Search

Mixed-effects models are frequently used in a variety of disciplines because they can appropriately specify multiple sources of variation. However, precisely because they distinguish between multiple sources of variation, it is difficult to specify a standardized effect size, such as η2. Several approaches to this problem have been proposed, but most do not address models with crossed random factors, and none allows for the range of data and models that researchers typically test. For example, no existing approach handles random slopes for a continuous predictor. We introduce several new, flexible approaches to estimating η2 in mixed-effect models with crossed random factors. We then conduct a simulation to assess new and old methods. We examine their respective strengths and weaknesses and offer recommendations for a simple approach based on the work of Snijders and Bosker (2011).

Recent theorizing suggests that religious people's moral convictions are quite strategic (albeit unconsciously so), designed to make their worlds more amenable to their favored approaches to solving life's basic challenges. In a meta-analysis of 5 experiments and a preregistered replication, we find that religious identity places a sex premium on moral judgments, causing people to judge violations of conventional sexual morality as particularly objectionable. The sex premium is especially strong among highly religious people, and applies to both legal and illegal acts. Religion's influence on moral reasoning emphasizes conventional sexual norms, and may reflect the strategic projects to which religion has been applied throughout history. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Regime shifts (periods of rapid change punctuating longer periods of lower variability) are observed in a wide range of ecosystems, and effective fisheries management requires the ability to detect these shifts. Detecting shifts is straightforward in single-species time series when transitions are detectable as periods of rapid change. However, shifts in complex and spatially structured communities may be harder to detect. We propose an approach to characterize community regime shifts, using nonparametric spatiotemporal regression models to estimate three indicators of community change (the among-species mean rate of change, mean per-capita rate of change, and standard deviation of per-capita rate of change). These indicators can detect shifts that result in either changes in abundance or composition. We applied our approach to a 37-year community biomass time series that spans the Newfoundland Shelf groundfish collapse. Our method detected a community shift earlier than alternative single-indicator breakpoint approaches and gave additional insight into the spatiotemporal pattern of the change, including detecting three separate periods of change and characterizing the first locations to show signs of recovery. The indicators applied in this study provide novel insights into Newfoundland groundfish dynamics and should be useful in the characterization of other abrupt ecological changes.

Significance Political polarization impeded public support for policies to address the spread of COVID-19, much as polarization hinders responses to other societal challenges. The present cross-country study demonstrates how the cues from political elites and affective polarization are analogous across countries addressing COVID-19. Far from being an outlier, the United States faces polarization challenges similar to those of other countries. Importantly, the results demonstrate that policies to combat public health crises are more supported when proposed by nonpartisan experts and bipartisan coalitions of political leaders. These results provide clear guidance on depolarizing communication strategies to improve global responses to health crises., Political polarization impeded public support for policies to reduce the spread of COVID-19, much as polarization hinders responses to other contemporary challenges. Unlike previous theory and research that focused on the United States, the present research examined the effects of political elite cues and affective polarization on support for policies to manage the COVID-19 pandemic in seven countries (n = 12,955): Brazil, Israel, Italy, South Korea, Sweden, the United Kingdom, and the United States. Across countries, cues from political elites polarized public attitudes toward COVID-19 policies. Liberal and conservative respondents supported policies proposed by ingroup politicians and parties more than the same policies from outgroup politicians and parties. Respondents disliked, distrusted, and felt cold toward outgroup political elites, whereas they liked, trusted, and felt warm toward both ingroup political elites and nonpartisan experts. This affective polarization was correlated with policy support. These findings imply that policies from bipartisan coalitions and nonpartisan experts would be less polarizing, enjoying broader public support. Indeed, across countries, policies from bipartisan coalitions and experts were more widely supported. A follow-up experiment replicated these findings among US respondents considering international vaccine distribution policies. The polarizing effects of partisan elites and affective polarization emerged across nations that vary in cultures, ideologies, and political systems. Contrary to some propositions, the United States was not exceptionally polarized. Rather, these results suggest that polarizing processes emerged simply from categorizing people into political ingroups and outgroups. Political elites drive polarization globally, but nonpartisan experts can help resolve the conflicts that arise from it.

People believe they should consider how their behavior might negatively impact other people, Yet their behavior often increases others’ health risks. This creates challenges for managing public health crises like the COVID-19 pandemic. We examined a procedure wherein people reflect on their personal criteria regarding how their behavior impacts others’ health risks. We expected structured reflection to increase people's intentions and decisions to reduce others’ health risks. Structured reflection increases attention to others’ health risks and the correspondence between people's personal criteria and behavioral intentions. In four experiments during COVID-19, people (N = 12,995) reported their personal criteria about how much specific attributes, including the impact on others’ health risks, should influence their behavior. Compared with control conditions, people who engaged in structured reflection reported greater intentions to reduce business capacity (experiment 1) and avoid large social gatherings (experiments 2 and 3). They also donated more to provide vaccines to refugees (experiment 4). These effects emerged across seven countries that varied in collectivism and COVID-19 case rates (experiments 1 and 2). Structured reflection was distinct from instructions to carefully deliberate (experiment 3). Structured reflection increased the correlation between personal criteria and behavioral intentions (experiments 1 and 3). And structured reflection increased donations more among people who scored lower in cognitive reflection compared with those who scored higher in cognitive reflection (experiment 4). These findings suggest that structured reflection can effectively increase behaviors to reduce public health risks.

