To innovate or not: contrasting effects of social groupings on safe and risky foraging in Indian mynahs

Wild raccoons demonstrate flexibility and individuality in innovative problem-solving

Cognitive skills, such as innovative problem-solving, are hypothesized to aid animals in urban environments. However, the significance of innovation in wild populations, and its expression across individuals and socio-ecological conditions, is poorly understood. To identify how and when innovation arises in urban-dwelling species, we used advanced technologies and new testing and analytical methods to evaluate innovative problem-solving abilities of wild raccoons (Procyon lotor). We deployed multi-compartment puzzle boxes with either one or multiple solution types and identified raccoons using radio frequency identification. Raccoons solved these novel extractive foraging tasks, and their success was influenced by age and exploratory diversity. Successful raccoons always discovered multiple different solution types, highlighting flexible problem-solving. Using a unique, comparative sequence analysis approach, we found that variation in raccoon solving techniques was greater between individuals than within individuals, and this self-similarity intensified during times of competition. Finally, the inclusion of an easier solution in the multi-solution trials enabled previously unsuccessful raccoons to bootstrap their learning and successfully open multiple difficult solutions. Our study suggests that innovative problem-solving is probably influenced by many factors and has provided novel field and analytical methods, as well as new insights on the socio-ecological dynamics of urban populations.

An investigation of population variation in maze exploration and its predictors in wild Trinidadian guppies (Poecilia reticulata)

Individuals often face unpredictable and harsh environments, presenting them with novel ecological problems. Behaviour can provide an adaptive response in such conditions and where these conditions vary between populations, we may predict development and evolution to shape differences in behaviour such as exploration, innovation, and learning, as well as other traits. Here, we compared in the wild the maze swimming performance of groups of female guppies from two Trinidadian populations that differ in numerous ecological characteristics, the Upper and Lower Aripo river. Compared to Upper Aripo fish, Lower Aripo fish were slower to complete the maze, our measure of propensity to innovate, and scored lower on a combined measure of activity and exploration. More active-exploratory groups were faster to complete the maze, but only in the Lower Aripo. We found no evidence for learning the maze. Our results suggest that activity-exploratory and innovative propensities can vary between populations, as can predictors of innovation. These findings are consistent with high predation risk shaping decreased activity-exploratory propensities, but further population comparisons are required to reliably determine the drivers of the observed population difference. Our results emphasize that individual and population differences in activity-exploration and innovation can be shaped by numerous factors.

Eat yourself sexy: how selective macronutrient intake influences the expression of a visual signal in common mynas

Producing colored signals often requires consuming dietary carotenoid pigments. Evidence that food deprivation can reduce coloration, however, raises the question of whether other dietary nutrients contribute to signal coloration, and furthermore, whether individuals can voluntarily select food combinations to achieve optimal coloration. We created a two-way factorial design to manipulate macronutrient and carotenoid access in common mynas (Acridotheres tristis) and measured eye patch coloration as a function of the food combinations individuals selected. Mynas had access to either water or carotenoid-supplemented water and could either eat a standard captive diet or choose freely between three nutritionally defined pellets (protein, lipid or carbohydrate). Mynas supplemented with both carotenoids and macronutrient pellets had higher color scores than control birds. Male coloration tended to respond more to nutritional manipulation than females, with color scores improving in macronutrient- and carotenoid-supplemented individuals compared with controls. All mynas consuming carotenoids had higher levels of plasma carotenoids, but only males showed a significant increase by the end of the experiment. Dietary carotenoids and macronutrient intake consumed in combination tended to increase plasma carotenoid concentrations the most. These results demonstrate for the first time that consuming specific combinations of macronutrients along with carotenoids contributes to optimizing a colorful signal, and point to sex-specific nutritional strategies. Our findings improve our knowledge of how diet choices affect signal expression and, by extension, how nutritionally impoverished diets, such as those consumed by birds in cities, might affect sexual selection processes and, ultimately, population dynamics.

Social position indirectly influences the traits yellow-bellied marmots use to solve problems

Animals adapt to changing environments by behaving flexibly when solving problems. Traits, such as sex and age, and specifically behavioral traits like persistence-the amount of time spent attempting to solve a problem, are positively associated with successful problem-solving. However, individuals face social pressures, such as aggression, which may directly alter an individual's behavior or interact with sex or age, when they attempt to problem-solve. We examined the direct and indirect effects of social position and individual behavioral traits on solving a novel puzzle box in facultatively social yellow-bellied marmots (Marmota flaviventer), using both generalized linear mixed models and confirmatory path analysis. We found strong support that marmots who used a diversity of behaviors were more successful problem-solvers and weak support that those who received more aggression were less successful. Additionally, marmots who received more aggression were less behaviorally diverse, less behaviorally selective and less persistent while trying to open the puzzle box. Thus, we show that aggression indirectly decreases problem-solving success by acting on the behavioral traits that an individual uses. We conclude that specific social relationships, including the type of interaction and whether they are recipients or initiators, influences the ways in which an individual interacts with cognitive tests and should be considered in analysis of individual problem-solving.

