Aggression, in its broadest sense, is behavior, or a disposition, that is forceful, hostile or attacking. It may occur either in retaliation or without provocation. In narrower definitions that are used in social sciences and behavioral sciences, aggression is an intention to cause harm or an act intended to increase relative social dominance. Predatory or defensive behavior between members of different species may not be considered aggression in the same sense. Aggression can take a variety of forms and can be physical or be communicated verbally or non-verbally. Aggression differs from what is commonly called assertiveness, although the terms are often used interchangeably among laypeople, e.g. an aggressive salesperson.^[1]

Overview[link]

Two broad categories of aggression are commonly defined. One is described as affective (emotional), hostile or retaliatory aggression, and the other as instrumental, goal-oriented or predatory aggression.^[2] In the context of violence, data from a range of disciplines lend some support to a distinction between affective and predatory aggression.^[3] However, others question the usefulness of a hostile vs instrumental distinction in humans, despite its ubiquity in research, on the basis that in real life most cases involve mixed motives and many factors.^[4]

Another distinction drawn is between aggression that is enacted physically, and relational aggression. The latter can include covert bullying and social manipulation, including isolating others. It has also been understood and dealt with by distinguishing between reactive versus instrumental types.^[5]

A number of other classifications and dimensions of aggression have been advanced. Some questions that have been considered are whether harm to others is intended or not; whether the aggression is verbal or physical; whether it is carried out actively or expressed passively; and whether it is aimed directly or indirectly. Related emotions (e.g. anger) and mental states (e.g. impulsivity, hostility) have also been addressed, as well as behaviors in and of themselves (aggression in the strictest sense).^[6] Aggression may occur in response to non-social as well as social factors, and can have a close relationship with stress coping style.^[7] Aggression may be displayed in order to intimidate.

Aggression may be defined in particular ways within some moral or political views, for example in the non-aggression principle. There are also specific definitions used in relations between countries, such as in the International Criminal Court's proposed jurisdiction to prosecute crimes of aggression.^[8] Furthermore, there may be particular attitudes towards aggression, both sanctioned and unsanctioned, in competitive sports.^[9] Other specific contexts may also be examined, such as workplace aggression.

Etymology[link]

The term aggression comes from the Latin aggressio, meaning attack. The Latin was itself a joining of ad- and gradi-, which meant to step or to go. The first known use dates back to 1611, in the sense of an unprovoked attack.^[10] A psychological sense of 'hostile or destructive behavior' dates back to 1912, in an English translation of the writing of Sigmund Freud.^[11] Alfred Adler had theorized about an 'aggressive drive' in 1908. Child raising experts began to refer to aggression rather than anger from the 1930s.^[12]

Ethology[link]

Male elephant seals fighting

Aggression is one type of behavior addressed by the scientific study of animal behavior known as ethology. Aggression may be involved in the gaining and securing of territories and other resources including food, water and mating opportunities, as well as to protect the self or offspring.^[13] Direct aggression can involve bodily contact such as biting, hitting or pushing. Threat displays and intimidating thrusts may also be classed as aggression, and the majority of conflicts are settled in this way; including through display of body size, antlers, claws or teeth; stereotyped signals within a species; vocalizations including bird song; chemicals; pigments, and aggressive facial expressions.^[14] The concept of agonistic behaviour may alternatively be used to refer to all of the above.

Additionally, many ethnologists believe that in the animal kingdom, aggression does have certain biological advantages. For instance, hostile behavior forces a population of animals into new territories. These animals have to adapt to these new environments which increases the genetic flexibility of the concerned species. Another advantageous situation, which arises via aggression, is evident in the mating rituals which involve the male species fighting one another in order to mate with a subsequent female. This perpetuates the selection of the healthier/more vigorous animal.^[15]

Aggression against outsiders[link]

The most apparent type of interspecific aggression is that observed in the interaction between a predator and its prey.

According to many researchers, predation is not aggression. Cats do not hiss or arch their backs when in pursuit of a rat, and the active areas in their hypothalamuses are more similar to those that reflect hunger than those that reflect aggression.^[16] However, others refer to it as predatory aggression, and point out cases that show more similarity such as mouse-killing by rats.^[17] Aggressive mimicry refers to cases where a predator has the appearance of a harmless organism or object, which then attracts the prey, which the predator then attacks.

An animal defending itself against a predator may become aggressive in order to survive and to ensure the survival of its offspring. It may engage in either "fight or flight" in response to predator attack or threat of attack, depending on how strong they gauge the predator to be relative to themselves. Different animals may also use a range of antipredator adaptations, including alarm signals.

In terms of aggression between groups, defined as a willingness to enter a fight, studies suggest that animals may take into account numerical advantage, distance from home territories, how often the groups encounter each other, competitive abilities, differences in body size, and who is intruding on who. In addition, any given individual is more likely to become aggressive the more other aggressive group members there are nearby.^[18] One particular phenomenon - the formation of intense coordinated coalitions to raid neighbouring territories to kill conspecifics - has only been documented in two species in the animal kingdom: 'common' chimpanzees and humans.^[19]

Aggression within a group[link]

Aggression between conspecifics in a group occurs in a number of contexts having to do with access to resources and breeding. One of the most common is in the establishment of a dominance hierarchy. When certain types of animals are first placed in a common environment, the first thing they do is fight to assert their role in the dominance hierarchy.^[20] In general, the more dominant animals will be more aggressive than their subordinates.^[21][22] The majority of conspecific aggression ceases about 24 hours after the introduction of the animals being tested.^[20][23] Aggression has been defined from this viewpoint as "behavior which is intended to increase the social dominance of the organism relative to the dominance position of other organisms".^[24] Losing confrontations may be referred to as social defeat, and winning or losing is associated with a range of practical and psychological consequences.^[25]

Conflicts of interest occur in many contexts in animal life, such as between potential mating partners, between parents and offspring, and between competitors for resources. Group-living animals may also dispute over the direction of travel or the allocation of time to joint activities. Various factors limit the escalation of aggression, including communicative displays, conventions and routines. In addition, following incidents, various forms of conflict resolution have many observed in mammal species, particularly in gregarious primates. This can mitigate or repair possible ongoing consequences, especially for the recipient of aggression who may become vulnerable to attacks, including possibly from other individuals joining in. Conciliatory acts vary by species and may simply involve more proximity and interaction between the individuals involved in an incident, or specific gestures. Conflicts over food are rarely followed by post conflict reunions, however, even though they are the most frequent type as foraging takes up a large amount of the time of wild primates.^[26]

