Sociable Individuals Research Articles

THE ROLE OF SOCIABILITY IN OLDER ADULTS' ADAPTATION TO COVID-19

Abstract Some older adults may be particularly sensitive to the negative effects of social disruptions due to COVID-19 (Tyrrell & Williams, 2020). For example, the unique circumstances of the pandemic may have made greater sociability a liability (Wijngaards et al., 2020). The current study used a community sample of 136 older adults (M age = 67.77, range 50-91; 69.3% females; 93% White) to explore whether sociability moderated links between disruptions to contact with friends and family and indicators of mental health. Using a series of hierarchical linear regressions, we found that sociability moderated the association between disruptions in family interactions and depressive symptoms. For more sociable individuals, disruptions in family interactions were more strongly positively associated with depressive symptoms. Given the potential for future social disruptions due to COVID-19, our findings point to the importance of considering the role of sociability in developing interventions targeting older adults.

Does the match between individual and group behavior matter in shoaling sticklebacks?

In animals living in groups, the social environment is fundamental to shaping the behaviors and life histories of an individual. A mismatch between individual and group behavior patterns may have disadvantages if the individual is incapable of flexibly changing its state in response to the social environment that influences its energy gain and expenditure. We used different social groups of juvenile three‐spined sticklebacks (Gasterosteus aculeatus) with experimentally manipulated compositions of individual sociability to study the feedback between individual and group behaviors and to test how the social environment shapes behavior, metabolic rate, and growth. Experimentally created unsociable groups, containing a high proportion of less sociable fish, showed bolder collective behaviors during feeding than did corresponding sociable groups. Fish within groups where the majority of members had a level of sociability similar to their own gained more mass than did those within mismatched groups. Less sociable individuals within sociable groups tended to have a relatively low mass but a high standard metabolic rate. A mismatch between the sociability of an individual and that of the majority of the group in which it is living confers a growth disadvantage probably due to the expression of nonadaptive behaviors that increase energetic costs.

Sociability as a personality trait in animals: methods, causes and consequences.

Within animal populations there is variation among individuals in their tendency to be social, where more sociable individuals associate more with other individuals. Consistent inter-individual variation in 'sociability' is considered one of the major axes of personality variation in animals along with aggressiveness, activity, exploration and boldness. Not only is variation in sociability important in terms of animal personalities, but it holds particular significance for, and can be informed by, two other topics of major interest: social networks and collective behaviour. Further, knowledge of what generates inter-individual variation in social behaviour also holds applied implications, such as understanding disorders of social behaviour in humans. In turn, research using non-human animals in the genetics, neuroscience and physiology of these disorders can inform our understanding of sociability. For the first time, this review brings together insights across these areas of research, across animal taxa from primates to invertebrates, and across studies from both the laboratory and field. We show there are mixed results in whether and how sociability correlates with other major behavioural traits. Whether and in what direction these correlations are observed may differ with individual traits such as sex and body condition, as well as ecological conditions. A large body of evidence provides the proximate mechanisms for why individuals vary in their social tendency. Evidence exists for the importance of genes and their expression, chemical messengers, social interactions and the environment in determining an individual's social tendency, although the specifics vary with species and other variables such as age, and interactions amongst these proximate factors. Less well understood is how evolution can maintain consistent variation in social tendencies within populations. Shifts in the benefits and costs of social tendencies over time, as well as the social niche hypothesis, are currently the best supported theories for how variation in sociability can evolve and be maintained in populations. Increased exposure to infectious diseases is the best documented cost of a greater social tendency, and benefits include greater access to socially transmitted information. We also highlight that direct evidence for more sociable individuals being safer from predators is lacking. Variation in sociability is likely to have broad ecological consequences, but beyond its importance in the spread of infectious diseases, direct evidence is limited to a few examples related to dispersal and invasive species biology. Overall, our knowledge of inter-individual variation in sociability is highly skewed towards the proximate mechanisms. Our review also demonstrates, however, that considering research from social networks and collective behaviour greatly enriches our understanding of sociability, highlighting the need for greater integration of these approaches into future animal personality research to address the imbalance in our understanding of sociability as a personality trait.

