Individual Behavioral Responses Research Articles

Behavioural plasticity across social contexts is regulated by the directionality of inter-individual differences

An individual’s behavioural phenotype is a combination of its unique behavioural propensities and its responsiveness to environmental variation, also known as behavioural plasticity. In social species, we must not only explore how individuals respond to variations in the physical environment but also how they react to changes in their social environment. A growing body of work has demonstrated that the behavioural heterogeneity of a group can alter its responsiveness, decision making, and fitness. Whether an individual is more or less extreme than a partner – what we term its ‘relative personality’ – may also alter individual behavioural responses. We determined exploratory tendencies of individual zebrafish (Danio rerio) and then constructed pairs with varying differences in ‘relative personality’ to determine the effect of differences between partners on behavioural plasticity. We find that relative personality, but not the magnitude of the difference between partners, is the most important determinant of behavioural plasticity across social treatments. Despite this overall effect, pairs of fish exhibited no predictable leader-follower interactions, suggesting that details of the experimental paradigm may be important in shaping social dynamics.

Individual variation in an acute stress response reflects divergent coping strategies in a large herbivore

Individuals differ in the manner that they cope with risk. When these behavioral differences are manifested in risky or challenging environments (i.e. stressful situations), they are generally interpreted within the “coping style” framework. As studying inter-individual variability in behavior is particularly challenging in the wild, we used a captive facility to explore consistency in the individual behavioral response to an acute stress in roe deer (Capreolus capreolus). Using behavioral and physiological parameters measured six times across a calendar year, we first quantified individual repeatability and, second, explored the correlations among these parameters that might indicate a coherent stress response. Finally, we analyzed the link between the stress response and individual body mass, a reliable indicator of phenotypic quality in roe deer. We found that the measured parameters were highly repeatable across seasons, indicating that the individual stress response is consistent over time. Furthermore, there was considerable covariation among the stress response parameters, describing a proactivity-reactivity gradient at the individual level. Finally, proactive individuals had higher body mass than reactive individuals. We suggest that consistent individual differences in energy metabolism and physiology may promote consistent individual differences in behavioral traits, providing a mechanistic link between food acquisition tactics and demographic performance.

Communicating transportation carbon dioxide emissions information: Does gender impact behavioral response?

General concern and knowledge on climate change have been increasingly studied over the past decades. Gender differences have been found for general environmental concern and knowledge, but mixed findings exist with respect to climate change. In transportation, research has examined potential relations between environmental attitudes and transportation behavior, with mixed findings as well. Recently, the use of carbon dioxide (CO2) emissions information to influence choice has been tested with women being found more willing to pay to reduce their personal impacts, suggesting that women are either more willing to change or that their response to information on climate change is stronger. However, those studies used CO2 mass and studies that examined understanding of CO2 information as a mass have found that people struggle to understand it. If concern and knowledge about climate change differ amongst individuals, then, according to theories such as the Transtheoretical Model, the type of information used to motivate choices is likely important. Using a unique data set (n=236) it is possible to take a first look at how gender might affect concern, knowledge, and action in terms of transportation and climate change. Further, it is also possible to examine behavioral responses to transportation climate change information. Finally, an empirical analysis is conducted of the effect of how the information is presented might differ by gender. Thus, this work aims to investigate whether gender differences might contribute to the explanation of individual behavioral responses (from concern to action) in a transportation climate change context.