Questions that have been considered in the study of primate aggression, including in humans, is how aggression maintains the organization of a group; what costs are incurred by aggression; and why some primates avoid aggressive behavior.^[27] For example, bonobo chimpanzee groups are known for low levels of aggression within a partially matriarchal society. Captive animals including primates may show abnormal levels of social aggression and self-harm related to aspects of the physical, sensory or social environment; this depends on the species and individual factors such as gender, age and background (e.g. raised wild or captive).^[28]

Evolutionary explanations[link]

Like many behaviors, aggression can be examined in terms of its ability to help an animal survive and reproduce, or alternatively to risk survival and reproduction. This cost-benefit analysis can be looked at in terms of evolution. There are profound differences in the extent of acceptance of a biological or evolutionary basis for human aggression, however.^[29]

Violence and conflict[link]

Aggression can involve violence that may be adaptive under certain circumstances in terms of natural selection. This is most obviously the case in terms of attacking prey to obtain food, or in anti-predatory defense. It may also be the case in competition between members of the same species or subgroup, if the average reward (e.g. status, access to resources, protection of self or kin) outweighs average costs (e.g. injury, exclusion from the group, death). There are some hypotheses of specific adaptions for violence in humans under certain circumstances, including for homicide, but it is often unclear what behaviors may have been selected for and what may have been a byproduct, as in the case of collective violence.^{[30][31][32][33]}

Although aggressive encounters are ubiquitous in the animal kingdom, with often high stakes, most are resolved through posturing, displays and trials of strength. Game theory is used to understand how such behaviors might spread by natural selection within a population, and potentially become 'Evolutionary Stable Strategies'. An initial model of resolution of conflicts is the Hawk-Dove game; others include the Sequential assessment model and the Energetic war of attrition. These try to understand not just one-off encounters but protracted stand-offs, and mainly differ in the criteria by which an individual decides to give up rather than risk loss and harm in physical conflict (such as through estimates of Resource holding potential).^[34]

Gender[link]

There are multiple theories that seek to explain findings that males and females of the same species can have differing aggressive behaviors. In general, sexual dimorphism can be attributed to greater intraspecific competition in one sex, either between rivals for access to mates and/or to be chosen by mates. This may stem from the other gender being constrained by providing greater parental investment, in terms of factors such as gamete production, gestation, lactation, or upbringing of young. Although there is much variation in species generally the more physically aggressive sex is the male, particularly in mammals. In species where parental care by both sexes is required there tends to be less of a difference. When the female can leave the male to care for the offspring, then females may be the larger and more physically aggressive. Competitiveness despite parental investment has also been observed in some species.^[35] A related factor is the rate at which males and females are able to mate again after producing offspring, and the basic principles of sexual selection are also influenced by ecological factors affecting the ways or extent to which one sex can compete for the other. The role of such factors in human evolution is controversial. The pattern of male and female aggression is argued to be consistent with evolved sexually-selected behavioral differences, while alternative or complimentary views emphasize conventional social roles stemming from physical evolved differences.^[36] Aggression in women may have evolved to be, on average, less physically dangerous and more covert or indirect.^[37][38] However, there are critiques for using animal behavior to explain human behavior. Especially in the application of evolutionary explanations to contemporary human behavior, including differences between the genders.^[39]

Regarding sexual dimorphism, humans fall into an intermediate group with moderate sex differences in body size but relatively large testes. This is a typical pattern of primates where several males and females live together in a group and the male faces an intermediate amount of challenges from other males compared to exclusive polygyny and monogamy but frequent sperm competition.^[40]

Evolutionary psychology and sociobiology have also discussed and produced theories for some specific forms of male aggression such as sociobiological theories of rape and theories regarding the Cinderella effect.

Physiology[link]

Brain pathways[link]

Many researchers focus on the brain to explain aggression. Numerous circuits within both neocortical and subcortical structures play a central role in controlling aggressive behavior, depending on the species, and the exact role of pathways may vary depending on the type of trigger or intention.

In mammals, the hypothalamus and periaqueductal gray of the midbrain are critical areas, as shown in studies on cats, rats, and monkeys. These brain areas control the expression of both behavioral and autonomic components of aggression in these species, including vocalization. Electrical stimulation of the hypothalamus causes aggressive behavior^[41] and the hypothalamus has receptors that help determine aggression levels based on their interactions with serotonin and vasopressin.^[42] These midbrain areas have direct connections with both the brainstem nuclei controlling these functions, and with structures such as the amygdala and prefrontal cortex.

Stimulation of the amygdala results in augmented aggressive behavior in hamsters,^[43][44] while lesions of an evolutionarily homologous area in the lizard greatly reduce competitive drive and aggression (Bauman et al. 2006).^[45] In rhesus monkeys, neonatal lesions in the amygdala or hippocampus results in reduced expression of social dominance, related to the regulation of aggression and fear.^[46] Several experiments in attack-primed Syrian Golden hamsters, for example, support the claim of circuity within the amygdala being involved in control of aggression.^[47] The role of the amygdala is less clear in primates and appears to depend more on situational context, with lesions leading to increases in either social affiliatory or aggressive responses.

The broad area of the cortex known as the prefrontal cortex (PFC) has been implicated in aggression, along with many other functions. such as including inhibition of emotions. Reduced activity of the prefrontal cortex, in particular its medial and orbitofrontal portions, has been associated with violent/antisocial aggression.^[48]

The role of the chemicals in the brain, particularly neurotransmitters, in aggression has also been examined. This varies depending on the pathway, the context and other factors such as gender. A deficit in serotonin has been theorized to have a primary role in causing impulsivity and aggression.Nevertheless, low levels of serotonin transmission may explain a vulnerability to impulsiveness, potential aggression, and may have an effect through interactions with other neurochemical systems. These include dopamine systems which are generally associated with attention and motivation toward rewards, and operate at various levels. Norepinephrine, also known as noradrenaline, may influence aggression responses both directly and indirectly through the hormonal system, the sympathetic nervous system or the central nervous system (including the brain). It appears to have different effects depending on the type of triggering stimulus, for example social isolation/rank versus shock/chemical agitation which appears not to have a linear relationship with aggression. Similarly, GABA, although associated with inhibitory functions at many CNS synapses, sometimes shows a positive correlation with aggression, including when potentiated by alcohol.^[49][50]

The hormonal neuropeptides vasopressin and oxytocin play a key role in complex social behaviours in many mammals such as regulating attachment, social recognition, and aggression. Vasopressin has been implicated in male-typical social behaviors which includes aggression. Oxytocin may have a particular role in regulating female bonds with offspring and mates, including the use of protective aggression. Initial studies in humans suggest some similar effects.^[51][52]