Fear of being near: Fear supersedes sociability when interacting amid a pandemic

In the COVID-19 era, physical interactions ubiquitously pose a disease threat. Using a novel online paradigm, this study tested whether under such unique circumstances, the fundamental motivation to avoid disease-related threats interacts with individual differences in sociability, such that: (i) responses to others are slowed down, particularly among sociable individuals, reflecting motivational tension; (ii) the role of sociability in predicting interaction likelihood is diminished. Participants (Israeli young adults, N = 207) listened to auditory descriptions of everyday social situations, taking place in either the physical or virtual space, and decided quickly whether to interact. Participants also completed the Sociability Scale (Cheek & Buss, 1981). Responses were slower in the physical compared to virtual space, regardless of sociability. The association between interaction likelihood and sociability was stronger in the virtual space, with sociability mirrored by self-reported fear of COVID-19 in predicting interaction likelihood. We propose that when physical contact with others poses a threat to safety, fear supersedes sociability in guiding behavior in physical interactions.

The Joint Log-Lift Task: A Social Foraging Paradigm.

Behavioural cooperation is under intense research. Yet, popular experimental paradigms often employ artificial tasks, require training, or do not permit partner choice, possibly limiting their biological relevance. We developed the joint log-lift task, a social foraging paradigm in which animals have to jointly lift a log to each obtain a food reward. The task relies on an obligate strategy, meaning that the only way to benefit is to work jointly. We hypothesised that (1) animals learn to spontaneously solve the task, and that (2) kin and (3) more sociable individuals would engage more often together in the task and achieve greater success than non-kin and less sociable individuals, respectively. We presented the task to 8 groups of juvenile domestic pigs (Sus scrofa domesticus) in their home pen for 30 min daily. Over the course of 9 days, the pigs showed evidence of learning by progressively switching from individual to joint behaviours, leading to 68% (62 out of 91 pigs) spontaneously solving the task. Success was influenced by sociability, but not kinship. There were large differences in success among dyads, hinting at the possible role of social dynamics and inter-individual differences in the ability and/or motivation to solve the task. The joint log-lift task allows researchers to investigate spontaneous cooperative tendencies of individuals, dyads and groups in the home environment through ad libitum engagement with the apparatus. This ecologically relevant paradigm opens the way to investigate social foraging experimentally at large scale, by giving animals free choice about when and with whom to work jointly.

Success of Hand Movement Imagination Depends on Personality Traits, Brain Asymmetry, and Degree of Handedness

Brain-computer interfaces (BCIs), based on motor imagery, are increasingly used in neurorehabilitation. However, some people cannot control BCI, predictors of this are the features of brain activity and personality traits. It is not known whether the success of BCI control is related to interhemispheric asymmetry. The study was conducted on 44 BCI-naive subjects and included one BCI session, EEG-analysis, 16PF Cattell Questionnaire, estimation of latent left-handedness, and of subjective complexity of real and imagery movements. The success of brain states recognition during imagination of left hand (LH) movement compared to the rest is higher in reserved, practical, skeptical, and not very sociable individuals. Extraversion, liveliness, and dominance are significant for the imagination of right hand (RH) movements in “pure” right-handers, and sensitivity in latent left-handers. Subjective complexity of real LH and of imagery RH movements correlates with the success of brain states recognition in the imagination of movement of LH compared to RH and depends on the level of handedness. Thus, the level of handedness is the factor influencing the success of BCI control. The data are supposed to be connected with hemispheric differences in motor control, lateralization of dopamine, and may be important for rehabilitation of patients after a stroke.

The influence of sex, rearing history, and personality on abnormal behaviour in zoo-housed bonobos (Pan paniscus)

Abnormal behaviours are often used as a welfare indicator in zoo-housed great apes. While previous studies report on the occurrence of abnormal behaviours in zoo-housed chimpanzees (Pan troglodytes), there is currently a lack of knowledge about such behaviours in the closely related bonobo (Pan paniscus). Here we report on the prevalence, diversity and frequency of abnormal behaviours, based on 1531 h of observations in 51 adult bonobos, living in six zoos. We also investigate the potential influence of age, sex, rearing history and four previously established personality traits (Activity, Boldness, Openness and Sociability) on the diversity and frequency of abnormal behaviours. Our results document the presence of a total of 13 abnormal behaviours in the population, with the five most frequent ones being Coprophagy, Poke anus, Social hair pluck, Regurgitation and Head shake. We find that wild-born bonobos show a higher diversity of abnormal behaviours compared to mother-reared individuals, likely due to their abnormal early-life experiences. Mother-reared individuals and males show lower frequencies of Poke anus. The frequency of abnormal behaviours is also linked to personality. Bonobos scoring lower on Activity, associated with more self-scratching and lower activity, engage more in Coprophagy and Head shaking. More sociable individuals, on the other hand, had higher frequencies of Social hair pluck, which follows a previous finding that this behaviour is embedded in grooming. Finally, more sociable individuals also had lower frequencies of Coprophagy, an indicator that higher sociability might cause higher resilience to stressors. Our study provides a first overview of the abnormal behaviours in zoo-housed bonobos. We discuss that not all abnormal behaviours may be suitable indicators of poor welfare. These results form an important base in our understanding of the repertoire of abnormal behaviours in zoo-housed bonobos, which is a crucial step for optimising their welfare.

