The use of social information in vulture flight decisions

Animals rely on a balance of personal and social information to decide when and where to move next in order to access a desired resource. The benefits from cueing on conspecifics to reduce uncertainty about resource availability can be rapidly overcome by the risks of within-group competition, often exacerbated toward low-ranked individuals. Being obligate soarers, relying on thermal updraughts to search for carcasses around which competition can be fierce, vultures represent ideal models to investigate the balance between personal and social information during foraging movements. Linking dominance hierarchy, social affinities and meteorological conditions to movement decisions of eight captive vultures, Gyps spp., released for free flights in natural soaring conditions, we found that they relied on social information (i.e. other vultures using/having used the thermals) to find the next thermal updraught, especially in unfavourable flight conditions. Low-ranked individuals were more likely to disregard social cues when deciding where to go next, possibly to minimize the competitive risk of social aggregation. These results exemplify the architecture of decision-making during flight in social birds. It suggests that the environmental context, the context of risk and the social system as a whole calibrate the balance between personal and social information use.

Conspiracy believers claim to be free thinkers but (Under)Use advice like everyone else

Conspiracy believers often claim to be critical thinkers their 'own research' instead of relying on others' testimony. In two preregistered behavioural studies conducted in the United Kingdom and Pakistan (Nparticipants  = 864, Ntrials  = 5408), we test whether conspiracy believers have a general tendency to discount social information (in favour of their own opinions and intuitions). We found that conspiracy mentality is not associated with social information use in text-based (Study 1) and image-based (Study 2) advice-taking tasks. Yet, we found discrepancies between self-reported and actual social information use. Conspiracy believers were more likely to report relying less on social information than actually relying less on social information in the behavioural tasks. Our results suggest that the scepticism of conspiracy believers towards epistemic authorities is unlikely to be the manifestation of a general tendency to discount social information. Conspiracy believers may be more permeable to social influence than they sometimes claim.

Social learning in non-grouping animals

Social learning is widespread in the animal kingdom and is involved in behaviours from navigation and predator avoidance to mate choice and foraging. While social learning has been extensively studied in group-living species, this article presents a literature review demonstrating that social learning is also seen in a range of non-grouping animals, including arthropods, fishes and tetrapod groups, and in a variety of behavioural contexts. We should not be surprised by this pattern, since non-grouping animals are not necessarily non-social, and stand to benefit from attending to and responding to social information in the same ways that group-living species do. The article goes on to ask what non-grouping species can tell us about the evolution and development of social learning. First, while social learning may be based on the same cognitive processes as other kinds of learning, albeit with social stimuli, sensory organs and brain regions associated with detection and motivation to respond to social information may be under selection. Non-grouping species may provide useful comparison taxa in phylogenetic analyses investigating if and how the social environment drives selection on these input channels. Second, non-grouping species may be ideal candidates for exploring how ontogenetic experience of social cues shapes the development of social learning, allowing researchers to avoid some of the negative welfare implications associated with raising group-living animals under restricted social conditions. Finally, while non-grouping species may be capable of learning socially under experimental conditions, there is a need to consider how non-grouping restricts access to learning opportunities under natural conditions and whether this places a functional constraint on what non-grouping animals actually learn socially in the wild.

The price of being late: short- and long-term consequences of a delayed migration timing

Choosing the right migration timing is critical for migrants because conditions encountered en route influence movement costs, survival, and, in social migrants, the availability of social information. Depending on lifetime stages, individuals may migrate at different times due to diverging constraints, affecting the composition of migration groups. To examine the consequences of a delayed migration timing, we artificially delayed the migration of juvenile white storks (Ciconia ciconia) and thereby altered their physical and social environment. Using nearly continuous 1 Hz GPS trajectories, we examined their migration behaviour, ranging from sub-second level performance to global long-distance movement, in relation to two control groups. We found that delayed storks experienced suboptimal soaring conditions, but better wind support and thereby achieved higher flight speeds than control storks. Delayed storks had a lower mortality rate than the control storks and wintered closer to the breeding area. In fact, none of the delayed storks reached the traditional African wintering areas. Thus, our results show that juvenile storks can survive migrating at the 'wrong' time. However, this had long-term consequences on migration decisions. We suggest that, when timing their migration, storks balance not just energy and time, but also the availability of social information.

No evidence of social learning in a socially roosting butterfly in an associative learning task

Insects may acquire social information by active communication and through inadvertent social cues. In a foraging setting, the latter may indicate the presence and quality of resources. Although social learning in foraging contexts is prevalent in eusocial species, this behaviour has been hypothesized to also exist between conspecifics in non-social species with sophisticated behaviours, including Heliconius butterflies. Heliconius are the only butterfly genus with active pollen feeding, a dietary innovation associated with a specialized, spatially faithful foraging behaviour known as trap-lining. Long-standing hypotheses suggest that Heliconius may acquire trap-line information by following experienced individuals. Indeed, Heliconius often aggregate in social roosts, which could act as 'information centres', and present conspecific following behaviour, enhancing opportunities for social learning. Here, we provide a direct test of social learning ability in Heliconius using an associative learning task in which naive individuals completed a colour preference test in the presence of demonstrators trained to feed randomly or with a strong colour preference. We found no evidence that Heliconius erato, which roost socially, used social information in this task. Combined with existing field studies, our results add to data which contradict the hypothesized role of social learning in Heliconius foraging behaviour.

Ecological and evolutionary consequences of selective interspecific information use

Recent work has shown that animals frequently use social information from individuals of their own species as well as from other species; however, the ecological and evolutionary consequences of this social information use remain poorly understood. Additionally, information users may be selective in their social information use, deciding from whom and how to use information, but this has been overlooked in an interspecific context. In particular, the intentional decision to reject a behaviour observed via social information has received less attention, although recent work has indicated its presence in various taxa. Based on existing literature, we explore in which circumstances selective interspecific information use may lead to different ecological and coevolutionary outcomes between two species, such as explaining observed co-occurrences of putative competitors. The initial ecological differences and the balance between the costs of competition and the benefits of social information use potentially determine whether selection may lead to trait divergence, convergence or coevolutionary arms race between two species. We propose that selective social information use, including adoption and rejection of behaviours, may have far-reaching fitness consequences, potentially leading to community-level eco-evolutionary outcomes. We argue that these consequences of selective interspecific information use may be much more widespread than has thus far been considered.

Incidental physical pain reduces brain activities associated with affective social feedback and increases aggression

Physical pain may lead to aggressive behavior in a social context. However, it is unclear whether this is related to changes of social information processing. Thus, this study aimed to investigate the neural mechanisms underlying pain-induced aggression using functional magnetic resonance imaging. In the experiment, 59 healthy participants were recruited: 31 were treated with topical capsaicin cream (pain group) and 28 with hand cream (control group). Participants completed a social network aggression task, during which they underwent two phases: feedback processing and attack exerting. The results revealed that participants in the pain group exhibited more aggression than those in the control group. During the feedback-processing phase, physical pain reduced brain activation in the right insula, left orbitofrontal cortex and anterior cingulate cortex, which typically exhibited stronger activation in response to negative (and positive) vs neutral social feedback in the control group. However, during the attack-exerting phase, pain did not significantly alter the activation of the dorsolateral prefrontal cortex. These findings suggest that pain increased aggression, while before that, it suppressed brain activities of the salience network involved in the process of salient social information and the value system associated with the value representation of social events.

