Group Process Research Articles

The Grouping Patterns of Cervus canadensis songaricus in the Tianchi Bogda Peak Nature Reserve of Tianshan Mountain, Northwestern China.

Grouping behavior is a fundamental component of animal population dynamics, shaped by both environmental factors and the social interactions among individuals, ultimately enhancing adaptability to their habitats. However, the social organization of the wapiti subspecies inhabiting the Tian Shan Mountains remains poorly understood. In this study, we investigated the grouping behavior of Tianshan wapiti in the Bogda Peak Nature Reserve, northwestern China from July 2019 to November 2020. Using infrared-triggered camera traps, we analyzed seasonal variation in group size and group frequency, as well as sex-specific aggregation and segregation pattern. Our results showed that Tianshan wapiti group sizes varied considerably, ranging from 1 to 32 individuals, with most groups being relatively smaller, typically consisting of 1 to 9 individuals. Seasonal differences in group size were significant (H = 28.91, df = 3, p < 0.05). Additionally, group type showed significant variation across seasons (χ2 = 93.32, df = 18, p < 0.05). Anakysis of sex-specifia aggregation and segregation (SSAS) indicated no consistent segregation of females and males throughout the year. However, there was a notable tendency for sex-specific aggregation during July and from October to December. These findings provide new insights into the social organization and seasonal grouping behavior of Tianshan wapiti, contributing to a better understanding of their behavioral ecology and informing conservation and management strategies for this subspecies.

Toward a microscopic picture of superfluid Helium-4

Taking inspiration from F. Bloch’s seminal work (PRA 7, 2187 (1973)), we investigate the quantum many-body states of superfluid 4He, unveiling a novel characteristic in the system’s energy levels. Below the transition temperature, the thermally active low-energy levels exhibit a distinctive grouping behavior, with each level belonging exclusively to a single group. In a superflow state, the system establishes thermal equilibrium with its surroundings on a group-specific basis. Specifically, the levels within a chosen group, initially populated, undergo thermal redistribution, while the remaining groups of levels stay vacant due to absence of transitions between groups. The macroscopic properties of the system, such as its superflow velocity and thermal energy density, are statistically determined by the thermal distribution of the occupied group. Additionally, we infer that the thermal energy of a superflow has an unusual relationship with flow velocity, such that the larger the flow velocity, the smaller the thermal energy. This relationship is responsible for a range of intriguing phenomena, including the mechano-caloric effect and the fountain effect, which demonstrate a fundamental coupling between the thermal motion and hydrodynamic motion of the system. Furthermore, we present experimental evidence of a self-heating effect in 4He superflows, confirming that a 4He superflow carries significant thermal energy related to its velocity.

Unsupervised Decision Trees for Axis Unimodal Clustering

The use of decision trees for obtaining and representing clustering solutions is advantageous, due to their interpretability property. We propose a method called Decision Trees for Axis Unimodal Clustering (DTAUC), which constructs unsupervised binary decision trees for clustering by exploiting the concept of unimodality. Unimodality is a key property indicating the grouping behavior of data around a single density mode. Our approach is based on the notion of an axis unimodal cluster: a cluster where all features are unimodal, i.e., the set of values of each feature is unimodal as decided by a unimodality test. The proposed method follows the typical top-down splitting paradigm for building axis-aligned decision trees and aims to partition the initial dataset into axis unimodal clusters by applying thresholding on multimodal features. To determine the decision rule at each node, we propose a criterion that combines unimodality and separation. The method automatically terminates when all clusters are axis unimodal. Unlike typical decision tree methods, DTAUC does not require user-defined hyperparameters, such as maximum tree depth or the minimum number of points per leaf, except for the significance level of the unimodality test. Comparative experimental results on various synthetic and real datasets indicate the effectiveness of our method.

