The suicide rate among American adolescents between the ages of 14-25 has dramatically increased during the last 50 years, and this fact has been the focus of extensive social-scientific investigation. To date, however, research focusing on the joint effects of mental health, family, and contextual-level predictors on adolescents' suicidal…

Statistical learning mechanisms play an important role in theories of language acquisition and processing. Recurrent neural network models have provided important insights into how these mechanisms might operate. We examined whether such networks capture two key findings in human statistical learning. In Simulation 1, a simple recurrent network…

The assumption of strongly ignorable treatment assignment is required for eliminating selection bias in observational studies. To meet this assumption, researchers often rely on a strategy of selecting covariates that they think will control for selection bias. Theory indicates that the most important covariates are those highly correlated with…

Recently, Vul and Pashler (2008) demonstrated that the average of 2 responses from a single subject to general knowledge questions was more accurate than either single estimate. Importantly, this reveals that each guess contributes unique evidence relevant to the decision, contrary to views that eschew probabilistic representations of the…

The output of binary cuing systems, such as alerts or alarms, depends on the threshold setting--a parameter that is often user-adjustable. However, it is unknown if users are able to adequately adjust thresholds and what information may help them to do so. Two experiments tested threshold settings for a binary classification task based on binary…

A Metropolis-Hastings Robbins-Monro (MH-RM) algorithm for high-dimensional maximum marginal likelihood exploratory item factor analysis is proposed. The sequence of estimates from the MH-RM algorithm converges with probability one to the maximum likelihood solution. Details on the computer implementation of this algorithm are provided. The…

Genetics is a unifying theme of biology that poses a major challenge for students across a wide range of post-secondary institutions, because it entails complex problem solving. This article reports a new intelligent learning environment called the Genetics Cognitive Tutor, which supports genetics problem solving. The tutor presents complex,…

Everyday conditional reasoning is typically influenced by prior knowledge and belief in the form of specific exceptions known as counterexamples. This study explored whether adolescents with autism spectrum disorder (ASD; N = 26) were less influenced by background knowledge than typically developing adolescents (N = 38) when engaged in conditional…

Two experiments examined the effects of phonotactic probability and neighborhood density on word learning by 3-, 4-, and 5-year-old children. Nonwords orthogonally varying in probability and density were taught with learning and retention measured via picture naming. Experiment 1 used a within story probability/across story density exposure…

This investigation sought to determine when colleges should conduct assessments to identify first-year students at risk of dropping out. Thirty-five variables were used to predict the persistence of 2,024 first-year students from four universities in the southeastern United States. The predictors were subdivided into groups according to when they…

This study examines the institutional factors associated with student loan default. When a college has more than 30% of its students default on their loans, then the institution faces federal sanctions that could make them ineligible from participating in the federal student loan program. Using Integrated Postsecondary Education Data System…

During the 2014 White House Science Fair, President Barack Obama used a sports metaphor to explain why we must address the shortage of women in science, technology, engineering, and mathematics (STEM), particularly in the engineering and computing fields: "Half our team, we're not even putting on the field. We've got to change those…

During the 2014 White House Science Fair, President Barack Obama used a sports metaphor to explain why we must address the shortage of women in science, technology, engineering, and mathematics (STEM), particularly in the engineering and computing fields: "Half our team, we're not even putting on the field. We've got to change those…

What do we know about the impact and implementation of Career Academies? This paper provides answers to this question. Career Academies have been around for over 30 years. Their original design stressed facilitating the school-to-work transition. In the early 1990's the focus began to shift to preparing participating students for both college and…

This dissertation considers three research questions. Why do scientists become postdoctoral scholars (postdocs)? What role do postdocs play relative to other categories of labor in research production? What factors are associated with a postdoc being dissatisfied? The literature review in Chapter 2 summarizes findings about which scientists are…