False alarms and information transmission in grouping animals

A key benefit of grouping in prey species is access to social information, including information about the presence of predators. Larger groups of prey animals respond both sooner and at greater distances from predators, increasing the likelihood that group members will successfully avoid capture. However, identifying predators in complex environments is a difficult task, and false alarms (alarm behaviours without genuine threat) appear surprisingly frequent across a range of taxa including insects, amphibians, fish, mammals, and birds. In some bird flocks, false alarms have been recorded to substantially outnumber true alarms. False alarms can be costly in terms of both the energetic costs of producing alarm behaviours as well as lost opportunity costs (e.g. abandoning a feeding patch which was in fact safe, losing sleep if an animal is resting/roosting, or losing mating opportunities). Models have shown that false alarms may be a substantial but underappreciated cost of group living, introducing an inherent risk to using social information and a vulnerability to the propagation of false information. This review will focus on false alarms, introducing a two-stage framework to categorise the different factors hypothesised to influence the propensity of animal groups to produce false alarms. A number of factors may affect false alarm rate, and this new framework splits these factors into two core processing stages: (i) individual perception and response; and (ii) group processing of predator information. In the first stage, individuals in the group monitor the environment for predator cues and respond. The factors highlighted in this stage influence the likelihood that an individual will misclassify stimuli and produce a false alarm (e.g. lower light levels can make predator identification more difficult and false alarms more common). In the second stage, alarm information from individuals is processed by the group. The factors highlighted in this stage influence the likelihood of alarm information being copied by group members and propagated through the group (e.g. some animals implement group processing mechanisms that regulate the spread of behavioural responses such as consensus decision making through the quorum response). This review follows the structure of this new framework, focussing on the causes of false alarms, factors that influence false alarm rate, the transmission of alarm information through animal groups, mechanisms to mitigate the spread of false alarms, and the consequences of false alarms.

Habitat detection, habitat choice copying or mating benefits: What drives conspecific attraction in a nomadic songbird?

Conspecific attraction during habitat selection is common among animals, but the ultimate (i.e. fitness-related) reasons for this behaviour often remain enigmatic. We aimed to evaluate the following three hypotheses for conspecific attraction during the breeding season in male Wood Warblers (Phylloscopus sibilatrix): the habitat detection hypothesis, the habitat choice copying hypothesis and the female preference hypothesis. These hypotheses make different predictions with respect to the relative importance of social and nonsocial information during habitat assessment, and whether benefits accrue as a consequence of aggregation. We tested the above hypotheses using a combination of a 2-year playback experiment, spatial statistics and mate choice models. The habitat detection hypothesis was the most likely explanation for conspecific attraction and aggregation in male Wood Warblers, based on the following results: (1) males were attracted to conspecific song playbacks, but fine-scale habitat heterogeneity was the better predictor of spatial patterns in the density of settling males; (2) male pairing success did not increase, but instead slightly decreased, as connectivity with other males (i.e. the number and proximity of neighbouring males) increased. Our study highlights how consideration of the process by which animals detect and assess habitat, together with the potential fitness consequences of resulting aggregations, are important for understanding conspecific attraction and spatially clustered distributions.

Does the Power of Social Example Fade? Nudge Effect of Social Information on Individual's Donation Behaviors During the COVID-19 Pandemic: A Moderated Mediation Model with Three-Wave Cross-Sectional Data

Purpose

This study assesses how various social information influence individuals' money donation behaviors towards charitable funds against the COVID-19 pandemic at different stages of the pandemic. It also explores the mediating role of social anxiety and the moderating role of self-control.

Materials and Methods

This three-wave study was conducted with online survey experiments using convenience sampling at the pandemic's outbreak stage (April-June 2020), trough stage (February-March 2021), and resurgence stage (May 2022) in China. The nudge power of social information was measured by whether participants changed their initial money donation decisions after informed positive or negative social information. Self-report scales were used to measure levels of social anxiety (Social Interaction Anxiety Scale) and self-control (Self-Control Scale). The final data set included 1371 participants from 26 provinces of mainland China. Stata medeff package and SPSS PROCESS were used to analyze the data.

Results

Individuals' initial donation behaviors did not fluctuate along with the pandemic status, but the nudge effect of social information did. From outbreak stage to trough stage, the nudge power of positive social information significantly declined, but did not significantly change again at the resurgence stage. By contrast, the nudge power of negative social information did not significantly differ between outbreak and trough stage but did significantly increase at the resurgence stage. Social anxiety played a significant mediating role in the relationship between COVID-19 status and power of social information. Moreover, self-control moderated the direct effect of COVID-19 status on power of social information and the indirect effect via social anxiety.

Conclusion

Our findings enrich research on the nudge power variation of social information on individuals' donation behaviors along with the pandemic status and its potential psychological influence factors. This study also helps guide organizations to better design and carry out social information nudge mechanism.

Gaze following: A socio-cognitive skill rooted in deep time

Social gaze has received much attention in social cognition research in both human and non-human animals. Gaze following appears to be a central skill for acquiring social information, such as the location of food and predators, but can also draw attention to important social interactions, which in turn promotes the evolution of more complex socio-cognitive processes such as theory of mind and social learning. In the past decades, a large number of studies has been conducted in this field introducing differing methodologies. Thereby, various factors influencing the results of gaze following experiments have been identified. This review provides an overview of the advances in the study of gaze following, but also highlights some limitations within the research area. The majority of gaze following studies on animals have focused on primates and canids, which limits evolutionary interpretations to only a few and closely related evolutionary lineages. This review incorporates new insights gained from previously understudied taxa, such as fishes, reptiles, and birds, but it will also provide a brief outline of mammal studies. We propose that the foundations of gaze following emerged early in evolutionary history. Basic, reflexive co-orienting responses might have already evolved in fishes, which would explain the ubiquity of gaze following seen in the amniotes. More complex skills, such as geometrical gaze following and the ability to form social predictions based on gaze, seem to have evolved separately at least two times and appear to be correlated with growing complexity in brain anatomy such as increased numbers of brain neurons. However, more studies on different taxa in key phylogenetic positions are needed to better understand the evolutionary history of this fundamental socio-cognitive skill.

Alarm cues and alarmed conspecifics: neural activity during social learning from different cues in Trinidadian guppies

Learning to respond appropriately to novel dangers is often essential to survival and success, but carries risks. Learning about novel threats from others (social learning) can reduce these risks. Many species, including the Trinidadian guppy (Poecilia reticulata), respond defensively to both conspecific chemical alarm cues and conspecific anti-predator behaviours, and in other fish such social information can lead to a learned aversion to novel threats. However, relatively little is known about the neural substrates underlying social learning and the degree to which different forms of learning share similar neural mechanisms. Here, we explored the neural substrates mediating social learning of novel threats from two different conspecific cues (i.e. social cue-based threat learning). We first demonstrated that guppies rapidly learn about threats paired with either alarm cues or with conspecific threat responses (demonstration). Then, focusing on acquisition rather than recall, we discovered that phospho-S6 expression, a marker of neural activity, was elevated in guppies during learning from alarm cues in the putative homologue of the mammalian lateral septum and the preoptic area. Surprisingly, these changes in neural activity were not observed in fish learning from conspecific demonstration. Together, these results implicate forebrain areas in social learning about threat but raise the possibility that circuits contribute to such learning in a stimulus-specific manner.

