, and the executive processing system. Language comprehension will be examined with sentence comprehension and working-memory span tasks; visuo-spatial reasoning will be examined in the block design task and the mental rotation tasks; executive processes will be examined with the Tower of London task and a Piagetian reasoning task. The studies are expected to show that the visuo-spatial system is relatively spared in autism, although performance in visuo-spatial tasks can be impaired if the task places a large demand on executive processes. However, it is uncertain whether the language comprehension system is inherently impaired in autism, or alternatively, whether it produces impaired performance only in conjunction with an impaired executive system when executive processing demands are high. The converging multi-level approaches are expected to produce a characterization of autism that will provide new insights for therapy and and for facilitating daily functioning.
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0.916 |