Are you what you emoji? How skin tone emojis and profile pictures shape attention and social inference processing

Emojis can express emotions and some aspects of the sender’s identity; however, only limited research has explored how the choice of skin tone in emojis influences the perceptions of the users. We examined the interaction between emoji skin tones and profile pictures in instant messaging, using self-reported and eye tracking measures. White participants viewed 14 screenshots of conversations (9 target and 5 fillers) where the sender used an emoji in a Darker or Lighter skin tone, or the default Yellow; alongside profile pictures displaying a Black or White individual, or a landscape as a neutral condition. Results showed that Black senders using Darker emojis were seen as warmer and closer to the receiver, but less competent, suggesting a dimensional compensation effect. Conversely, Black senders using Lighter emojis appeared more competent, but less warm. In the Neutral condition, Lighter emojis improved warmth and relationship quality, but reduced competence inferences, unlike Yellow and Darker emojis, suggesting a black sheep effect (in-group strictness). Yellow emojis were assumed to be sent by White individuals. Eye-tracking measures revealed an implicit bias towards White senders using Darker emojis, although such an impact was not observed for Black senders using Lighter emojis. Overall, findings indicate that skin tone emojis and profile pictures influence sender perception and challenge the neutrality of Yellow emojis.

Impacts of climate-related stressors on social group cohesion and individual sociability in fish.

Group-living in animals comes with a number of benefits associated with predator avoidance, foraging, and reproduction. A large proportion of fish species display grouping behaviour. Fish may also be particularly vulnerable to climate-related stressors including thermal variation, hypoxia, and acidification. As climate-related stressors are expected to increase in magnitude and frequency, any effects on fish behaviour may be increased and affect the ability of fish species to cope with changing conditions. Here we conduct a systematic review of the effects of temperature, hypoxia, and acidification on individual sociability and group cohesion in shoaling and schooling fishes. Searches of the published and grey literature were carried out, and studies were included or excluded based on selection criteria. Data from studies were then included in a meta-analysis to examine broad patterns of effects of climate-related stressors in the literature. Evidence was found for a reduction in group cohesion at low oxygen levels, which was stronger in smaller groups. While several studies reported effects of temperature and acidification, there was no consistent effect of either stressor on sociability or cohesion. There was some evidence that marine fishes are more strongly negatively affected by acidification compared with freshwater species, but results are similarly inconsistent and more studies are required. Additional studies of two or more stressors in combination are also needed, although one study found reduced sociability following exposure to acidification and high temperatures. Overall, there is some evidence that hypoxia, and potentially other climate-related environmental changes, impact sociability and group cohesion in fishes. This may reduce survival and adaptability in shoaling and schooling species and have further ecological implications for aquatic systems. However, this synthesis mainly highlights the need for more empirical studies examining the effects of climate-related factors on social behaviour in fishes.

Exemplary Self-Discipline, Leniency towards Others: Competitive Contexts Amplify the "Black Sheep Effect" in Restoring Ingroup Trust.

Intergroup interaction, a pivotal aspect of social interaction, encompasses both cooperation and competition. Group identity significantly impacts individual behaviors and decision-making processes. This influence manifests in two contrasting ways when addressing rule-breaking by interaction partners: in-group favoritism, where individuals are more lenient towards infractions committed by in-group members, and the black sheep effect, where in-group members are penalized for their rule-breaking. Although trust is crucial in intergroup interactions, the precise impact of group identity on trust restoration and the potential moderating role of intergroup interaction types remain to be elucidated. This study presents two experiments designed to explore these dynamics. In Study 1, the manipulation of group identity through a point estimation task was utilized to evaluate its impact on intergroup trust restoration via a series of repeated trust games. Study 2 aimed to explore the moderating role of intergroup interaction on intergroup trust restoration by contrasting cooperation and competition situations. The results uncovered a "black sheep effect", where participants demonstrated a greater propensity for trust restoration with out-group members than with in-group members. This effect, however, was only evident in competitive contexts. Conversely, in cooperative contexts, the individual's trust in the in-group and out-group members is effectively repaired. These findings contribute to a deeper comprehension of trust dynamics in intergroup interactions, promoting trust establishment and repair between diverse groups, thereby boosting team collaboration efficiency and mitigating conflicts.