Testosterone[link]

Hormones are chemicals that circulate in the body affecting cells and the nervous system, including the brain. Testosterone is a steroid hormone from the androgen group, which is most linked to the prenatal and postnatal development of the male gender and physique, which in turn has been linked on average to more physical aggression in many species. Testosterone is present to a lesser extent in females, who may be more sensitive to its effects. Animal studies have also indicated a link between incidents of aggression and the individual level of circulating testosterone. However, results in relation to primates, particularly humans, are less clear cut and are at best only suggestive of a positive association in some contexts.^[53]

Challenge Hypothesis[link]

Washington State Song Sparrow

The challenge hypothesis outlines the dynamic relationship between plasma testosterone levels and aggression in mating contexts in many species. It proposes that testosterone is linked to aggression when it is beneficial for reproduction, such as in mate guarding and preventing the encroachment of intrasexual rivals. The challenge hypothesis predicts that seasonal patterns in testosterone levels in a species are a function of mating system (monogamy versus polygyny), paternal care, and male-male aggression in seasonal breeders. This pattern between testosterone and aggression was first observed in seasonally breeding birds, such as the Song Sparrow, where testosterone levels rise modestly with the onset of the breeding season to support basic reproductive functions.^[54] It has subsequently expanded and been modified to predict relationships between testosterone and aggression in other species. For example, chimpanzees, which are continuous breeders, show significantly raised testosterone levels and aggressive male-male interactions when receptive and fertile females are present.^[55] Currently, no research has specified a relationship between the modified challenge hypothesis and human behavior, or the human nature of concealed ovulation, although some suggest it may apply.^[56]

Effects on the nervous system[link]

Testosterone to Estradiol conversion

Another line of research has focused on the proximate effects of circulating testosterone on the nervous system, as mediated by local metabolism within the brain. Testosterone can be metabolized to 17b-estradiol by the enzyme aromatase, or to 5-alpha-dihydrotestosterone (DHT) by 5a-reductase.

Aromatase is highly expressed in regions involved in the regulation of aggressive behavior, such as the amygdala and hypothalamus. In studies using genetic knock-out techniques in inbred mice, male mice that lacked a functional aromatase enzyme displayed a marked reduction in aggression. Long-term treatment with estradiol partially restored aggressive behavior, suggesting that the neural conversion of circulating testosterone to estradiol and its effect on estrogen receptors influences inter-male aggression. In addition, two different estrogen receptors, ERa and ERb, have been identified as having the ability to exert different effects on aggression in mice. However, the effect of estradiol appears to vary depending on the strain of mouse, and in some strains it reduces aggression during long days (16 h of light), while during short days (8 h of light) estradiol rapidly increases aggression.^[57]

Another hypothesis is that testosterone influences brain areas that control behavioral reactions. Studies in animal models indicate that aggression is affected by several interconnected cortical and subcortical structures within the so-called social behavior network. A study involving lesions and electrical-chemical stimulation in rodents and cats revealed that such a neural network consists of the medial amygdala, medial hypothalamus and periaqueductal grey (PAG), and it positively modulates reactive aggression.^[58] Moreover, a study done in human subjects showed that prefrontal-amygdala connectivity is modulated by endogenous testosterone during social emotional behavior.^[59]

In human studies, testosterone-aggression research has also focused on the role of the orbitofrontal cortex (OFC). This brain area is strongly associated with impulse control and self-regulation systems that integrate emotion, motivation, and cognition to guide context-appropriate behavior.^[60] Patients with localized lesions to the OFC engage in heightened reactive aggression.^[61] Aggressive behavior may be regulated by testosterone via reduced medial OFC engagement following social provocation.^[60] When measuring participants’ salivary testosterone, higher levels can predict subsequent aggressive behavioral reactions to unfairness faced during a task. Moreover, brain scanning with fMRI shows reduced activity in the medial OFC during such reactions. Such findings may suggest that a specific brain region, the OFC, is a key factor in understanding reactive aggression.

General associations with behavior[link]

Scientists have for a long time been interested in the relationship between testosterone and aggressive behavior. In most species, males are more aggressive than females. Castration of males usually has a pacifying effect on aggressive behavior in males. In humans, males engage in crime and especially violent crime more than females. The involvement in crime usually rises in the early teens to mid teens which happen at the same time as testosterone levels rise. Research on the relationship between testosterone and aggression is difficult since the only reliable measurement of brain testosterone is by a lumbar puncture which is not done for research purposes. Studies therefore have often instead used more unreliable measurements from blood or saliva.^[62]

The Handbook of Crime Correlates, a review of crime studies, states most studies support a link between adult criminality and testosterone although the relationship is modest if examined separately for each sex. However, nearly all studies of juvenile delinquency and testosterone are not significant. Most studies have also found testosterone to be associated with behaviors or personality traits linked with criminality such as antisocial behavior and alcoholism. Many studies have also been done on the relationship between more general aggressive behavior/feelings and testosterone. About half the studies have found a relationship and about half no relationship.^[62]

Studies of testosterone levels of male athletes before and after a competition revealed that testosterone levels rise shortly before their matches, as if in anticipation of the competition, and are dependent on the outcome of the event: testosterone levels of winners are high relative to those of losers. No specific response of testosterone levels to competition was observed in female athletes, although a mood difference was noted.^[63] In addition, some experiments have failed to find a relationship between testosterone levels and aggression in humans.^[64][65][66]

The possible correlation between testosterone and aggression could explain the "roid rage" that can result from anabolic steroid use,^[67][68] although an effect of abnormally high levels of steroids does not prove an effect at physiological levels.

Dehydroepiandrosterone[link]

Dehydroepiandrosterone (DHEA) is the most abundant circulating androgen hormone and can be rapidly metabolized within target tissues into potent androgens and estrogens. Gonadal steroids generally regulate aggression during the breeding season, but non-gonadal steroids may regulate aggression during the non-breeding season. Castration of various species in the non-breeding season has no effect on territorial aggression. In several avian studies, circulating DHEA has been found to be elevated in birds during the non-breeding season. These data support the idea that non-breeding birds combine adrenal and/or gonadal DHEA synthesis with neural DHEA metabolism to maintain territorial behavior when gonadal testosterone secretion is low. Similar results have been found in studies involving different strains of rats, mice, and hamsters. DHEA levels also have been studied in humans and may play a role in human aggression. Circulating DHEAS (its sulfated ester) levels rise during adrenarche (~7 years of age) while plasma testosterone levels are relatively low. This implies that aggression in pre-pubertal children with aggressive conduct disorder might be correlated with plasma DHEAS rather than plasma testosterone, suggesting an important link between DHEAS and human aggressive behavior.^[57]