A conceptual framework to predict social information use based on food ephemerality and individual resource requirements

Environmental variability poses a range of challenges to foraging animals trying to meet their energetic needs. Where food patches are unpredictable but shareable, animals can use social information to locate patches more efficiently or reliably. However, resource unpredictability can be heterogeneous and complex. The behavioural strategies animals employ to exploit such resources also vary, particularly if, when, and where animals use available social information. We reviewed the literature on social information use by foraging animals and developed a novel framework that integrates four elements - (1) food resource persistence; (2) the relative value of social information use; (3) behavioural context (opportunistic or coordinated); and (4) location of social information use - to predict and characterize four strategies of social information use - (1) local enhancement; (2) group facilitation; (3) following; and (4) recruitment. We validated our framework by systematically reviewing the growing empirical literature on social foraging in bats, an ideal model taxon because they exhibit extreme diversity in ecological niche and experience low predation risk while foraging but function at high energy expenditures, which selects for efficient foraging behaviours. Our framework's predictions agreed with the observed natural behaviour of bats and identified key knowledge gaps for future studies. Recent advancements in technology, methods, and analysis will facilitate additional studies in bats and other taxa to further test the framework and our conception of the ecological and evolutionary forces driving social information use. Understanding the links between food distribution, social information use, and foraging behaviour will help elucidate social interactions, group structure, and the evolution of sociality for species across the animal kingdom.

The Effect of Ingroup vs. Outgroup Members' Behavior on Charity Preference: A Drift-Diffusion Model Approach

Providing potential donors with information about the behavior of others (i.e., social information) is an increasingly used strategy to nudge prosocial decision-making. In the present study, we investigated the effect of ingroup vs. outgroup information on participants' charity preferences by applying a Drift Diffusion Model (DDM) approach. In a joint evaluation scenario, we manipulated different levels of ingroup/outgroup preference ratios for two charities within subjects. Every subject was presented with three stimulus types (i.e., high, medium, and low ingroup ratio) randomized in 294 trials divided into six blocks. We expected that for stimuli with a high ingroup/outgroup ratio, participants should more often and faster decide for the ingroup's most favored charity. We expected that the speed of evidence accumulation will be higher the larger the ingroup/outgroup ratio. Additionally, we investigated whether variations in model parameters can explain individual differences in participants' behaviors. Our results showed that people generally followed ingroup members' preferences when deciding for a charity. However, on finding an unexpected pattern in our results, we conducted post-hoc analyses which revealed two different behavioral strategies used by participants. Based on participants' decisions, we classified them into “equality driven” individuals who preferred stimuli with the least difference between ingroup and outgroup percentages or “ingroup driven” individuals who favored stimuli with the highest ingroup/outgroup ratio. Results are discussed in line with relevant literature, and implications for practitioners are given.

Social information use shapes the coevolution of sociality and virulence

Social contacts can facilitate the spread of both survival-related information and infectious diseases, but little is known about how these processes combine to shape host and parasite evolution. Here, we use a theoretical model that captures both infection and information transmission processes to investigate how host sociality (contact effort) and parasite virulence (disease-associated mortality rate) (co)evolve. We show that selection for sociality (and in turn, virulence) depends on both the intrinsic costs and benefits of social information and infection as well as their relative prevalence in the population. Specifically, greater sociality and lower virulence evolve when the risk of infection is either low or high and social information is neither very common nor too rare. Lower sociality and higher virulence evolve when the prevalence patterns are reversed. When infection and social information are both at moderate levels in the population, the direction of selection depends on the relative costs and benefits of being infected or informed. We also show that sociality varies inversely with virulence, and that parasites may be unable to prevent runaway selection for higher contact efforts. Together, these findings provide new insights for our understanding of group living and how apparently opposing ecological processes can influence the evolution of sociality and virulence in a range of ways.

The Power of Population Effect in Temnothorax Ant House-Hunting: A Computational Modeling Approach

The decentralized cognition of animal groups is both a challenging biological problem and a potential basis for bioinspired design. In this study, we investigated the house-hunting algorithm used by emigrating colonies of Temnothorax ants to reach consensus on a new nest. We developed a tractable model that encodes accurate individual behavior rules, and estimated our parameter values by matching simulated behaviors with observed ones on both the individual and group levels. We then used our model to explore a potential, but yet untested, component of the ants' decision algorithm. Specifically, we examined the hypothesis that incorporating site population (the number of adult ants at each potential nest site) into individual perceptions of nest quality can improve emigration performance. Our results showed that attending to site population accelerates emigration and reduces the incidence of split decisions. This result suggests the value of testing empirically whether nest site scouts use site population in this way, in addition to the well-demonstrated quorum rule. We also used our model to make other predictions with varying degrees of empirical support, including the high cognitive capacity of colonies and their rational time investment during decision-making. In addition, we provide a versatile and easy-to-use Python simulator that can be used to explore other hypotheses or make testable predictions. It is our hope that the insights and the modeling tools can inspire further research from both the biology and computer science community.

Do male meadow voles (Microtus pennsylvanicus) always prefer and signal to 'popular' females? The role of social information context

For males, the behaviour of rival conspecifics can provide vital information about finding reproductively available females, and which have high-quality phenotypes. While valuable, this information represents sperm competition risk and even the potential for rejection by females. Thus, males should show flexibility in signalling behaviours towards females based on social information acquired with emphasis on the context of that information. We examined male meadow vole scent-marking behaviours and preferences for females based on previously obtained social information across different contexts. Social information context resulted in increased scent marking depending on the social odour pairing. Males scent marked more near a female whose odour had associated with three older rivals than one younger rival. But males marked equally toward a female whose odour had associated with three younger rivals and a female whose odour had associated with one older rival. This demonstrates that social odours are not of all equal value and that males can distinguish differences. Males then use these differences to tailor their signalling towards potentially high-quality phenotype females thereby maximizing their reproductive opportunities.

Social factors and the neurobiology of pathogen avoidance

Although the evolutionary causes and consequences of pathogen avoidance have been gaining increasing interest, there has been less attention paid to the proximate neurobiological mechanisms. Animals gauge the infection status of conspecifics and the threat they represent on the basis of various sensory and social cues. Here, we consider the neurobiology of pathogen detection and avoidance from a cognitive, motivational and affective state (disgust) perspective, focusing on the mechanisms associated with activating and directing parasite/pathogen avoidance. Drawing upon studies with laboratory rodents, we briefly discuss aspects of (i) olfactory-mediated recognition and avoidance of infected conspecifics; (ii) relationships between pathogen avoidance and various social factors (e.g. social vigilance, social distancing (approach/avoidance), social salience and social reward); (iii) the roles of various brain regions (in particular the amygdala and insular cortex) and neuromodulators (neurotransmitters, neuropeptides, steroidal hormones and immune components) in the regulation of pathogen avoidance. We propose that understanding the proximate neurobiological mechanisms can provide insights into the ecological and evolutionary consequences of the non-consumptive effects of pathogens and how, when and why females and males engage in pathogen avoidance.

