Object Exploration of Garden and Sardinian Warblers Peaks in Spring

Body mass and sex, but not breeding condition and season, influence open-field exploration in the yellow-necked mouse

Theory predicts that risk taking should be influenced by external (e.g., season) and internal (e.g., breeding condition, sex, and body mass) conditions. We investigated whether these factors are associated with a potentially risky behavior: exploration of a novel environment. We conducted repeated open-field tests of exploration in a common forest rodent, the yellow-necked mouse Apodemus flavicollis. Contrary to expectations, the exploration did not vary with the season (spring vs. fall) or the reproductive status of the tested animals. Also unexpectedly, there was an inverted U-shaped relationship between body mass and exploration: animals with intermediate body mass tended to have the highest exploration tendencies. Males were more exploratory than females. Finally, even after adjusting for the effects of body mass and sex, individuals exhibited consistent, repeatable differences in exploration tendencies ("behavioral types" or "personalities"). The discrepancies between certain broad generalizations and our results suggest that risk taking depends on details of species-specific biology.

Intra-specific Variation in the Social Behavior of Barbary macaques (Macaca sylvanus)

Non-human primates show an impressive behavioral diversity, both across and within species. However, the factors explaining intra-specific behavioral variation across groups and individuals are yet understudied. Here, we aimed to assess how group size and living conditions (i.e., captive, semi-free-ranging, wild) are linked to behavioral variation in 5 groups of Barbary macaques (N=137 individuals). In each group, we collected observational data on the time individuals spent in social interactions and on the group dominance style, along with experimental data on social tolerance over food and neophobia. Our results showed that differences in group size predicted differences in the time spent in social interactions, with smaller groups spending a higher proportion of time in close spatial proximity, but a lower proportion of time grooming. Moreover, group size predicted variation in dominance style, with smaller groups being more despotic. Social tolerance was affected by both group size and living conditions, being higher in smaller groups and in groups living in less natural conditions. Finally, individual characteristics also explained variation in social tolerance and neophobia, with socially integrated individuals having higher access to food sources, and higher-ranking ones being more neophobic. Overall, our results support the view that intra-specific variation is a crucial aspect in primate social behavior and call for more comparative studies to better understand the sources of within-species variation.

Intraspecific variation in exploratory behavior and elevational affinity in a widely distributed songbird

Populations of the same species can vary substantially in their behavioral and morphometric traits when they are subject to different environmental pressures, which may lead to the development of different adaptive strategies. We quantified variation in exploratory behavior and morphometric traits among two rufous-collared sparrow populations that occur at low and high elevations in central Chile. Moreover, we used census and δ²H values of feather and blood to evaluate migration. We found that individual sparrows inhabiting high elevations were larger and showed more intense exploratory behavior in comparison with those that were captured at lower elevation. Moreover, we observed a steady decline in sparrow abundance during the winter and similar δ²H values for blood collected in the winter and summer at this site, which were significantly lower than blood δ²H values observed at low elevation. This pattern suggests that individuals do not move long distances during winter, and likely they remain at similar elevations in refuge habitats. As predicted, our results support the existent of different adaptive strategies among populations of the same species, and suggest that the combination of behavioral, morphometric, and stable isotope data is a novel and robust integrative approach to assess differences in adaptation across environmental gradients.

Innovativeness as an emergent property: a new alignment of comparative and experimental research on animal innovation

Innovation and creativity are key defining features of human societies. As we face the global challenges of the twenty-first century, they are also facets upon which we must become increasingly reliant. But what makes Homo sapiens so innovative and where does our high innovation propensity come from? Comparative research on innovativeness in non-human animals allows us to peer back through evolutionary time and investigate the ecological factors that drove the evolution of innovativeness, whereas experimental research identifies and manipulates underpinning creative processes. In commenting on the present theme issue, I highlight the controversies that have typified this research field and show how a paradigmatic shift in our thinking about innovativeness will contribute to resolving these tensions. In the past decade, innovativeness has been considered by many as a trait, a direct product of cognition, and a direct target of selection. The evidence I review here suggests that innovativeness will be hereon viewed as one component, or even an emergent property of a larger array of traits, which have evolved to deal with environmental variation. I illustrate how research should capitalize on taxonomic diversity to unravel the full range of psychological processes that underpin innovativeness in non-human animals.

Seasonal changes in neophobia and its consistency in rooks: the effect of novelty type and dominance position

Neophobia, or the fear of novelty, may offer benefits to animals by limiting their exposure to unknown danger, but can also impose costs by preventing the exploration of potential resources. The costs and benefits of neophobia may vary throughout the year if predation pressure, resource distribution or conspecific competition changes seasonally. Despite such variation, neophobia levels are often assumed to be temporally and individually stable. Whether or not neophobia expression changes seasonally and fluctuates equally for all individuals is crucial to understanding the drivers, consequences and plasticity of novelty avoidance. We investigated seasonal differences and individual consistency in the motivation and novelty responses of a captive group of rooks, Corvus frugilegus, a seasonally breeding, colonial species of corvid that is known for being neophobic. We tested the group around novel objects and novel people to determine whether responses generalized across novelty types, and considered whether differences in dominance could influence the social risk of approaching unknown stimuli. We found that the group's level of object neophobia was stable year-round, but individuals were not consistent between seasons, despite being consistent within seasons. In contrast, the group's avoidance of novel people decreased during the breeding season, and individuals were consistent year-round. Additionally, although subordinate birds were more likely to challenge dominants during the breeding season, this social risk taking did not translate to greater novelty approach. Since seasonal variation and individual consistency varied differently towards each novelty type, responses towards novel objects and people seem to be governed by different mechanisms. Such a degree of fluctuation has consequences for other individually consistent behaviours often measured within the nonhuman personality literature.