Punishment can reform uncooperative behavior and hence could have contributed to humans’ ability to live in large-scale societies. Punishment by unaffected third parties has received extensive scientific scrutiny because third parties punish transgressors in laboratory experiments on behalf of strangers that they will never interact with again. Often overlooked in this research are interactions involving people who are not strangers, which constitute many interactions beyond the laboratory. Across three samples in two countries (United States and Japan; N = 1,294), we found that third parties’ anger at transgressors, and their intervention and punishment on behalf of victims, varied in real-life conflicts as a function of how much third parties valued the welfare of the disputants. Punishment was rare (1–2%) when third parties did not value the welfare of the victim, suggesting that previous economic game results have overestimated third parties’ willingness to punish transgressors on behalf of strangers.

The Dictator Game, a face valid measure of altruism, and the Trust Game, a face valid measure of trust and trustworthiness, are among the most widely used behavioural measures in human cooperation research. Researchers have observed considerable covariation among these and other economic games, leading them to assert that there exists a general human propensity to cooperate that varies in strength across individuals and manifests itself across a variety of social settings. To formalize this hypothesis, we created an S–1 bifactor model using 276 participants’ Dictator Game and Trust Game decisions. The general factor had significant, moderate associations with self–reported and peer–reported altruism, trust, and trustworthiness. Thus, the positive covariation among economic games is not reducible to the games’ shared situational features. Two hundred participants returned for a second session. The general factor based on Dictator Game and Trust Game decisions from this session did not significantly predict self–reported and peer–reported cooperation, suggesting that experience with economic games causes them to measure different traits from those that are reflected in self–assessments and peer–assessments of cooperativeness. © 2018 European Association of Personality Psychology

Despite some evidence of the benefits of self-compassion training among socially anxious individuals, little is known about whether enhancing self-compassion prior to exposure therapy increases initial exposure engagement. Additionally, manipulations have relied on broad definitions of self-compassion, rendering it difficult to distinguish the impact of individual components. This study employed three experiential exercises designed to enhance one facet of self-compassion-common humanity. Socially anxious undergraduates (N = 63) were randomized in groups to 1) common humanity-enhanced exposure (n = 32) or 2) exposure alone (n = 31). In the common humanity condition, participants wrote self-compassionately, shared fears, and completed a common humanity-focused lovingkindness meditation. All participants then completed a speech exposure in front of live judges followed by an optional second exposure. Within the common humanity condition, positive self-responding to the speech exposure increased (b = 0.30, p = .026). Common humanity participants also remained in the first exposure longer, relative to exposure alone (b = -30.92, p = .002). Participants rated exercises as at least moderately helpful, with sharing fears rated most helpful. In sum, a brief group-based multi-modal common humanity induction represents a promising approach to improving initial engagement with feared contexts among socially anxious individuals.

Place: Hoboken Publisher: Wiley WOS:000531110000001; International audience; The distributions of highly mobile marine species such as cetaceans are increasingly modeled at basin scale by combining data from multiple regions. However, these basin-wide models often overlook geographical variations in species habitat relationships between regions. We tested for geographical variations in habitat relationships for a suite of cetacean taxa between the two sides of the North Atlantic basin. Using cetacean visual survey data and remote sensing data from the western and eastern basin in summer, we related the probability of presence of twelve cetacean taxa from three guilds to seafloor depth, sea surface temperature and primary productivity. In a generalized additive model framework, we fitted 1) basin-wide (BW) models, assuming a single global relationship, 2) region-specific intercepts (RI) models, assuming relationships with the same shape in both regions, but allowing a region-specific intercept and 3) region-specific shape (RS) models, assuming relationships with different shapes between regions. RS models mostly yielded significantly better fits than BW models, indicating cetacean occurrences were better modeled with region-specific than with global relationships. The better fits of RS models over RI models further provided statistical evidence for differences in the shapes of region-specific relationships. Baleen whales showed striking differences in both the shapes of relationships and their mean presence probabilities between regions. Deep diving whales and delphinoids showed contrasting relationships between regions with few exceptions (e.g. non-statistically different shapes of region-specific relationships for harbor porpoise and beaked whales with depth). Our findings stress the need to account for geographical differences in habitat relationships between regions when modeling species distributions from combined data at the basin scale. Our proposed hypotheses offer a roadmap for understanding why habitat relationships may geographically vary in cetaceans and other highly mobile marine species.