Behavioral determinants of antibiotic resistance: The role of social information

The increasing development of resistant pathogens is one of the greatest global health challenges. As antibiotic overuse amplifies antibiotic resistance, antibiotic intake poses a social dilemma in which individuals need to decide whether to prosocially reduce their intake in the collective interest versus to (over)use it even in case of mild diseases. We devise a novel behavioral game paradigm to model the social dilemma of antibiotic intake. Using this new method in an incentivized laboratory experiment (N = 272 German participants), we varied whether players had mutual knowledge about their antibiotic intake. The results indicate that there was substantial antibiotic overuse in the absence of social information. Overuse decreased when social information was present. Our postexperimental survey data further suggest that social information impacts people's behavioral motivation, evaluation of the other player, and positive affect. Taken together, providing social information about people's antibiotic intake may help in reducing antibiotic overuse. On a more general level, the novel behavioral game may be adapted to study other aspects of antibiotic intake to promote prudent use of antibiotics.

Do cognitive load and ADHD traits affect the tendency to prioritise social information in scenes?

We report two experiments investigating the effect of working memory (WM) load on selective attention. Experiment 1 was a modified version of Lavie et al. and confirmed that increasing memory load disrupted performance in the classic flanker task. Experiment 2 used the same manipulation of WM load to probe attention during the viewing of complex scenes while also investigating individual differences in attention deficit hyperactivity disorder (ADHD) traits. In the image-viewing task, we measured the degree to which fixations targeted each of two crucial objects: (1) a social object (a person in the scene) and (2) a non-social object of higher or lower physical salience. We compared the extent to which increasing WM load would change the pattern of viewing of the physically salient and socially salient objects. If attending to the social item requires greater default voluntary top-down resources, then the viewing of social objects should show stronger modulation by WM load compared with viewing of physically salient objects. The results showed that the social object was fixated to a greater degree than the other object (regardless of physical salience). Increased salience drew fixations away from the background leading to slightly increased fixations on the non-social object, without changing fixations on the social object. Increased levels of ADHD-like traits were associated with fewer fixations on the social object, but only in the high-salient, low-load condition. Importantly, WM load did not affect the number of fixations on the social object. Such findings suggest rather surprisingly that attending to a social area in complex stimuli is not dependent on the availability of voluntary top-down resources.

Understanding the Relationship Between Official and Social Information About Infectious Disease: Experimental Analysis

BACKGROUND

Communicating official public health information about infectious diseases is complicated by the fact that individuals receive much of their information from their social contacts, either via interpersonal interaction or social media, which can be prone to bias and misconception.

OBJECTIVE

This study aims to evaluate the effect of public health campaigns and the effect of socially communicated health information on learning about diseases simultaneously. Although extant literature addresses the effect of one source of information (official or social) or the other, it has not addressed the simultaneous interaction of official information (OI) and social information (SI) in an experimental setting.

METHODS

We used a series of experiments that exposed participants to both OI and structured SI about the symptoms and spread of hepatitis C over a series of 10 rounds of computer-based interactions. Participants were randomly assigned to receive a high, low, or control intensity of OI and to receive accurate or inaccurate SI about the disease.

RESULTS

A total of 195 participants consented to participate in the study. Of these respondents, 186 had complete responses across all ten experimental rounds, which corresponds to a 4.6% (9/195) nonresponse rate. The OI high intensity treatment increases learning over the control condition for all symptom and contagion questions when individuals have lower levels of baseline knowledge (all P values ≤.04). The accurate SI condition increased learning across experimental rounds over the inaccurate condition (all P values ≤.01). We find limited evidence of an interaction between official and SI about infectious diseases.

CONCLUSIONS

This project demonstrates that exposure to official public health information increases individuals' knowledge of the spread and symptoms of a disease. Socially shared information also facilitates the learning of accurate and inaccurate information, though to a lesser extent than exposure to OI. Although the effect of OI persists, preliminary results suggest that it can be degraded by persistent contradictory SI over time.

Prospecting and informed dispersal: Understanding and predicting their joint eco-evolutionary dynamics

The ability of individuals to leave a current breeding area and select a future one is important, because such decisions can have multiple consequences for individual fitness, but also for metapopulation dynamics, structure, and long-term persistence through non-random dispersal patterns. In the wild, many colonial and territorial animal species display informed dispersal strategies, where individuals use information, such as conspecific breeding success gathered during prospecting, to decide whether and where to disperse. Understanding informed dispersal strategies is essential for relating individual behavior to subsequent movements and then determining how emigration and settlement decisions affect individual fitness and demography. Although numerous theoretical studies have explored the eco-evolutionary dynamics of dispersal, very few have integrated prospecting and public information use in both emigration and settlement phases. Here, we develop an individual-based model that fills this gap and use it to explore the eco-evolutionary dynamics of informed dispersal. In a first experiment, in which only prospecting evolves, we demonstrate that selection always favors informed dispersal based on a low number of prospected patches relative to random dispersal or fully informed dispersal, except when individuals fail to discriminate better patches from worse ones. In a second experiment, which allows the concomitant evolution of both emigration probability and prospecting, we show the same prospecting strategy evolving. However, a plastic emigration strategy evolves, where individuals that breed successfully are always philopatric, while failed breeders are more likely to emigrate, especially when conspecific breeding success is low. Embedding information use and prospecting behavior in eco-evolutionary models will provide new fundamental understanding of informed dispersal and its consequences for spatial population dynamics.

The COVID-19 Pandemic Changes the Nudging Effect of Social Information on Individuals' Blood Donation Intention

The positive effect of social information on nudging prosocial behavior is context dependent. Understanding how sensitive intervention outcomes are to changes in the choice context is essential for policy design, especially in times of great uncertainty, such as the current COVID-19 pandemic. The present paper explores the effectiveness of social information in changing voluntary blood donation intention in two contexts: before and after the peak of the COVID-19 pandemic in China. In addition to the dimension of context, information content and its source are also important. Using a survey administered to 1,116 participants, we conducted an intertemporal randomized-controlled experiment to systematically analyze how information can effectively nudge the intention to donate blood. Compared with content featuring blood donors' commendation information, blood users' demand information is found to have a stronger nudging effect. An official information source has a greater influence on participants' donation intention than an unofficial source. Furthermore, our analysis of two waves of experimental data (i.e., before and after the peak of the COVID-19 pandemic) shows that the COVID-19 pandemic has further enhanced the nudging effect of blood users' demand information and official information sources. These findings provide a theoretical basis and policy recommendations for relevant institutions to develop effective blood donation campaign strategies.

An exploration of the relationship between recruitment communication and foraging in stingless bees

Social information is widely used in the animal kingdom and can be highly adaptive. In social insects, foragers can use social information to find food, avoid danger, or choose a new nest site. Copying others allows individuals to obtain information without having to sample the environment. When foragers communicate information they will often only advertise high-quality food sources, thereby filtering out less adaptive information. Stingless bees, a large pantropical group of highly eusocial bees, face intense inter- and intra-specific competition for limited resources, yet display disparate foraging strategies. Within the same environment there are species that communicate the location of food resources to nest-mates and species that do not. Our current understanding of why some species communicate foraging sites while others do not is limited. Studying freely foraging colonies of several co-existing stingless bee species in Brazil, we investigated if recruitment to specific food locations is linked to 1) the sugar content of forage, 2) the duration of foraging trips, and 3) the variation in activity of a colony from 1 day to another and the variation in activity in a species over a day. We found that, contrary to our expectations, species with recruitment communication did not return with higher quality forage than species that do not recruit nestmates. Furthermore, foragers from recruiting species did not have shorter foraging trip durations than those from weakly recruiting species. Given the intense inter- and intraspecific competition for resources in these environments, it may be that recruiting species favor food resources that can be monopolized by the colony rather than food sources that offer high-quality rewards.

