Aggression in Psychology

Aggression is a state which is inherent to most people, implying behavior intended at hurting others. This emotion is difficult to define, and psychologists, judges, and lawyers have been trying to determine what actions should and should not be considered aggressive for a long time. To estimate the behavior of others, it is required to analyze the situation and understand the reasons for certain actions. Aggression is also regarded as a negative emotion, which is found in animals as well as in humans. However, the reason for this behavior in the animal world is justified by their fight for food or dominance, while people choose to behave aggressively for multiple reasons. All over the world, psychologists debate on these issues, trying to prove whether the origin of aggression is natural and innate, or it is an acquired behavior. Thus, aggression is a complex state involving consequences both for the individual and people around, generally thought to be caused by a certain part of the brain, in combination with different biological and external factors.

The Types of Aggression

Classification According to the Inflictor

Aggression is a complex notion, implying a negative emotion or action directed at another individual. According to the World Health Organization, it is “the intentional use of physical force <…> against oneself or someone else or against a group or society, what causes <…> physical damage, psychological pain, <…> or deprivation” (World Health Organization, n.d. , para. 2). Based on this definition, there is a developed classification of the types of aggression, dividing them, depending on the addressee or originator:

  • Auto-aggression, meaning violence, is directed at oneself. It implies suicide, or its attempt, or self-wounding;

Interpersonal violence, directed at a partner or a relative. It is often manifested through

  • domestic violence, as well as aggression towards unknown individuals. This group includes acts, such as rapes, aggression in schools and workplaces, and others;
  • Group violence, which is characterized by instrumental use of aggression by the members of a certain social group against other communities. This type includes genocide, repressions, terrorism, and armed conflicts.

From this perspective, aggression is a trait which combines numerous characteristics and can manifest itself in different ways, depending on the situation.

Classification According to the Character of the Incident

There is another classification of the types of aggression, based on the ability of a person to cope with their emotions. It divides the types of aggression into three major groups: impulsive, proactive, and psychotic (Çetin, 2017). The most common category is impulsive aggression (54%), followed by proactive (also known as organized, instrumental, or predatory) aggression (29%), and psychotic aggression (17%) (Çetin, 2017). The last type is related to obvious symptoms of psychosis, including hallucinations or delusions. In proactive aggression, a person tends to achieve a certain goal, such as gaining money or taking revenge with the help of aggressive behavior. Impulsive type is usually associated with the feelings of fear, or anger, manifested by threat, stress, or provocation. This classification highlights the importance of careful research of the most widespread category of aggression, connected with emotional behavior under certain circumstances when a person cannot cope with an impulse.

Classification According to the Type of Manifestation

Psychologists also distinguish two major types of aggression: verbal and physical. Physical violence involves inflicting damage to other people and may include hitting, kicking, or even shooting. The verbal type does not involve harm for the body but is manifested through oral forms of violent behavior, such as yelling, swearing, calling names, bullying, gossiping, spreading rumors, turning people against others, and many others. Recently, technological advance has led to the appearance of another variation of verbal aggression, which seriously impacts children. It is called cyberbullying, and it is inflicted through computers, smartphones, and other electronic devices. It is violence, which can be directed at any student; however, the most frequently chosen targets are minority groups, such as LGBT.

It is obvious that physical aggression causes real damage to the body of another person, while the consequences of verbal type are more complex and not always seen on the surface. For example, children, being the victims of bullying, appeared to be more prone to depression and anxiety than their peers. Those who faced aggression and violence tend to remain lonely and reject the company of their friends. They often begin to experience various forms of stress as a result of this event, including psychological disorders, smoking, alcohol abuse, and even suicide. In addition to its influence on emotions, verbal forms of aggression also have a negative effect on people’s success and performance at school or at work.

