Subliminal priming as a task-characteristic artifact

The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file.Title from title screen of research.pdf file (viewed on November 1, 2007)Includes bibliographical references.Thesis (M.A.) University of Missouri-Columbia 2007.Dissertations, Academic -- University of Missouri--Columbia -- Psychology.Demonstrations of subliminal priming rely on a dual task design: A target identification task in which the priming effect is measured, and a prime identification task in which visibility of the primes is assessed. The validity of this design relies on the critical assumption that the estimates of prime visibility accurately reflect prime visibility in the target identification task. Here it is suggested that the difference in difficulty between the two tasks results in a violation of this assumption. Specifically, the target identification task is easy while the prime identification task is extremely difficult. It is shown that decreasing the overall difficulty of the prime identification task results in increased prime identifiably. It is also shown that primes which are unable to be identified in a task which accurately estimates prime identifiably do not elicit a priming effect. Hence, we conclude that demonstrations of subliminal priming are an artifact of this violation rather than a real phenomenon

Assessing single- and dual-process accounts of recognition memory using hierarchical Bayesian models

Title from PDF of title page (University of Missouri--Columbia, viewed on May 27. 2010).The entire thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file; a non-technical public abstract appears in the public.pdf file.Dissertation advisor: Dr. Jeffrey N. Rouder.Vita.Ph. D. University of Missouri--Columbia 2010.Recognition memory refers to a person's ability to recognize something that has been previously encountered. For several decades recognition memory has been thought to be governed by a single process whereby the strength of a memory for an item dictates whether people judge the item as having been previously encountered or not. More recently, it has been proposed that recognition memory is governed by two, independent processes: Sometimes a memory judgement is based on strength, sometimes it is based on explicit recollection. Whereas this two-process theory has been embraced by many researchers, others claim that only one process is necessary to explain recognition memory. Here, I argue that all previous evidence for both the one and the two-process theories is questionable -- because all models of recognition memory are non-linear models, averaging data over factors that vary (e.g., items) will distort the conclusions drawn. In all previous work it has been necessary to average data over items in order to fit formal models. To avoid the distortions from averaging, I develop hierarchical versions of popular recognition memory models that simultaneously account for person and item variability. These models are fit to data from several experiments to assess the veracity of previous claims. The results of this hierarchical modeling suggest that 1) ROC asymmetry, which has served as strong evidence for particular one and two-process model, is not an artifact of averaging, 2) The Yonelinas two-process model provides a superior account of recognition memory data when compared with the unequal-variance signal detection model via the DIC model-fit statistic, and 3) Two-process model fits reveal that estimates of recollection and familiarity co-vary across items and people. Moreover, manipulations of depth-of-processing, perceptual matchmismatch, response deadline, and list length all affect both recollection and familiarity to some degree. This result implies that, although the two-process model is the best-fitting parametric model, the data are being generated from a yet-to-be specified one-process model.Includes bibliographical reference

Comparison of Proteomic Assessment Methods in Multiple Cohort Studies

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/155922/1/pmic13292_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/155922/2/pmic13292.pd

Type 2 Diabetes Modifies the association of Cad Genomic Risk Variants With Subclinical atherosclerosis

BACKGROUND: Individuals with type 2 diabetes (T2D) have an increased risk of coronary artery disease (CAD), but questions remain about the underlying pathology. Identifying which CAD loci are modified by T2D in the development of subclinical atherosclerosis (coronary artery calcification [CAC], carotid intima-media thickness, or carotid plaque) may improve our understanding of the mechanisms leading to the increased CAD in T2D. METHODS: We compared the common and rare variant associations of known CAD loci from the literature on CAC, carotid intima-media thickness, and carotid plaque in up to 29 670 participants, including up to 24 157 normoglycemic controls and 5513 T2D cases leveraging whole-genome sequencing data from the Trans-Omics for Precision Medicine program. We included first-order T2D interaction terms in each model to determine whether CAD loci were modified by T2D. The genetic main and interaction effects were assessed using a joint test to determine whether a CAD variant, or gene-based rare variant set, was associated with the respective subclinical atherosclerosis measures and then further determined whether these loci had a significant interaction test. RESULTS: Using a Bonferroni-corrected significance threshold of CONCLUSIONS: These results highlight T2D as an important modifier of rare variant associations in CAD loci with CAC

