25 research outputs found
Application of a Theory-Driven Approach to Detect Cognitively Disengaged Test-Taker Behavior
Bottom-up, data-driven response filtering methods that exclude unrealistically fast responses from calculating test scores have been successfully applied to improve test validity. We introduce a top-down, theory-driven method to detect cognitively disengaged behavior, compare it with a data-driven method using data from a nationally representative reading assessment, and discuss its potential and limitations
Morphological and Pathological Evolution of the Brain Microcirculation in Aging and Alzheimer’s Disease
Key pathological hallmarks of Alzheimer’s disease (AD), including amyloid plaques, cerebral amyloid angiopathy (CAA) and neurofibrillary tangles do not completely account for cognitive impairment, therefore other factors such as cardiovascular and cerebrovascular pathologies, may contribute to AD. In order to elucidate the microvascular changes that contribute to aging and disease, direct neuropathological staining and immunohistochemistry, were used to quantify the structural integrity of the microvasculature and its innervation in three oldest-old cohorts: 1) nonagenarians with AD and a high amyloid plaque load; 2) nonagenarians with no dementia and a high amyloid plaque load; 3) nonagenarians without dementia or amyloid plaques. In addition, a non-demented (ND) group (average age 71 years) with no amyloid plaques was included for comparison. While gray matter thickness and overall brain mass were reduced in AD compared to ND control groups, overall capillary density was not different. However, degenerated string capillaries were elevated in AD, potentially suggesting greater microvascular “dysfunction” compared to ND groups. Intriguingly, apolipoprotein ε4 carriers had significantly higher string vessel counts relative to non-ε4 carriers. Taken together, these data suggest a concomitant loss of functional capillaries and brain volume in AD subjects. We also demonstrated a trend of decreasing vesicular acetylcholine transporter staining, a marker of cortical cholinergic afferents that contribute to arteriolar vasoregulation, in AD compared to ND control groups, suggesting impaired control of vasodilation in AD subjects. In addition, tyrosine hydroxylase, a marker of noradrenergic vascular innervation, was reduced which may also contribute to a loss of control of vasoconstriction. The data highlight the importance of the brain microcirculation in the pathogenesis and evolution of AD
Combining cognitive theory and data driven approaches to examine students’ search behaviors in simulated digital environments
Abstract Background Digital Information Literacy (DIL) refers to the ability to obtain, understand, evaluate, and use information in digital contexts. To accurately capture various dimensions of DIL, assessment designers have increasingly looked toward complex, interactive simulation-based environments that afford more authentic learner performances. These rich assessment environments can capture process data produced by students’ goal driven interactions with digital sources but linking this data to inferences about the target constructs introduces significant measurement challenges which cognitive theory can help us address. Methods In this paper, we analyzed data generated from a simulated web search tool embedded within a theoretically-grounded virtual world assessment of multiple-source inquiry skills. We describe a multi-step clustering approach to identify patterns in student’s search processes by bringing together theory-informed process data indicators and sequence clustering methods. Results We identified four distinct search behaviors captured in students’ process data. We found that these search behaviors differed both in their contribution to the web search tool subscores as well as correlations with task level multiple-source inquiry subconstructs such as locating, evaluating, and synthesizing information. We argue that the search behaviors reflect differences in how students generate and update their task goals. Conclusion The data-driven approach we describe affords a qualitative understanding of student strategy use in a complex, dynamic simulation- and scenario-based environment. We discuss some of the strengths and challenges of using a theoretical understanding of multiple-source inquiry to inform how we processed, analyzed, and interpreted the data produced from this assessment tool and the implications of this approach for future research and development
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Assessing Online Collaborative Inquiry And Social Deliberation Skills As Learners Navigate Multiple Sources And Perspectives
Learners in today’s knowledge society have access to an overwhelming, ever-increasing amount of information. The Internet has become a universal source of information with new content increasing more than five exabytes every day (Internet Live Stats, 2016). Sorting through, processing, learning from, and effectively using this information demands a wide range of online research and inquiry skills. To answer questions and solve problems, individuals must rely on their own knowledge and ability to analyze and construct meaning from the tremendous amount of information with which they are confronted each day (Leu, Kinzer, Coiro, Castek, and Henry, 2013)
Assessing collaborative online inquiry and social deliberation in digital environments
We describe efforts to design and validate a digitally-based assessment of collaborative online inquiry and social deliberation using a digital virtual world platform with embedded supports for real-time collaboration. Cognitive validity studies were conducted to examine the collaborative prompts and the overall task, with 21 dyads participating in either Face-to-Face (FTF; n=5) or Computer-Mediated (CM; n=16) conditions. Quantitative results suggest the task captured variation in dyads’ inquiry performances and processes