Increasing Group Size Research Articles

Does religion make people moral?

I address three common empirical questions about the connection between religion and morality: (1) Do religious beliefs and practices shape moral behavior? (2) Do all religions universally concern themselves with moral behavior? (3) Is religion necessary for morality? I draw on recent empirical research on religious prosociality to reach several conclusions. First, awareness of supernatural monitoring and other mechanisms found in religions encourage prosociality towards strangers, and in that regard, religions have come to influence moral behavior. Second, religion’s connection with morality is culturally variable; this link is weak or absent in small-scale groups, and solidifies as group size and societal complexity increase over time and across societies. Third, moral sentiments that encourage prosociality evolved independently of religion, and secular institutions can serve social monitoring functions; therefore religion is not necessary for morality. Supernatural monitoring and related cultural practices build social solidarity and extend moral concern to strangers as a result of a cultural evolutionary process.

Vergleichende Qualitätsmessungen Teil 3: Funnel Plots

Comparative quality measurements between organisations or institutions are common. Quality measures need to be standardised and risk adjusted. Random error must also be taken adequately into account. Rankings without consideration of the precision lead to flawed interpretations and enhances "gaming". Application of confidence intervals is one possibility to take chance variation into account. Funnel plots are modified control charts based on Statistical Process Control (SPC) theory. The quality measures are plotted against their sample size. Warning and control limits that are 2 or 3 standard deviations from the center line are added. With increasing group size the precision increases and so the control limits are forming a funnel. Data points within the control limits are considered to show common cause variation; data points outside special cause variation without the focus of spurious rankings. Funnel plots offer data based information about how to evaluate institutional performance within quality management contexts.

Human Disturbances, Habitat Characteristics and Social Environment Generate Sex-Specific Responses in Vigilance of Mediterranean Mouflon

In prey species, vigilance is an important part of the decision making process related to predation risk effects. Therefore, understanding the mechanisms shaping vigilance behavior provides relevant insights on factors influencing individual fitness. We investigated the role of extrinsic and intrinsic factors on vigilance behavior in Mediterranean mouflon (Ovis gmelini musimon×Ovis sp.) in a study site spatially and temporally contrasted in human pressures. Both sexes were less vigilant in the wildlife reserve compared to surrounding unprotected areas, except for males during the hunting period. During this period, males tended to be less strictly restricted to the reserve than females what might lead to a pervasive effect of hunting within the protected area, resulting in an increase in male vigilance. It might also be a rutting effect that did not occur in unprotected areas because males vigilance was already maximal in response to human disturbances. In both sexes, yearlings were less vigilant than adults, probably because they traded off vigilance for learning and energy acquisition and/or because they relied on adult experience present in the group. Similarly, non-reproductive females benefited of the vigilance effort provided by reproductive females when belonging to the same group. However, in the absence of reproductive females, non-reproductive females were as vigilant as reproductive females. Increasing group size was only found to reduce vigilance in females (up to 17.5%), not in males. We also showed sex-specific responses to habitat characteristics. Females increased their vigilance when habitat visibility decreased (up to 13.8%) whereas males increased their vigilance when feeding on low quality sites, i.e., when concomitant increase in chewing time can be devoted to vigilance with limited costs. Our global approach was able to disentangle the sex-specific sources of variation in mouflon vigilance and stressed the importance of reserves in managing and conserving wild sheep populations.

Influence of food availability on the diet and activity budget of two western lowland gorilla (Gorilla gorilla gorilla) groups of differing size in the Dzanga-Ndoki National Park, Central African Republic