Personality affects dynamics of an experimental pathogen in little brown bats.

Host behaviour can affect host–pathogen dynamics and theory predicts that certain individuals disproportionately infect conspecifics during an epidemic. Consistent individual differences in behaviour, or personality, could influence this variation with the most exploratory or sociable individuals most likely to spread pathogens. We quantified exploration and sociability in little brown bats (Myotis lucifugus) and then experimentally manipulated exposure to a proxy pathogen (i.e. ultraviolet (UV) fluorescent powder) to test two related hypotheses: (i) more sociable and more exploratory individuals would be more likely to transmit infections to other individuals, and (ii) more sociable and more exploratory individuals uninfected with an invading pathogen would be more likely to acquire infections. We captured 10 groups of 16 bats at a time and held each group in an outdoor flight tent equipped with roosting-boxes. We used hole-board and Y-maze tests to quantify exploration and sociability of each bat and randomly selected one individual from each group for ‘infection’ with non-toxic, UV fluorescent powder. Each group of 10 bats was released into the flight tent for 24 h, which represented an experimental infection trial. After 24 h, we removed bats from the trial, photographed each individual under UV light and quantified infection intensity from digital photographs. As predicted, the exploratory behaviour of the experimentally infected individual was positively correlated with infection intensity in their group-mates, while more exploratory females had higher pathogen acquisition. Our results highlight the potential influence of host personality and sex on pathogen dynamics in wildlife populations.

Come together: trust, sociability and individual investors' stock-portfolio returns

PurposePrevious studies have found that trusting and sociable individuals are more likely to participate in the stock market and hold risky assets. The purpose of this paper is to explore if trust and sociability also are related to individual investors' stock-portfolio returns.Design/methodology/approachThe authors study the questions in the paper by linking survey measures of trust and sociability to investors' actual stock portfolios.FindingsThe authors find that trusting investors acquire higher raw and risk-adjusted stock-portfolio returns, but that the returns do not differ depending on how sociable investors are. These results suggest that trust is important for investors' stock-portfolio decisions, and that trusting investors tend to perform better in the stock market than less-trusting investors.Originality/valueThis is, to the best of the authors’ knowledge, the first paper that relates survey measures of trust and sociability to investors' actual stock-portfolio holdings. This is important to increase the understanding for how trust and sociability are related to the financial decisions individuals makes.

Individual behavioral differences and health of golden-headed lion tamarins (Leontopithecus chrysomelas).

Individual behavioral differences may influence how animals cope with altered environments. Depending on their behavioral traits, individuals may thus vary in how their health is affected by environmental conditions. We investigated the relationship between individual behavior of free-living golden-headed lion tamarins (Leontopithecus chrysomelas) responding to a novel object (to assess exploration-avoidance), and their habitat use and health status (endoparasitism; clinical measures: biometric data, heart rate, respiratory frequency, and temperature; fecal glucocorticoid metabolites). As parasite transmission can be affected by individual variation in social contact and social grooming, we also evaluated whether more sociable individuals show higher endoparasite loads compared with less sociable animals. Four groups living in landscapes with different levels of human disturbance were investigated: two in degraded forest fragments in an agricultural matrix (DFAM-higher disturbance), and two in a cocoa agroforestry system (cabruca-lower disturbance) in the Atlantic forest of South Bahia, Brazil. Using a subjective ratings approach, highly correlated adjective descriptors were combined to produce z-score ratings of one derived variable ("confidence"), which was selected to characterize the tamarins' exploration/avoidance responses during a novel object test. The higher the confidence score, the longer female tamarins spent foraging for prey independent of landscape, and the greater their body mass independent of sex and landscape. Only DFAM individuals showed intestinal parasite infection. Endoparasite loads were positively correlated with the number of grooming partners, suggesting an association between social grooming and transmission (more groomers = more endoparasites). Individual behavior, including in a test situation, may thus have some predictive value for behavior in a free-living context, and for its health consequences.