The Social Heuristics Hypothesis claims that cooperation is intuitive because it is positively reinforced in everyday life, where behaviour typically has reputational consequences1,2. Consequently, participants will cooperate in anonymous laboratory settings unless they either reflect on the one-shot nature of the interaction or learn through experience with such settings that cooperation does not promote self-interest. Experiments reveal that cognitive-processing manipulations (which increase reliance on either intuition or deliberation) indeed affect cooperation3, but may also introduce confounds4,5. Here, we elide the interpretation issues created by between-subjects designs in showing that people are less cooperative over time in laboratory paradigms in which cooperation cannot promote self-interest, but are just as cooperative over time in paradigms that have the potential to promote self-interest. Contrary to previous findings6,7, we find that cooperation is equally intuitive for men and women: unilateral giving did not differ across gender at the first study session, and decreased equally for both genders across sessions.

Walleye (Sander vitreus) populations are declining in Wisconsin and neighboring regions, motivating broader interest in walleye biology amidst ecological change. In fishes, growth integrates variation in ecological drivers and provides a signal of changing ecological conditions. We used a 23-year data set of length-at-age from 353 walleye populations across Wisconsin to test whether walleye growth rates changed over time and what ecological factors best predicted these changes. Using hierarchical models, we tested whether spatiotemporal variation in walleye growth was related to adult walleye density (density-dependent effects), water temperature, and largemouth bass (Micropterus salmoides) catch per unit effort (CPUE; predator or competitor effects). The average length of young walleye increased over time, and as a result, time to reach harvestable size declined significantly. In contrast, average lengths of older walleye have remained relatively constant over time. Juvenile walleye length-at-age was positively correlated with largemouth bass CPUE and surface water temperatures, but negatively correlated with adult walleye density. Our finding of widespread and long-term changes in walleye growth rates provides additional insights into how inland fisheries are responding to environmental change.

The present study, conducted immediately after the 2020 presidential election in the United States, examined whether Democrats’ and Republicans’ polarized assessments of election legitimacy increased over time. In a naturalistic survey experiment, people (N= 1,236) were randomly surveyed either during the week following Election Day, with votes cast but the outcome unknown, or during the following week, after President Joseph Biden was widely declared the winner. The design unconfounded the election outcome announcement from the vote itself, allowing more precise testing of predictions derived from cognitive dissonance theory. As predicted, perceived election legitimacy increased among Democrats, from the first to the second week following Election Day, as their expected Biden win was confirmed, whereas perceived election legitimacy decreased among Republicans as their expected President Trump win was disconfirmed. From the first to the second week following Election Day, Republicans reported stronger negative emotions and weaker positive emotions while Democrats reported stronger positive emotions and weaker negative emotions. The polarized perceptions of election legitimacy were correlated with the tendencies to trust and consume polarized media. Consumption of Fox News was associated with lowered perceptions of election legitimacy over time whereas consumption of other outlets was associated with higher perceptions of election legitimacy over time. Discussion centers on the role of the media in the experience of cognitive dissonance and the implications of polarized perceptions of election legitimacy for psychology, political science, and the future of democratic society.

Here we examine the roles of interpersonal valuation and gratitude in the formation of cooperative relationships. Building on prior work, we draw on the concept of a welfare tradeoff ratio (WTR), an internally computed index of the extent to which one person values another person's welfare relative to his or her own. We test several predictions regarding the effects of benefit delivery on changes in WTR, gratitude, and subsequent cooperation. We show that benefit delivery by a stranger: (i) raises the beneficiary's valuation of the stranger's welfare, (ii) predicts downstream cooperative behavior by the beneficiary toward the stranger, and (iii) is coincident with beneficiaries' expressions of gratitude. We find evidence that cooperation and gratitude, while both sparked via benefit delivery and both underpinned by estimates of welfare valuation, are nevertheless produced in parallel via different paths. Specifically, the updated magnitude—not the initial magnitude or degree of change—of a beneficiary's WTR toward a stranger predicts the beneficiary's downstream cooperative behavior. By contrast, the extent to which the beneficiary's WTR positively changes —and not the initial or updated WTR magnitude—predicts gratitude production, a feature proposed to reinforce the benefactor's actions and foreshadow future cooperative intent on the part of the beneficiary. Taken together, our findings point to the possibility that cooperative behavior might operate via internal estimates of welfare valuation, and that gratitude signals benefit reception and the intent to engage in a cooperative relationship.