Variation in food availability, body size and group size are known to influence primate diet and activity budgets. Here we report how seasonal food availability shapes the diet and activity patterns of two habituated western lowland gorilla (WLG) groups of differing size. WLGs are ripe fruit opportunists, showing dietary flexibility when preferred foods are scarce. However, as fruit can be rare/ patchily distributed, as intra-group feeding competition increases with group size, access to individual patches may be limited. We thus predicted that frugivory decreases with increased group size and influences diet and activity budgets accordingly (increased diet breadth and time feeding since relying on alternative/lower quality food). First, we compared food availability between home-ranges by monitoring leafing/fruiting patterns of major gorilla food trees. Second, we compared the groups’ activity budgets and diet composition/diversity, testing for differences between high (HF) and low fruit seasons (LF). We measured gorilla activity over six months by continuous focal sampling of 16 target animals rotated daily from both groups (N=9 and N=15). Our results confirm that WLG diet consisted mainly of fruits (36%, then: stems 24%; leaves 21%; insects 14%; other food types 3%, and bark 2%) and spend most of their time feeding (39%, then: resting 33%; traveling 19%; social 5%, and other activities 4%). However, contrary to our predictions, we found no group differences within or between seasons: irrespective of group size both spent significantly less time feeding, but more time traveling and socializing, and consumed significantly more fruits, less leaves and bark during the HF compared to the LF. Our results show that WLG activity budgets and diet appear to vary more in response to ripe fruit availability than group size. We suggest that WLGs may cope with increased group size costs through other mechanisms such as group spread, rather than lowering diet quality or further changing activity patterns. Such flexibility may better allow WLG groups to track ripe fruits when available but, unlike sympatric chimpanzees, switch to more herbivorous diets when necessary, adjusting activity budgets accordingly ; WLGs thus may be considered more resilient faced with environmental change such as forest degradation.

Effects of an Increase in Group Size on the Social Behavior of a Group of Rough-Toothed Dolphins (Steno bredanensis)

Effects of an Increase in Group Size on the Social Behavior of a Group of Rough-Toothed Dolphins (Steno bredanensis)

Horizontal Transfer of Fipronil Is Enhanced With Increased Group Size in <I>Coptotermes formosanus</I> (Isoptera: Rhinotermitidae)

Fipronil is a widely used insecticide for termite control. Although transfer of fipronil among termite cohorts has been investigated in previous studies, no study has yet focused on the influence of termite group size (density) on horizontal transfer. In this study, the mortality of donor and recipient Coptotermes formosanus Shiraki (Isoptera: Rhinotermitidae) was compared among groups of 10, 25, and 50 workers. Most donor termites were dead within 20 h. There was a significantly higher mortality of recipient termites starting at 44 h when in bigger groups. LT50 and LT90 of recipient termites decreased with increase in group size, being significantly shorter in groups of 50 termites compared with groups of 10 termites. Moreover, the variance (within-group difference) of recipient mortality and lethal time estimations was lowest in the groups of 50 termites, indicating a more uniform horizontal transfer of fipronil by termites in bigger groups. Our findings suggest that group size has an influence on fipronil transfer among C. formosanus workers and should be considered as a variable of importance.

Experimental evidence for the influence of group size on cultural complexity

The remarkable ecological and demographic success of humanity is largely attributed to our capacity for cumulative culture. The accumulation of beneficial cultural innovations across generations is puzzling because transmission events are generally imperfect, although there is large variance in fidelity. Events of perfect cultural transmission and innovations should be more frequent in a large population. As a consequence, a large population size may be a prerequisite for the evolution of cultural complexity, although anthropological studies have produced mixed results and empirical evidence is lacking. Here we use a dual-task computer game to show that cultural evolution strongly depends on population size, as players in larger groups maintained higher cultural complexity. We found that when group size increases, cultural knowledge is less deteriorated, improvements to existing cultural traits are more frequent, and cultural trait diversity is maintained more often. Our results demonstrate how changes in group size can generate both adaptive cultural evolution and maladaptive losses of culturally acquired skills. As humans live in habitats for which they are ill-suited without specific cultural adaptations, it suggests that, in our evolutionary past, group-size reduction may have exposed human societies to significant risks, including societal collapse.