Exploring athletes’ gendered views of coaches and their impact of coach competency ratings

This study draws on social role theory, role congruity theory, and the black sheep effect to explore athletes’ gendered perceptions of coach competence. The study relied on a sample of 308 New Zealand athletes across sports levels and modalities who completed an online survey. Participants were randomly assigned to one of four vignettes, in which coach gender (female vs. male) and coaching style (communal vs. agentic) were manipulated, and athlete gender was considered. The results show that male and female coaches did not receive significantly different coach competency scores (relational and strategic competencies), that a communal coaching style was linked to higher ratings in both relational and strategic competencies, and that the interplay of athlete gender, coach gender, and gender conforming/non-conforming coaching style did not significantly affect coach competence scores. However, participants’ comments to the open-ended question presented at the end of the survey suggest that athletes still hold gendered views of coaching competence at the elite level. We discuss the research and practical implications of our findings.

Effect of Acoustics on Droplet Grouping Behaviour in a Single Stream of Droplets

Droplet and particle grouping can be influenced by applying an acoustic field and have practical applications such as particle scavenging and aerosol filters of engine exhaust and air purifiers. The present work experimentally investigates the influence of a standing acoustic wave on a single stream of droplets. The experimental setup consists of an acoustic transducer and a reflector plate through which the droplet stream passes in the presence or absence of an external pressure field generated by a standing acoustic wave. A droplet stream is generated with the help of a nozzle connected to a pressurized working fluid supply and piezoelectric transducer to control the spacing between droplets. The effect of the acoustic pressure field on the droplet stream generated by the nozzle operated at different piezoelectric excitation frequencies and fluid pressures is investigated. Droplet stream characteristics at every nozzle excitation frequency are observed with a high-speed camera when the acoustic field is switched OFF and ON. The competing effect of nozzle excitation frequency and acoustic field is observed. At lower nozzle frequencies, the nozzle generates an unstable stream of droplets having different sizes and spacings between them. When the acoustic field is applied at these lower frequencies, the stream of droplets becomes organized, and in some cases, it becomes equispaced and of the same size. However, an opposite behavior is observed at higher frequencies. In these cases, as the acoustic field is applied, an equispaced mono-disperse droplet stream becomes unstable due to the coalescence of droplets within the stream.

An individual-based movement model for contacts between mule deer (Odocoileus hemionus)

Contacts between individuals are key for the spread of infectious disease. Although essential to understanding disease spread, contact rates are difficult to predict, based simply on population demographics in wildlife populations, because contact rates depend upon environmental features as well as the nature of social interactions within and between groups of individuals. We developed a detailed, behaviorally structured, individual-based model (IBM) in Netlogo to simulate contacts between- and within-groups of individual mule deer (Odocoileus hemionus), a species particularly susceptible to chronic wasting disease. The model tracks contacts (defined as two individuals coming within five meters of one another), recorded as between- or within-group depending on the social group membership of the two individuals (dyad). We parameterized the model with data from mule deer with global positioning systems (GPS) collars in east-central Alberta, Canada. Individuals move according to habitat preferences, home range attraction, and grouping behaviours. Animals were tracked at two-hour time steps and were modelled as selecting locations relative to preferred resources based on sex-specific integrated step-selection functions (iSSFs) with steps biased toward a home range centroid. Total within-group contacts increased with group size and were sensitive to changes in movement cohesion of the group and movement persistence, particularly movement cohesion. Total between-group contacts were sensitive only to the number of groups. We compared model predictions for where the locations of deer contacts occurred against an existing statistical model for the relative contact probabilities (RCP) on the same landscape (Dobbin et al. 2023). Predicted locations of deer contacts generally were consistent with higher predicted RCP values. When disease transmission is a function of contact rate, the model can be used to assess the interaction between model components (e.g., movement rates, grouping rules, home ranges, animal densities) and the spatial distribution of key natural and artificial resources that may attract deer and potentially increase disease spread.