The Nature and Reasons of Aggression

Brain Regions Responsible for Aggression Appearance

Studies have shown that subcortical brain regions, especially the limbic system and the amygdala, are associated with emotions. The amygdala is “an almond-shaped structure located bilaterally in the temporal lobes. Its average size in humans ranges from 1.24 to 1.63 cm³” (Gouveia et al., 2019, para. 18). This part of the brain plays an important role in processing threatening stimuli and creating behavioral and neuroendocrine responses, helping the human organism to adapt to social and environmental circumstances and changes. The amygdala is connected with the cortical areas, and it is “responsible for information processing that subserves emotion, learning, motor control, cognition, decision-making and social interaction (Gongora et al., 2019, p. 2379). This part of the brain is situated between the emotional center and the cerebral cortex, and in case of its damage, there may be a loss of negative feelings suppression, appearing as a response to provocative stimuli.

There are two possible sequences in the process of irritant detection which define the person’s reaction. The first one “follows the cortex sensory pathways and then is sent to the amygdala, <…> and subsequently investigates the “importance” (Gongora et al., 2019, p. 2390). The other one goes directly to the amygdala and “generates emotional and behavioral responses without immediate awareness” (Gongora et al., 2019, p. 2390). The amygdala mediates and controls a wide range of emotions, such as love, affection, fear, anger, and aggression. This regulation is necessary for self-preservation by identifying the disturbance and creating a feeling of anxiety, alertness, and others. Moreover, numerous studies have shown that the amygdala is a major structure in numerous conditions, such as simple mood disorders and even such complex illnesses as autism and schizophrenia. Thus, it is an important part of the brain, which is responsible for a variety of mental processes, including the appearance of negative emotions, such as aggression and violence.

Biological Factors Influencing Aggression

Apart from the processes in the brain, there are also a number of biological factors influencing the appearance of aggression, such as hormones, specifically, testosterone and serotonin. There is an established link between impulsive anger and serotonin in the prefrontal cortex, as this hormone is a neuromodulator, which is associated with a developmental signal. It has a “critical role on the regulation of essential events in neuronal and glial development, such as cell proliferation, differentiation, migration, apoptosis, and synaptogenesis” (Çetin et al., 2016, para. 1). This hormone is considered to play a key role in a variety of mental conditions, such as anxiety and autism spectrum, due to its multifunctional performance. In addition, a serotonergic system is generally thought to predominate on two important endophenotypes: impulsivity and aggression (Çetin et al., 2016). Numerous researches suggested that this hormone is associated with impulsive aggression, meaning the type where a person acts under the weight of a certain emotion, having no time to think about their reactions.

The male sex hormone testosterone is also important in regard to the aggression appearance, and it is usually associated with increased violence in animals, as well as in humans. Testosterone is critical in the arousal of the negative behavior manifestations in the brain areas, which are responsible for aggression. However, the relationships between this hormone and anger are only correlational, as it does not provoke violence but increases under the influence of negative emotions. It is proven that the levels of testosterone are higher in individuals with aggressive behavior, such as criminals. Multiple studies have also shown that the hormone levels increase during the active phases of sports games, and they are especially high in the winners of competitions. Testosterone participates in the activation of the amygdala, which, in turn, gives rise to the process of emotional appearance and the resistance to maintaining control. Thus, this hormone influences the subcortical areas of the brain and plays an important part in aggression production together with serotonin.

External Factors Influence

Apart from physiological and biological factors, there are external influences which can become a reason for violent behavior. Numerous experts have proven that alcohol or drug abuse is one of the problems with a serious impact on emotions. There are numerous drugs that “distort perceptions and change mood — drugs that take you up, let you down, and move you across town” (Rathus, 2016, p. 107). The use of substances increases the chances that people will respond aggressively to provocations. Even those individuals who are usually non-violent can show signs of anger when being intoxicated. There are two reasons capable of explaining why this can happen. First, alcohol and drugs destroy executive functions, the cognitive abilities helping people plan, organize, and control emotions and behavior. Second, when being intoxicated, people become more self-focused and less aware of their surroundings; as a result, they tend not to notice the social constraints which typically prevent them from anger manifestation.