Predicting dispersal paths of marine larvae with extended pelagic durations, such as American lobster (Homarus americanus H. Milne Edwards, 1837), requires understanding the cues to which larvae respond, and how that response reflects changes in larval behaviour. If larvae respond to conspecific presence by varying their movement, then this behaviour can bias laboratory estimates of environmental responses. We tested whether larvae actively decreased their local intraspecific density by measuring how the vertical distribution of larvae changed under high versus low concentrations of conspecifics. We observed weak increases in vertical dispersion at higher concentrations both in newly hatched larvae and in postlarvae, but not in intermediate larval stages. We also tested for differences in horizontal swimming behaviour in high and low concentrations, by fitting a novel random walk model that allowed us to model both larval interactions and persistent turning behaviours. We showed substantial reduction in diffusive behaviour under high concentration conditions resulting from more frequent turns by each larva, but no evidence for consistent avoidance of conspecifics. Our study is the first to demonstrate concentration-dependent behaviours in lobster larvae.

The Safe Operating Space (SOS) of a recreational fishery is the multidimensional region defined by levels of harvest, angler effort, habitat, predation and other factors in which the fishery is sustainable into the future. SOS boundaries exhibit trade-offs such that decreases in harvest can compensate to some degree for losses of habitat, increases in predation and increasing value of fishing time to anglers. Conversely, high levels of harvest can be sustained if habitat is intact, predation is low, and value of fishing effort is moderate. The SOS approach recognizes limits in several dimensions: at overly high levels of harvest, habitat loss, predation, or value of fishing effort, the stock falls to a low equilibrium biomass. Recreational fisheries managers can influence harvest and perhaps predation, but they must cope with trends that are beyond their control such as changes in climate, loss of aquatic habitat or social factors that affect the value of fishing effort for anglers. The SOS illustrates opportunities to manage harvest or predation to maintain quality fisheries in the presence of trends in climate, social preferences or other factors that are not manageable.

Gratitude is an emotion that promotes cooperative relationships and is elicited when an act reveals that an actor values the recipient, especially when the benefit conferred is greater than the recipient expected. But, recipient expectations might vary depending on how much the benefactor is perceived to value the recipient — all else equal, the greater the benefactor is perceived to value the recipient's welfare, the greater the recipient's expectations of benefit delivery. Thus, at a given benefit level, it might be easier to exceed the threshold of expectation in a relationship for which the recipient holds low expectations (e.g., a stranger) as compared to a relationship for which the recipient holds high expectations (e.g., a sibling). This leads to the prediction that cognitive representations of welfare valuation inversely correlate with gratitude: The greater the expected welfare valuation, the more difficult it is to exceed expectations of benefit delivery and, therefore, the less felt gratitude. To test this prediction, we conducted two experiments in which subjects estimated how much they perceived a particular person in their social network to value the subject's welfare. Next, subjects estimated how grateful they would feel if this person provided them with differing levels of benefits. Contrary to our model, we found that gratitude was predicted by the magnitude of the benefit, but not by the recipient's perception of the benefactor's valuation of the recipient.

We appreciate Drescher’s perspective (1), which elaborates on several points made in our initial paper (2) and underscores the need for additional research on how trees can be used to mitigate urban heat. We note in our paper that optimizing cooling with a limited number of trees can be achieved by increasing cover in areas where tree canopy cover is >40%, because benefits accrue rapidly above this threshold. However, Drescher (1) rightly emphasizes the greatest need for cooling is often in areas with

This work was funded by Fisheries and Oceans Canada, Natural Science and Engineering Research Council of Canada (NSERC) Discovery Grant (RGPIN-2014-04032), by OPNAV N45 and the SURTASS LFA Settlement Agreement, managed by the U.S. Navy’s Living Marine Resources Program under Contract No. N39430-17-C-1982, and by the USAID PREDICT-2 Program. In this paper, we discuss an extension to two popular approaches to modeling complex structures in ecological data: the generalized additive model (GAM) and the hierarchical model (HGLM). The hierarchical GAM (HGAM), allows modeling of nonlinear functional relationships between covariates and outcomes where the shape of the function itself varies between different grouping levels. We describe the theoretical connection between HGAMs, HGLMs, and GAMs, explain how to model different assumptions about the degree of intergroup variability in functional response, and show how HGAMs can be readily fitted using existing GAM software, the mgcv package in R. We also discuss computational and statistical issues with fitting these models, and demonstrate how to fit HGAMs on example data. All code and data used to generate this paper are available at: github.com/eric-pedersen/mixed-effect-gams. Publisher PDF