Regional homogeneity of intrinsic brain activity correlates with auditory-motor processing of vocal pitch errors

It has been well documented that speakers produce rapid compensatory vocal adjustments for errors they perceive in their auditory feedback. The fact that they differ greatly in the degree to which they compensate for perceived errors, however, has received much less attention. The present study investigated whether intrinsic brain activity during resting can predict an individual's behavioral and cortical responses in compensating for pitch-shifted auditory feedback during vocalization. This relationship was investigated by correlating the regional homogeneity (ReHo) of resting-state fMRI signals with the vocal compensation and event-related potentials (N1 and P2) in response to pitch shifts of −200 and −500 cents. Behaviorally, the magnitudes of vocal compensation were significantly correlated with the ReHo values in the right supplementary motor area (SMA) for both −200 and −500 cents, the right primary motor cortex (M1) for −200 cents, and the left premotor cortex (PMC) for −500 cents. For both pitch shift sizes, there were significant correlations between ReHo and N1 amplitude in the left inferior frontal gyrus (IFG), right superior temporal gyrus (STG), bilateral M1, and left SMA. Significant correlations between ReHo and P2 amplitude were observed in the bilateral IFG, right STG, left SMA and M1 for −200 and −500 cents, the left PMC for −200 cents, and the right SMA for −500 cents. These findings provide the first evidence that regional homogeneity of intrinsic brain activity can predict behavioral and cortical responses in compensating for pitch errors in voice auditory feedback.

Activity in the rat olfactory cortex is correlated with behavioral response to odor: a microPET study.

How olfactory cortical areas interpret odor maps evoked in the olfactory bulb and translate odor information into behavioral responses is still largely unknown. Indeed, rat olfactory cortices encompass an extensive network located in the ventral part of the brain, thus complicating the use of invasive functional methods. In vivo imaging techniques that were previously developed for brain activation studies in humans have been adapted for use in rodents and facilitate the non-invasive mapping of the whole brain. In this study, we report an initial series of experiments designed to demonstrate that microPET is a powerful tool to investigate the neural processes underlying odor-induced behavioral response in a large-scale olfactory neuronal network. After the intravenous injection of [18F]Fluorodeoxyglucose ([18F]FDG), awake rats were placed in a ventilated Plexiglas cage for 50min, where odorants were delivered every 3min for a 10-s duration in a random order. Individual behavioral responses to odor were classified into categories ranging from 1 (head movements associated with a short sniffing period in response to a few stimulations) to 4 (a strong reaction, including rearing, exploring and sustained sniffing activity, to several stimulations). After [18F]FDG uptake, rats were anesthetized to perform a PET scan. This experimental session was repeated 2weeks later using the same animals without odor stimulation to assess the baseline level of activation in each individual. Two voxel-based statistical analyses (SPM 8) were performed: (1) a two-sample paired t test analysis contrasting baseline versus odor scan and (2) a correlation analysis between voxel FDG activity and behavioral score. As expected, the contrast analysis between baseline and odor session revealed activations in various olfactory cortical areas. Significant increases in glucose metabolism were also observed in other sensory cortical areas involved in whisker movement and in several modules of the cerebellum involved in motor and sensory function. Correlation analysis provided new insight into these results. [18F]FDG uptake was correlated with behavioral response in a large part of the anterior piriform cortex and in some lobules of the cerebellum, in agreement with the previous data showing that both piriform cortex and cerebellar activity in humans can be driven by sniffing activity, which was closely related to the high behavioral scores observed in our experiment. The present data demonstrate that microPET imaging offers an original perspective for rat behavioral neuroimaging.

Accounting for heterogeneity in behavioural responses to health-risk information treatments

ABSTRACTTraditional revealed and stated preference models consider a typical individual's behavioural responses to various policy-based information treatments. For some cost–benefit applications in which resource managers are concerned with responses from a representative individual, this is sufficient. However, as behavioural responses to information treatments can vary across respondents, we develop a latent class analysis with covariates to examine unobserved heterogeneity responses to health-risk information treatments. Results from a probabilistic model indicate that classes of consumers respond differently to the health-risk information treatments. Principally, we find that the media form of the information treatment is important, with raw consumer groups typically more responsive to a brochure information treatment, while cooked oyster consumers are more responsive to the same information in a video format. We also find that a proposed US Food and Drug Administration policy on processing all raw oysters before market has a greater effect on reducing demand for consumers of cooked oysters. However, with an associated price premium, all consumer classes reduce demand. Overall, the results suggest that future policy-based research could benefit from examining potential heterogeneity in individuals’ responses to risk information treatments in order to fully understand the efficacy of treatments on behaviour.

