The Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) statement, published in 2009, was designed to help systematic reviewers transparently report why the review was done, what the authors did, and what they found. Over the past decade, advances in systematic review methodology and terminology have necessitated an update to the guideline. The PRISMA 2020 statement replaces the 2009 statement and includes new reporting guidance that reflects advances in methods to identify, select, appraise, and synthesise studies. The structure and presentation of the items have been modified to facilitate implementation. In this article, we present the PRISMA 2020 27-item checklist, an expanded checklist that details reporting recommendations for each item, the PRISMA 2020 abstract checklist, and the revised flow diagrams for original and updated reviews.

https://www.bmj.com/content/bmj/372/bmj.n71.full.pdf

The PRISMA 2020 statement: an updated guideline for reporting systematic reviews

/pdf/the-prisma-2020-statement-an-updated-guideline-for-reporting-137rnghtc1.pdf

https://pure.bond.edu.au/ws/files/73563879/The_PRISMA_2020_statement_an_updated_guideline_for_reporting.pdf

The PRISMA 2020 statement: An updated guideline for reporting systematic reviews.

Why do people purchase proenvironmental "green" products? We argue that buying such products can be construed as altruistic, since green products often cost more and are of lower quality than their conventional counterparts, but green goods benefit the environment for everyone. Because biologists have observed that altruism might function as a "costly signal" associated with status, we examined in 3 experiments how status motives influenced desire for green products. Activating status motives led people to choose green products over more luxurious nongreen products. Supporting the notion that altruism signals one's willingness and ability to incur costs for others' benefit, status motives increased desire for green products when shopping in public (but not private) and when green products cost more (but not less) than nongreen products. Findings suggest that status competition can be used to promote proenvironmental behavior.

Going green to be seen: Status, reputation, and conspicuous conservation.

Not by Genes Alone: How Culture Transformed Human Evolution

What is the function of disgust? Whereas traditional models have suggested that disgust serves to protect the self or neutralize reminders of our animal nature, an evolutionary perspective suggests that disgust functions to solve 3 qualitatively different adaptive problems related to pathogen avoidance, mate choice, and social interaction. The authors investigated this 3-domain model of disgust across 4 studies and examined how sensitivity to these functional domains relates to individual differences in other psychological constructs. Consistent with their predictions, factor analyses demonstrated that disgust sensitivity partitions into domains related to pathogens, sexuality, and morality. Further, sensitivity to the 3 domains showed predictable differentiation based on sex, perceived vulnerability to disease, psychopathic tendencies, and Big 5 personality traits. In exploring these 3 domains of disgust, the authors introduce a new measure of disgust sensitivity. Appreciation of the functional heterogeneity of disgust has important implications for research on individual differences in disgust sensitivity, emotion, clinical impairments, and neuroscience.

/pdf/microbes-mating-and-morality-individual-differences-in-three-17vwcxlipy.pdf

Microbes, mating, and morality: individual differences in three functional domains of disgust.

Interest in and research on disgust has surged over the past few decades. The field, however, still lacks a coherent theoretical framework for understanding the evolved function or functions of disgust. Here we present such a framework, emphasizing 2 levels of analysis: that of evolved function and that of information processing. Although there is widespread agreement that disgust evolved to motivate the avoidance of contact with disease-causing organisms, there is no consensus about the functions disgust serves when evoked by acts unrelated to pathogen avoidance. Here we suggest that in addition to motivating pathogen avoidance, disgust evolved to regulate decisions in the domains of mate choice and morality. For each proposed evolved function, we posit distinct information processing systems that integrate function-relevant information and account for the trade-offs required of each disgust system. By refocusing the discussion of disgust on computational mechanisms, we recast prior theorizing on disgust into a framework that can generate new lines of empirical and theoretical inquiry.