Space allowance and pen size affect welfare indicators and performance of growing pigs under Comfort Class conditions

Comfort Class offers each 110kg growing–finishing pig housed at 2.4m² with bedding in groups of 12 premium welfare to meet their behavioural needs. Conventionally housed, growing–finishing pigs in the Netherlands are allowed 0.8m², based on 0.035×BW0.667. The extra space offered with Comfort Class is a major financial barrier to introduce this system in practice. In order to establish whether or not welfare and performance could be maintained whilst reducing space allowance, a 3×2 factorial trial was designed to compare pigs housed at 2.4m², 1.6m² or 1.2m² per pig in pens of 29 and 58m². Video recordings, skin and tail lesions, lameness scores and performance were collected during three replicates involving 216 pigs each.Results indicate that pigs housed at 2.4, 1.6 or 1.2m² per animal would be lying in the kennels for 62%, 54% and 48% of the time (P<0.001) respectively and pigs housed at 2.4m² spent more time eating than those housed at 1.2m² (4.7% and 4.4% of the time respectively, P<0.05). Pigs housed in the small pens spent less time in the kennel and more time rooting than those in the large pens (53.0% vs. 55.8% in kennel, P=0.046; 1.78% vs. 1.22% rooting, P<0.001). Pigs housed in the small pens had less tail lesions and those housed at 2.4 and 1.6m² tended to have less skin lesions on their hinds than those housed at 1.2m² per pig. Daily weight gain was higher in the small than the large pens (823 vs. 797g/d, P=0.003) and higher at 2.4 and 1.6m² than 1.2m² (827 and 817 vs. 786g/d, P=0.002).Overall, an increase in group size and stocking density both had unfavourable effects on welfare and performance, even at these high space allowances. However, performance benefits from higher space allowances did not compensate for increases in housing costs.

A Simulation Model of Fission–Fusion Dynamics and Long-Term Settlement Change

Archaeological analyses often detect abrupt changes over time in the hierarchy of settlement sizes and the spatial distribution of residential units. These transformations have been explained looking at a variety of possible causes, from climatic changes to the sudden release of slowly cumulating political tensions. While many of these models offer plausible explanations for specific historical contexts, a broad-breadth model is desirable if cross-cultural analysis is sought. This paper tackles this problem by starting from the theoretical proposition that human groups are characterised by a non-linear relationship between size and per-capita fitness. Increasing group size has beneficial effects, but once a certain threshold is exceeded, negative frequency dependence will start to predominate leading to a decline in the per-capita fitness. Such a relationship can potentially have long-term implications in the spatial structure of human settlements if individuals have the possibility to modify their fitness through group fission–fusion dynamics. I will illustrate the equilibrium properties of these dynamics by means of an abstract agent-based simulation and discuss its implication for understanding long-term changes in human settlement pattern. Results suggest that changes in settlement pattern can originate from internal dynamics alone if the system is highly integrated and interconnected.

The role of social environment on parental care: offspring benefit more from the presence of female than male helpers

Investment in offspring depends on the costs and benefits to the carer, which can vary with sex and social status. Investment also depends on the effort of others by allowing for compensation (load-lightening), with biparental care studies showing that this depends on the state and type of the other carer. By contrast, studies on cooperative breeders have solely focussed on the effects of group size rather than its composition (i.e. social environment). Here we propose and provide the first test of the 'Social Environment' hypothesis, that is, how the characteristics (here the sex) of other helpers present in the group affect parental care and how this in turn affects offspring fitness in cooperatively breeding red-winged fairy-wrens (Malurus elegans). Breeders provisioned nestlings at a higher rate than helpers, but there was no sex difference in provisioning rate. Compensation to increasing group size varied little with sex and status, but strongly depended on social environment. All group members reduced their provisioning rates in response to an increasing number of male (load-lightening), but not female helpers (additive care). As a result, nestlings received more food and grew faster in the presence of female helpers. The increased nestling growth did convey a fitness advantage due to a higher post-fledging survival to adulthood. Our study provides the first evidence that parental care can depend on social environment. This could be an important overlooked aspect to explain variation in parental care in cooperative breeders in general and in particular the enormous variation between the sexes, which we reveal in a literature overview.