Thinking about Change: An Integrative Approach for Examining Cognition in a Changing World.

We are currently experiencing shifts in climate at rates not previously recorded. One important aspect of this change is a tendency toward extremes--extremes in temperature and moisture, both within and among years. Numerous studies focus on the physiological consequences of environmental change, especially in terms of ectothermic taxa's thermal regime and use of habitat. For many species, though, cognitive responses may be a means of response to environmental perturbation. However, the effects of environmental change on the general mechanisms of cognitive processes and their implications for larger phenomena are seldom examined. Moreover, at a larger scale, we do not fully understand the features of the environment that might select for cognitive enhancements or their mechanisms, making us unable to accurately predict which species might experience the most severe response to environmental change and in which environments. This symposium brought together scientists from numerous disciplines to examine the role of cognition in how organisms cope with changing environments. We cover topics from the perspectives of the physiological mechanisms underlying and driving cognition to the complexity of individual behavioral responses in changing environments to emergent large-scale processes influencing species' abilities to respond to such change. Our ultimate goals are to explore how animals use cognition to cope with rapid environmental change, how such coping mechanisms "scale up" to affect ecological and evolutionary patterns, and how we might determine which features of the environment have been (and will become) most important for the conservation of biodiversity.

Spatiotemporal variation in selection of roads influences mortality risk for canids in an unprotected landscape

Ecologists are increasingly documenting individual variation in resource selection across populations in response to temporal or spatial environmental context. These behavioral patterns are assumed to be adaptive although previous studies have not linked them directly to survival and reproductive data to verify the assumed relationship between behavior and fitness. Recent work documented that higher density of secondary roads within home ranges of free‐ranging canids (wolves, coyotes and hybrids) increased mortality risk in the hybrid zone adjacent to Algonquin Park in Ontario, Canada. Here, we examine individual behavioral responses of canids to spatially varying levels of human‐disturbance and determine whether these responses to secondary roads resulted in differential mortality risk for canids across the hybrid zone. Specifically, we investigated resource selection within home ranges with GPS telemetry to determine whether canids selected roads more at night than during the day to minimize dangerous encounters with humans. Next, we modeled individual variation in spatial and temporal responses to secondary roads to evaluate the relative importance of intrinsic (Canisancestry) and extrinsic (resource availability) influences on their behavior. Behavioral responses to roads were not well explained by variation inCanisancestry. Instead, canids avoided roads more during day than at night as a non‐linear function of increased road availability. Furthermore, canids that survived exhibited a stronger relationship between day–night selection of roads and road availability than canids that died suggesting an adaptive nature of this behavior. By modifying their selection of roads between day and night, canids appear to be able to exploit the beneficial attributes of roads while mitigating human‐caused mortality risk. However, not all canids responded adaptively highlighting the importance of explicitly linking patterns of resource selection to components of fitness to accurately model and interpret individual variation in resource selection behavior of animals.

Accounting for behavioral responses during a flu epidemic using home television viewing.

BackgroundTheory suggests that individual behavioral responses impact the spread of flu-like illnesses, but this has been difficult to empirically characterize. Social distancing is an important component of behavioral response, though analyses have been limited by a lack of behavioral data. Our objective is to use media data to characterize social distancing behavior in order to empirically inform explanatory and predictive epidemiological models.MethodsWe use data on variation in home television viewing as a proxy for variation in time spent in the home and, by extension, contact. This behavioral proxy is imperfect but appealing since information on a rich and representative sample is collected using consistent techniques across time and most major cities. We study the April-May 2009 outbreak of A/H1N1 in Central Mexico and examine the dynamic behavioral response in aggregate and contrast the observed patterns of various demographic subgroups. We develop and calibrate a dynamic behavioral model of disease transmission informed by the proxy data on daily variation in contact rates and compare it to a standard (non-adaptive) model and a fixed effects model that crudely captures behavior.ResultsWe find that after a demonstrable initial behavioral response (consistent with social distancing) at the onset of the outbreak, there was attenuation in the response before the conclusion of the public health intervention. We find substantial differences in the behavioral response across age subgroups and socioeconomic levels. We also find that the dynamic behavioral and fixed effects transmission models better account for variation in new confirmed cases, generate more stable estimates of the baseline rate of transmission over time and predict the number of new cases over a short horizon with substantially less error.ConclusionsResults suggest that A/H1N1 had an innate transmission potential greater than previously thought but this was masked by behavioral responses. Observed differences in behavioral response across demographic groups indicate a potential benefit from targeting social distancing outreach efforts.