Glucocorticoids[link]

Glucocorticoid hormones have an important role in regulating aggressive behavior. In adult rats, acute injections of corticosterone promote aggressive behavior and acute reduction of corticosterone decreases aggression; however, a chronic reduction of corticosterone levels can produce abnormally aggressive behavior. In addition, glucocorticoids affect development of aggression and establishment of social hierarchies. Adult mice with low baseline levels of corticosterone are more likely to become dominant than are mice with high baseline corticosterone levels.^[57]

Glucocorticoids are released by the hypothalamic pituitary adrenal (HPA) axis in response to stress, of which cortisol is the most prominent in humans. Results in adults suggest that reduced levels of cortisol, linked to lower fear or a reduced stress response, can be associated with more aggression. However, it may be that proactive aggression is associated with low cortisol levels while reactive aggression may be accompanied by elevated levels. Differences in assessments of cortisol may also explain a diversity of results, particularly in children.^[53]

The HPA axis is related to the general fight-or-flight response or acute stress reaction, and the role of catecholamines such as epinephrine, popularly known as adrenaline.

Pheromones[link]

In many animals, aggression can be linked to pheromones released between conspecifics. In mice, major urinary proteins (Mups) have been demonstrated to promote innate aggressive behavior in males.^[69][70] Mups activate olfactory sensory neurons in the vomeronasal organ (VNO), a subsystem of the nose known to detect pheromones via specific sensory receptors, of mice^[70] and rats.^[71] Pheremones have also been identified in fruit flies, detected by neurons in the antenna, that send a message to the brain eliciting aggression; it has been noted that aggression pheremones have not been identified in humans.^[72]

Genetics[link]

In general, differences in a continuous phenotype such as aggression are likely to result from the action of a large number of genes each of small effect, which interact with each other and the environment through development and life.

In a non-mammalian example of genes related to aggression, the fruitless gene in fruit flies is a critical determinant of certain sexually dimorphic behaviors, and its artificial alteration can result in a reversal of stereotypically male and female patterns of aggression in fighting. However, in what was thought to be a relatively clear case, inherent complexities have been reported in deciphering the connections between interacting genes in an environmental context and a social phenotype involving multiple behavioral and sensory interactions with another organism.^[73]

In mice, candidate genes for differentiating aggression between the sexes are the Sry (sex determining region Y) gene, located on the Y chromosome and the Sts (steroid sulfatase) gene. The Sts gene encodes the steroid sulfatase enzyme, which is pivotal in the regulation of neurosteroid biosynthesis. It is expressed in both sexes, is correlated with levels of aggression among male mice, and increases dramatically in females after parturition and during lactation, corresponding to the onset of maternal aggression.^[47]

In humans, there is good evidence that the basic human neural architecture underpinning the potential for flexible aggressive responses is influenced by genes as well as environment. In terms of variation between individual people, more than 100 twin and adoption studies studies have been conducted in recent decades examining the genetic basis of aggressive behavior and related constructs such as conduct disorders. According to a meta-analysis published in 2002, approximately 40% of variation between individuals is explained by differences in genes, and 60% by differences in environment (mainly non-shared environmental influences rather than those that would be shared by being raised together). However, such studies have depended on self-report or observation by others including parents, which complicates interpretation of the results. The few laborotory-based analyses have not found significant amounts of individual variation in aggression explicable by genetic variation in the human population. Furthermore, linkage and association studies that seek to identify specific genes, for example that influence neurotransmitter or hormone levels, have generally resulted in contradictory findings characterized by failed attempts at replication. One possible factor is an allele (variant) of the MAO-A gene which, in interaction with certain life events such as childhood maltreatment (which may show a main effect on its own), can influence development of brain regions such as the amygdala and as a result some types of behavioral response may be more likely. The generally unclear picture has been compared to equally difficult findings obtained in regard to other complex behavioral phenotypes.^[74][75]

In humans[link]

Humans share aspects of aggression with non-human animals, and have specific aspects and complexity related to factors such as genetics, early development, social learning and flexibility, culture and morals.

Culture[link]

Culture is a factor that plays a role in aggression.

Tribal or band societies existing before or outside of modern states have sometimes been depicted as peaceful 'noble savages' or alternatively as brutish 'beasts'. The Kung Bushmen were described as 'The Harmless People' in a popular work by Elizabeth Marshall Thomas in 1958,^[76] while Lawrence Keeley's 1996 War Before Civilization suggested that regular warfare without modern technology was conducted by most groups throughout human history, including most Native American tribes.^[77] Studies of hunter-gatherers show a range of different societies. In general, aggression, conflict and violence sometimes occur, but direct confrontation is generally avoided and conflict is socially managed by a variety of verbal and non-verbal methods. Different rates of aggression or violence, currently or in the past, within or between groups, have been linked to the structuring of societies and environmental conditions influencing factors such as resource or property acquisition, land and subsistence techniques, and population change.^[78]

Analyzing aggression culturally or politically is complicated by the fact that the label 'aggressive' can itself be used as a way of asserting a judgement from a particular point of view. Whether a coercive or violent method of social control is perceived as aggression - or as legitimate versus illegitimate aggression - depends on the position of the relevant parties in relation to the social order of their culture. This in turn can relate to factors such as: norms for coordinating actions and dividing resources; what is considered self-defense or provocation; attitudes towards 'outsiders', attitudes towards specific groups such as women, the disabled or the lower status; the availability of alternative conflict resolution strategies; trade interdependence and collective security pacts; fears and impulses; and ultimate goals regarding material and social outcomes.^[79]

Insignia of the 18th Aggressor Squadron

Cross-cultural research has found differences in attitudes towards aggression in different cultures. In one questionnaire study of university students, in addition to men overall justifying some types of aggression more than women, USA respondents justified defensive physical aggression more readily than Japanese or Spanish respondents, whereas Japanese students preferred direct verbal aggression (but not indirect) more than their American and Spanish counterparts.^[80] Within American culture, southern men were shown in a study on university students to be more affected and to respond more aggressively than northerners when randomly insulted after being bumped into, which was theoretically related to a traditional culture of honor in the Southern United States.^[81] A similar sociological concept that may be applied in different cultures is 'face'. Other cultural themes sometimes applied to the study of aggression include individualistic versus collectivist styles, which may relate, for example, to whether disputes are responded to with open competition or by accommodating and avoiding conflicts. Other comparisons made in relation to aggression or war include democratic versus authoritarian political systems and egalitarian versus stratified societies.^[79] The economic system known as capitalism has been viewed by some as reliant on the leveraging of human competitiveness and aggression in pursuit of resources and trade, which has been considered in both positive and negative terms.^[82] Attitudes about the social acceptability of particular acts or targets of aggression are also important factors. This can be highly controversial, as for example in disputes between religions or nation states, for example in regard to the Arab–Israeli conflict.^[83][84]

