Increased aggression during human group contests when competitive ability is more similar

Is there meaningful influence from situational and environmental factors on the physical and technical activity of elite football players? Evidence from the data of 5 consecutive seasons of the German Bundesliga

The study aimed to identify the effects of situational (match location, match outcome and strength of team/opponent team) and environmental (ambient temperature, relative humidity, WBGT, ground and weather condition) factors on the physical and technical activity of elite football on individual playing positions. Physical and technical activity were collected from 779 football players competing in the German Bundesliga during 5 domestic seasons, from 2014/2015 to 2018/2019, totalling 1530 matches. The data on players' physical and technical activity was taken from the IMPIRE AG system. Based on the available data, 11 variables were selected to quantify the match activity profiles of players. The results showed that situational variables had major effects on the technical performance (especially number of passes performed) but minor effects on physical performance. In turn, among the analysed environmental factors, temperature is the most sensitive, which affects the Total Distance and Sprint Efforts of players in all five positions. This investigation demonstrated that, given that passing is a key technical activity in modern football, players and training staff should be particularly aware that passing maybe affected by situational variables. Professional players are able to react and adapt to various environmental conditions, modifying physical activity depending on the needs in German Bundesliga. These results could help coaches and analysts to better understand the influences of situational and environmental variables on individual playing positions during the evaluation of players' physical and technical performance.

The Male Warrior Hypothesis: Testosterone-related Cooperation and Aggression in the Context of Intergroup Conflict

The Male Warrior Hypothesis (MWH) establishes that men's psychology has been shaped by inter-group competition to acquire and protect reproductive resources. In this context, sex-specific selective pressures would have favored cooperation with the members of one's group in combination with hostility towards outsiders. We investigate the role of developmental testosterone, as measured indirectly through static markers of prenatal testosterone (2D:4D digit ratio) and pubertal testosterone (body musculature and facial masculinity), on both cooperation and aggressive behavior in the context of intergroup conflict among men. Supporting the MWH, our results show that the intergroup conflict scenario promotes cooperation within group members and aggression toward outgroup members. Regarding the hormonal underpinnings of this phenomenon, we find that body musculature is positively associated with aggression and cooperation, but only for cooperation when context (inter-group competition) is taken into account. Finally, we did not find evidence that the formidability of the group affected individual rates of aggression or cooperation, controlling for individual characteristics.

Evolution of technical activity in various playing positions, in relation to match outcomes in professional soccer

The study presented below aimed to examine the position-specific evolution of technical activity among soccer players and how it is related to match outcomes over three consecutive domestic seasons in Germany’s Bundesliga. The research was based on a sample of 13,032 individual match observations of 556 soccer players during the 2014/2015, 2015/2016 and 2016/2017 seasons. These players were classified into five positional roles: central defenders (CD), full-backs (FB), central midfielders (CM), wide midfielders (WM) and forwards (F). The activity of the players was analysed using the Impire AG motion analysis system. Our study indicates that over the course of the three seasons: 1) the total numbers of shots by CMs decreased in the case of won or drawn matches; 2) the number of passes by CD players increased in matches won, and by CM and WM players in matches won, drawn and lost, whereas percentage pass accuracy increased at the CM position in won and drawn matches; 3) players at each position engaged in a substantially smaller number of duels, no matter what the match outcome, while the percentage of encounters won in subsequent seasons decreased among CD, and increased among WM in matches won and at F positions in both won and drawn matches. This research clearly shows that the evolution of technique among professional soccer players is heading in the direction of increased accuracy, with a simultaneous stabilisation of, or even a decline in, the number of activities engaged in.

3D anthropometric assessment and perception of male body morphology in relation to physical strength

OBJECTIVES

The assessment of men's physical strength is an important part of human social perception, for which observers rely on different kinds of cues. However, besides previous studies being limited in considerable ways, as yet there is no comprehensive investigation of a range of somatometric measures in relation to both objectively measured and observer-perceived physical strength using valid stimuli.

METHODS

We examined observer-perceptions of physical strength from 3D body scans of n = 165 men, the usage and validity of somatometric measures as cues to strength, differences between strength ratings from stimuli presented on computer monitors vs in real-life size using a projector, and between male and female observers.

RESULTS

A medium-sized correlation between measured and perceived strength was found, partly mediated by target men's chest-to-hip ratio, body density, ankle girth, height, upper arm, and forearm girth. No significant differences between men's and women's strength perceptions or the method of stimuli presentation (computer monitor vs projector) emerged.

CONCLUSIONS

Our findings suggest that men's physical strength can be assessed with moderate accuracy from 3D body models and that some somatometric measures represent valid cues, which were used by observers, positively predicting both measured and perceived physical strength.

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.

