The Making of Psychological Methods

Psychological Methods celebrated its 20-year anniversary recently, having published its first quarterly issue in March 1996. It seemed time to provide a brief overview of the history, the highlights over the years, and the current state of the journal, along with tips for submissions. The article is organized to discuss: (1) the background and development of the journal, (2) the top articles, authors and topics over the years, (3) an overview of the journal today, and (4) a summary of the features of successful articles that usually entail rigorous and novel methodology described in clear and understandable writing and that can be applied in meaningful and relevant areas of psychological research

The Wave Function of Vasiliev's Universe - A Few Slices Thereof

We study the partition function of the free Sp(N) conformal field theory recently conjectured to be dual to asymptotically de Sitter higher-spin gravity in four-dimensions. We compute the partition function of this CFT on a round sphere as a function of a finite mass deformation, on a squashed sphere as a function of the squashing parameter, and on an S2xS1 geometry as a function of the relative size of S2 and S1. We find that the partition function is divergent at large negative mass in the first case, and for small $S^1$ in the third case. It is globally peaked at zero squashing in the second case. Through the duality this partition function contains information about the wave function of the universe. We show that the divergence at small S1 occurs also in Einstein gravity if certain complex solutions are included, but the divergence in the mass parameter is new. We suggest an interpretation for this divergence as indicating an instability of de Sitter space in higher spin gravity, consistent with general arguments that de Sitter space cannot be stable in quantum gravity.Comment: 30 pages plus appendices, 6 figure

Big Data in Psychology: Introduction to the Special Issue

The introduction to this special issue on psychological research involving big data summarizes the highlights of 10 articles that address a number of important and inspiring perspectives, issues, and applications. Four common themes that emerge in the articles with respect to psychological research conducted in the area of big data are mentioned, including: 1. The benefits of collaboration across disciplines, such as those in the social sciences, applied statistics, and computer science. Doing so assists in grounding big data research in sound theory and practice, as well as in affording effective data retrieval and analysis. 2. Availability of large datasets on Facebook, Twitter, and other social media sites that provide a psychological window into the attitudes and behaviors of a broad spectrum of the population. 3. Identifying, addressing, and being sensitive to ethical considerations when analyzing large datasets gained from public or private sources. 4. The unavoidable necessity of validating predictive models in big data by applying a model developed on one dataset to a separate set of data or hold-out sample. Translational abstracts that summarize the articles in very clear and understandable terms are included in Appendix A, and a glossary of terms relevant to big data research discussed in the articles is presented in Appendix B. Keywords: big data, machine learning, statistical learning theory, social media data, digital footprint, decision trees and forests

Burst avalanches in solvable models of fibrous materials

We review limiting models for fracture in bundles of fibers, with statistically distributed thresholds for breakdown of individual fibers. During the breakdown process, avalanches consisting of simultaneous rupture of several fibers occur, and the distribution $D(\Delta)$ of the magnitude $\Delta$ of such avalanches is the central characteristics in our analysis. For a bundle of parallel fibers two limiting models of load sharing are studied and contrasted: the global model in which the load carried by a bursting fiber is equally distributed among the surviving members, and the local model in which the nearest surviving neighbors take up the load. For the global model we investigate in particular the conditions on the threshold distribution which would lead to anomalous behavior, i.e. deviations from the asymptotics $D(\Delta) \sim \Delta^{-5/2}$, known to be the generic behavior. For the local model no universal power-law asymptotics exists, but we show for a particular threshold distribution how the avalanche distribution can nevertheless be explicitly calculated in the large-bundle limit.Comment: 28 pages, RevTeX, 3 Postscript figure

Reporting Practices and Use of Quantitative Methods in Canadian Journal Articles in Psychology

With recent focus on the state of research in psychology, it is important to assess the nature of the methods and analyses used and reported. To study this, we coded information about the statistical content reported in articles in the four major Canadian psychology journals published in 2013. We first classified whether the articles were quantitative, qualitative, or theoretical in nature. Our main focus was on articles that used quantitative methods; whereby we investigated the prevalence of different statistical procedures, as well as further details of reporting practices. Few articles in any of the journals used qualitative approaches, as 92.9% of empirical articles included a quantitative study. Analysis of variance (ANOVA), t-tests, and multiple regression were the statistical analyses most often reported in the investigated articles. The majority of articles used hypothesis testing, and while most of these tests were accompanied by an effect size, this rarely included a confidence interval. Many of the quantitative studies provided minimal details about their statistical analyses and less than a third of the studies presented on data complications such as missing data and statistical assumptions. Further discussion highlights strengths and areas for improvement for reporting quantitative results. The paper concludes with recommendations for how researchers and reviewers can improve comprehension in statistical reporting

Hanford Single-Shell Tank Leak Causes and Locations - 241-A Farm

This document identifies 241-A Tank Farm (A Farm) leak causes and locations for the 100 series leaking tanks (241-A-104 and 241-A-105) identified in RPP-ENV-37956, Hanford A and AX Farm Leak Assessment Report. This document satisfies the A Farm portion of the target (T04) in the Hanford Federal Facility Agreement and Consent Order milestone M-045-91F

A new method for monitoring global volcanic activity

The ERTS Data Collection System makes it feasible for the first time to monitor the level of activity at widely separated volcanoes and to relay these data rapidly to one central office for analysis. While prediction of specific eruptions is still an evasive goal, early warning of a reawakening of quiescent volcanoes is now a distinct possibility. A prototypical global volcano surveillance system was established under the ERTS program. Instruments were installed in cooperation with local scientists on 15 volcanoes in Alaska, Hawaii, Washington, California, Iceland, Guatemala, El Salvador and Nicaragua. The sensors include 19 seismic event counters that count four different sizes of earthquakes and six biaxial borehole tiltmeters that measure ground tilt with a resolution of 1 microradian. Only seismic and tilt data are collected because these have been shown in the past to indicate most reliably the level of volcano activity at many different volcanoes. Furthermore, these parameters can be measured relatively easily with new instrumentation

Modeling multiple health behaviors and general health

Multiple Health Behavior Change assumes health behaviors are related to one another, although research evidence is mixed. More research is needed to understand which behaviors are most closely related and how they collectively predict health. Principle component analysis and structural equation modeling were used to establish a model showing relations between health behaviors, including fruit/vegetable consumption, aerobic and strength exercise, alcohol intake, and smoking, and how these behaviors relate to general physical and mental health functioning in a large, national sample. Although health behaviors were found to coalesce into a health-promoting factor of diet, and exercise, a better overall model fit was found when all behaviors were modeled as separate independent variables. Results suggest that health behaviors relate to one another in complex ways, with perceived health status serving as a mediating variable between specific health behaviors and a factor of physical and mental health. Future research should further investigate how other health behaviors relate to perceptions and overall health, especially among subpopulations

Scaling in the time-dependent failure of a fiber bundle with local load sharing

We study the scaling behaviors of a time-dependent fiber-bundle model with local load sharing. Upon approaching the complete failure of the bundle, the breaking rate of fibers diverges according to $r(t)\propto (T_f-t)^{-\xi}$, where $T_f$ is the lifetime of the bundle, and $\xi \approx 1.0$ is a quite universal scaling exponent. The average lifetime of the bundle $$ scales with the system size as $N^{-\delta}$, where $\delta$ depends on the distribution of individual fiber as well as the breakdown rule.Comment: 5 pages, 4 eps figures; to appear in Phys. Rev.