Winner and loser effects in human competitions. Evidence from equally matched tennis players

Learning from fights: Males' social dominance status impact reproductive success in Drosophila melanogaster

In animals, the access to vital resources often relies on individuals' behavioural personality, strength, motivation, past experiences and dominance status. Dominant individuals would be more territorial, providing them with a better access to food resources and mate. The so-called winner and loser effects induce individuals' behavioural changes after experiencing a victory or a defeat, and lead to an individual persistent state influencing the outcome of subsequent fights. However, whether and how development of winner and loser effects affect individuals' fitness is controversial. The aim of this study is to evaluate how individuals' fitness can be influenced by previous fighting experience in Drosophila melanogaster. In this study, we assess various behavioural performances as indicators for dominant and subordinate fitness. Our results show that subordinates are less territorial than dominants although their locomotor abilities are not affected. We also demonstrate that in a non-competitive context, experiencing a defeat reduces males' motivation to court females but not the reproductive success while in a competitive context, it negatively affects males' reproductive success. However, we found no impact upon either males' ability to distinguish potential mates nor on females' choice of a specific mating partner. Overall, these results indicate that previous defeats reduce reproductive success, a commonly used estimate of individual fitness.

Does success breed success? An investigation of momentum in elite recurve archery

We investigate the existence of momentum or the "hot hand" phenomenon in recurve archery, in which archers have three shots per set. We collected the performance of archers along with the control variable (player difference) and game data (set score difference, shooting order and game type). We set out to compare the outcome (bullseye, 10 points, probability) and performance (scores of the third shot) in a range of cases with the previous two shots. The most obvious finding to emerge from this study is the powerful evidence for positive momentum in recurve archery. The key finding that hitting the bullseye creates momentum and momentum leads to better performance has been confirmed as the "success breeds success" mechanism. Furthermore, the performance of the third shot is influenced by competitive ability and match importance (Olympic Games or not).

Male intrasexual aggression and partial dominance of females over males in vervet monkeys

Females dominate a subset of the males in a minority of mammalian species despite male-biased sexual dimorphism. How this may arise is suggested by a computational model, DomWorld. The model represents male-biased sexual dimorphism through the males’ greater initial dominance and higher intensity of aggression, meaning that fights initiated by males have a greater impact than those by females. The model shows that female dominance over males increases with a greater proportion of males in the group. This happens because when males are involved in a larger fraction of fights this results in greater hierarchical differentiation (i.e., steepness). This causes rank overlap between the sexes (i.e., partial female dominance). We test the validity of these processes in vervet monkeys (Cercopithecus pygerythrus), a primate species with partial female dominance. We confirm that the proportion of males in the group is significantly positively correlated with the degree of dominance by females over males and with the steepness of the hierarchy among males exclusively, but not with the steepness of the hierarchy among all adults of the group. The steepness in male hierarchies correlated positively with female dominance over males in these groups. We show that steeper hierarchies among vervet males resulted from male-to-male fights being a larger proportion of the fights among all adults of the group. We conclude that the higher frequency of male intrasexual aggression favors female dominance in vervet monkeys. We also show that females received coalitionary support when they were in conflict with a male, mainly from other females, and that this favors female dominance in this species, but this does not explain why partial female dominance increased with the proportion of males in the group. We advocate further investigation of the influence of male intrasexual aggression on the degree of female dominance over males in other species with partial female dominance.

The Neural Circuit Architecture of Social Hierarchy in Rodents and Primates

Social status is recognized as a major determinant of social behavior and health among animals; however, the neural circuits supporting the formation and navigation of social hierarchies remain under extensive research. Available evidence suggests the prefrontal cortex is a keystone in this circuit, but upstream and downstream candidates are progressively emerging. In this review, we compare and integrate findings from rodent and primate studies to create a model of the neural and cellular networks supporting social hierarchies, both from a macro (i.e., circuits) to a micro-scale perspective (microcircuits and synapses). We start by summarizing the literature on the prefrontal cortex and other relevant brain regions to expand the current “prefrontal-centric” view of social hierarchy behaviors. Based on connectivity data we also discuss candidate regions that might inspire further investigation, as well as the caveats and strategies that have been used to further our understanding of the biological substrates underpinning social hierarchy and dominance.

Effect of Exercise Training on Physical Fitness Among Young Tennis Players: A Systematic Review

Background

Physical fitness comprises both health- and skill-related components that have been shown to correlate with the competitive ability of the athletes. Competitive ability of the athletes is strongly related to the positive or poor characteristics of physical fitness. Additionally, the adolescent stage is critical for the development of physical fitness. Physical fitness training for young tennis players should receive more attention. However, the current literature is deficient in in-depth reviews of the effects of exercise training on the physical fitness of young tennis players.