Media[link]

Some scholars believe that behaviors like aggression may be partially learned by watching and imitating the behavior of others. Some scholars have concluded that media may have some small effects on aggression.^[85] There is also research questioning this view.^[86] For instance, a recent long-term outcome study of youth found no long-term relationship between playing violent video game and youth violence or bullying.^[87] One study suggested there is a smaller effect of violent video games on aggression than has been found with television violence on aggression. This effect is positively associated with type of game violence and negatively associated to time spent playing the games.^[88] The author concluded that insufficient evidence exists to link video game violence with aggression. However, another study suggested links to aggressive behavior.^[89] One study suggested that adults (i.e. parents) suffering from dissociative symptoms related to post-traumatic stress disorder may be more likely to expose their children to violent programs and video games; links between these issues were also related to poverty.^[90]

Children[link]

The frequency of physical aggression in humans peaks at around 2–3 years of age. It then declines gradually on average.^[91][92] These observations suggest that physical aggression is not only a learned behavior but that development provides opportunities for the learning and biological development of self-regulation. However, a small subset of children fail to acquire all the necessary self-regulatory abilities and tend to show atypical levels of physical aggression across development. These may be at risk for later violent behavior or, conversely, lack of aggression that may be considered necessary within society. Some findings suggest that early aggression does not necessarily lead to aggression later on, however, although the course through early childhood is an important predictor of outcomes in middle childhood. In addition, physical aggression that continues is likely occurring in the context of family adversity, including socioeconomic factors. Moreover, 'opposition' and 'status violations' in childhood appear to be more strongly linked to social problems in adulthood than simply aggressive antisocial behavior.^[93][94] Social learning through interactions in early childhood has been seen as a building block for levels of aggression which play a crucial role in the development of peer relationships in middle childhood.^[95] Overall, an interplay of biological, social and environmental factors can be considered.^[96]

What is typically expected of children?

• Young children preparing to enter kindergarten need to develop the socially important skill of being assertive. Examples of assertiveness include asking others for information, initiating conversation, or being able to respond to peer pressure.
• In contrast, some young children use aggressive behavior, such as hitting or biting, as a form of communication.
• Aggressive behavior can impede learning as a skill deficit, while assertive behavior can facilitate learning. However, with young children, aggressive behavior is developmentally appropriate and can lead to opportunities of building conflict resolution and communication skills.
• By school age, children should learn more socially appropriate forms of communicating such as expressing themselves through verbal or written language; if they have not, this behavior may signify a disability or developmental delay

What triggers aggressive behavior in children?

• Physical fear of others
• Family difficulties
• Learning, neurological, or conduct/behavior disorders
• Psychological trauma

Corporal punishment such as spanking increases subsequent aggression in children.^[97]

The Bobo doll experiment was conducted by Albert Bandura in 1961. In this work, Bandura found that children exposed to an aggressive adult model acted more aggressively than those who were exposed to a nonaggressive adult model. This experiment suggests that anyone who comes in contact with and interacts with children can have an impact on the way they react and handle situations.^[98]

Summary points from recommendations by national associations

• American Academy of Pediatrics (2011): "The best way to prevent aggressive behavior is to give your child a stable, secure home life with firm, loving discipline and full-time supervision during the toddler and preschool years. Everyone who cares for your child should be a good role model and agree on the rules he’s expected to observe as well as the response to use if he disobeys."^[99]
• National Association of School Psychologists (2008): "Proactive aggression is typically reasoned, unemotional, and focused on acquiring some goal. For example, a bully wants peer approval and victim submission, and gang members want status and control. In contrast, reactive aggression is frequently highly emotional and is often the result of biased or deficient cognitive processing on the part of the student."^[100]

Gender[link]

Gender is a factor that plays a role in both human and animal aggression. Males are historically believed to be generally more physically aggressive than females from an early age,^[101][102] and men commit the vast majority of murders (Buss 2005). This is one of the most robust and reliable behavioral sex differences, and it has been found across many different age groups and cultures. However, some empirical studies have found the discrepancy in male and female aggression to be more pronounced in childhood and the gender difference in adults to be modest.^[103] Still, there is evidence that males are quicker to aggression (Frey et al. 2003) and more likely than females to express their aggression physically.^[104] When considering indirect forms of non-violent aggression, such as relational aggression and social rejection, some scientists argue that females can be quite aggressive although female aggression is rarely expressed physically.^{[105][106][107]}

Studies show, that females in general have better control over their emotions in comparison to males. Also, males are more likely to retaliate when provoked to gain recognition; females are less likely to retaliate in a violent way because they are shielded by moral sense. ^[108] Although females are less likely to initiate physical violence, they can express aggression by using a variety of non-physical means. Exactly which method women use to express aggression is something that varies from culture to culture. On Bellona Island, a culture based on male dominance and physical violence, women tend to get into conflicts with other women more frequently than with men. When in conflict with males, instead of using physical means, they make up songs mocking the man, which spread across the island and humiliate him. If a woman wanted to kill a man, she would either convince her male relatives to kill him or hire an assassin. Although these two methods involve physical violence, both are forms of indirect aggression, since the aggressor herself avoids getting directly involved or putting herself in immediate physical danger.^[109]

See also the sections on testosterone and evolutionary explanations for gender differences above.

Situational factors[link]

There has been some links between those prone to violence and their alcohol use. Those who are prone to violence and use alcohol are more likely to carry out violent acts.^[110] Alcohol impairs judgment, making people much less cautious than they usually are (MacDonald et al. 1996). It also disrupts the way information is processed (Bushman 1993, 1997; Bushman & Cooper 1990).

Pain and discomfort also increase aggression. Even the simple act of placing one's hands in hot water can cause an aggressive response. Hot temperatures have been implicated as a factor in a number of studies. One study completed in the midst of the civil rights movement found that riots were more likely on hotter days than cooler ones (Carlsmith & Anderson 1979). Students were found to be more aggressive and irritable after taking a test in a hot classroom (Anderson et al. 1996, Rule, et al. 1987). Drivers in cars without air conditioning were also found to be more likely to honk their horns (Kenrick & MacFarlane 1986), which is used as a measure of aggression and has shown links to other factors such as generic symbols of aggression or the visibility of other drivers.^[111]

Frustration is another major cause of aggression. The Frustration aggression theory states that aggression increases if a person feels that he or she is being blocked from achieving a goal (Aronson et al. 2005). One study found that the closeness to the goal makes a difference. The study examined people waiting in line and concluded that the 2nd person was more aggressive than the 12th one when someone cut in line (Harris 1974). Unexpected frustration may be another factor. In a separate study to demonstrate how unexpected frustration leads to increased aggression, Kulik & Brown (1979) selected a group of students as volunteers to make calls for charity donations. One group was told that the people they would call would be generous and the collection would be very successful. The other group was given no expectations. The group that expected success was more upset when no one was pledging than the group who did not expect success (everyone actually had horrible success). This research suggests that when an expectation does not materialize (successful collections), unexpected frustration arises which increases aggression.