Investigating flock-associated mimicry: examining the evidence for, and drivers of, plumage mimicry in the greater and lesser necklaced laughingthrush.

Visual mimicry is less understood in birds than in other taxa. The interspecific social dominance mimicry (ISDM) hypothesis asserts that subordinate species resemble dominant ones to reduce aggression. Plumage mimicry has also been consistently noted in mixed-species flocks (MSFs), suggesting a connection to grouping behaviour, although it is unclear whether this is linked to ISDM. We studied greater necklaced laughingthrush (GNLT, Pterorhinus pectoralis) and lesser necklaced laughingthrush (LNLT, Garrulax monileger), which were recently placed in different genera. Measurements of 162 museum specimens showed LNLT converging in sympatry with GNLT in necklace colour, but diverging in necklace to body ratio, with proportionally smaller necklaces. The species were closely associated in six of seven MSF systems from Nepal to China. In a study of foraging behaviour in Nepal, aggression was rare between the species, LNLT followed GNLT and had lower foraging rates when further from GNLT. Our data suggest a link between this MSF-associated mimicry and ISDM, and that the subordinate LNLT may be the mimic and gain more from the resemblance. The species spend much time together in dense and poorly lit vegetation, where the LNLTs resemblance to GNLTs potentially allows them to forage closer to GNLTs than would be otherwise possible.

Bat Hibernation: In Groups or Individually?

This study focuses on the hibernation behavior of the western barbastelle bat (Barbastella barbastellus) in underground systems in Poland from 2006 to 2011, specifically during the peak hibernation months of December to February. The impact of climate parameters, namely temperature (T), humidity (Rh), and air flow velocity (v), on the clustering behavior of bats during hibernation was investigated. The climate parameters varied within specific ranges: T fluctuated between 6.0 and 12.4 °C, Rh ranged from 56.4 to 91.8%, and v varied from 0.01 to 1.17 m/s. The quantile linear regression method for statistical analysis of the results was employed. This study found that certain combinations of climate parameters influenced the grouping behavior of bats during hibernation. The model structural parameters revealed the following relationships: 1. An increase in the product of T and v led to an increase in the bats’ group size. 2. For pairs of variables such as T and Rh, and Rh and v, an increase in their product resulted in a decrease in the bats’ group size. 3. When considering the product of T, Rh, and v, a decrease in the bats’ group size was also observed.

Fitness benefits of grouping during foraging in beef cattle: Social behaviour or affinity to vegetation resources?

Grouping behaviour in gregarious species expresses a dynamic cost-benefit equilibrium. The balance between costs and benefits differs amongst individuals that were selected to maximize their individual fitness. In environments where resources are limited, benefits of grouping may come at the expense of increased competition over resources. This study aimed to test whether grouping behaviour during foraging in a free-ranging beef cattle herd is a social choice bearing fitness benefits for all participants, or reflects affinity to vegetation resources with possible differentiating fitness benefits. GPS location data were recorded in a herd of 60 beef cows grazing a semi-arid pasture in northern Israel. Pasture vegetation was chemically and spectrally analysed. GPS location data were used to investigate individual and shared foraging locations and the temporal sequence of initiating foraging movement. Co-travel function in ArcPro v3.0 was used to investigate the amount and variability of individual proximity associations and their correlation with fitness. Fitness proxies were conception result (yes/no) and the interval between calving and conception within the cows who conceived. A positive correlation was found between fitness and the individual number of proximity associations, but not with the variability in associations' partners. No significant correlations were found between fitness and vegetation biomass, N content and spectral properties measured by REEVI2 index in foraging locations. Individual sequence of arrival at shared foraging locations and foraging movement initiation sequence were also not correlated with fitness. Vegetation biomass in grouping locations was lower than in individually foraged locations, but no difference was found in N content between individual and shared foraging locations. No differences were found in vegetation biomass and N content between herd foraging locations and random locations, thus no evidence for herd foraging strategy aimed to increase biomass or N consumption was found. No further differences in pasture resources availability, i.e., water, shade, human or predator presence could explain grouping. Circular variance values implied the absence of preferred movement direction. Our results suggest that grouping during foraging is fitness beneficial and is not related to vegetation biomass or N content. Our results further suggest the absence of consistent leading individuals and no significant correlations between foraging movement initiation and fitness. This study provides insights into social and vegetation factors affecting cattle foraging behaviour in constrained pasture, and may allow ranchers to improve grazing management systems. We suggest that further research into pasture characteristics that affect beef cattle pasture location choice is needed.