Factors increasing snake detection and perceived threat in captive rhesus macaques (Macaca mulatta)

The primary predators of primates are all ambush hunters, and yet felids, raptors, and snakes differ in aspects of their ecology that affect the evasive strategies of their primate prey. Felids and raptors can traverse long distances quickly, thus the urgency of threat they present increases as they come closer in proximity to primates. In contrast, snakes do not move rapidly over long distances, and so primates may be reasonably safe even at close distances provided snakes can be detected and monitored. We investigated the ability of captive rhesus macaques (Macaca mulatta) to detect snakes at distances ranging from 15 to 1.5 m. We also examined variation in intensity of perceived threat by applying a Hidden Markov Model to infer changes in underlying state from observable behaviors, that is, increased attention and mobbing. We found that the macaques often failed to detect snake models but that closer proximity improved snake detection, which is necessary before threat can be perceived. We also found that having only one individual in fairly close proximity (≤ 7.5 m) was sufficient to alert the rest of the group and so the chances of detection did not increase with increasing group size. Finally, we found that when the snakes were perceived, they did not elicit greater intensity of response with closer proximity. These results provide evidence that the threat from snakes is greatest when they are in proximity to primates but are unseen. When snakes are seen, however, distance appears not to affect primates' perceived risk, in contrast to their perceived risk from raptors and felids.

Intra-group relatedness affects parental and helper investment rules in offspring care

In any system where multiple individuals jointly contribute to rearing offspring, conflict is expected to arise over the relative contributions of each carer. Existing theoretical work on the conflict over care has: (a) rarely considered the influence of tactical investment during offspring production on later contributions to offspring rearing; (b) concentrated mainly on biparental care, rather than cooperatively caring groups comprising both parents and helpers; and (c) typically ignored relatedness between carers as a potential influence on investment behavior. We use a game-theoretical approach to explore the effects of female production tactics and differing group relatedness structures on the expected rearing investment contributed by breeding females, breeding males, and helpers in cooperative groups. Our results suggest that the breeding female should pay higher costs overall when helpful helpers are present, as she produces additional offspring to take advantage of the available care. We find that helpers related to offspring through the breeding female rather than the breeding male should contribute less to care, and decrease their contribution as group size increases, because the female refrains from producing additional offspring to exploit them. Finally, within-group variation in helper relatedness also affects individual helper investment rules by inflating the differences between the contributions to care of dissimilar helpers. Our findings underline the importance of considering maternal investment decisions during offspring production to understand investment across the entire breeding attempt, and provide empirically testable predictions concerning the interplay between maternal, paternal and helper investment and how these are modified by different relatedness structures.

Validation of a refined technique for taking repeated blood samples from juvenile and adult mice

Repeated blood sampling from laboratory animals is desirable in certain experimental designs and also for reducing the number of animals used in research. Biochemical methods for analysing blood samples require only small blood volumes to be collected (typically 20-40 µL). In juvenile mice, the small blood volume of the animals also requires only small samples to be taken. Furthermore, for behavioural studies it is desirable to have a method that does not require anaesthesia or the use of invasive indwelling cannulae. We report the validation of a refined method for repeated blood sampling (up to 3 times at 24 h intervals) in juvenile and adult mice using the tail incision method to sample from the lateral tail vein. This method is not stressful, as assessed by low basal levels of the stress hormone corticosterone. Since repeated blood samples can be collected from the same animal at multiple time points, it is not necessary to increase group size for terminal sample collection. Thus, in addition to being a refined method requiring no warming of the tail, no anaesthesia and only gentle restraint, this method also reduces the numbers of mice used for experiments.

Scalar social dynamics in female vervet monkey cohorts.