There is some evidence to suggest that the presence of violent objects such as a gun can trigger aggression. In a study done by Leonard Berkowitz and Anthony Le Page (1967), college students were made angry and then left in the presence of a gun or badminton racket. They were then led to believe they were delivering electric shocks to another student, as in the Milgram experiment. Those who had been in the presence of the gun administered more shocks. It is possible that a violence-related stimulus increases the likelihood of aggressive cognitions by activating the semantic network.

A new proposal links military experience to anger and aggression, developing aggressive reactions and investigating these effects on those possessing the traits of a serial killer. Castle and Hensley state, "The military provides the social context where servicemen learn aggression, violence, and murder."^[112] Post-traumatic stress disorder (PTSD) is also a serious issue in the military, also believed to sometimes lead to aggression in soldiers who are suffering from what they witnessed in battle. They come back to the civilian world and may still be haunted by flashbacks and nightmares, causing severe stress. In addition, it has been claimed that in the rare minority who are claimed to be inclined toward serial killing, violent impulses may be reinforced and refined in war, possibly creating more effective murderers.^{[citation needed]}

Aggression as a positive adaptation theory[link]

Some recent scholarship has questioned traditional psychological conceptualizations of aggression as universally negative.^[24] Most traditional psychological definitions of aggression focus on the harm to the recipient of the aggression, implying this is the intent of the aggressor, however this may not always be the case.^[113] From this alternate view, although the recipient may or may not be harmed, the intent is to increase the status of the aggressor, not necessarily to harm the recipient.^[114] Such scholars contend that traditional definitions of aggression have no validity.^{[citation needed]}

From this view, rather than concepts such as assertiveness, aggression, violence and criminal violence existing as distinct constructs, they exist instead along a continuum with moderate levels of aggression being most adaptive.^[24] Such scholars do not consider this a trivial difference, noting that many aggression measures may measure outcomes lower down in the continuum, at levels which are adaptive, yet generalize their findings to non-adaptive levels of aggression, thus losing precision.^[115]

See also[link]

References[link]

External links[link]

Look up aggression or aggressive in Wiktionary, the free dictionary.

Wikiquote has a collection of quotations related to: Aggression

Wikimedia Commons has media related to: Aggression

• When Family Life Hurts: Family experience of aggression in children – Parentline plus, 31 October 2010
• Aggression and Violent Behavior, a Review Journal
• International Society for Research on Aggression (ISRA)
• Problems in the Concepts and Definitions of Aggression, Violence and some Related Terms by Johan van der Dennen, originally published in 1980

Wanderlei César da Silva ( /ˈvændərleɪ/ VAN-dər-lay; Portuguese: [vɐ̃dɛɾˈlej ˈsɛzɐr dɐ ˈsiɫvɐ];^[1] Japanese: [ba̠nda̠ɽe̞i ɕiü͍βa̠]; born July 3, 1976), nicknamed "The Axe Murderer", is a Brazilian mixed martial artist, who has competed in Japan's Pride Fighting Championships and the American based Ultimate Fighting Championship (UFC). Silva is known for his aggressive fighting style with the majority of his fights ending in knockout or referee stoppage due to strikes. His style includes engaging opponents with punches and knees from the Muay Thai clinch. He holds the record for the most wins and knockouts in Pride FC history. He is currently ranked as #22 best middleweight fighter in the world by FightMatrix.com.^[2]

Silva began his training under Rudimar Fedrigo at the Chute Boxe Academy in his hometown of Curitiba, Brazil. Although he specializes in muay Thai, he has also trained and received his black belt in Brazilian jiu-jitsu from trainer Cristiano Marcello.^[3] Silva was given the nickname "Cachorro Louco" ("Mad Dog") in Brazil because of his aggressive style and his pre-fight opponent "stare down".^[4] He is the former IVC Light heavyweight Champion, former PRIDE Middleweight Champion, and the 2003 PRIDE Middleweight Grand Prix Tournament Winner.

After spending a majority of his career in Brazil and Japan, Silva moved to the United States in 2007 and he trained at Xtreme Couture in Las Vegas. Preferring a more aggressive gym atmosphere, like he had at Chute Boxe, he opened his own gym, The Wand Fight Team Training & Conditioning Center, in Las Vegas.^[5] Silva currently trains there with his former Chute Boxe coach Rafael Cordeiro. In 2011 Silva trained at Reign Training Center, along side top middleweight contenders such as Mark Munoz.^[6]

Mixed martial arts career[link]

Early career[link]

Silva's aggressive style is rooted in street brawling, refined with elements of Muay Thai and kickboxing. As a late teen he joined the military and was quickly recognized for his fighting talents and rose up in the ranks. Silva enlisted after already winning fight tournaments in his age group in Brazil.^[7]

Silva's first professional match was on November 1, 1996, in the Brazilian Vale Tudo Fighting organization (BVF), where he knocked out Dilson Filho via strikes at BVF 6. He fought in one other match in BVF, BVF 10 on July 1, 1997, against Marcelo Barbosa, who submitted due to a shoulder injury.

Silva fought six matches in four different IVC events, IVC 2, IVC 6, IVC 9 and IVC 10, from 1997 to 1999. He won five of these matches by KO/TKO, with his one loss being the result of a cut stoppage against Artur Mariano in the IVC 2 show on September 15, 1997. The cut was above his left eyelid and opened back up several times, partially because Silva continued to use the cut side of his head to inflict many headbutts on Mariano over the course of the match.^[8] The doctor observed the cut several times before the fight was ended.^[8]

Silva culminated his IVC career by winning the promotion's light heavyweight belt with a submission win over Eugene Jackson in the IVC 10 show on April 27, 1999. It was after this fight that Silva earned the nickname "The Axe Murderer".

Silva participated in one Meca World Vale Tudo event, Meca 2 on August 12, 2000, where he knocked out Todd Medina with muay thai knees.