As cities warm and the need for climate adaptation strategies increases, a more detailed understanding of the cooling effects of land cover across a continuum of spatial scales will be necessary to guide management decisions. We asked how tree canopy cover and impervious surface cover interact to influence daytime and nighttime summer air temperature, and how effects vary with the spatial scale at which land-cover data are analyzed (10-, 30-, 60-, and 90-m radii). A bicycle-mounted measurement system was used to sample air temperature every 5 m along 10 transects (∼7 km length, sampled 3–12 times each) spanning a range of impervious and tree canopy cover (0–100%, each) in a midsized city in the Upper Midwest United States. Variability in daytime air temperature within the urban landscape averaged 3.5 °C (range, 1.1–5.7 °C). Temperature decreased nonlinearly with increasing canopy cover, with the greatest cooling when canopy cover exceeded 40%. The magnitude of daytime cooling also increased with spatial scale and was greatest at the size of a typical city block (60–90 m). Daytime air temperature increased linearly with increasing impervious cover, but the magnitude of warming was less than the cooling associated with increased canopy cover. Variation in nighttime air temperature averaged 2.1 °C (range, 1.2–3.0 °C), and temperature increased with impervious surface. Effects of canopy were limited at night; thus, reduction of impervious surfaces remains critical for reducing nighttime urban heat. Results suggest strategies for managing urban land-cover patterns to enhance resilience of cities to climate warming.

The meaning, mechanism, and function of imitation in early infancy have been actively discussed since Meltzoff and Moore's (1977) report of facial and manual imitation by human neonates. Oostenbroek et al. (2016) claim to challenge the existence of early imitation and to counter all interpretations so far offered. Such claims, if true, would have implications for theories of social-cognitive development. Here we identify 11 flaws in Oostenbroek et al.'s experimental design that biased the results toward null effects. We requested and obtained the authors' raw data. Contrary to the authors' conclusions, new analyses reveal significant tongue-protrusion imitation at all four ages tested (1, 3, 6, and 9 weeks old). We explain how the authors missed this pattern and offer five recommendations for designing future experiments. Infant imitation raises fundamental issues about action representation, social learning, and brain-behavior relations. The debate about the origins and development of imitation reflects its importance to theories of developmental science.

Punishment can reform uncooperative behavior, and hence could have contributed to humans’ ability to live in large-scale societies. Punishment by unaffected third parties has received extensive scientific scrutiny because third parties punish transgressors in laboratory experiments on behalf of strangers that they will never interact with again. Often overlooked in this research are interactions involving people who are not strangers, which constitute many interactions beyond the laboratory. Across three samples in two countries (US and Japan; N = 1,294), we found that third parties’ anger at transgressors, and their intervention and punishment on behalf of victims, varied in real-life conflicts as a function of how much third parties valued the welfare of the disputants. Punishment was rare (1-2%) when third parties did not value the welfare of the victim, suggesting that previous economic game results have overestimated third parties’ willingness to punish transgressors on behalf of strangers.

In this paper, we discuss an extension to two popular approaches to modelling complex structures in ecological data: the generalized additive model (GAM) and the hierarchical model (HGLM). The hierarchical GAM (HGAM), allows modelling of nonlinear functional relationships between covariates and outcomes where the shape of the function itself varies between different grouping levels. We describe the theoretical connection between these models, HGLMs and GAMs, explain how to model different assumptions about the degree of inter-group variability in functional response, and show how HGAMs can be readily fitted using existing GAM software, the mgcv package in R. We also discuss computational and statistical issues with fitting these models, and demonstrate how to fit HGAMs on example data.

A predicted and communicated decline in the Newfoundland and Labrador snow crab (Chionoecetes opilio) resource, the basis of the world’s largest snow crab fishery for two decades, has come to fruition. Given considerable lead time, this scenario creates an interesting dynamic to investigate how crab harvesters may have formed anticipatory behavioural responses to mitigate against the decline. In this analysis, economic, stock status, and vessel activity indicators are examined along with spatiotemporal fishing patterns before, during, and after the decline to assess harvester behaviour and fleet dynamics. We hypothesize that behaviours indicative of increased competition and a race to fish would emerge in response to the forecasted decline. Contrary to our expectations, we find no evidence of earlier or more rapid fishing, nor broader or more intense fishing patterns. Increased gear soak times were the most common adaptive response employed by harvesters, which were marginally successful in mitigating against declining catch rates and reducing discards. The majority of harvesters appeared to prosecute the fishery in a similar fashion as they historically had, and simply accepted reducing catch rates on known fishing grounds. Some historically dominant fishing grounds even became abandoned with little to no apparent adaptive responses by harvesters. Specific reasons for the general lack of behavioural adaptations to the forecasted fishery decline are unknown but are associated with an Individual Quota system, favourable product prices that have more than offset revenue losses from reduced catch, and small-scale management areas that may have rendered little or no capacity to develop adaptive strategies.