Objective

This review is aimed to investigate the effects of exercise training on physical fitness among young tennis players.

Methods

From October 2020, a comprehensive search was undertaken in four electronic databases (SCOPUS, PubMed, EBSCOhost (SPORTDiscus), and CINAHL Plus) and also on Google Scholar and other sources of gray literature references. The methodological quality of included studies was assessed using the Physiotherapy Evidence Database scale and the over scientific evidence was determined using the best evidence synthesis (BES). This review included only studies that employed an experimental design to assess the physical fitness components of young tennis players.

Results

Nine articles on exercise training met all inclusion criteria and were included in this systematic review. The studies were of a high standard of quality. The research findings are relatively credible. The results indicated that speed (n = 8) and agility (n = 8) were the most often investigated performance characteristics in exercise training interventions with young tennis players, followed by power (n = 7), strength (n = 4), and flexibility (n = 1). Exercise training significantly increased the physical fitness of young tennis players in terms of speed and agility. There is a lack of evidence about strength and flexibility. Meanwhile, there is conflicting evidence regarding the effect on power, and yet there is no evidence regarding the effect of exercise training on endurance.

Conclusions

This systematic review established a compelling case for the beneficial effects of exercise training interventions on physical fitness in youngtennis players. The review identifies current research gaps (i.e., athlete gender, with a particular emphasis on female athletes) that should be addressed in future experimental studies.

Systematic Review Registration

https://www.crd.york.ac.uk/prospero, identifier CRD 42020213145.

Testosterone and socioeconomic position: Mendelian randomization in 306,248 men and women in UK Biobank

Men with more advantaged socioeconomic position (SEP) have been observed to have higher levels of testosterone. It is unclear whether these associations arise because testosterone has a causal impact on SEP. In 306,248 participants of UK Biobank, we performed sex-stratified genome-wide association analysis to identify genetic variants associated with testosterone. Using the identified variants, we performed Mendelian randomization analysis of the influence of testosterone on socioeconomic position, including income, employment status, neighborhood-level deprivation, and educational qualifications; on health, including self-rated health and body mass index; and on risk-taking behavior. We found little evidence that testosterone affected socioeconomic position, health, or risk-taking. Our results therefore suggest that it is unlikely that testosterone meaningfully affects these outcomes in men or women. Differences between Mendelian randomization and multivariable-adjusted estimates suggest that previously reported associations with socioeconomic position and health may be due to residual confounding or reverse causation.

Correlation of exercise style to mental health and social adaptability of college students

BACKGROUND

Talents are the basis of all development and comprehensive strength of a country. As college students who are about to contact the society, their mental health and social adaptability are the most critical factors for their entry into society.

OBJECTIVE

Therefore, this study explores the correlation of exercise style to mental health and social adaptability of college students.

METHODS

Based on the sample processing of college students in 4 universities in a city, 1,000 students are selected for research on the correlation of exercise style to mental health and social adaptability. In addition, the impacts of college students participating in sports activities on their mental health and social adaptability are analyzed.

RESULTS

When the duration of a single sports activity is 30-60 min, the mental health of students reaches optimal. On the contrary, when the duration of a single sports activity exceeds 90 min, the mental health of students is low. This indicates that the more students participate in sports activities, the stronger the social adaptability is. When the intensity of sports activities for students is moderate, the average scores of interpersonal communication ability of students are the highest. When the duration of a single sports activity is 60-90 min, the average scores of living adaptability of students are the highest. If students keep the appropriate duration and intensity of sports activities, their social adaptability will be improved notably.

CONCLUSION

The social adaptability of students is related to the number of times they participate in sports activities, the duration of a single sports activity, and the intensity of sports activities. However, while exercising, students should plan the duration of sports activities to avoid excessively prolonged exercise time. In addition, students should beware their exercise intensity of sports activities. The optimal choice of exercise intensity is moderate or slightly tired.

Biased perceptions about momentum: Do comeback teams have higher chances to win in basketball overtimes?