UFC[link]

Silva entered the Ultimate Fighting Championship on October 16, 1998, at UFC Brazil: Ultimate Brazil, in a match against Vitor Belfort. The match has arguably been Silva's worst defeat in his career, lasting only 44 seconds and ending with Silva being knocked down by Belfort's punches then being stopped by the referee. Silva won his next UFC match on May 7, 1999, at UFC 20 where he knocked out Tony Petarra with knees. On April 14, 2000, Silva was given a chance to fight for the UFC light heavyweight championship, but lost via decision to Tito Ortiz at UFC 25.

Pride Fighting Championships[link]

Silva debuted in Pride at the Pride 7 event on September 12, 1999, winning against Carl Malenko by decision. From 1999 to 2004, Silva won eighteen-straight fights in Pride, excluding a draw against Mirko "Cro Cop" Filipovic (under slightly modified rules in which if the match would go the distance, the bout would be declared a draw) and a no contest against Gilbert Yvel (Silva accidentally kicked Yvel in the groin), giving him a twenty-fight unbeaten streak. Silva's reputation as a formidable MMA fighter grew as he developed a successful 5 year win record in the middle weight division (205 lb) of Pride.

Silva fought Japanese superstar Kazushi Sakuraba for the first time at Pride 13: Collision Course on March 25, 2001. Silva won via TKO (knees and soccer kick) at 1:38 into the first round. At Pride 17: Championship Chaos on November 3, 2001, Silva won the inaugural Pride middleweight (205 lb) championship when he defeated Sakuraba for the second time. Sakuraba suffered a broken clavicle and was forced to withdraw after the first round, giving Silva a TKO win via doctor's stoppage. The two fought for a third time on August 10, 2003 at Pride Total Elimination 2003, part of Pride's middleweight tournament. Silva knocked out Sakuraba with a two punch combination at 5:01 into the first round.

Silva faced Quinton "Rampage" Jackson at Pride Final Conflict 2003 on November 9, 2003. Silva won by TKO after delivering seventeen consecutive knees to Jackson. Silva became Pride's 2003 tournament champion with the win. The two fought again on October 31, 2004 at Pride 28: High Octane. Jackson knocked Silva down near the end of the first round and mounted him as the bell rang. In round two Silva caught Jackson with a counter right hand and followed up with knees from the thai clinch knocking Jackson out, successfully defending the Pride middleweight championship with the win. In Japan, Silva additionally gained his reputation as a fighter who has never been defeated by any Japanese opponent, resulting in a trend of various Japanese fighters being arranged by Pride to face him.

Silva's undefeated 5-year streak (18 wins, 13 knockouts) in Pride was broken by heavy weight Mark Hunt, a K-1 champion on December 31, 2004 at the Pride Shockwave 2004 event. Hunt won the non-title match by split decision. The decision was controversial because some who felt that Hunt's weight of 280 lb (125 kg), over 80 lb more than Silva, as well as Silva's performance in rounds two and three, had not been sufficiently considered by the judges in their decision; Randy Couture and Bas Rutten, both being commentators at the event, expressed disagreement with the judges decision. Silva also took this fight on two days notice. Nonetheless, Silva's 2004 campaign earned him Fighter of the Year honors from both Sherdog and the Wrestling Observer Newsletter.

Silva's former status as Pride's middleweight champion first came under debate and criticism with his loss to Ricardo Arona (who subsequently lost the tournament to Silva's team-mate, Mauricio "Shogun" Rua) on August 28, 2005 at Pride Final Conflict 2005. The loss, by unanimous decision in the tournament's semi-finals, was Silva's first defeat in a middleweight match in Pride; however, since it was not a title fight and held under special rules due to the grand prix format (2 rounds instead of 3), Silva was still recognized as the middleweight champion. A rematch between Arona and Silva took place at the Pride Shockwave 2005 event on December 31, 2005, with Silva winning by split decision.

On May 18, 2006, Pride's parent company, Dream Stage Entertainment (DSE), announced that Silva would replace Pride heavyweight champion Fedor Emelianenko in the Open Weight Grand Prix. Emelianenko's doctors stated that his hand, which had recently undergone surgery, would not be in good enough shape to fight because the metal implant would still be present. Because Silva was also a champion, he received a first round bye and fought in the second round at Pride Critical Countdown Absolute, which took place on July 1, 2006. Silva moved to the semi-finals of the Open Weight Grand Prix after defeating Kazuyuki Fujita by TKO (punches and soccer kicks) at 9:21 of round one.

On July 8, 2006, at UFC 61: Bitter Rivals, UFC president Dana White announced Silva would face Chuck Liddell in a UFC event held in November, provided Liddell beat Renato "Babalu" Sobral at UFC 62. Liddell did end up winning that fight. However, talks dwindled and the fight as advertised did not happen.

On September 10, 2006, at Pride Final Conflict Absolute, Wanderlei Silva was knocked out by Mirko "Cro Cop" Filipovic in their rematch during the Open Weight Grand Prix semi-finals. After a brief stoppage to tend to a swollen eye on Silva, "Cro Cop" struck Silva in the head with a left kick, knocking him out. On October 21, 2006 at Pride 32: The Real Deal, Wanderlei issued his challenge to Chuck Liddell to a fight inside a Pride ring in February, when the promotion returned to Las Vegas, however Dana White stated that the fight would not be happening, citing Silva's recent KO loss to Mirko Filipovic which would have not allowed the NSAC to clear him medically for the fight that soon after being knocked out.

Silva put his Pride middleweight title on the line against Dan Henderson, Pride's welterweight (183 lb) champion at Pride 33: The Second Coming, held on February 24, 2007, in Las Vegas, Nevada.^[9] In a night of upsets, Henderson knocked out Silva in the third round with a left hook to become the new middleweight champion. This fight was held under unified rules which prevent knees and kicks to the head of a downed opponent as well as having five 5 minute rounds. Many believe this hindered Silva's ability to fully utilize his offensive arsenal. Silva was denied the ability to participate in Pride 34 due to medical suspension by the Nevada State Athletic Commission (NSAC) which made this his last Pride appearance.^[10] Silva never lost under pure Pride rules^{[attribution needed]} at 205 pounds.

Return to the UFC[link]

On August 17, 2007, the UFC announced that they had signed Wanderlei Silva to compete in the organization and that he would return to the Octagon on December 29, 2007 at UFC 79.^[12][13] After months of speculation about Silva's opponent, UFC President Dana White announced that Chuck Liddell would be Silva's opponent for his return match.^[14] The long-awaited match happened on December 29, with Wanderlei Silva losing to Chuck Liddell by unanimous decision. After the fight Silva said, "Win or lose I like to give the emotion for my fans"^[15] He also added that he gave his best and promised that next time he will deliver a win.