Primate social life and behaviour is contingent on a number of levels: phylogenetic, functional and proximate. Although this contingency is recognized by socioecological theory, variability in behaviour is still commonly viewed as 'noise' around a central tendency, rather than as a source of information. An alternative view is that selection has acted on social reaction norms that encompass demographic variation both between and within populations and demes. Here, using data from vervet monkeys (Chlorocebus aethiops pygerythrus), we illustrate how this alternative approach can provide a more nuanced account of social structure and its relation to contingent events at the ecological and demographic levels. Female vervets in our South African study population live in large groups, where they experience demographic stress and increased levels of feeding competition relative to an East African population in Amboseli, Kenya. Females in the South African population did not respond to this stress by intensifying competition for high-value grooming partners to help alleviate the effects of this stress, did not show the expected rank-related patterns of grooming, nor did they show any spatial association with their preferred grooming partners. Increased group size therefore resulted in a reorganization of female social engagement that was both qualitatively and quantitatively different to that seen elsewhere, and suggests that female vervets possess the flexibility to shift to alternative patterns of social engagement in response to contingent ecological and demographic conditions.

Mixtures of Nonionic Surfactants made from Renewable Resources with Alkyl Sulfates and Sodium n‐Alkanecarboxylates: Comparison of Mixing Behavior using Rubingh's Treatment

AbstractBinary aqueous mixtures of (1) alkyl glucopyranosides (glycosides), (2) alkyl maltopyranosides (maltosides), or (3) alkyl N‐methyl glucamines with (1′) sodium alkyl sulfates or (2′) sodium n‐alkyl carboxylates were investigated in an effort to evaluate physiochemical properties for mixtures of surfactants from renewable resources. Solutions at various concentrations and mixture ratios were tested and evaluated to determine critical micelle concentrations (CMCs). The greatest reduction in CMC was found for surfactants with long and intermediate hydrophobe lengths. In agreement with other studies, an increase in hydrophilic group size and flexibility decreased the electrostatic repulsion of ionic‐nonionic mixed micelles as evidenced by a more negative Rubingh's β parameter. However, at low hydrophobe length, carboxylate and glycoside headgroup mixtures produced mixed micelle interactions displaying synergism at low nonionic surfactant mole fractions and slight antagonism at high nonionic mole fractions. The asymmetry in interaction produces an S‐shaped CMC curve and demonstrates that the one‐parameter Rubingh model is insufficient in describing both synergism and antagonism for this binary mixture.

Accurate decisions in an uncertain world: collective cognition increases true positives while decreasing false positives

In a wide range of contexts, including predator avoidance, medical decision-making and security screening, decision accuracy is fundamentally constrained by the trade-off between true and false positives. Increased true positives are possible only at the cost of increased false positives; conversely, decreased false positives are associated with decreased true positives. We use an integrated theoretical and experimental approach to show that a group of decision-makers can overcome this basic limitation. Using a mathematical model, we show that a simple quorum decision rule enables individuals in groups to simultaneously increase true positives and decrease false positives. The results from a predator-detection experiment that we performed with humans are in line with these predictions: (i) after observing the choices of the other group members, individuals both increase true positives and decrease false positives, (ii) this effect gets stronger as group size increases, (iii) individuals use a quorum threshold set between the average true- and false-positive rates of the other group members, and (iv) individuals adjust their quorum adaptively to the performance of the group. Our results have broad implications for our understanding of the ecology and evolution of group-living animals and lend themselves for applications in the human domain such as the design of improved screening methods in medical, forensic, security and business applications.

Effects of temperature on micellar-assisted bimolecular reaction of methylnaphtalene-2-sulphonate with bromide and chloride ions

Reactivity of methyl naphthalene-2-sulphonate, MeONs, with H2O, Br− and Cl− in water and in cationic micelles of cetyltrialkylammonium surfactants, n-C16H33N+R3X−, R=Me (CTA+), n-Pr (CTPA+), X=Br, Cl, CH3SO3, has been investigated in the temperature range 25–45°C. Micellar rate effects were analysed by using the pseudophase treatment, and the second-order rate constants in the micellar pseudophase were evaluated at the various temperatures. Values of these rate constants increase with temperature, and the effect is less important in micelles than in water and more important for chloride than for bromide ions. Micelles lead to an ion behaviour discrimination, whose extent depends on surfactant type and on temperature, with maximum effect in CTPA+ at 25°C and with bromide being always more reactive than chloride.Quantitative analysis of the temperature effect by the Eyring equation showed that micelles speed up reaction of MeONs with halide ions by decreasing the activation enthalpies, which is partially offset by decreases in the activation entropies. The rate acceleration by increase in surfactant head group size has only enthalpic origin for bromide and only entropic origin for chloride: this different behaviour was rationalised taking into account both solvation of anions and the hydrophobic effect.