Match outcome and running performance in different intensity ranges among elite soccer players

The monitoring of players’ work-rate profiles during competition is now feasible through computer-aided motion analysis. The aim of the present study was to examine how various playing positions and match outcomes (i.e. won, drawn, lost) affect the total distance, and the distances covered at different intensities, by soccer players in Germany’s Bundesliga. Match performance data were collected for 556 soccer players competing in the Bundesliga during the 2014/15, 2015/16 and 2016/17 domestic seasons. A total of 13 039 individual match observations were made of outfield players (goalkeepers excluded). The analysis was carried out using an IMPIRE AG motion analysis system, with records of all players’ movements in all the 918 matches. The recorded variables included total distance covered [km] and distance covered at intensities in the ranges below 11 km/h, 11-14 km/h, 14-17 km/h, 17-21 km/h, 21-24 km/h, and above 24 km/h. In won matches, as opposed to drawn and lost matches, the wide midfielders and forwards ran a significantly longer distance, primarily covered at intensities of 21-23.99 and above 24 km/h (p ≤ 0.05). The analysis of full-backs, central defenders and central midfielders in won matches – as opposed to drawn and lost matches – in turn reveals that players ran a significantly shorter distance, most likely to be covered at intensities of 17-20.99 and 21-23.99 km/h (p ≤ 0.05). The results of the present study emphasise the importance of match outcome and playing positions during the assessment of physical aspects of soccer performance.

Evaluating the heat-aggression hypothesis: The role of temporal and social factors in predicting baseball related aggression

We examined the role that season progression and social threats play in the heat-aggression hypothesis within Major League Baseball put forward by Reifman, Larrick, and Fein (1991). Box score data from 38,870 Major League Baseball games between the years of 2000 and 2015 was used to test the heat-aggression relationship, while accounting for temporal and social factors that may be simultaneously exerting influence on player behavior. Controlling for a number of other variables, we observed that the effect of temperature on aggressive behavior is partially contingent on the point of the season in which the game took place. Aggressive behavior was also more likely to occur when teams played divisional (compared to league and inter-league) rivals, however this relationship was contingent on season progression. We provide potential boundary conditions relating to the heat-aggression relationship, indicating this may not be a ubiquitous phenomenon.

Individual participation in intergroup contests is mediated by numerical assessment strategies in black howler and tufted capuchin monkeys

Asymmetries in resource-holding potential between opposing groups frequently determine outcomes of intergroup contests. Since both numerical superiority and high intergroup dominance rank may confer competitive advantages, group members should benefit from assessing the relative strength of rivals prior to engaging in defensive displays. However, differences in individual assessment may emerge when cost-benefit trade-offs differ among group members. We examine the influence of numerical superiority and intergroup dominance relationships on individual participation in intergroup encounters in black howler monkeys (Alouatta pigra) and tufted capuchin monkeys (Sapajus nigritus). Black howlers responded with longer vocal displays during encounters with neighbours with an equal number of resident males, while tufted capuchins increased their participation with increasing relative male group size. Within each species, males and females responded similarly to varying numerical odds, suggesting that despite pay-off asymmetries between males and females, both sexes were similarly influenced by numerical asymmetries in deciding to participate in collective group defence. Whereas the outcome of contests among tufted capuchins was determined by relative male group size, reflected in a pronounced intergroup dominance hierarchy, the absence of dominance relationships among black howler groups may have provoked prolonged vocal displays in order to assess rival groups with matching competitive abilities.

Who Punishes? The Status of the Punishers Affects the Perceived Success of, and Indirect Benefits From, “Moralistic” Punishment

“Moralistic” punishment of free riders can provide a beneficial reputation, but the immediate behavior is costly to the punisher. In Study 1, we investigated whether variation in status would be perceived to offset or mitigate the costs of punishment. One hundred and nineteen participants were presented with a vignette describing a punishment scenario. Participants predicted whether punishment would occur, how successful it would be, and indicated their attitude to the punisher. Participants believed only intervention by a high-status (HS) individual would be successful and that low-status (LS) individuals would not intervene at all. HS individuals predicted to punish successfully were seen as more formidable and likable. Study 2 investigated whether punishment was necessary to maintain an HS position. One hundred and seventeen participants were presented with a vignette describing a punishment scenario. Participants were asked to indicate whether they wished to be led by the punisher. HS individuals who did not punish were less likely to be chosen as leaders compared to HS punishers, whereas LS individuals who punished were no more or less likely to be chosen than nonpunishers. The results of both studies suggest that only HS individuals are expected to punish, likely because such a position offsets some of the costs of punishment. As a result, only HS individual can access the reputation benefits from punishment. Furthermore, an HS position may be dependent on the willingness to punish antisocial behavior. The ramifications that these results may have for the evolution of moralistic punishment are discussed.

What determines the duration of war? Insights from assessment strategies in animal contests

Interstate wars and animal contests both involve disputed resources, restraint and giving up decisions. In both cases it seems illogical for the weaker side to persist in the conflict if it will eventually lose. In the case of animal contests analyses of the links between opponent power and contest duration have provided insights into what sources of information are available to fighting animals. I outline the theory of information use during animal contests and describe a statistical framework that has been used to distinguish between two strategies that individuals use to decide whether to persist or quit. I then apply this framework to the analysis of interstate wars. War duration increases with the power of winners and losers. These patterns provide no support for the idea that wars are settled on the basis of mutual assessment of capabilities but indicate that settlement is based on attrition. In contrast to most animal contests, war duration is as closely linked to the power of the winning side as to that of the losing side. Overall, this analysis highlights a number of similarities between animal contests and interstate war, indicating that both could be investigated using similar conceptual frameworks.