Certainty and integration of options in animal movement

Physical energy defines the energy landscape and determines the species-specific cost of movement, thus influencing movement decisions. In unpredictable and dynamic environments, observing the locomotion of others increases individual certainty in the distribution of physical energy to increase movement efficiency. Beyond the physical energy landscape, social sampling increases certainty in all ecological landscapes that influence animal movement (including fear and resource landscapes), and individuals use energy to express each of these. We call for the development of an 'optimal movement theory' (OMT) that integrates the multidimensional reality of movement decisions by combining ecological landscapes according to a single expectation of energy cost-benefit, where social sampling provides up-to-date information under uncertain conditions. This mechanistic framework has implications for predicting individual movement patterns and for investigating the emergence of aggregations.

Optimal use of simplified social information in sequential decision-making

Social animals can improve their decisions by attending to those made by others. The benefit of this social information must be balanced against the costs of obtaining and processing it. Previous work has focused on rational agents that respond optimally to a sequence of prior decisions. However, full decision sequences are potentially costly to perceive and process. As such, animals may rely on simpler social information, which will affect the social behaviour they exhibit. Here, I derive the optimal policy for agents responding to simplified forms of social information. I show how the behaviour of agents attending to the aggregate number of previous choices differs from those attending to just the most recent prior decision, and I propose a hybrid strategy that provides a highly accurate approximation to the optimal policy with the full sequence. Finally, I analyse the evolutionary stability of each strategy, showing that the hybrid strategy dominates when cognitive costs are low but non-zero, while attending to the most recent decision is dominant when costs are high. These results show that agents can employ highly effective social decision-making rules without requiring unrealistic cognitive capacities, and indicate likely ecological variation in the social information different animals attend to.

Do Emotional Cues Influence the Performance of Domestic Dogs in an Observational Learning Task?

Using social information is not indiscriminate and being able to choose what to copy and from whom to copy is critical. Dogs are able to learn socially, to recognize, and respond to dog as well as human emotional expressions, and to make reputation-like inferences based on how people behave towards their owner. Yet, the mechanisms dogs use for obtaining and utilizing social information are still to be fully understood, especially concerning whether emotional cues influence dogs’ social learning. Therefore, our main aim was to test the hypothesis that an emotionally charged (negative, positive, or neutral) interaction with the demonstrator of a “V” detour task prior to testing would affect subjects’ performance, by: (i) changing the value of the information provided by the demonstrator or (ii) changing the valence of the learning environment. Our experimental design consisted of three phases: pre-test (subjects were allowed to solve the task alone); emotional display (dogs watched the unfamiliar human behaving in either a positive, negative or neutral way towards their owner); test (demonstrator showed the task and subjects were allowed to move freely). Only dogs that failed in pre-test were considered for analysis (n = 46). We analyzed four dependent variables: success, time to solve the task, latency to reach the fence and matching the side of demonstration. For each, we used four models (GEEs and GLMMs) to investigate the effect of (1) demographic factors; (2) experimental design factors (including emotional group); (3) behavior of the dog; and (4) side chosen and matching. All models took into account all trials (random effect included) and the first trials only. Our findings corroborate previous studies of social learning, but present no evidence to sustain our hypothesis. We discuss the possibility of our stimuli not being salient enough in a task that involves highly motivating food and relies on long and highly distracting interval between phases. Nevertheless, these results represent an important contribution to the study of dog behavior and social cognition and pave the way for further investigations.

Effects of social information on duration perception by different mechanisms in sub- and supra-second range: Evidence from face features

Human faces convey abundant social information. The influence of social information on duration estimation was examined by comparing a cartoon face (CF; social) condition with geometric plane figures, or CFs with internal elements disturbed from their normal position (non-social) condition, and also by comparing a human portrait facing the front (more social interaction) condition with the portrait facing the back (less social interaction) condition. Results showed that in the supra-second range, both CFs and human portraits facing the front led to an underestimation compared with non-social or less social information conditions. In the sub-second range, only portraits facing the front were overestimated compared with those facing the back and with the CFs. These results suggest that in the millisecond range, the biological information conveyed by faces may lead to higher arousal, which may result in accelerated clock speed and overestimation. In the supra-second range, it is possible that attention was diverted by social information, resulting in duration underestimation. Taken together, our results suggest that the different mechanisms were involved in duration perception of social information conveyed by face feature in the sub- and supra-second range.

Follow the straggler: zebrafish use a simple heuristic for collective decision-making

Animal groups often make decisions sequentially, from the front to the back of the group. In such cases, individuals can use the choices made by earlier ranks, a form of social information, to inform their own choice. The optimal strategy for such decisions has been explored in models which differ on, for example, whether or not agents take into account the sequence of observed choices. The models demonstrate that choices made later in a sequence are more informative, but it is not clear if animals use this information or rely instead on simpler heuristics, such as quorum rules. We show that a simple rule 'copy the last observed choice', gives similar predictions to those of optimal models for most likely sequences. We trained groups of zebrafish to choose one arm of a Y-maze and used them to demonstrate various sequences to naive fish. We show that the naive fish appear to use a simple rule, most often copying the choice of the last demonstrator, which results in near-optimal choices at a fraction of the computational cost.

A review of conspecific attraction for habitat selection across taxa

Many species across taxa select habitat based on conspecific presence, known as conspecific attraction. Studies that document conspecific attraction typically provide social information (i.e., cues that indicate the presence of a given species) and then determine if a given species is more likely to settle at locations where the social information is provided compared to those locations that do not. Although the number of studies examining conspecific attraction has grown in recent years, a comprehensive review has not yet been undertaken. Here, we conducted a review of the literature and found 151 studies investigating conspecific attraction across eight taxa. We found that conspecific attraction is widespread with between 80% and 100% of studies, depending on taxa, documenting positive associations between habitat selection and the presence of conspecific cues. Conspecific attraction has been documented more frequently in bird and fish species with less attention given to invertebrate and mammal species. We use the patterns we found to (a) provide an overview of the current state of research on conspecific attraction and (b) discuss how important factors, such as cue characteristics and life history traits, may play a role in shaping conspecific attraction patterns within and across taxa.

Oviposition in the onion fly Delia antiqua (Diptera: Anthomyiidae) is socially facilitated by visual cues

Ovipositional decisions in herbivorous insects may be affected by social information from conspecifics. Social facilitation of oviposition has been suggested for the onion fly Delia antiqua. In the current study, we found that D. antiqua oviposition was unequal between paired oviposition stations of equal quality and that more eggs were laid on an oviposition station baited with decoy flies than on the control. The increased oviposition toward the decoys continued over time >8 h. When decoys were placed upside down, the number of eggs laid did not differ between the decoy and control sides of oviposition stations, suggesting that social facilitation of oviposition is mediated by visual cues. Based on these findings, mechanisms of social facilitation of oviposition in D. antiqua were discussed.