Modeling the 2014 Ebola Virus Epidemic - Agent-Based Simulations, Temporal Analysis and Future Predictions for Liberia and Sierra Leone.

We developed an agent-based model to investigate the epidemic dynamics of Ebola virus disease (EVD) in Liberia and Sierra Leone from May 27 to December 21, 2014. The dynamics of the agent-based simulator evolve on small-world transmission networks of sizes equal to the population of each country, with adjustable densities to account for the effects of public health intervention policies and individual behavioral responses to the evolving epidemic. Based on time series of the official case counts from the World Health Organization (WHO), we provide estimates for key epidemiological variables by employing the so-called Equation-Free approach. The underlying transmission networks were characterized by rather random structures in the two countries with densities decreasing by ~19% from the early (May 27-early August) to the last period (mid October-December 21). Our estimates for the values of key epidemiological variables, such as the mean time to death, recovery and the case fatality rate, are very close to the ones reported by the WHO Ebola response team during the early period of the epidemic (until September 14) that were calculated based on clinical data. Specifically, regarding the effective reproductive number Re, our analysis suggests that until mid October, Re was above 2.3 in both countries; from mid October to December 21, Re dropped well below unity in Liberia, indicating a saturation of the epidemic, while in Sierra Leone it was around 1.9, indicating an ongoing epidemic. Accordingly, a ten-week projection from December 21 estimated that the epidemic will fade out in Liberia in early March; in contrast, our results flashed a note of caution for Sierra Leone since the cumulative number of cases could reach as high as 18,000, and the number of deaths might exceed 5,000, by early March 2015. However, by processing the reported data of the very last period (December 21, 2014-January 18, 2015), we obtained more optimistic estimates indicative of a remission of the epidemic in Sierra Leone, as reflected by the derived Re (~0.82, 95% CI: 0.81-0.83).

Low social status decreases the neural salience of unfairness.

Social hierarchy exists in almost all social species and affects everything from resource allocation to the development of intelligence. Previous studies showed that status within a social hierarchy influences the perceived fairness of income allocation. However, the effect of one’s social status on economic decisions is far from clear, as are the neural processes underlying these decisions. In this study, we dynamically manipulated participants’ social status and analyzed their behavior as recipients in the ultimatum game (UG), during which event-related potentials (ERPs) were recorded. Behavioral results showed that acceptance rates for offers increased with the fairness level of offers. Importantly, participants were less likely to accept unfair offers when they were endowed with high status than with low status. In addition, cues indicating low status elicited a more positive P2 than cues indicating high status in an earlier time window (170–240 ms), and cues indicating high status elicited a more negative N400 than cues indicating low status in a later time window (350–520 ms). During the actual reception of offers, the late positivity potential (LPP, 400–700 ms) for unfair offers was more positive in the high status condition than in the low status condition, suggesting a decreased arousal for unfair offers during low status. These findings suggest a strong role of social status in modulating individual behavioral and neural responses to fairness.