1 Aggregation during dispersal from source to settlement sites can allow 2 persistence of weak competitors, by creating conditions where stronger 3 competitors are more likely to interact with conspecifics than with less 4 competitive heterospecifics. However, different aggregation mechanisms across 5 scales can lead to very different patterns of settlement. Little is known about 6 what ecological conditions are required for this mechanism to work effectively. We 7 derive a metacommunity approximation of aggregated dispersal that shows how 8 three different scales interact to determine competitive outcomes: the spatial scale 9 of aggregation, the spatial scale of interactions between individuals, and the 10 time-scale of arrival rates of aggregations. We use stochastic simulations and a 11 novel metacommunity approximation to show that an inferior competitor can 12 invade only when the superior competitor is aggregated over short spatial scales, 13 and aggregations of new settlers are small and rare. 14

From birth, human and nonhuman primates attend more to faces with direct gaze compared with averted gaze, and previous studies report that attention to the eyes is linked to the emergence of later social skills. Here, we explored whether early experiences influence attraction to eye contact in infant macaques by examining their attention to face pairs varying in their gaze direction across the first 13 weeks of life. Infants raised by human caretakers had limited conspecific interactions (nursery‐reared; N = 16) and were compared to infants raised in rich social environments (mother‐reared; N = 20). Both groups looked longer to faces and the eyes of direct compared to averted‐gaze faces. Looking to all faces and eyes also increased with age. Nursery‐reared infants did not display age‐associated increases in attention to direct‐gaze faces specifically, suggesting that, while there may be an initial preference for direct‐gaze faces from birth, social experiences may support its early development.

Many social scientists believe humans possess an evolved motivation to punish violations of norms-including norm violations that do not harm them directly. However, most empirical evidence for so-called altruistic punishment comes from experimental economics games that create experimental demand for third-party punishment, raising the possibility that the third-party punishment uncovered in these experiments has been motivated by a desire to appear concerned about social norms rather than by actual concern about upholding them. Here we present the results of five experiments in which we used an aggression paradigm to contrast second-party and third-party punishment with minimal experimental demand. We also summarize the results of these experiments meta-analytically. We found robust evidence that participants who were insulted by a stranger experienced anger and punished the insulter. To a lesser degree, participants who witnessed a friend receive an insult also became angry and punished the insulter. In contrast, we found robust evidence that participants who witnessed a stranger receive an insult did not punish the insulter, although they did experience modest amounts of anger. In only one experiment did we find any punishment on behalf of a stranger, and this result could plausibly be explained by the desire to escape the moral censure of other bystanders. Our results suggest that experimental designs that rely on demand-laden methods to test hypotheses about third-party punishment may have overstated the case for the existence of this trait. (PsycINFO Database Record

The Social Heuristics Hypothesis claims that cooperation is intuitive because it is positively reinforced in everyday life, where behaviour typically has reputational consequences

Why would people pay costs to deliver benefits to anonymous strangers in one-shot interactions? The Social Heuristics Hypothesis (SHH) claims that cooperation is intuitive because it is positively reinforced in everyday life, where behavior typically has reputational consequences. Consequently, participants will cooperate in anonymous laboratory settings unless they either reflect on the one-shot nature of the interaction or learn through experience with such settings that cooperation does not promote self-interest. Experiments reveal that cognitive-processing manipulations (which increase reliance on either intuition or deliberation) indeed affect cooperation, but may also introduce confounds. Here, we elide the interpretation issues created by between-subjects designs in showing that people are less cooperative over time in laboratory paradigms in which cooperation cannot promote self-interest, but are just as cooperative over time in paradigms that have the potential to promote self-interest. Contrary to previous findings, we find that cooperation is equally intuitive for men and women: Unilateral giving did not differ across gender at the first study session, and decreased equally for both genders across sessions.

The Dictator Game, a face valid measure of altruism, and the Trust Game, a face valid measure of trust and trustworthiness, are among the most widely used behavioural measures in human cooperation research. Researchers have observed considerable covariation among these and other economic games, leading them to assert that there exists a general human propensity to cooperate that varies in strength across individuals and manifests itself across a variety of social settings. To formalize this hypothesis, we created an S‐1 bifactor model using 276 participants' Dictator Game and Trust Game decisions. The general factor had significant, moderate associations with self‐reported and peer‐reported altruism, trust, and trustworthiness. Thus, the positive covariation among economic games is not reducible to the games' shared situational features. Two hundred participants returned for a second session. The general factor based on Dictator Game and Trust Game decisions from this session did not significantly predict self‐reported and peer‐reported cooperation, suggesting that experience with economic games causes them to measure different traits from those that are reflected in self‐assessments and peer‐assessments of cooperativeness.