COPDGene® 2019: Redefining the Diagnosis of Chronic Obstructive Pulmonary Disease

Background:Chronic obstructive pulmonary disease (COPD) remains a major cause of morbidity and mortality. Present-day diagnostic criteria are largely based solely on spirometric criteria. Accumulating evidence has identified a substantial number of individuals without spirometric evidence of COPD who suffer from respiratory symptoms and/or increased morbidity and mortality. There is a clear need for an expanded definition of COPD that is linked to physiologic, structural (computed tomography [CT]) and clinical evidence of disease. Using data from the COPD Genetic Epidemiology study (COPDGene®), we hypothesized that an integrated approach that includes environmental exposure, clinical symptoms, chest CT imaging and spirometry better defines disease and captures the likelihood of progression of respiratory obstruction and mortality. Methods:Four key disease characteristics - environmental exposure (cigarette smoking), clinical symptoms (dyspnea and/or chronic bronchitis), chest CT imaging abnormalities (emphysema, gas trapping and/or airway wall thickening), and abnormal spirometry - were evaluated in a group of 8784 current and former smokers who were participants in COPDGene® Phase 1. Using these 4 disease characteristics, 8 categories of participants were identified and evaluated for odds of spirometric disease progression (FEV1 > 350 ml loss over 5 years), and the hazard ratio for all-cause mortality was examined. Results:Using smokers without symptoms, CT imaging abnormalities or airflow obstruction as the reference population, individuals were classified as Possible COPD, Probable COPD and Definite COPD. Current Global initiative for obstructive Lung Disease (GOLD) criteria would diagnose 4062 (46%) of the 8784 study participants with COPD. The proposed COPDGene® 2019 diagnostic criteria would add an additional 3144 participants. Under the new criteria, 82% of the 8784 study participants would be diagnosed with Possible, Probable or Definite COPD. These COPD groups showed increased risk of disease progression and mortality. Mortality increased in patients as the number of their COPD characteristics increased, with a maximum hazard ratio for all cause-mortality of 5.18 (95% confidence interval [CI]: 4.15-6.48) in those with all 4 disease characteristics. Conclusions:A substantial portion of smokers with respiratory symptoms and imaging abnormalities do not manifest spirometric obstruction as defined by population normals. These individuals are at significant risk of death and spirometric disease progression. We propose to redefine the diagnosis of COPD through an integrated approach using environmental exposure, clinical symptoms, CT imaging and spirometric criteria. These expanded criteria offer the potential to stimulate both current and future interventions that could slow or halt disease progression in patients before disability or irreversible lung structural changes develop

A double prime test of spreading activation in semantic priming [abstract]

Abstract only availableFaculty Mentor: Dr. Jeffrey Rouder, Psychological SciencesPeople read words better in context than in isolation. One explanation of this phenomena is that words are stored in an associative network. Activating one word automatically activates semantic associates; for example, reading "candle" automatically activates "wax". We tested automatic activation of semantic associates theory (termed spreading activation) with a semantic priming task. In a semantic priming task, the participant reads a briefly flashed target word that is followed by a mask. Because the target is presented quickly and masked, performance is not perfect. In previous research with this task, targets are read more accurately when preceded by a semantically related word than by an unrelated one; this result is the main line of support for spreading activation theory. In our test, participants decided if the target was one of two similar alternatives; for example "war" and "wax" may serve as alternatives. Targets were preceded by two primes, both were either related to the alternatives (e.g., "candle", "soldier") or neither were related to the alternatives (e.g., "phone", "table"). Spreading activation predicts better performance in the double-related prime condition because one of the words is always related to the target; hence one can spread activation to it. Across four experiments with94 participants, we found no performance advantage in the double-related prime condition over the double-unrelated prime condition. We advocate, as an alternative to spreading activation, a post-lexical decision theory in which primes bias decisions about subsequent targets but do not affect their activation in memory