The Personal Values of University Students in South Africa

The failure of ethical standards amongst managers is one of the causes of fraud, corruption, corporate scandals and business failures. Values are a powerful force behind the behavioural responses of individuals. The objective of the study was to investigate the personal values of university students in South Africa. Universities have an important role to play in solving the ethical problems that currently affect the business environment. Data was collected through the use of self-administered questionnaire in a survey. The study used the Schwartz Portrait Value Questionnaire. The results indicated that achievement is the most significant value. The next four most important values are self-direction, benevolence, security and universalism. In addition, there is a relatively high score for conformity value. This suggests that students will behave properly and will avoid doing wrong things. DOI: 10.5901/mjss.2014.v5n23p758

Behavioral responses to changing environments

Humans have brought about unprecedented changes to environments worldwide. For many species, behavioral adjustments represent the first response to altered conditions. In this review, we consider the pivotal role that behavior plays in determining the fate of species under human-induced environmental change and highlight key research priorities. In particular, we discuss the importance of behavioral plasticity and whether adaptive plastic responses are sufficient in keeping pace with changing conditions. We then examine the interplay between individual behavioral responses and population processes and consider the many ways in which changes in behavior can affect ecosystem function and stability. Lastly, we turn to the evolutionary consequences of anthropogenic change and consider the impact of altered behaviors on the evolutionary process and whether behavior can facilitate or hinder adaptation to environmental change.

One-Child Policy and the Rise of Man-Made Twins

This paper examines an unintended response to the one-child policy in China: births of twins. Analysis of population census data shows that the one-child policy has accounted for more than one-third of the increase in the reported births of twins since the 1970s. Investigation using birth spacing with prior births and height difference within twins suggests that the increase in the birth of twins is partly due to parents reporting regularly spaced children as twins to avoid the policy violation punishment. The study highlights the possibility of individual behavioral response to undesirable government policies and the potential social consequences.

Personality predicts social dominance in male domestic fowl.

Individuals in social species commonly form dominance relationships, where dominant individuals enjoy greater access to resources compared to subordinates. A range of factors such as sex, age, body size and prior experiences has to varying degrees been observed to affect the social status an individual obtains. Recent work on animal personality (i.e. consistent variation in behavioural responses of individuals) demonstrates that personality can co-vary with social status, suggesting that also behavioural variation can play an important role in establishment of status. We investigated whether personality could predict the outcome of duels between pairs of morphologically matched male domestic fowl (Gallus gallus domesticus), a species where individuals readily form social hierarchies. We found that males that more quickly explored a novel arena, or remained vigilant for a longer period following the playback of a warning call were more likely to obtain a dominant position. These traits were uncorrelated to each other and were also uncorrelated to aggression during the initial part of the dominance-determining duel. Our results indicate that several behavioural traits independently play a role in the establishment of social status, which in turn can have implications for the reproductive success of different personality types.

Attachment and responses to employment dissolution

We propose that theory and research on how individuals deal with loss or potential loss of personal relationships can inform our understanding of how employees deal with the loss or potential loss of the employment relationship. In particular, we examine the possibility that attachment theory – which plays a central role in explaining an individual's affective, cognitive and behavioral response to the loss of central close relationships – may explain the psychological mechanisms and behavioral reactions associated with the loss of an employment relationship. A key tenet underlying attachment theory is the idea that people develop internal models of attachment, which determine how individuals handle a variety of life's adversities, including but not confined to relationship loss. This research provides a theoretical perspective suggesting that the psychological and physiological effects of job loss may perhaps be related to the emotional trauma, grief and abandonment associated with the loss of the “employment relationship”, rather than the financial and social strains associated with the job loss. Further, our research also suggests that strong psychological ties with the organization are not always associated with positive outcomes for the organization, specifically, in the event of employment dissolution. Theoretical and practical implications are discussed.

Effects of behavioral response and vaccination policy on epidemic spreading--an approach based on evolutionary-game dynamics.