Momentum is often cited in the media and in other sources as an important factor in performance over time in business, politics, sports and other areas. Yet, academic research on whether momentum actually exists is mixed. This study aims to assess momentum perceptions in a context in which momentum could be relevant, but where empirical data have shown that no momentum exists. In particular, we take the scenario of a basketball game that is tied at the end of regulation time. We designed questionnaires where one of the teams closed a moderate or a large score gap during the last few minutes of the fourth quarter (and in a control treatment, the score was balanced during these minutes). In the first study, 107 fans and 73 practitioners answered these questionnaires. Then, in the second study, 250 additional respondents completed questionnaires containing the same game scenarios but with additional “opposite-framing” versions and a set of questions regarding the reasons for momentum-based beliefs. The respondents also answered several questions about their level of knowledge and interest in basketball, which allowed us to categorize them to fans and laymen. The responses revealed that coming back into the game by reducing a significant score gap during the final minutes of regular time was perceived to increase the teams’ chances to win in overtime (which can be interpreted as a positive momentum). Fans exhibit stronger momentum beliefs compared to laymen. Overall, respondents’ perceptions contradict the existing empirical evidence that shows that the comeback team does not have higher chances to win the game in overtime. We discuss possible reasons for the discrepancy between the perceptions we observed and the empirical data.

Searching for momentum in NBA triplets of free throws

The literature on momentum is still undecided, with mixed results whether momentum exists or is only perceived to exist ("hot hand fallacy"). We explore whether momentum exists by looking at cases in which a basketball player has three consecutive free throws. A free throw is a well-defined task executed in a stable environment, allegedly giving momentum optimal chances to occur. Taking 14 NBA seasons we collected over 4500 three-free-throw sets (triplets). We obtained the outcomes of the shots as well as some additional variables about the player and the game: the player's average free-throw percentage, home or away, and the game score and the quarter when the free throws were attempted. We first analyse the hit rates in the three shots and then proceed to regression analysis that also controls for the abovementioned variables. We address several concerns raised in the literature. All comparisons and analyses yield the same conclusion that there is no evidence for momentum in the data.

Further mismeasures of animal contests: a new framework for assessment strategies

Competition for resources is a ubiquitous feature of life, and a central topic in behavioral ecology. Organisms use assessment strategies to resolve contests, which can be delineated into two broad categories by the information individuals use to make decisions: mutual assessment (MA) or self-assessment (SA). Most research hitherto has worked to bin a species into one of these categories. In this review, we discuss the limitations of this approach and provide solutions. We posit that assessment strategies do not need to be fixed within a species, individuals, or interactions, and that many organisms should adjust their assessment strategy as the environment, opponent, and opportunities for information gathering change. We show that assessment strategies are an individual-level characteristic, can vary within and between contests, and are not mutually exclusive. We argue that MA is the midpoint along a spectrum of self only and opponent only assessment. We discuss the effects of resource distribution, demographics, experience, information transfer, and ontogeny on assessment strategy evolution and behavior. We conclude by providing empirical guidelines and an example with a simulated dataset.

Using knowledge from human research to improve understanding of contest theory and contest dynamics

Our understanding of animal contests and the factors that affect contest dynamics and decisions stems from a long and prosperous collaboration between empiricists and theoreticians. Over the last two decades, however, theoretical predictions regarding the factors that affect individual decisions before, during and after a contest are becoming increasingly difficult to test empirically. Extremely large sample sizes are necessary to experimentally test the nuanced theoretical assumptions surrounding how information is used by animals during a contest, how context changes the information used, and how individuals change behaviour as a result of both the information available and the context in which the information is acquired. In this review, we discuss how the investigation of contests in humans through the collaboration of biologists and psychologists may advance contest theory and dynamics in general. We argue that a long and productive history exploring human behaviour and psychology combined with technological advancements provide a unique opportunity to manipulate human perception during contests and collect unbiased data, allowing more targeted examinations of particular aspects of contest theory (e.g. winner/loser effects, information use as a function of age). We hope that our perspective provides the impetus for many future collaborations between biologists and psychologists.

Combining field work and laboratory work in the study of financial risk-taking

A contribution to a special issue on Hormones and Human Competition. Financial markets are periodically destabilized by bubbles and crashes during which investors display respectively what has been called "irrational exuberance" and "irrational pessimism". How can we best study these pathologies in competitive and risk-taking behaviours? In this article, we argue that a science of risk-taking and of the financial markets needs to draw heavily on physiology and especially endocrinology, due to their central roles in moderating human behaviour. Importantly, this science of competition and risk requires the same spectrum of research protocols as is found in mature biological and medical sciences, a spectrum running from field work conducted within financial institutions themselves to more controlled laboratory studies, which permit cause to be distinguished from effect. Such a spectrum of studies is especially important for translational behavioural science.