Foraging behaviour alters with social environment in a juvenile songbird

Early independence from parents is a critical period where social information acquired vertically may become outdated, or conflict with new information. However, across natural populations, it is unclear if newly independent young persist in using information from parents, or if group-level effects of conformity override previous behaviours. Here, we test if wild juvenile hihi (Notiomystis cincta, a New Zealand passerine) retain a foraging behaviour from parents, or if they change in response to the behaviour of peers. We provided feeding stations to parents during chick-rearing to seed alternative access routes, and then tracked their offspring's behaviour. Once independent, juveniles formed mixed-treatment social groups, where they did not retain preferences from their time with parents. Instead, juvenile groups converged over time to use one access route- per group, and juveniles that moved between groups switched to copy the locally favoured option. Juvenile hihi did not copy specific individuals, even if they were more familiar with the preceding bird. Our study shows that early social experiences with parents affect initial foraging decisions, but social environments encountered later on can update transmission of arbitrary behaviours. This suggests that conformity may be widespread in animal groups, with potential cultural, ecological and evolutionary consequences.

Trail Pheromone Does Not Modulate Subjective Reward Evaluation in Lasius niger Ants

Comparing the value of options is at the heart of economic decision-making. While an option may have an absolute quality (e.g. a food source has a fixed energy content), the perceived value of the option may be malleable. The factors affecting the perceived value of an option may thus strongly influence which option is ultimately chosen. Expectations have been shown to be a strong driver of perceived value in both humans and social insects, causing an undervaluation of a given option if a better option was expected, and an overvaluation if a poorer one was expected. In humans, perceived value can be strongly affected by social information. Value perception in some insects has also been shown to be affected by social information, showing conformism as in humans and other animals. Here, over a series of experiments, we tested whether pheromone trail presence, a social information source, influenced the perceived value of a food source in the ant Lasius niger. We found that the presence of pheromone trails leading to a sucrose solution does not influence food acceptance, pheromone deposition when returning from a food source, drinking time, or frequency of U-turns on return from the food. Two further assays for measuring changes in food acceptance, designed to increase sensitivity by avoiding ceiling effects, also showed no effect of pheromone presence on food acceptance. In a separate study, L. niger have also been found to show no preference for, or avoidance of, odors associated with foods found in the presence of pheromone. We are thus confident that trail pheromone presence does not affect the perceived value of a food source in these ants.

Personality composition determines social learning pathways within shoaling fish

In shaping how individuals explore their environment and interact with others, personality may mediate both individual and social learning. Yet increasing evidence indicates that personality expression is contingent on social context, suggesting that group personality composition may be key in determining how individuals learn about their environment. Here, we used recovery latency following simulated predator attacks to identify Trinidadian guppies (Poecilia reticulata) that acted in a consistently bold or shy manner. We then employed network-based diffusion analysis to track the spread of a novel foraging behaviour through groups containing different proportions of bold and shy fish. Informed associates promoted learning to a greater extent in bold individuals, but only within groups composed predominately of bold fish. As the proportion of shy fish within groups increased, bold individuals instead emerged as especially effective demonstrators that facilitated learning in others. Individuals were also more likely to learn overall within shy-dominated groups than in bold-dominated ones. We demonstrate that whether and how individuals learn is conditional on group personality composition, indicating that selection may favour traits enabling individuals to better match their behavioural phenotype to their social environment.

Effect of conspecific neighbors on the foraging activity levels of the wintering Oriental Storks (Ciconia boyciana): Benefits of social information

Animals prefer to aggregate in patches with high abundance and availability of food resources. Group foragers typically receive information about food resources by monitoring external events and the behavior of neighbors. The Information Centre Hypothesis proposes that aggregations increase foraging activity levels as a result of social information provided by conspecifics. Increasing the foraging rate has as a result decreasing time devoted to anti-predator vigilance and may intensify competition among group members. Studies have shown that foraging activities are influenced by factors other than flock size, such as the number and foraging intensity of neighbors. To test these hypotheses, we examined the effect of number and foraging intensity of neighbors on the foraging activity levels (foraging rate, foraging effort, and foraging success rate) of the wintering Oriental Storks (Ciconia boyciana). In this study, we collected focal sampling data on the foraging behavior of storks at Shengjin Lake during winter from 2017 to 2019, controlling the effects of other variables (group identity, wintering years, and wintering periods). We found that foraging activity levels were higher in the presence of foraging neighbors than in their absence. Moreover, individuals adjusted their foraging activity levels according to social information gathered from the behavior of neighboring conspecifics. Focal individuals' foraging rate and foraging effort were positively correlated with the average foraging rate of neighbors. Their foraging success rate was not influenced by the average foraging rate and foraging success rate of neighbors; however, it was positively correlated with the average foraging effort of neighbors. In conclusion, foraging activity levels of individuals are primarily driven by the intensity of the foraging activity of neighbors. This result differs from the results of previous studies that suggested that flock size was the most important factor determining individual foraging activity levels.

Quantitative genetics of the use of conspecific and heterospecific social cues for breeding site choice

Social information use for decision‐making is common and affects ecological and evolutionary processes, including social aggregation, species coexistence, and cultural evolution. Despite increasing ecological knowledge on social information use, very little is known about its genetic basis and therefore its evolutionary potential. Genetic variation in a trait affecting an individual's social and nonsocial environment may have important implications for population dynamics, interspecific interactions, and, for expression of other, environmentally plastic traits. We estimated repeatability, additive genetic variance, and heritability of the use of conspecific and heterospecific social cues (abundance and breeding success) for breeding site choice in a population of wild collared flycatchers Ficedula albicollis. Repeatability was found for two social cues: previous year conspecific breeding success and previous year heterospecific abundance. Yet, additive genetic variances for these two social cues, and thus heritabilities, were low. This suggests that most of the phenotypic variation in the use of social cues and resulting conspecific and heterospecific social environment experienced by individuals in this population stems from phenotypic plasticity. Given the important role of social information use on ecological and evolutionary processes, more studies on genetic versus environmental determinism of social information use are needed.

Collective Computation in Animal Fission-Fusion Dynamics

Recent work suggests that collective computation of social structure can minimize uncertainty about the social and physical environment, facilitating adaptation. We explore these ideas by studying how fission-fusion social structure arises in spider monkey (Ateles geoffroyi) groups, exploring whether monkeys use social knowledge to collectively compute subgroup size distributions adaptive for foraging in variable environments. We assess whether individual decisions to stay in or leave subgroups are conditioned on strategies based on the presence or absence of others. We search for this evidence in a time series of subgroup membership. We find that individuals have multiple strategies, suggesting that the social knowledge of different individuals is important. These stay-leave strategies provide microscopic inputs to a stochastic model of collective computation encoded in a family of circuits. Each circuit represents an hypothesis for how collectives combine strategies to make decisions, and how these produce various subgroup size distributions. By running these circuits forward in simulation we generate new subgroup size distributions and measure how well they match food abundance in the environment using transfer entropies. We find that spider monkeys decide to stay or go using information from multiple individuals and that they can collectively compute a distribution of subgroup size that makes efficient use of ephemeral sources of nutrition. We are able to artificially tune circuits with subgroup size distributions that are a better fit to the environment than the observed. This suggests that a combination of measurement error, constraint, and adaptive lag are diminishing the power of collective computation in this system. These results are relevant for a more general understanding of the emergence of ordered states in multi-scale social systems with adaptive properties-both natural and engineered.