How effective are governmental incentives to achieve widespread vaccination coverage so as to prevent epidemic outbreak? The answer largely depends on the complex interplay among the type of incentive, individual behavioral responses, and the intrinsic epidemic dynamics. By incorporating evolutionary games into epidemic dynamics, we investigate the effects of two types of incentives strategies: partial-subsidy policy in which certain fraction of the cost of vaccination is offset, and free-subsidy policy in which donees are randomly selected and vaccinated at no cost. Through mean-field analysis and computations, we find that, under the partial-subsidy policy, the vaccination coverage depends monotonically on the sensitivity of individuals to payoff difference, but the dependence is non-monotonous for the free-subsidy policy. Due to the role models of the donees for relatively irrational individuals and the unchanged strategies of the donees for rational individuals, the free-subsidy policy can in general lead to higher vaccination coverage. Our findings indicate that any disease-control policy should be exercised with extreme care: its success depends on the complex interplay among the intrinsic mathematical rules of epidemic spreading, governmental policies, and behavioral responses of individuals.

Reference-Dependent Preferences and Charitable Giving

Previous studies on charitable giving usually estimate the effect of tax price and income on charitable giving. In this paper, I find a new behavioral response of individuals to their income changes. Specifically, I introduce a model of charitable giving with reference-dependent preferences of individuals. The model implies that when the consumption level is above (below) the reference level, individuals increase (decrease) charitable giving as their income rises. This is in stark contrast to the positive income effect that is taken for granted in virtually all studies on charitable giving. Using the 2007 Survey of Consumer Finances, I confirm the predictions of the model, suggesting that people have reference-dependent preferences. I also find that the elasticity of charitable giving with respect to tax price (one minus marginal tax rate) is much higher for those who are away from the reference level than for those who are near the reference level.

The Future of Marine Invertebrates in Face of Global Climate Change

Global Warming and Sea Temperature Rise Average sea surface temperature is now 0.6°C warmer than at the start of the industrial revolution [1], and a further increase of 3-6°C is forecasted by the end of this century because of elevated levels of atmospheric carbon dioxide [2,3]. The effects of global warming on marine species include range shifts, population collapses, local extinctions, and phase shifts, which result from individual physiological and behavioural responses to increasing temperature throughout the species’ geographic range [3-9]. For ectothermic organisms, habitat temperature is a critically important environmental factor because of the effects of temperature on all biological processes, from molecular to physiological to behavioural [8,10-12]. Local adaptation to thermal gradients can cause populations in different parts of the geographic range to exhibit different responses to temperature variation [11,13-15]. Obviously, forecasting the response of animals to global climate change drivers must encompass more than just physiological sensitivity, e.g., the animal’s ability to buffer the effects of climate change through behavior. Consequently, comparing the effects of temperature increases in different populations is essential for generating robust predictions about the impact of global warming on animal community at large spatial scales.

Maintaining the clinical relevance of animal models in translational studies of post-traumatic stress disorder.

The diagnosis of Post-Traumatic Stress Disorder (PTSD) is conditional on directly experiencing or witnessing a significantly threatening event and the presence of a certain minimal number of symptoms from each of four symptom clusters (re-experiencing, avoidance, negative cognition and mood, and hyperarousal) at least one month after the event (DSM 5) (American Psychiatric Association 2013). Only a proportion of the population exposed develops symptoms fulfilling the criteria. The individual heterogeneity in responses of stress-exposed animals suggested that adapting clearly defined and reliably reproducible "diagnostic", i.e. behavioral, criteria for animal responses would augment the clinical validity of the analysis of study data. We designed cut-off (inclusion/exclusion) behavioral criteria (CBC) which classify study subjects as being severely, minimally or partially affected by the stress paradigm, to be applied retrospectively in the analysis of behavioral data. Behavioral response classification enables the researcher to correlate (retrospectively) specific anatomic, bio-molecular and physiological parameters with the degree and pattern of the individual behavioral response, and also introduces "prevalence rates" as a valid study-parameter. The cumulative results of our studies indicate that, by classifying the data from individual subjects according to their response patterns, the animal study can more readily be translated into clinical "follow-up" studies and back again. This article will discuss the concept of the model and its background, and present a selection of studies employing and examining the model, alongside the underlying translational rationale of each.