Differential Evaluation of Straight and Gay Men for Nonverbal Effeminate Behavior.

The purpose of this study was to determine how violation of gender-based expectancies might influence straight men's attitudes toward men who differ by sexual orientation (i.e., straight or gay). This study was specifically designed to avoid methodological issues that may have been present in similar research. Hypotheses were informed by Expectancy-Violation Theory (EVT) and the Black Sheep Effect (BSE), which together suggest that an effeminate straight man should be evaluated by other straight men more negatively than an effeminate gay man because the former target negatively violated expectations. Additionally, EVT suggests that a masculine gay man should be evaluated more positively than a masculine straight man because the former positively violates expectations, while the BSE instead suggests the latter should be evaluated more positively than the former due to ingroup bias. Self-identified straight men evaluated a male target whose sexual orientation and gender conformity were manipulated through a photo and vignette. A moderated mediation analysis was performed to determine if perceived expectancy violation mediated the relationship between sexual orientation and evaluations for both effeminate and masculine men. Straight effeminate targets were evaluated more negatively than gay effeminate targets; however, straight masculine targets were evaluated more favorably than gay masculine targets, a finding more consistent with the BSE. In addition, perceived expectancy violation did not mediate the relationship between sexual orientation and evaluations regardless of gender expression. More research should be conducted to identify the mechanisms through which evaluations of straight and gay targets differ based on gender expression.

Evolution of larval gregariousness is associated with host plant specialisation, but not host morphology, in Heliconiini butterflies.

Insect herbivores, such as lepidopteran larvae, often have close evolutionary relationships with their host plants, with which they may be locked in an evolutionary arms race. Larval grouping behaviour may be one behavioural adaptation that improves host plant feeding, but aggregation also comes with costs, such as higher competition and limited resource access. Here, we use the Heliconiini butterfly tribe to explore the impact of host plant traits on the evolution of larval gregariousness. Heliconiini almost exclusively utilise species from the Passifloraceae as larval host plants. Passifloraceae display incredible diversity in leaf shape and a range of anti-herbivore defences, suggesting they are responding to, and influencing, the evolution of Heliconiini larvae. By analysing larval social behaviour as both a binary (solitary or gregarious) and categorical (increasing larval group size) trait, we revisit the multiple origins of larval gregariousness across Heliconiini. We investigate whether host habitat, leaf defences and leaf size are important drivers of, or constraints on, larval gregariousness. Whereas our data do not reveal links between larval gregariousness and the host plant traits included in this study, we do find an interaction between host plant specialisation and larval behaviour, revealing gregarious larvae to be more likely to feed on a narrower range of host plant species than solitary larvae. We also find evidence that this increased specialisation typically precedes the evolutionary transition to gregarious behaviour. The comparatively greater host specialisation of gregarious larvae suggests that there are specific morphological and/or ecological features of their host plants that favour this behaviour.