/pdf/disgust-evolved-function-and-structure-3kjca4rw3v.pdf

Disgust: Evolved Function and Structure

Evolved mechanisms for assessing genetic relatedness have been found in many species, but their existence in humans has been a matter of controversy. Here we report three converging lines of evidence, drawn from siblings, that support the hypothesis that kin detection mechanisms exist in humans. These operate by computing, for each familiar individual, a unitary regulatory variable (the kinship index) that corresponds to a pairwise estimate of genetic relatedness between self and other. The cues that the system uses were identified by quantitatively matching individual exposure to potential cues of relatedness to variation in three outputs relevant to the system’s evolved functions: sibling altruism, aversion to personally engaging in sibling incest, and moral opposition to third party sibling incest. As predicted, the kin detection system uses two distinct, ancestrally valid cues to compute relatedness: the familiar other’s perinatal association with the individual’s biological mother, and duration of sibling coresidence. Inbreeding is a bad thing, and many animals have evolved mechanisms for assessing genetic relatedness in order to avoid it. Whether such an in-built mechanism exists in humans has been controversial, but a new study of sibling behaviour finds evidence to support the idea. The study suggests that we use two distinct cues to compute a 'kinship index'. If a potential sibling is younger, we watch to see how much time he or she spends with our mother. If the sibling is older, we assess how much time we ourselves have spent with that person. How did humans learn who they are related to, to avoid inbreeding and mate with someone outside their family? This paper proposes that humans use evidence from their environment to compute a 'kinship index' and use it to estimate genetic relatedness to another human.

/pdf/the-architecture-of-human-kin-detection-4aez3nclci.pdf

The architecture of human kin detection

Kin-recognition systems have been hypothesized to exist in humans, and adaptively to regulate altruism and incest avoidance among close genetic kin. This latter function allows the architecture of the kin recognition system to be mapped by quantitatively matching individual variation in opposition to incest to individual variation in developmental parameters, such as family structure and co-residence patterns. Methodological difficulties that appear when subjects are asked to disclose incestuous inclinations can be circumvented by measuring their opposition to incest in third parties, i.e. morality. This method allows a direct test of Westermarck's original hypothesis that childhood co-residence with an opposite-sex individual predicts the strength of moral sentiments regarding third-party sibling incest. Results support Westermarck's hypothesis and the model of kin recognition that it implies. Co-residence duration objectively predicts genetic relatedness, making it a reliable cue to kinship. Co-residence duration predicts the strength of opposition to incest, even after controlling for relatedness and even when co-residing individuals are genetically unrelated. This undercuts kin-recognition models requiring matching to self (through, for example, major histocompatibility complex or phenotypic markers). Subjects' beliefs about relatedness had no effect after controlling for co-residence, indicating that systems regulating kin-relevant behaviours are non-conscious, and calibrated by co-residence, not belief.

/pdf/does-morality-have-a-biological-basis-an-empirical-test-of-2arknq7abh.pdf

Does morality have a biological basis? An empirical test of the factors governing moral sentiments relating to incest.

Disgust, an emotion related to avoiding harmful substances, has been linked to moral judgments in many behavioral studies. However, the fact that participants report feelings of disgust when thinking about feces and a heinous crime does not necessarily indicate that the same mechanisms mediate these reactions. Humans might instead have separate neural and physiological systems guiding aversive behaviors and judgments across different domains. The present interdisciplinary study used functional magnetic resonance imaging (n = 50) and behavioral assessment to investigate the biological homology of pathogen-related and moral disgust. We provide evidence that pathogen-related and sociomoral acts entrain many common as well as unique brain networks. We also investigated whether morality itself is composed of distinct neural and behavioral subdomains. We provide evidence that, despite their tendency to elicit similar ratings of moral wrongness, incestuous and nonsexual immoral acts entrain dramatically separate, while still overlapping, brain networks. These results (i) provide support for the view that the biological response of disgust is intimately tied to immorality, (ii) demonstrate that there are at least three separate domains of disgust, and (iii) suggest strongly that morality, like disgust, is not a unified psychological or neurological phenomenon.

/pdf/infection-incest-and-iniquity-investigating-the-neural-iglg4xcd6b.pdf

Debra Lieberman

Papers

Microbes, mating, and morality: individual differences in three functional domains of disgust.

Disgust: Evolved Function and Structure

The architecture of human kin detection

Does morality have a biological basis? An empirical test of the factors governing moral sentiments relating to incest.

Infection, incest, and iniquity: Investigating the neural correlates of disgust and morality