Do alternative reproductive tactics predict problem-solving performance in African striped mice?

In changing environments, animals face unexpected problems to solve. Not all individuals in a population are equally able to solve new problems. It still remains unclear what factors (e.g. age and body condition) influence the propensity of problem solving. We investigated variation in problem-solving performance among males following alternative reproductive tactics (ARTs). We studied a free-ranging population of the African striped mouse (Rhabdomys pumilio). Adult male striped mice can employ 3 ARTs: (1) dominant group-living breeders, (2) philopatric living in their natal group, and (3) solitary-living roamers. ARTs in male striped mice reflect differences in competitiveness, sociality and physiology which could influence their problem-solving performance. We tested a total of 48 males in 2 years with two tasks: a string-pulling task to reach food and a door-opening task to reach the nest. Since male striped mice differ in personality traits independent of ARTs, we also measured activity, boldness and exploration. In addition, we assessed the association of body condition and age with problem solving. Problem solving was related the interaction of age and ARTs. The younger philopatrics had better performance in a food-extraction task whereas the older breeders were faster at solving the door-opening task. Individual differences in traits related to personality were significant correlates of problem-solving performance: pro-active mice (i.e. more active and explorative and bolder) performed better in both tasks. Finally, problem-solving performance was not consistent between the two tasks. Our study provides evidence of correlates of ARTs, age and personality on problem-solving abilities.

Innovation in wild Barbary macaques (Macaca sylvanus)

Innovation is the ability to solve novel problems or find novel solutions to familiar problems, and it is known to affect fitness in both human and non-human animals. In primates, innovation has been mostly studied in captivity, although differences in living conditions may affect individuals’ ability to innovate. Here, we tested innovation in a wild group of Barbary macaques (Macaca sylvanus). In four different conditions, we presented the group with several identical foraging boxes containing food. To understand which individual characteristics and behavioural strategies best predicted innovation rate, we measured the identity of the individuals manipulating the boxes and retrieving the food, and their behaviour during the task. Our results showed that success in the novel task was mainly affected by the experimental contingencies and the behavioural strategies used during the task. Individuals were more successful in the 1-step conditions, if they participated in more trials, showed little latency to approach the boxes and mainly manipulated functional parts of the box. In contrast, we found no effect of inhibition, social facilitation and individual characteristics like sex, age, rank, centrality, neophobia and reaction to humans, on the individuals’ ability to innovate.

Variation in neophobia among cliff swallows at different colonies

Animal groups often represent nonrandom subsets of individuals, and increasing evidence indicates that individuals may sort among groups based on their personalities. The size of a group can predict its personality composition in some species due to differential suitability of a personality for groups of certain sizes, and the group itself may function more effectively if particular personality types are present. We quantified cliff swallow (Petrochelidon pyrrhonota) behavioral measures using linear and generalized linear mixed models to identify whether they: (1) varied among individuals within colonies and among colonies, (2) were related to reproductive success, and (3) predicted levels of parental care. Significant among-individual and among-colony site variation in a cliff swallow's latency to enter its nest when presented with a novel stimulus was revealed. We also found significant among-individual variation in the number of attacks directed toward a novel stimulus at the nest and in the response to broadcast of a cliff swallow alarm call recording, but among site variation in these measures was not significant. We did not find evidence for behavioral syndromes linking the personalities measured. Differences among individuals in latency to enter the nest and the number of attacks were not significantly related to reproductive success or to the extent to which birds fed their nestlings. However, extent of nestling feeding was significantly predicted by the number of mist net captures. The limited evidence in general of systematic variation in the behavior we measured among cliff swallow colonies may reflect the different and sometimes opposing selection pressures on behavior in different social environments. Future work should perhaps examine variation in other behavioral traits, such as foraging, in cliff swallow colonies of different sizes.