Group personality judgments at zero acquaintance: Communication among judges versus aggregation of independent evaluations

The current study (N=264) compared the validity of personality judgments made by groups of 2, 3, or 4 people to the validity of personality judgments from 2, 3, or 4 aggregated individual reports. I replicated the general increase in validity that accompanies the aggregation of independent judgments. However, group judgments did not follow this pattern. Small groups outperformed the average single rater, but increasing group size did not lead to similar increases in validity. In short, two heads are better than one across both judgment scenarios, but the point of diminishing returns on additional group members occurs more quickly when judgments are made interactively.

Could Relatedness Help Explain Why Individuals Lead in Bottlenose Dolphin Groups?

In many species, particular individuals consistently lead group travel. While benefits to followers often are relatively obvious, including access to resources, benefits to leaders are often less obvious. This is especially true for species that feed on patchy mobile resources where all group members may locate prey simultaneously and food intake likely decreases with increasing group size. Leaders in highly complex habitats, however, could provide access to foraging resources for less informed relatives, thereby gaining indirect benefits by helping kin. Recently, leadership has been documented in a population of bottlenose dolphins (Tursiops truncatus) where direct benefits to leaders appear unlikely. To test whether leaders could benefit indirectly we examined relatedness between leader-follower pairs and compared these levels to pairs who associated but did not have leader-follower relationship (neither ever led the other). We found the average relatedness value for leader-follower pairs was greater than expected based on chance. The same was not found when examining non leader-follower pairs. Additionally, relatedness for leader-follower pairs was positively correlated with association index values, but no correlation was found for this measure in non leader-follower pairs. Interestingly, haplotypes were not frequently shared between leader-follower pairs (25%). Together, these results suggest that bottlenose dolphin leaders have the opportunity to gain indirect benefits by leading relatives. These findings provide a potential mechanism for the maintenance of leadership in a highly dynamic fission-fusion population with few obvious direct benefits to leaders.

Group size effect on vigilance and daytime activity budgets of theEquus kiang(Equidae, Perissodactyla) in Arjinshan National Nature Reserve, Xinjiang, China

Vigilance is recognized as the response to potential predation threats. Many factors influence vigilance behaviour, and the effect of group size has had a great deal of attention in recent years. The group size effect hypothesis proposes that there is a negative relationship between group size and vigilance, which has been proven ture for many birds and mammal species. However this relationship has not been investigated for a number of other species including the Equus kiang. The E. kiang is the largest wild ass in the world, and endemic to the Tibetan Plateau. Previous studies have reported its distribution and reproduction, but information about their behaviour especially their daytime activity budgets is still very limited. Also unknown is if the distinctive habitat of the Tibetan Plateau makes their behaviour different from other Equidae species. So in this paper, we discuss our behavioural observations of the daytime activity budgets and the group size effect on vigilance for the E. kiang population in the Arjinshan National Nature Reserve, Xinjiang, China. The results indicate that group size has a significant effect on the vigilance levels: with an increase in group size, both the group scan level decreased and group scan frequency increased. Our results also showed that E. kiang spent most of their time feeding (51.41 ± 2.74 %), followed by moving (22.49 ± 1.40 %), standing (19.62 ± 6.74 %), resting (18.41 ± 2.13 %), and other activities (8.64 ± 0.72 %). Their feeding behaviour showed three distinct activity peaks during the day: early morning (8:00-11:00), midday (14:30-15:30), and around sunset (18:00-19:30). During the peaks of activity, E. kiang spent most of their time feeding, and during the period of inactivity, E. kiang spent most of their time resting and standing. So the group size effect was supported for E. kiang by this study, and our results are consistent with research on other Equidae species.