The meaning, mechanism, and function of imitation in early infancy have been actively discussed since Meltzoff and Moore's (1977) report of facial and manual imitation by human neonates. Oostenbroek etal. (2016) claim to challenge the existence of early imitation and to counter all interpretations so far offered. Such claims, if true, would have implications for theories of social-cognitive development. Here we identify 11 flaws in Oostenbroek etal.'s experimental design that biased the results toward null effects. We requested and obtained the authors’ raw data. Contrary to the authors’ conclusions, new analyses reveal significant tongue-protrusion imitation at all four ages tested (1, 3, 6, and 9 weeks old). We explain how the authors missed this pattern and offer five recommendations for designing future experiments. Infant imitation raises fundamental issues about action representation, social learning, and brain–behavior relations. The debate about the origins and development of imitation reflects its importance to theories of developmental science.

Neonatal imitation is the matching of (often facial) gestures by newborn infants. Some studies suggest that performance of facial gestures is due to general arousal, which may produce false positives on neonatal imitation assessments. Here we examine whether arousal is linked to facial gesturing in newborn infant rhesus macaques (Macaca mulatta). We tested 163 infants in a neonatal imitation paradigm in their first postnatal week and analyzed their lipsmacking gestures (a rapid opening and closing of the mouth), tongue protrusion gestures, and yawn responses (a measure of arousal). Arousal increased during dynamic stimulus presentation compared to the static baseline across all conditions, and arousal was higher in the facial gestures conditions than the nonsocial control condition. However, even after controlling for arousal, we found a condition-specific increase in facial gestures in infants who matched lipsmacking and tongue protrusion gestures. Thus, we found no support for the arousal hypothesis. Consistent with reports in human newborns, imitators’ propensity to match facial gestures is based on abilities that go beyond mere arousal. We discuss optimal testing conditions to minimize potentially confounding effects of arousal on measurements of neonatal imitation.

The Northwest Atlantic cod stocks collapsed in the early 1990s and have yet to recover, despite the subsequent establishment of a continuing fishing moratorium. Efforts to understand the collapse and lack of recovery have so far focused mainly on the dynamics of commercially harvested species. Here, we use data from a 33-year scientific trawl survey to determine to which degree the signatures of the collapse and recovery of the cod are apparent in the spatial and temporal dynamics of the broader groundfish community. Over this 33-year period, the groundfish community experienced four phases of change: (i) a period of rapid, synchronous biomass collapse in most species, (ii) followed by a regime shift in community composition with a concomitant loss of functional diversity, (iii) followed in turn by periods of slow compositional recovery, and (iv) slow biomass growth. Our results demonstrate how a community-wide perspective can reveal new aspects of the dynamics of collapse and recovery unavailable from the analysis of individual species or a combination of a small number of species. Overall, we found evidence that such community-level signals should be useful for designing more effective management strategies to ensure the persistence of exploited marine ecosystems.

Conflict is an inevitable component of social life, and natural selection has exerted strong effects on many organisms to facilitate victory in conflict and to deter conspecifics from imposing harms upon them. Like many species, humans likely possess cognitive systems whose function is to motivate revenge as a means of deterring individuals who have harmed them from harming them again in the future. However, many social relationships often retain value even after conflicts have occurred between interactants, so natural selection has very likely also endowed humans with cognitive systems whose function is to motivate reconciliation with transgressors whom they perceive as valuable and nonthreatening, notwithstanding their harmful prior actions. In a longitudinal study with 337 participants who had recently been harmed by a relationship partner, we found that conciliatory gestures (e.g., apologies, offers of compensation) were associated with increases in victims' perceptions of their transgressors' relationship value and reductions in perceptions of their transgressors' exploitation risk. In addition, conciliatory gestures appeared to accelerate forgiveness and reduce reactive anger via their intermediate effects on relationship value and exploitation risk. These results strongly suggest that conciliatory gestures facilitate forgiveness and reduce anger by modifying victims' perceptions of their transgressors' value as relationship partners and likelihood of recidivism.

The code of honor, which is characterized by a preoccupation with reputation and willingness to take retaliatory action, has been used extensively to explain individual and cultural differences in peoples' tendencies to behave aggressively. However, research on the relationship between the code of honor and emotional responses to social interactions has been limited in scope, focusing primarily on anger in response to insults and reputational threats. Here we broaden this scope by examining the relationship between code of honor and emotional reactions in response to an unfair economic exchange that resulted in unequal monetary earnings among 3 laboratory participants. We found that endorsement of the code of honor was related to anger and envy in response to unfair monetary distributions. Interestingly, code of honor predicted envy above and beyond what could be accounted for by anger, but the converse was not the case. This suggests that the code of honor influenced perceptions of how subjects viewed their own earnings relative to those of others, which consequently was responsible for their apparent anger as a result of the economic transaction. Furthermore, the unique relationship between code of honor and envy was present only for subjects who received unfair treatment and not for subjects who merely witnessed unfair treatment. Additionally, we replicated previous findings that harsh childhood environmental conditions are associated with endorsement of the code of honor, highlighting the potential value of incorporating a life history theoretical approach to investigating individual differences in endorsement of the code of honor.