Larger group sizes facilitate the emergence and spread of innovations in a group-living bird

The benefits of group living have traditionally been attributed to risk dilution or the efficient exploitation of resources; individuals in social groups may therefore benefit from access to valuable information. If sociality facilitates access to information, then individuals in larger groups may be predicted to solve novel problems faster than individuals in smaller groups. Additionally, larger group sizes may facilitate the subsequent spread of innovations within animal groups, as has been proposed for human societies. We presented a novel foraging task (where a food reward could be accessed by pushing a self-shutting sliding door) to 16 groups of wild, cooperatively breeding Australian magpies, Cracticus tibicen dorsalis, ranging in size from two to 11 individuals. We found a nonlinear decline in the time taken for the innovative behaviour to emerge with increasing group size, and social information use facilitated the transmission of novel behaviour, with it spreading more quickly in larger than smaller groups. This study provides important evidence for a nonlinear relationship between group size and the emergence of innovation (and its subsequent transmission) in a wild population of animals. Further work investigating the scope and strength of group size-innovation relationships, and the mechanisms underpinning them, will help us understand the potential advantages of living in larger social groups.

A single factor explanation for associative learning performance on colour discrimination problems in common pheasants (Phasianus colchicus)

It remains unclear whether performance of non-human animals on cognitive test batteries can be explained by domain general cognitive processes, as is found in humans. The persistence of this dispute is likely to stem from a lack of clarity of the psychological or neural processes involved. One broadly accepted cognitive process, that may predict performance in a range of psychometric tasks, is associative learning. We therefore investigated intra-individual performances on tasks that incorporate processes of associative learning, by assessing the speed of acquisition and reversal learning in up to 187 pheasants (Phasianus colchicus) on four related binary colour discrimination tasks. We found a strong, positive significant bivariate relationship between an individual's acquisition and reversal learning performances on one cue set. Weak, positive significant bivariate relationships were also found between an individual's performance on pairs of reversal tasks and between the acquisition and reversal performances on different cue sets. A single factor, robust to parallel analysis, explained 36% of variation in performance across tasks. Inter-individual variation could not be explained by differential prior experience, age, sex or body condition. We propose that a single factor explanation, which we call 'a', summarises the covariance among scores obtained from these visual discrimination tasks, as they all assess capacities for associative learning. We argue that 'a' may represent an underlying cognitive ability exhibited by an individual, which manifests across a variety of tasks requiring associative processes.

The effect of social context on measures of boldness: Zebra finches (Taeniopygia guttata) are bolder when housed individually

Boldness can be quantified as latency to access resources in novel contexts. Although social interactions influence boldness, especially in species such as zebra finches (Taeniopygia guttata) that are sociable and live in groups, the boldness of individuals is generally characterized in isolation. The objective of this study was to examine how proximity of and familiarity with flock members influenced boldness, which is often assumed to be stable across contexts. We measured boldness as the latency of adult zebra finches to forage when a novel object was within a food dish in five social contexts: (1) social isolation, (2) adjacent to novel flock, (3) adjacent to familiar flock, (4) within novel flock, (5) within familiar flock. Our measure of boldness showed individual consistency across social contexts. However, when mean response values across different social contexts were compared, individuals were bolder (i.e. had lower latencies) when housed and tested individually, regardless of the presence or absence of a flock nearby. We found no evidence of sex, dominance rank, or flock members' boldness on the boldness of a focal bird. Our study deepens understanding of the influence of the social environment on boldness in zebra finches by demonstrating an influence of physical proximity. We encourage continued work examining boldness in different social contexts in zebra finches, as rigorous work in one system may help us understand the factors that influence the relative stability or flexibility of this trait.

Mary C, Avery ML. Social conformity affects experimental measurement of boldness in male but not female monk parakeets (Myiopsitta monachus)

The standard approach for characterizing boldness rarely considers the influence of social environment on the expression of boldness in group-living animals. We studied a wild-caught, captive population of monk parakeets (Myiopsitta monachus) to investigate the impact of conspecific presence on boldness — a personality trait in monk parakeets — in a controlled environment. We quantified seven boldness metrics across three types of behavioural assay: novel object, emergence, and predator exposure tests in the presence of a companion pair of flock mates. Because of the high degree of sociality in this species, we hypothesized that the presence of companion birds would facilitate the focal individuals’ behavioural responses (i.e., increase the average boldness level). We found that behavioural response in a risky foraging context was inversely correlated between solitary and social condition in males, but not in females. Our results have implications for characterizing sex-specific differences of risk-taking behaviour in social animals.

