Evaluating the Impact of the Positive Choices Intervention on Substance Use, Psychological, and Care Engagement Outcomes Relevant to Current National HIV Prevention Goals

The HIV epidemic in the United States continues to be a significant public health problem, with approximately 50,000 new infections occurring each year. National public health priorities have shifted in recent years towards targeted HIV prevention efforts among people living with HIV/AIDS (PLWHA) that include: increasing engagement in and retention in care, improving HIV treatment adherence, and increasing screening for and treatment of substance use and psychological difficulties. This study evaluated the efficacy of Positive Choices (PC), a brief, care-based, theory-driven, 3-session counseling intervention for newly HIV-diagnosed men who have sex with men (MSM), in the context of current national HIV prevention priorities. The study involved secondary analysis of data from a preliminary efficacy trial of the PC intervention (n=102). Descriptive statistics examined baseline substance use, psychological characteristics and strategies, and care engagement and HIV-related biological outcomes. Generalized Estimating Equations (GEE) examined longitudinal changes in these variables by study condition. Results indicated that PC improved adherence to HIV treatment, but increased use of illicit drugs, specifically amyl nitrates and other stimulant drugs; additionally, moderation analyses indicated differences in patterns of change over time in viral load by baseline depression status. Implications of the findings and suggestions for future research are discussed.

Latent Space and Social Psychological Models of Diffusion

The problem of social diffusion has animated sociological thinking on topics ranging from the spread of an idea, an innovation or a disease, to the foundations of collective behavior and political polarization. While network diffusion has been a productive metaphor, the reality of diffusion processes is often muddier. Ideas and innovations diffuse differently from diseases, but, with a few exceptions, the diffusion of ideas and innovations has been modeled under the same assumptions as the diffusion of disease. In this dissertation, I develop two new diffusion models for "socially meaningful" contagions that address two of the most significant problems with current diffusion models: (1) that contagions can only spread along observed ties, and (2) that contagions do not change as they spread between people. I augment insights from these statistical and simulation models with an analysis of an empirical case of diffusion - the use of enterprise collaboration software in a large technology company. I focus the empirical study on when people abandon innovations, a crucial, and understudied aspect of the diffusion of innovations. Using timestamped posts, I analyze when people abandon software to a high degree of detail.

To address the first problem, I suggest a latent space diffusion model. Rather than treating ties as stable conduits for information, the latent space diffusion model treats ties as random draws from an underlying social space, and simulates diffusion over the social space. Theoretically, the social space model integrates both actor ties and attributes simultaneously in a single social plane, while incorporating schemas into diffusion processes gives an explicit form to the reciprocal influences that cognition and social environment have on each other. Practically, the latent space diffusion model produces statistically consistent diffusion estimates where using the network alone does not, and the diffusion with schemas model shows that introducing some cognitive processing into diffusion processes changes the rate and ultimate distribution of the spreading information. To address the second problem, I suggest a diffusion model with schemas. Rather than treating information as though it is spread without changes, the schema diffusion model allows people to modify information they receive to fit an underlying mental model of the information before they pass the information to others. Combining the latent space models with a schema notion for actors improves our models for social diffusion both theoretically and practically.

The empirical case study focuses on how the changing value of an innovation, introduced by the innovations' network externalities, influences when people abandon the innovation. In it, I find that people are least likely to abandon an innovation when other people in their neighborhood currently use the software as well. The effect is particularly pronounced for supervisors' current use and number of supervisory team members who currently use the software. This case study not only points to an important process in the diffusion of innovation, but also suggests a new approach -- computerized collaboration systems -- to collecting and analyzing data on organizational processes.

Psychological and Interpersonal Implications of Believing that Everything is One: Identity, Personality, Values, and Worldviews

For thousands of years, people from a variety of philosophical, religious, spiritual, and scientific perspectives have believed in the fundamental unity of all that exists, and this belief appears to be increasingly prevalent in Western cultures. The present research was the first investigation of the psychological and interpersonal implications of believing in oneness. Self-report measures were developed to assess three distinct variants of the belief in oneness – belief in the fundamental oneness of everything, of all living things, and of humanity – and studies examined how believing in oneness is associated with people’s self-views, attitudes, personality, emotions, and behavior. Using both correlational and experimental approaches, the findings supported the hypothesis that believing in oneness is associated with feeling greater connection and concern for people, nonhuman animals, and the environment, and in being particularly concerned for people and things beyond one’s immediate circle of friends and family. The belief is also associated with experiences in which everything is perceived to be one, and with certain spiritual and esoteric beliefs. Although the three variations of belief in oneness were highly correlated and related to other constructs similarly, they showed evidence of explaining unique variance in conceptually relevant variables. Belief in the oneness of humanity, but not belief in the oneness of living things, uniquely explained variance in prosociality, empathic concern, and compassion for others. In contrast, belief in the oneness of living things, but not belief in oneness of humanity, uniquely explained variance in beliefs and concerns regarding the well-being of nonhuman animals and the environment. The belief in oneness is a meaningful existential belief that is endorsed to varying degrees by a nontrivial portion of the population and that has numerous implications for people’s personal well-being and interactions with people, animals, and the natural world.