Grouping dynamics of the northernmost population of blackbuck (Antilope cervicapra) in Krishnasaar Conservation Area, Nepal

Blackbuck, Antilope cervicapra, are group-living grazers found in a wide range of habitats, from dry grasslands to open forests. Krishnasaar Conservation Area (KrCA) in Bardia, Nepal is home to the northernmost population of blackbuck. This population lives in close proximity to humans. As a population in an extreme of the species’ range and experiencing direct and indirect human influences, KrCA is suitable to study less explored facets of herbivore ecology and behavior. One such less explored behavior of herbivores is their grouping (herding) behavior. Grouping is commonly seen as an anti-predator response and could also be used in the context of anthropogenic threat. In this study we investigated herding behavior of blackbuck and ecological and anthropogenic factors that might influence the herding. To record the grouping behavior of blackbuck in the different habitat types, we used scan sampling methods for groups. A group was defined by including all individuals that are within 50 m of another individual. The influence of ecological and anthropogenic factors on herding pattern was assessed through simple regression modelling. We scanned animals for 89 hours and each hour had seven observations. The mean group size was 20.56 ±1.97 (mean ± SE). More than two-thirds of animals observed were female. We found larger herd sizes in the morning compared with herd sizes in the afternoon and evening. Our observations also showed that mixed herds were significantly larger in size than male-only, and female-only herds in both core and settlement zones. Our modelling of covariates predicted group type to be the single most influential factor influencing herd size. As herding behavior of animals reflect associated risk and resource factors, the finding of this work can be helpful in managing this isolated threatened population of blackbuck.

Quantitative text analysis of language use in rare dementia support groups

AbstractBackgroundQuantitative text analysis facilitates study of internal states of speakers in an interspace between self‐report measures and qualitative analyses. The methodology is well‐established in psychological research, including in numerous support group settings.MethodIn this study, Linguistic Inquiry and Word Count (LIWC2015) was employed to characterise conversations in online multi‐component (peers and professionals) support groups for familial caregivers of people living with young onset, atypical or inherited (rare) dementias. Using a corpus of transcripts (129,616 words) from 14 sessions, the differences between trained facilitators’ (n = 2) and participants’ (n = 14) speech were examined, and the impact of agenda on discussion was investigated. Sessions were semi‐structured, addressing independence and identity, or unstructured, without agenda. Statistical methods included comparison of linguistic features with natural speech, Poisson regression, and a clustering algorithm.ResultMeaningful differences between natural speech and the corpus emerged, including in emotional tone (Tone; d = ‐3.2, p&lt;0.001), level of analytic/informal language (Analytic; d = 0.8, p = 0.01), degree of expertise/confidence (Clout; d = 1.0, p = 0.002), and openness/guardedness (Authentic; d = ‐0.9, p = 0.006) (Figure 1). Differences were observed between facilitators and participants in the descriptive (Figure 1) and inferential (Figures 2&amp;3) statistical methods employed. Differences between unstructured and semi‐structured sessions, including between different agendas in the semi‐structured sessions, were observed. Sessions 2 and 4 focused on the participant while sessions 1 and 3 focused on their loved one (Figure 2). The clustering algorithm categorised participants’ conversational turns into three groups: sharing experience (EXP), self‐reflection (SELF), and group processes (GROUP). Contribution‐types were dispersed throughout sessions (Figure 3).ConclusionResults suggest that LIWC2015 can be used to distinguish support group conversations from natural speech, facilitators from participants, and different sessions based on agenda. The methodology could be adapted for use by other peer‐support services wanting insight into their groups using only session transcripts as raw data.