No evidence for individual recognition in threespine or ninespine sticklebacks (Gasterosteus aculeatus or Pungitius pungitius)

Recognition plays an important role in the formation and organization of animal groups. Many animals are capable of class-level recognition, discriminating, for example, on the basis of species, kinship or familiarity. Individual recognition requires that animals recognize distinct cues, and learn to associate these with the specific individual from which they are derived. In this study, we asked whether sticklebacks (Gasterosteus aculeatus and Pungitius pungitius) were capable of learning to recognize individual conspecifics. We have used these fish as model organisms for studying selective social learning, and demonstrating a capacity for individual recognition in these species would provide an exciting opportunity for studying how biases for copying specific individuals shape the dynamics of information transmission. To test for individual recognition, we trained subjects to associate green illumination with the provision of a food reward close to one of two conspecifics, and, for comparison, one of two physical landmarks. Both species were capable of recognizing the rewarded landmark, but neither showed a preference for associating with the rewarded conspecific. Our study provides no evidence for individual recognition in either species. We speculate that the fission-fusion structure of their social groups may not favour a capacity for individual recognition.

Collective decision-making by rational agents with differing preferences

Collective decisions can emerge from individual-level interactions between members of a group. These interactions are often seen as social feedback rules, whereby individuals copy the decisions they observe others making, creating a coherent group decision. The benefit of these behavioral rules to the individual agent can be understood as a transfer of information, whereby a focal individual learns about the world by gaining access to the information possessed by others. Previous studies have analyzed this exchange of information by assuming that all agents share common goals. While differences in information and differences in preferences have often been conflated, little is known about how differences between agents' underlying preferences affect the use and efficacy of social information. In this paper, I develop a model of social information use by rational agents with differing preferences, and demonstrate that the resulting collective behavior is strongly dependent on the structure of preference sharing within the group, as well as the quality of information in the environment. In particular, I show that strong social responses are expected by individuals that are habituated to noisy, uncertain environments where private information about the world is relatively weak. Furthermore, by investigating heterogeneous group structures, I demonstrate a potential influence of cryptic minority subgroups that may illuminate the empirical link between personality and leadership.

Mixed-species herding levels the landscape of fear

Prey anti-predator behaviours are influenced by perceived predation risk in a landscape and social information gleaned from herd mates regarding predation risk. It is well documented that high-quality social information about risk can come from heterospecific herd mates. Here, we integrate social information with the landscape of fear to quantify how these landscapes are modified by mixed-species herding. To do this, we investigated zebra vigilance in single- and mixed-species herds across different levels of predation risk (lion versus no lion), and assessed how they manage herd size and the competition-information trade-off associated with grouping behaviour. Overall, zebra performed higher vigilance in high-risk areas. However, mixed-species herding reduced vigilance levels. We estimate that zebra in single-species herds would have to feed for approximately 35 min more per day in low-risk areas and approximately 51 min more in high-risk areas to compensate for the cost of higher vigilance. Furthermore, zebra benefitted from the competition-information trade-off by increasing the number of heterospecifics while keeping the number of zebra in a herd constant. Ultimately, we show that mixed-species herding reduces the effects of predation risk, whereby zebra in mixed-species herds, under high predation risk, perform similar levels of vigilance compared with zebra in low-risk scenarios.

Social learning of acoustic anti-predator cues occurs between wild bird species

In many species, individuals gather information about their environment both through direct experience and through information obtained from others. Social learning, or the acquisition of information from others, can occur both within and between species and may facilitate the rapid spread of antipredator behaviour. Within birds, acoustic signals are frequently used to alert others to the presence of predators, and individuals can quickly learn to associate novel acoustic cues with predation risk. However, few studies have addressed whether such learning occurs only though direct experience or whether it has a social component, nor whether such learning can occur between species. We investigate these questions in two sympatric species of Parids: blue tits (Cyanistes caeruleus) and great tits (Parus major). Using playbacks of unfamiliar bird vocalizations paired with a predator model in a controlled aviary setting, we find that blue tits can learn to associate a novel sound with predation risk via direct experience, and that antipredator response to the sound can be socially transmitted to heterospecific observers, despite lack of first-hand experience. Our results suggest that social learning of acoustic cues can occur between species. Such interspecific social information transmission may help to mediate the formation of mixed-species aggregations.

Bats use social information within and across species

In Focus: LewanzikD., , SundaramurthyA. K., , GoerlitzH. R., (2019). Insectivorous bats integrate social information about species identity, conspecific activity and prey abundance to estimate cost–benefit ratio of interactions. Journal of Animal Ecology, 88, 1462–1473.30945281

Social interactions can generate social structures that shape the fate of individuals and populations. A key feature of social environments is the information produced by others. Whether actively shared or obtained via ‘eavesdropping’, individuals of many species use publically available information to guide their decision making in important ways. Lewanzik et al. (2019) explore social information use within and across several echolocating bat species. They experimentally manipulated the content of social information about prey abundance with playback experiments of echolocation calls. All species were found to use heterospecific and conspecific social information about conspecific activity levels and prey abundance. This is a rare experimental confirmation of social information use at a community level.

Foraging ecology drives social information reliance in an avian eavesdropping community

Vertebrates obtain social information about predation risk by eavesdropping on the alarm calls of sympatric species. In the Holarctic, birds in the family Paridae function as sentinel species; however, factors shaping eavesdroppers' reliance on their alarm calls are unknown. We compared three hypothesized drivers of eavesdropper reliance: (a) foraging ecology, (b) degree of sociality, and (c) call relevance (caller-to-eavesdropper body-size difference). In a rigorous causal-comparative design, we presented Tufted Titmouse (Baeolophus bicolor) alarm calls to 242 individuals of 31 ecologically diverse bird species in Florida forests and recorded presence/absence and type (diving for cover or freezing in place) of response. Playback response was near universal, as individuals responded to 87% of presentations (N = 211). As an exception to this trend, the sit-and-wait flycatcher Eastern Phoebe (Sayornis phoebe) represented 48% of the nonresponses. We tested 12 predictor variables representing measures relevant to the three hypothesized drivers, distance to playback speaker, and vulnerability at time of playback (eavesdropper's microhabitat when alarm call is detected). Using model-averaged generalized linear models, we determined that foraging ecology best predicted playback response, with aerial foragers responding less often. Foraging ecology (distance from trunk) and microhabitat occupied during playback (distance to escape cover) best predicted escape behavior type. We encountered a sparsity of sit-and-wait flycatchers (3 spp.), yet their contrasting responses relative to other foraging behaviors clearly identified foraging ecology as a driver of species-specific antipredator escape behavior. Our findings align well with known links between the exceptional visual acuity and other phenotypic traits of flycatchers that allow them to rely more heavily on personal rather than social information while foraging. Our results suggest that foraging ecology drives species-specific antipredator behavior based on the availability and type of escape cover.