Regulation between personality traits: individual social tendencies modulate whether boldness and leadership are correlated

Although consistent behavioural differences between individuals (i.e. personality variation) are now well established in animals, these differences are not always expressed when individuals interact in social groups. This can be key in important social dynamics such as leadership, which is often positively related to personality traits such as boldness. Individuals consistently differ in how social they are (their sociability), so if other axes of personality variation, such as boldness, can be suppressed during social interactions, this suppression should be stronger in more sociable individuals. We measured boldness (latency to leave a refuge when alone) and sociability (time spent with a conspecific) in three-spined sticklebacks (Gasterosteus aculeatus) and tested the boldness–leadership association in pairs of these fish. Both boldness and sociability were repeatable, but were not correlated. When splitting the data between the 50% most sociable and 50% less sociable fish, boldness was more strongly associated with leadership in less rather than more sociable individuals. This is consistent with more sociable fish conforming to their partner's behaviour due to their greater social tendency. One axis of personality variation (sociability) can thus modulate the relationship between others (boldness and leadership), with potential implications for selection on personality variation in social animals.

Are we assessing temperament appropriately? The Emotionality Activity Sociability and Impulsivity (EASI) Temperament Scale: A systematic psychometric review.

Researchers have dedicated decades to the study of temperament; nevertheless, a single definition has yet to be outlined and several theories with varying numbers of traits continue to coexist (Conture, Kelly, & Walden, 2013). Researchers generally agree that temperament contributes to individual differences, with a common thread among the many definitions of temperament being that traits remain consistent across situations and moderately stable over time (Conture et al., 2013). Given the variability in conceptualizations of temperament, various measures, both self- and parent-report, have been developed; for example, the Emotionality Activity Sociability and Impulsivity Scale-III (EASI-III; Buss & Plomin, 1975); Colorado Childhood Temperament Inventory (CCTI; Rowe & Plomin, 1977); Revised Infant Temperament Questionnaire (RITQ; Carey & McDevitt, 1978); Dimensions of Temperament Survey (Lerner, Palermo, Spiro, & Nesselroade, 1982); Toddler Temperament Questionnaire (TTQ; Fullard, McDevitt, & Carey, 1984); Children's Behaviour Questionnaire (Rothbart, Ahadi, Hershey, & Fisher, 2001); Infant Behaviour Questionnaire-Revised (IBQ-R; Gartstein & Rothbart, 2003). However, in this article we have chosen to focus on one of the most widely used parent-rated measures of temperament: the Emotionality, Activity, Sociability, and Impulsivity Scale (EASI; Buss, Plomin, & Willerman, 1973) and its iteration, the Emotionality, Activity, Sociability, and Shyness Temperament Survey (EAS; Buss & Plomin, 1984). Although several existing measures of temperament are appropriate for adults (i.e., EASI-III), infants (RITQ and IBQ-R), or young children (TTQ), the EASI and EAS are of the few measures of temperament designed specifically for children (originally ages 1-9 years). The EASI is an often-used measure of child temperament in the area of childhood preoperative anxiety research (e.g., Finley, Stewart, Buffett-Jerrott, Wright, & Millington, 2006; Fortier, Del Rosario, Martin, & Kain, 2010; Kain, Mayes, Caldwell-Andrews, Karas, & McClain, 2006; Kain et al., 1998; Kain, Mayes, Weisman, & Hofstadter, 2000; Wright, Stewart, & Finley, 2013), although the psychometric properties have not always been acceptable (noted specifically by Finley et al., 2006 and Wright, Wright et al., 2013). The measure (and its iteration) continues to be used without modification and has not been reviewed systematically.Development of EASI and EASEASIThe EASI was developed as a parent-rated measure of child temperament; however, there are parallel teacher-report and self- report versions as well (Buss & Plomin, 1984). The EASI is comprised of 20 parent-rated items, with five items on each of the four temperament subscales. Each item is rated on a scale of 1 (low) to 5 (high). After reverse-scoring one item from each scale, scores are summed and divided by five, resulting in four subscales (Emotionality, Activity, Sociability, and Impulsivity) with a possible score range of 5 to 25 (Buss & Plomin, 1975). Emotionality varies from an almost stoic lack of reaction to intense or out of control emotional reactions. Examples of high emotionality in children are extreme crying, tantrums, difficulty being soothed, and a low threshold for aversive stimuli (Buss & Plomin, 1975; Goldsmith et al., 1987). Activity refers to total energy output (Buss & Plomin, 1975). Individuals vary from lethargy to almost hypomanic energetic Spelling: behaviour (Goldsmith et al., 1987). The active person is typically busy and in a hurry (Buss & Plomin, 1975). Sociability is defined as the preference for being with others rather than being alone. Sociable individuals seek to share activities, receive attention from others, and engage in social interaction (Goldsmith et al., 1987). Impulsivity involves the tendency to respond quickly rather than inhibiting one's response or planning before acting (Buss & Plomin, 1975). …