Image Enhancement Approach for the Underwater Images Using the Optimized Color Balancing Model

Marine resources are one of the valuable resources that need to be explored and protected, but are affected due to environmental factors. The underwater images are distorted due to the light scattering and absorption phenomenon, which draws the attention of the researcher to restoring the underwater images which is a challenging task. High-quality underwater images help us to learn and study deep-sea environments, and also help in gaining deep knowledge about the ocean resources. In this research, deep learning methods are used for obtaining high-quality underwater images. Accordingly, a channel-based white balancing and social situation-aware guard optimization (WBSSGO) dependent multi-variant balancing color correction model is proposed by integrating the grouping behavior and adaptability nature of the guards and flocks, which acts as the search agents in the proposed optimization. A multi-variant-based white balancing model is employed for balancing the channels and correcting the distorted underwater images. The performance of the developed model is validated using PIQE, BRISQUE, and UCIQE, which acquired minimal values of 27.202, 24.692, and 29.725, respectively with comparative methods, while the higher value of SDME is 64.049 dB for the proposed method, which is reported to acquire the higher visual quality of underwater images.

Who did it? Moral wrongness for us and them in the UK, US, and Brazil

ABSTRACT Morality has traditionally been described in terms of an impartial and objective “moral law”, and moral psychological research has largely followed in this vein, focusing on abstract moral judgments. But might our moral judgments be shaped not just by what the action is, but who is doing it? We looked at ratings of moral wrongness, manipulating whether the person doing the action was a friend, a refugee, or a stranger. We looked at these ratings across various moral foundations, and conducted the study in Brazil, US, and UK samples. Our most robust and consistent findings are that purity violations were judged more harshly when committed by ingroup members and less harshly when committed by the refugees in comparison to the unspecified agents, the difference between refugee and unspecified agents decays from liberals to conservatives, i.e., conservatives judge them more harshly than liberals do, and Brazilians participants are harsher than the US and UK participants. Our results suggest that purity violations are judged differently according to who committed them and according to the political ideology of the judges. We discuss the findings in light of various theories of groups dynamics, such as moral hypocrisy, moral disengagement, and the black sheep effect.

Deep behavioral impairment in the pearl oyster Pinctada radiata exposed to anthropogenic noise and light stress

The pearl oyster Pinctada radiata is an iconic species in the Arabian Gulf, which is one of the ecosystems most at risk in the world because of the multiple sources of pollution it faces. Alongside chemical pollution, the Gulf is ranked first with regard to noise and light pollution, and pearl oyster populations are at risk. The impact of these latter types of pollution on marine invertebrates is still poorly known. We used the difference in noise and brightness that can exist between a very quiet room without artificial lighting and a standard laboratory room equipped with a standard aquarium as a testbed to explore the possible impact of noise and light pollution on the behavioral and biological traits of Pinctada radiata without added chemical exposure. During an experiment that lasted 2.5 months, we analyzed their grouping behavior, valve activity, biological rhythm, growth rate and spawning activity. In the standard aquarium kept in the laboratory room, the oysters dispersed instead of regrouping as in their natural environment, regrouping which was observed in the quiet room. They stayed closed longer, the opening amplitude of their valves was systematically lower, and in the closed position, they squeezed their valves more tightly when subjected to noise and light pollution. Their daily opening rhythm was strongly structured by switching the electric light on and off, and females showed significantly less egg-laying behavior. In conclusion, seemingly innocuous human activities can lead to very significant alterations in pearl oyster behavior. We propose that it could have significant effects on populations and ecosystems.

Morality's role in the Black Sheep Effect: When and why ingroup members are judged more harshly than outgroup members for the same transgression

AbstractWhen and why might someone judge an ingroup transgressor more harshly than an outgroup transgressor? Taking a social functionalist perspective, we argue that morality is central to this phenomenon–the Black Sheep Effect–and that it is driven by social cohesion concerns. Using mediation and moderation methods across our studies, we find that people judge ingroup (vs. outgroup) transgressors more harshly because of concerns regarding ingroup social cohesion (Studies 1a–4). We also find that ingroup derogation is stronger for moral transgressions than weak or non‐moral transgressions (Studies 2 and 3). Throughout our studies, we address alternative explanations, including moral relativism, naïve realism, moral parochialism and belief in a just world. Our work speaks to the emerging contention around the reliability of the Black Sheep Effect by noting when and why it surfaces.