Contagious risk taking: social information and context influence wild jackdaws' responses to novelty and risk

Although wild animals increasingly encounter human-produced food and objects, it is unknown how they learn to discriminate beneficial from dangerous novelty. Since social learning allows animals to capitalize on the risk-taking of others, and avoid endangering themselves, social learning should be used around novel and unpredictable stimuli. However, it is unclear whether animals use social cues equally around all types of novelty and at all times of year. We assessed whether wild, individually marked jackdaws-a highly neophobic, yet adaptable species-are equally influenced by social cues to consume novel, palatable foods and to approach a startling object. We conducted these tests across two seasons, and found that in both seasons observers were more likely to consume novel foods after seeing a demonstrator do so. In contrast, observers only followed the demonstrator in foraging next to the object during breeding season. Throughout the year more birds were wary of consuming novel foods than wary of approaching the object, potentially leading to jackdaws' greater reliance on social information about food. Jackdaws' dynamic social cue usage demonstrates the importance of context in predicting how social information is used around novelty, and potentially indicates the conditions that facilitate animals' adjustment to anthropogenic disturbance.

Multiple behavioural, morphological and cognitive developmental changes arise from a single alteration to early life spatial environment, resulting in fitness consequences for released pheasants

Subtle variations in early rearing environment influence morphological, cognitive and behavioural processes that together impact on adult fitness. We manipulated habitat complexity experienced by young pheasants (Phasianus colchicus) in their first seven weeks, adding a third accessible dimension by placing elevated perches in their rearing pens mimicking natural variation in habitat complexity. This simple manipulation provoked an interrelated suite of morphological, cognitive and behavioural changes, culminating in decreased wild mortality of birds from complex habitats compared with controls. Three mechanisms contribute to this: Pheasants reared with perches had a morphology which could enable them to fly to the higher branches and cope with prolonged roosting. They had a higher propensity to roost off the ground at night in the wild. More generally, these birds had more accurate spatial memory. Consequently, birds were at a reduced risk of terrestrial predation. The fitness consequences of variation in early rearing on behavioural development are rarely studied in the wild but we show that this is necessary because the effects can be broad ranging and not simple, depending on a complex interplay of behavioural, cognitive and morphological elements, even when effects that the treatments provoke are relatively short term and plastic.

Cognitive ecology: ecological factors, life-styles, and cognition

Cognitive ecology integrates cognition, ecology, and neurobiology in one topic and has recently broadened into an exciting diversity of themes covering the entire range of cognition and ecological conditions. The review identifies three major environmental factors interacting with cognition: environmental variation (predictable and unpredictable), environmental complexity and predation. Generally, variable environments favor cognitive abilities such as exploration, learning, innovation, memory and also result in larger brains as compared to stable environments. Likewise, cognition is enhanced in complex versus simple environments, whereas the relationship between predation and cognitive abilities can be positive or negative. However, organisms have often evolved entire life-styles (e.g., residency versus migration, food-caching versus noncaching, generalism versus specialism) to deal with these environmental factors. Considering cognition within this framework provides a much more diverse picture of how cognitive abilities evolved in conjunction with other adaptations to environmental challenges. This integrated approach identifies gaps of knowledge and allows the formulation of hypotheses for future testing. Several recently emerged approaches study cognitive abilities at a new and in part highly integrated level. For example, the effect that environment has on the development of cognitive abilities during ontogeny will improve our understanding about cause and effect and gene-environment interactions. Together with two recently emerged highly integrative approaches that link personality and pace-of-life syndromes with cognitive ecology these new directions will improve insight how cognition is interlinked with other major organizational processes. For further resources related to this article, please visit the WIREs website.

CONFLICT OF INTEREST

The author has declared no conflicts of interest for this article.

Does environmental enrichment reduce stress? An integrated measure of corticosterone from feathers provides a novel perspective

Enrichment is widely used as tool for managing fearfulness, undesirable behaviors, and stress in captive animals, and for studying exploration and personality. Inconsistencies in previous studies of physiological and behavioral responses to enrichment led us to hypothesize that enrichment and its removal are stressful environmental changes to which the hormone corticosterone and fearfulness, activity, and exploration behaviors ought to be sensitive. We conducted two experiments with a captive population of wild-caught Clark's nutcrackers (Nucifraga columbiana) to assess responses to short- (10-d) and long-term (3-mo) enrichment, their removal, and the influence of novelty, within the same animal. Variation in an integrated measure of corticosterone from feathers, combined with video recordings of behaviors, suggests that how individuals perceive enrichment and its removal depends on the duration of exposure. Short- and long-term enrichment elicited different physiological responses, with the former acting as a stressor and birds exhibiting acclimation to the latter. Non-novel enrichment evoked the strongest corticosterone responses of all the treatments, suggesting that the second exposure to the same objects acted as a physiological cue, and that acclimation was overridden by negative past experience. Birds showed weak behavioral responses that were not related to corticosterone. By demonstrating that an integrated measure of glucocorticoid physiology varies significantly with changes to enrichment in the absence of agonistic interactions, our study sheds light on potential mechanisms driving physiological and behavioral responses to environmental change.

Context-specific neophilia and its consequences for innovations

According to Ramsey and colleagues the main constituent psychological processes of innovation are response to novelty, exploration, and the ability to recognize a novel solution. I fully support this view but point out that novelty reactions are often context-specific. I will expand on this and discuss the possible consequences of context-specific novelty reactions on the emergence of innovations.