A new approach to measuring individual differences in sensitivity to facial expressions: influence of temperamental shyness and sociability

To examine individual differences in adults’ sensitivity to facial expressions, we used a novel method that has proved revealing in studies of developmental change. Using static faces morphed to show different intensities of facial expressions, we calculated two measures: (1) the threshold to detect that a low intensity facial expression is different from neutral, and (2) accuracy in recognizing the specific facial expression in faces above the detection threshold. We conducted two experiments with young adult females varying in reported temperamental shyness and sociability – the former trait is known to influence the recognition of facial expressions during childhood. In both experiments, the measures had good split half reliability. Because shyness was significantly negatively correlated with sociability, we used partial correlations to examine the relation of each to sensitivity to facial expressions. Sociability was negatively related to threshold to detect fear (Experiment 1) and to misidentify fear as another expression or happy expressions as fear (Experiment 2). Both patterns are consistent with hypervigilance by less sociable individuals. Shyness was positively related to misidentification of fear as another emotion (Experiment 2), a pattern consistent with a history of avoidance. We discuss the advantages and limitations of this new approach for studying individual differences in sensitivity to facial expressions.

Personality correlates of prepulse inhibition of the acoustic startle response and the N1 and P2 auditory evoked potentials

A growing body of psychophysiological evidence points to the possibility that individual differences in early auditory processing may contribute to social withdrawal and introverted tendencies. The present study assessed the response characteristics of the acoustic reflex arc of introverted–withdrawn and extraverted–sociable individuals. Introverts displayed a greater incidence of abnormal middle ear acoustic reflexes and lower acoustic reflex amplitudes than extraverts. These findings were strongest for stimuli presented at a frequency of 2000 Hz. Results are discussed in light of the controversy concerning the anatomic loci (peripheral vs. central neuronal activity) of the individual differences between introverts and extraverts in early auditory processing.

Are sociable people more beautiful? A zero-acquaintance analysis of agreeableness, extraversion, and attractiveness

Stereotypes ascribe positive social traits to attractive individuals. Such stereotypes are viewed as erroneous. However, these stereotypes may have a kernel of truth if more sociable individuals present themselves in a manner that increases their attractiveness, a plausible idea given social engagement goals. To examine this idea, two studies involving 217 participants used a zero-acquaintance design in which unacquainted judges rated the attractiveness of participants in impromptu photographs. Participants high in the self-reported traits of agreeableness or extraversion, the two Big 5 traits most relevant to interpersonal behavior, were rated more attractive. Further results indicated that personality–attraction relationships were mediated by a well-groomed appearance. The results suggest a kernel of truth to the idea that sociable individuals are also attractive.

Introversion and individual differences in middle ear acoustic reflex function

A growing body of psychophysiological evidence points to the possibility that individual differences in early auditory processing may contribute to social withdrawal and introverted tendencies. The present study assessed the response characteristics of the acoustic reflex arc of introverted–withdrawn and extraverted–sociable individuals. Introverts displayed a greater incidence of abnormal middle ear acoustic reflexes and lower acoustic reflex amplitudes than extraverts. These findings were strongest for stimuli presented at a frequency of 2000 Hz. Results are discussed in light of the controversy concerning the anatomic loci (peripheral vs. central neuronal activity) of the individual differences between introverts and extraverts in early auditory processing.

Emotional, Cognitive, Behavioral, and Temperament Characteristics of High-Empathy Children

Recent research has suggested that individual differences in young children's capacity for empathy and altruism has heritable components and may be related to early temperament. These individual differences, like other human capacities such as intelligence, may be distributed normally. Thus, “high-empathy” children may exhibit cognitive, emotional, and behavioral precocity in empathic and altruistic responding, and begin expressing these capacities early in life. Twenty-seven 2- to 8-year-old (M = 53 months), primarily Euro-American high-empathy children (10 male) were identified by childcare center staff. Ethnographically oriented interviews of their mothers provided detailed accounts of the children's empathic and altruistic responding in everyday interactions at home and school. As a group, the children were described as emotionally positive, especially sociable individuals whose empathic and altruistic responses were highly spontaneous, occurred more frequently, and differed from peers in depth, intensity, and persistence. Parallels were drawn between these capacities and temperamental dispositions for self-regulation and emotional reactivity. Limitations of the methodology and directions of future research are discussed.