Keeping to his promise, on May 24, 2008 at UFC 84 in Las Vegas, he earned a decisive knockout win against Keith Jardine at the 36-second mark of the very first round by referee stoppage, earning him Knockout of the Night honors.^[16] When Jardine threw a kick, Silva countered with a right-left-right combo that dropped him. Silva then finished the fight with ground strikes to earn the brutal knockout.

At UFC 92, Wanderlei fought Quinton "Rampage" Jackson, who he beat twice previously in Pride Fighting Championships.^[17] Jackson avenged his previous defeats by knocking Silva out with a left hook in the first round.^[18] Following the fight, Silva stated that he would like to fight Jackson again, for the 4th, and possibly in the future, even the 5th time, knowing he already has two knockouts of Jackson. The two fighters also buried the hatchet after this fight.

Wanderlei met Rich Franklin at UFC 99 in Germany at a catchweight bout of 195 lb.^[19] After a hard fought match on both sides, Silva lost via unanimous decision to Franklin. During the second round, Silva rocked Franklin hard with punches and almost finished the fight during that moment. This was counterbalanced by Franklin dropping Silva three times in that round, each time with singular strikes. Silva then announced he would be out of action until 2010, as he underwent facial surgery to repair his nose (which was broken during Silva's second fight with Cro Cop, and then repeatedly broken again in later matches) and remove some scar tissue from above his eyes to avoid bleeding and being easily cut open during future fights. The surgery allowed him to breathe through a once completely blocked nose thus increasing his oxygen intake by 30% by doctor's estimates. At UFC 110, announcer Joe Rogan emphatically stated that Wanderlei looked like a totally different person in the wake of his recent facial reconstructive surgery.

Silva made his middleweight (185 lb) debut during UFC 110 against British striker Michael Bisping on February 21, 2010.^[20] During the fight Bisping was able to take Silva down several times during the first round, however Wanderlei came back with a flurry of punches at the end of the first round, a tight guillotine choke in the second, and a right hook that dropped Bisping in the third. After three rounds of fighting, Silva was awarded the unanimous decision victory (29–28, 29–28, 29–28)^[21] and his first victory in almost two years.^[22] Although winning only one of his previous 6 bouts, he was slightly favored going into the fight as it was widely speculated that Bisping was apprehensive to fight toe-to-toe after being viciously knocked out by Dan Henderson on July 11, 2009 in UFC 100. After the fight Silva said, “In your life you have bad moments. Everybody has bad moments, but if you believe in God and working hard, good moments they’ll come,” an emotional Silva told the audience. Silva attributed his success to working with his previous trainer Raphael Cordeiro. Bisping added, “Wanderlei’s a great opponent...I felt the reason he got the decision was the knockdown right at the end.”^[23]

Wanderlei Silva was expected to face former K-1 HERO'S Light Heavyweight Champion Yoshihiro Akiyama at UFC 116.^[24] Unfortunately, on June 22, Wanderlei had to pull out due to breaking three ribs during training.^[25] Akiyama would instead be fighting on the card, against Chris Leben. After Leben defeated Akiyama with a triangle choke in the third round Leben verbally called out Silva saying "Come on Wanderlei, I'll take you out too" in his post fight interview.^[26] "He represented very well, he's a good opponent," said Silva of "The Crippler." "I think if he's gonna wait that I'm gonna fight him next however Dana White has not considered a Silva/Leben fight happening anytime soon."^[27]

Silva underwent knee surgery in late July 2010 and his doctors have stated that he will need to wait at least 4 months before returning to training. This means that he will not be seen fighting in the octagon again until early 2011.^[28]

Silva was scheduled to face Brian Stann at UFC 130.^[29] However, after Silva voiced his reluctance to face Stann, he was replaced on the card by returning UFC veteran Jorge Santiago.^[30] On April 4, 2011, the UFC announced that Silva's next opponent would be Chris Leben with the two scheduled to meet at UFC 132.^[31] on July 2, 2011. During the fight's first round Leben won by KO with several uppercuts before following Silva to the ground for a referees stoppage at the 27 second mark.^[32][33] When Dana White was asked about his thoughts on Wanderlei's possible retirement, he said he felt it would be the best time for Wanderlei to retire but in the end it is up to whether Wanderlei himself would like to fight again.

Silva faced Cung Le on November 19, 2011 at UFC 139. Silva defeated Le via second round TKO after a flurry of knees and punches, earning his third Fight of the Night award in the UFC.

Silva and Vitor Belfort will be the coaches for The Ultimate Fighter: Brazil A rematch with Belfort was expected to take place on June 23, 2012 at UFC 147 but due to a broken hand Vitor Belfort had to withdraw from the match.^[34] Silva is now scheduled to face Rich Franklin in a 190 lb catchweight at the event.^[35] Franklin and Silva fought once before at UFC 99, where Franklin won via unanimous decision.

Personal life[link]

Wanderlei and his wife Tea have a son named Thor. He also has a daughter named Rafaela from a previous relationship.^[36][37]

Championships and accomplishments[link]

Mixed Martial Arts[link]

• Ultimate Fighting Championship

• Fight of the Night (Three times)
• Knockout of the Night (One time)
• Most Wins & Knockouts in combined PRIDE FC & UFC History (25 Wins 17 Knockouts)

• PRIDE Fighting Championships

• PRIDE Middleweight Championship 2001-2007 (One time, First)
• 2003 PRIDE Middleweight Grand Prix Tournament Winner
• 2005 PRIDE Middleweight Grand Prix Semi-Finalist
• 2006 PRIDE Openweight Grand Prix Semi-Finalist
• Most Wins & Knockouts in PRIDE FC History (22 Wins 15 Knockouts)
• Most Wins & Knockouts in PRIDE FC Middleweight Division
• Longest Undefeated Streak in PRIDE FC History (20 Fights)
• Longest Win Streak in PRIDE FC History (18 Wins)
• Most Consecutive Title Defenses in PRIDE FC History
• Most Title Defenses in PRIDE FC History
• Most Title Defenses in PRIDE FC Middleweight Division

• International Vale Tudo Championship

• IVC Light Heavyweight Champion

• Sherdog

• 2004 Fighter of the Year [1]

• Wrestling Observer Newsletter

• 2001 Feud of the Year vs Kazushi Sakuraba
• 2001 Shootfighter of the Year
• 2003 Shootmatch of the Year vs Hidehiko Yoshida
• 2004 Shootfighter of the Year
• 2004 Shootmatch of the Year vs Quinton Jackson