Microbes and the Mind: How Bacteria Shape Affect, Neurological Processes, Cognition, Social Relationships, Development, and Pathology.

Recent data suggest that the human body is not so exclusively human after all. Specifically, humans share their bodies with approximately 10 trillion microorganisms, collectively known as the microbiome. Chief among these microbes are bacteria, and there is a growing consensus that they are critical to virtually all facets of normative functioning. This article reviews the ways in which bacteria shape affect, neurological processes, cognition, social relationships, development, and psychological pathology. To date, the vast majority of research on interactions between microbes and humans has been conducted by scientists outside the field of psychology, despite the fact that psychological scientists are experts in many of the topics being explored. This review aims to orient psychological scientists to the most relevant research and perspectives regarding the microbiome so that we might contribute to the now widespread, interdisciplinary effort to understand the relationship between microbes and the mind.

Toward an Integrative Framework for Studying Human Evaluation: Attitudes Toward Objects and Attributes.

Evaluation is central to human experience, and multiple literatures have studied it. This article pulls from research on attitudes, human and nonhuman mating preferences, consumer behavior, and beyond to build a more comprehensive framework for studying evaluation. First, we distinguish between evaluations of objects (persons, places, things) and evaluations of attributes (dimensions, traits, characteristics). Then, we further distinguish between summarized attribute preferences (a valenced response to a direction on a dimension, such as liking sweetness in desserts) and functional attribute preferences (a valenced response to increasing levels of a dimension in a set of targets, such as the extent to which sweetness predicts liking for desserts). We situate these constructs with respect to existing distinctions in the attitude literature (e.g., specific/general, indirect/direct). Finally, new models address how people translate functional into summarized preferences, as well as how attribute preferences affect (a) subsequent evaluations of objects and (b) situation selection.

Titi Monkeys as a Novel Non-Human Primate Model for the Neurobiology of Pair Bonding
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It is now widely recognized that social bonds are critical to human health and well-being. One of the most important social bonds is the attachment relationship between two adults, known as the pair bond. The pair bond involves many characteristics that are inextricably linked to quality of health, including providing a secure psychological base and acting as a social buffer against stress. The majority of our knowledge about the neurobiology of pair bonding comes from studies of a socially monogamous rodent, the prairie vole (Microtus ochrogaster), and from human imaging studies, which inherently lack control. Here, we first review what is known of the neurobiology of pair bonding from humans and prairie voles. We then present a summary of the studies we have conducted in titi monkeys (Callicebus cupreus)-a species of socially monogamous New World primates. Finally, we construct a neural model based on the location of neuropeptide receptors in the titi monkey brain, as well as the location of neural changes in our imaging studies, with some basic assumptions based on the prairie vole model. In this model, we emphasize the role of visual mating stimuli as well as contributions of the dopaminergic reward system and a strong role for the lateral septum. This model represents an important step in understanding the neurobiology of social bonds in non-human primates, which will in turn facilitate a better understanding of these mechanisms in humans.

Psychological Distance Moderates the Amplification of Shared Experience.

Sharing an experience with another person can amplify that experience. Here, we propose for the first time that amplification is moderated by the psychological distance between co-experiencers. We predicted that experiences would be amplified for co-experiencers who are psychologically proximate but not for co-experiencers who are psychologically distant. In two studies we manipulated both (a) whether or not a pleasant experience was shared and (b) the psychological distance between co-experiencers, via social distance (Study 1) and spatial distance (Study 2). In Study 1, co-experiencers either were unacquainted (i.e., strangers, socially distant) or became acquainted in the laboratory (i.e., socially proximate). In Study 2, co-experiencers were either in different rooms (i.e., spatially distant) or in the same room (i.e., spatially proximate). In both studies, the pleasant experience was amplified when shared compared with when not shared, but only when co-experiencers were psychologically proximate (vs. distant) to one another.