Manipulating social information to promote frugivory by birds on a Hawaiian Island

Animals across a range of taxa use social information when foraging. Fruit-eating vertebrates are no exception and use social information to find fruit, which may ultimately affect plant populations via seed dispersal. In many systems, mutualistic relationships between fruiting plants and frugivores are critical to maintain ecosystem functioning, especially in the tropics. On the island of O'ahu, Hawaii, USA, all native, fruit-eating birds are extinct and several plant species are experiencing reduced recruitment likely due to a lack of seed dispersal. Over the years, numerous bird species, many of which are frugivorous, have been introduced to the island. Yet, introduced birds may not recognize native fruits as a resource and social information may be needed for introduced frugivores to target and feed on native fruits. We investigated whether social information, in the form of broadcasted bird vocalizations, of introduced birds could increase visitations and more importantly frugivory on focal fruiting plants. We also tested whether the visitation rates of introduced bird species to focal plants were influenced by conspecific and/or heterospecific vocalizations. We conducted 80 playback experiments at native and introduced fruiting plants, and compared responses to silent control periods. Four times as many frugivores were detected and 10 times more frugivory events were recorded at plants with broadcasted vocalizations compared to control periods. The Japanese White-eye (Zosterops japonicus) exhibited the strongest response to both conspecific and heterospecific playbacks. White-eyes also consumed the most fruit from the widest array of plant species during trials. Introduced birds that use social information and readily identify novel resources may more effectively colonize new areas. We suggest that the White-eye's use of social information may help to support their robust population on O'ahu. Ecosystems throughout the world are affected by the loss of mutualistic relationships, many of which provide valuable ecological services. As humans continue to modify environments, novel conservation approaches may be required to maintain important ecological functions. The use of social information to facilitate frugivory may not only be important in Hawaii, but in other tropical systems where key frugivorous species are lost or abundances have been reduced.

Individuals fail to reap the collective benefits of diversity because of over-reliance on personal information

Collective intelligence refers to the ability of groups to outperform individuals in solving cognitive tasks. Although numerous studies have demonstrated this effect, the mechanisms underlying collective intelligence remain poorly understood. Here, we investigate diversity in cue beliefs as a mechanism potentially promoting collective intelligence. In our experimental study, human groups observed a sequence of cartoon characters, and classified each character as a cooperator or defector based on informative and uninformative cues. Participants first made an individual decision. They then received social information consisting of their group members' decisions before making a second decision. Additionally, individuals reported their beliefs about the cues. Our results showed that individuals made better decisions after observing the decisions of others. Interestingly, individuals developed different cue beliefs, including many wrong ones, despite receiving identical information. Diversity in cue beliefs, however, did not predict collective improvement. Using simulations, we found that diverse collectives did provide better social information, but that individuals failed to reap those benefits because they relied too much on personal information. Our results highlight the potential of belief diversity for promoting collective intelligence, but suggest that this potential often remains unexploited because of over-reliance on personal information.

The multi-dimensional nature of information drives prioritization of private over social information in ants

When personally gathered and socially acquired information conflict, animals often prioritize private information. We propose that this is because private information often contains details that social information lacks. We test this idea in an ant model. Ants using a food source learn its location and quality rapidly (private information), whereas pheromone trails (social information) provide good directional information, but lack reliable information about food quality. If this lack is indeed responsible for the choice of memory over pheromone trails, adding information that better food is available should cause foragers to switch their priority to social information. We show it does: while ants follow memory rather than pheromones when they conflict, adding unambiguous information about a better potential food source (a 2 µl droplet of good food) reverses this pattern, from 60% of ants following their memory to 75% following the pheromone trail. Using fluorescence microscopy, we demonstrate that food (and thus information) flows from fed workers to outgoing foragers, explaining the frequent contacts of ants on trails. Ants trained to poor food that contact nest-mates fed with good food are more likely to follow a trail than ants which received information about poor food. We conclude that social information may often be ignored because it lacks certain crucial dimensions, suggesting that information content is crucial for understanding how and when animals prioritize social and private information.

Male black widows parasitize mate-searching effort of rivals to find females faster

Mate-searching success is a critical precursor to mating, but there is a dearth of research on traits and tactics that confer a competitive advantage in finding potential mates. Theory and available empirical evidence suggest that males locate mates using mate-attraction signals produced by receptive females (personal information) and avoid inadvertently produced cues from rival males (social information) that indicate a female has probably already mated. Here, we show that western black widow males use both kinds of information to find females efficiently, parasitizing the searching effort of rivals in a way that guarantees competition over mating after reaching a female's web. This tactic may be adaptive because female receptivity is transient, and we show that (i) mate searching is risky (88% mortality) and (ii) a strongly male-biased operational sex ratio (from 1.2 : 1 to more than 10 : 1) makes competition inevitable. Males with access to rivals' silk trails moved at higher speeds than those with only personal information, and located females even when personal information was unreliable or absent. We show that following rivals can increase the potential for sexual selection on females as well as males and argue it may be more widespread in nature than is currently realized.

Differences in how macaques monitor others: Does serotonin play a central role?

Primates must balance the need to monitor other conspecifics to gain social information while not losing other resource opportunities. We consolidate evidence across the fields of primatology, psychology, and neuroscience to examine individual, population, and species differences in how primates, particularly macaques, monitor conspecifics. We particularly consider the role of serotonin in mediating social competency via social attention, aggression, and dominance behaviors. Finally, we consider how the evolution of variation in social tolerance, aggression, and social monitoring might be explained by differences in serotonergic function in macaques. This article is categorized under: Economics > Interactive Decision-Making Psychology > Comparative Psychology Neuroscience > Behavior Cognitive Biology > Evolutionary Roots of Cognition.

Personal information about danger trumps social information from avian alarm calls

Information about predators can mean the difference between life and death, but prey face the challenge of integrating personal information about predators with social information from the alarm calls of others. This challenge might even affect the structure of interspecific information networks: species vary in response to alarm calls, potentially because different foraging ecologies constrain the acquisition of personal information. However, the hypothesis that constrained personal information explains a greater response to alarm calls has not been experimentally tested. We used a within-species test to compare the antipredator responses of New Holland honeyeaters, Phylidonyris novaehollandiae, during contrasting foraging behaviour. Compared with perched birds, which hawk for insects and have a broad view, those foraging on flowers were slower to spot gliding model predators, showing that foraging behaviour can affect predator detection. Furthermore, nectar-foraging birds were more likely to flee to alarm call playbacks. Birds also assessed social information relevance: more distant calls, and those from another species, prompted fewer flights and slower reaction times. Overall, birds made flexible decisions about danger by integrating personal and social information, while weighing information relevance. These findings support the idea that a strategic balance of personal and social information could affect community function.

A four-questions perspective on public information use in sticklebacks (Gasterosteidae)

Whether learning primarily reflects general processes or species-specific challenges is a long-standing matter of dispute. Here, we present a comprehensive analysis of public information use (PI-use) in sticklebacks (Gasterosteidae). PI-use is a form of social learning by which animals are able to assess the relative quality of resources, here prey patches, by observing the behaviour of others. PI-use was highly specific with only Pungitius and their closest relative Culaea inconstans showing evidence of PI-use. We saw no effects of ontogenetic experience upon PI-use in Pungitius pungitius. Experiments with live demonstrators and animated fish revealed that heightened activity and feeding strikes by foraging conspecifics are important cues in the transmission of PI. Finally, PI-use was the only form of learning in which P. pungitius and another stickleback, Gasterosteus aculeatus differed. PI-use in sticklebacks is species-specific and may represent an 'ecological specialization' for social foraging. Whether this reflects selection on perception, attentional or cognitive processes remains to be determined.