Community interactions (e.g., predation, competition) can be characterized by two factors: their strengths and how they are structured between and within species. Both factors play a role in determining community dynamics. In addition to trophic interactions, dispersal acts as an interaction between separate populations. As with other interactions, the structure of dispersal can affect the stability of a system. However, the primary structure that has been studied in consumer-resource models has been hierarchical dispersal, where between-patch dispersal rates increase with trophic level. Here we use analytical, numerical, and simulation approaches on a two-patch, three-species metacommunity model to investigate the relationship between structure and community stability and resilience. We show that metacommunity stability is greater in systems with both weak and strong dispersal rates. Our system is stabilized by the formation of patterns when predators disperse frequently and herbivores disperse rarely, and via asynchrony when both predators and herbivores disperse infrequently. Our results show how interaction strengths within both trophic and spatial networks shape metacommunity stability.

Predicting dispersal paths of marine larvae with long pelagic durations, such as American lobster (Homarus americanus), requires understanding the cues to which larvae respond, and how that response reflects changes in larval behaviour. If larvae respond to conspecific presence by varying their movement, this behaviour can bias laboratory estimates of environmental responses. We tested whether larvae actively decreased their local intraspecific density by measuring how the vertical distribution of larvae changed under high versus low concentrations of conspecifics. We observed weak increases in vertical dispersion at higher concentrations in both newly-hatched larvae and in post-larvae, but not in intermediate larval stages. Further, we found that larvae from different mothers consistently differed in vertical distribution, which may indicate maternal effects on dispersal behavior. We also tested for differences in horizontal swimming behaviour in high and low concentrations, by fitting a novel random walk model that allowed us to model both larval interactions and persistent turning behaviours. We showed substantial reduction in diffusive behaviour under high concentration conditions resulting from more frequent turns by each larva, but no evidence for consistent avoidance of conspecifics. Our study is the first to demonstrate concentration-dependent behaviours in lobster larvae.

Aggregation during dispersal from source to settlement sites can allow persistence of weak competitors, by creating conditions where stronger competitors are more likely to interact with conspecifics than with less competitive heterospecifics. However, different aggregation mechanisms across scales can lead to very different patterns of settlement. Little is known about what ecological conditions are required for this mechanism to work effectively. We derive a metacommunity approximation of aggregated dispersal that shows how three different scales interact to determine competitive outcomes: the spatial scale of aggregation, the spatial scale of interactions between individuals, and the time-scale of arrival rates of aggregations. We use stochastic simulations and a novel metacommunity approximation to show that an inferior competitor can invade only when the superior competitor is aggregated over short spatial scales, and aggregations of new settlers are small and rare.

Searching for patchily distributed, highly localized, and seasonally variable resources in heterogeneous environments poses significant challenges for social species living in cohesive groups. Here, we studied the searching strategies of a highly social mammal, the white-lipped peccary (Tayassu pecari), in Calakmul Biosphere Reserve, Mexico. Calakmul Biosphere Reserve is a seasonal tropical forest where important resources, such as water and food, are patchy distributed and temporarily scarce. We attempted to determine what theoretical searching model best explained the movement patterns of groups of white-lipped peccaries, including short-tailed, long-tailed, and scale-free distributions. We found that the only distribution that was well supported by the data was a zero-inflated lognormal distribution; this implies a general pattern of normally short-range intensive searching with occasional long-distance directed movements taking the animals away from previously searched areas. We also found that groups concentrated foraging activities around sources of water during the dry season, behaving as central-place foragers while occasionally searching distant areas. We discuss the potential adaptive values of such behavioral strategies for social species living in highly heterogeneous environments.

The proteome of mature (MP) and in vitro germinating pollen (GP) of canola (Brassica napus) were analyzed using the DIGE technology with the objective of identifying proteins and their function in pollen germination. Of the 2,238 protein spots detected in gel images, 344 were differentially expressed in MP and GP samples of which 165 were subjected to MALDI-TOF/TOF and 130 were successfully identified using the NCBInr and Brassica EST databases. The major proteins up-regulated in GP, relative to MP, have roles in carbohydrate metabolism, protein metabolism, and cell wall remodeling. Others with roles in cytoskeleton dynamics, nucleotide and amino acid metabolism, signal transduction, and stress response also showed higher expression in GP. Proteins concerned with transcriptional regulation and ion transport were similar in MP and GP, and some catalases and LEA proteins were down-regulated in GP. A number of proteins including, oleosin, cruciferin, and enolase, were released into the pollen germination medium indicating their potential role in pollen-stigma interaction. Glycosylated proteins were also identified in MP and GP, but their protein profiles were not different. This study has documented the dynamics of protein expression during pollen germination and early tube growth in B. napus and provides insights into the fundamental mechanisms involved in these processes, and in cell growth, cell-cell communication, and cell signaling.