The effects of sociability on exploratory tendency and innovation repertoires in wild Sumatran and Bornean orangutans

It has been hypothesized that opportunities for social learning affect the size and complexity of the adult skill set of birds and mammals, their learning ability, and thus ultimately also their innovation frequency. To test these predictions we compared rates of social learning, rates of independent exploration (independent learning) and innovation repertoires between individuals of a highly sociable population of Pongo abelii at Suaq Balimbing and a less sociable population of Pongo pygmaeus wurmbii at Tuanan. Suaq immatures showed significantly higher rates of peering, even after controlling for differences in association time and diet complexity, implying that they make disproportionally greater use of their increased opportunities for social learning. As predicted, we found that immatures and adults at Suaq also showed significantly higher rates of exploratory behaviour. The difference between the individuals of the two popuations remained when controlling for association time, suggesting persistent developmental effects, intrinsic differences, or both. Accordingly, Suaq animals had a larger set of learned skills and a higher mean dietary complexity. Our findings show that population level sociability, individual rates of exploration and population-wide repertoires of innovations are positively linked, as predicted.

Personality and problem-solving in common mynas (Acridotheres tristis)

Animals show consistent individual differences in behaviour across time and/or contexts. Recently, it has been suggested that proactive personality types might also exhibit fast cognitive styles. The speed with which individuals sample environmental cues is one way in which correlations between personality and cognition might arise. Here, we measured a collection of behavioural traits (competitiveness, neophobia, neophilia, task-directed motivation and exploration) in common mynas (Acridotheres tristis) and measured their relationship with problem solving. We predicted that fast solving mynas would interact with (i.e. sample) the problem solving task at higher rates, but also be more competitive, less neophobic, more neophilic, and more exploratory. Mynas that were faster to solve a novel foraging problem were no more competitive around food and no more inclined to take risks. Unexpectedly, these fast-solving mynas had higher rates of interactions with the task, but also displayed lower levels of exploration. It is possible that a negative relation between problem solving and spatial exploration arose as a consequence of how inter-individual variation in exploration was quantified. We discuss the need for greater consensus on how to measure exploratory behaviour before we can advance our understanding of relationships between cognition and personality more effectively.

Eureka!: What Is Innovation, How Does It Develop, and Who Does It?

Innovation is not only central to changes in traditional practice but arguably responsible for humanity's remarkable success at colonizing the earth and diversifying the products, technologies, and systems within it. Surprisingly little is known of how this integral component of behavioral flexibility develops and the factors that are responsible for individual differences therein. This review highlights two primary ways in which the process and development of innovation may be better understood: By emulating the critical advances of animal behavior researchers in examining innovation in nonhuman species and establishing a clearer conceptualization of what is "innovation". A pathway to innovation is suggested and an innovation classification system offered to aid recognition of its appearance and potential cultural contributions.

A problem with problem solving: motivational traits, but not cognition, predict success on novel operant foraging tasks

Rates of innovative foraging behaviours and success on problem-solving tasks are often used to assay differences in cognition, both within and across species. Yet the cognitive features of some problem-solving tasks can be unclear. As such, explanations that attribute cognitive mechanisms to individual variation in problem-solving performance have revealed conflicting results. We investigated individual consistency in problem-solving performances in captive-reared pheasant chicks, Phasianus colchicus, and addressed whether success depends on cognitive processes, such as trial-and-error associative learning, or whether performances may be driven solely via noncognitive motivational mechanisms, revealed through subjects' willingness to approach, engage with and persist in their interactions with an apparatus, or via physiological traits such as body condition. While subjects' participation and success were consistent within the same problems and across similar tasks, their performances were inconsistent across different types of task. Moreover, subjects' latencies to approach each test apparatus and their attempts to access the reward were not repeatable across trials. Successful individuals did not improve their performances with experience, nor were they consistent in their techniques in repeated presentations of a task. However, individuals that were highly motivated to enter the experimental chamber were more likely to participate. Successful individuals were also faster to approach each test apparatus and more persistent in their attempts to solve the tasks than unsuccessful individuals. Our findings therefore suggest that individual differences in problem-solving success can arise from inherent motivational differences alone and hence be achieved without inferring more complex cognitive processes.

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Problem-solving performance was assessed in artificially reared pheasant chicks.

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Performance was consistent within same/similar tasks but not across different tasks.

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Successful solvers did not improve performance with trial and error experience.

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Differences between successful and unsuccessful birds were mediated by motivation.

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Success at problem solving may not reveal cognitive differences between individuals.

Animal and human innovation: novel problems and novel solutions

This theme issue explores how and why behavioural innovation occurs, and the consequences of innovation for individuals, groups and populations. A vast literature on human innovation exists, from the development of problem-solving in children, to the evolution of technology, to the cultural systems supporting innovation. A more recent development is a growing literature on animal innovation, which has demonstrated links between innovation and personality traits, cognitive traits, neural measures, changing conditions, and the current state of the social and physical environment. Here, we introduce these fields, define key terms and discuss the potential for fruitful exchange between the diverse fields researching innovation. Comparisons of innovation between human and non-human animals provide opportunities, but also pitfalls. We also summarize some key findings specifying the circumstances in which innovation occurs, discussing factors such as the intrinsic nature of innovative individuals and the environmental and socio-ecological conditions that promote innovation, such as necessity, opportunity and free resources. We also highlight key controversies, including the relationship between innovation and intelligence, and the notion of innovativeness as an individual-level trait. Finally, we discuss current research methods and suggest some novel approaches that could fruitfully be deployed.

Desperate Prawns: Drivers of Behavioural Innovation Vary across Social Contexts in Rock Pool Crustaceans

Innovative behaviour may allow animals to cope with changes in their environment. Innovative propensities are known to vary widely both between and within species, and a growing body of research has begun to examine the factors that drive individuals to innovate. Evidence suggests that individuals are commonly driven to innovate by necessity; for instance by hunger or because they are physically unable to outcompete others for access to resources. However, it is not known whether the factors that drive individuals to innovate are stable across contexts. We examined contextual variation in the drivers of innovation in rock pool prawns (Palaemon spp), invertebrates that face widely fluctuating environments and may, through the actions of tides and waves, find themselves isolated or in groups. Using two novel foraging tasks, we examined the effects of body size and hunger in prawns tested in solitary and group contexts. When tested alone, small prawns were significantly more likely to succeed in a spatial task, and faster to reach the food in a manipulation task, while hunger state had no effect. In contrast, size had no effect when prawns were tested in groups, but food-deprived individuals were disproportionately likely to innovate in both tasks. We suggest that contextual variation in the drivers of innovation is likely to be common in animals living in variable environments, and may best be understood by considering variation in the perception of relative risks and rewards under different conditions.

Innovation and problem solving: a review of common mechanisms

Behavioural innovations have become central to our thinking about how animals adjust to changing environments. It is now well established that animals vary in their ability to innovate, but understanding why remains a challenge. This is because innovations are rare, so studying innovation requires alternative experimental assays that create opportunities for animals to express their ability to invent new behaviours, or use pre-existing ones in new contexts. Problem solving of extractive foraging tasks has been put forward as a suitable experimental assay. We review the rapidly expanding literature on problem solving of extractive foraging tasks in order to better understand to what extent the processes underpinning problem solving, and the factors influencing problem solving, are in line with those predicted, and found, to underpin and influence innovation in the wild. Our aim is to determine whether problem solving can be used as an experimental proxy of innovation. We find that in most respects, problem solving is determined by the same underpinning mechanisms, and is influenced by the same factors, as those predicted to underpin, and to influence, innovation. We conclude that problem solving is a valid experimental assay for studying innovation, propose a conceptual model of problem solving in which motor diversity plays a more central role than has been considered to date, and provide recommendations for future research using problem solving to investigate innovation. This article is part of a Special Issue entitled: Cognition in the wild.

Perching but not foraging networks predict the spread of novel foraging skills in starlings

The directed social learning hypothesis suggests that information does not spread evenly through animal groups, but rather individual characteristics and patterns of physical proximity guide the social transmission of information along specific pathways. Network-based diffusion analysis (NBDA) allows researchers to test whether information spreads following a social network. However, the explanatory power of different social networks has rarely been compared, and current models do not easily accommodate random effects (e.g. allowing for individuals within groups to correlate in their asocial solving rates). We tested whether the spread of two novel foraging skills through captive starling groups was affected by individual- and group-level random and fixed effects (i.e. sex, age, body condition, dominance rank and demonstrator status) and perching or foraging networks. We extended NBDA to include random effects and conducted model discrimination in a Bayesian context. We found that social learning increased the rate at which birds acquired the novel foraging task solutions by 6.67 times, and acquiring one of the two novel foraging task solutions facilitated the asocial acquisition of the other. Surprisingly, the spread of task solutions followed the perching rather than the foraging social network. Upon acquiring a task solution, foraging performance was facilitated by the presence of group mates. Our results highlight the importance of considering more than one social network when predicting the spread of information through animal groups. This article is part of a Special Issue entitled: Cognition in the wild.