Another factor influencing the aggression is the environment in which a person grows. In case an individual is constantly facing various forms of aggression and violence, they tend to think that such behavior is normal and acceptable in society. The famous Bobo doll experiment proved that observing the aggressive behavior of others can play a significant role in learning this pattern (Cherry, 2020a). The research has demonstrated that children who watched a video showing an adult aggressively treating a doll later imitated those actions, thus, proving that the environment is one of the keys to violent behavior. In addition, there is a chance that genes also contribute to aggression, as the behavior patterns of an individual are often inherited. There is a science called behavioral genetics, which focuses on this aspect (Rathus, 2016). It suggests the traits causing certain patterns are transmitted by genes, making heredity the major factor of almost all the mental and personality processes.

Aggression has also been proven to be influenced by the surrounding nature. For example, one of the researches has shown that neighborhood green space is beneficial for reducing aggressive behaviors of people living there (Younan et al., 2016). There are a few possible reasons which could explain this paradox. First, exposure to greenery can improve mental health by reducing the level of stress and helping to cope with depression signs. Second, it encourages participation in physical activities, which is, in turn, capable of improving self-esteem and the general mental state. Third, modern air pollution and the level of noise are proven to contribute to aggressive behavior development, and green space may reduce their levels. Implying that the surrounding nature plays a significant role in supporting mental health, these reasons are able to cause negative emotions, such as aggression, when combined with other inner and external factors.

Factors Mediating Aggression

There are three inner processes occurring in each individual, which can have an impact on the risks of aggression development. The first one is the effect of emotions, as many of them can increase the chances of violence. For example, anger contributes to it through reducing inhibitions, as well as shame, making an individual feel as if their flaws are exposed to public, and jealousy, which is meaningful in cases with intimate partner violence. According to the research, “the anticipation of how one will feel in the future can be as important as how one currently feels in determining whether a person will be aggressive” (Warburton & Anderson, 2015, p. 379). Certain emotions can also help in fighting aggression, for example, empathy, which implies having concern for other people.

The second category in this classification is about cognition, which is thought to underlie aggression. It includes attitudes, perceptions, expectations, beliefs, and more complex notions such as scripts. According to the studies, “a variety of external triggers can increase the accessibility of aggressive cognitions in semantic memory” (Warburton & Anderson, 2015, p. 379). They can supposedly identify an aggressive behavioral pattern with the help of aggression-related actions or through the activation of aggressive behavior scripts. The last category implies the physiological and emotional arousal of a person. It is proven to increase aggression, regardless of the causes of this arousal, as a person under its influence has more chances to succumb to an impulse without properly thinking about the consequences. Meanwhile, low levels of arousal decrease the level of aggression because people in these cases lack the energy and motivation and not capable of demonstrating intense emotions.

Individual Factors and Signs of Aggression

Signs and symptoms of aggression include a big range of manifestation, which can point at the fact that a certain person can be potentially violent. Among the physical signs are huffing, rapid movements, facial expressions, such as staring or frowning, raised voice, aggressive actions, such as throwing objects in frustration, swearing, or threats. There are also mental issues capable of indicating the developing anger, including a feeling of anxiety, mood swings, agitation, disorientation, memory problems, depression, problems with concentration, poor communication skills, and proneness to conflicts. Aggression can also be accompanied by symptoms, influencing other body systems, including the change of appetite, a feeling of fatigue, seizures, and tremors. In addition, aggression may be a symptom of more serious mental conditions. Violent behavior can be a signal a person experiences a psychiatric or cognitive disorder, including antisocial personality disorder, autism, dementia or Alzheimer’s disease, post-traumatic stress disorder, schizophrenia, and others. In such a case, the individual requires an immediate help of a specialist, as being in serious stages of a disease, they can present danger to themselves and the people around them.

There are also numerous personal factors, which are capable of increasing the chances of aggressive behavior development. For one, there is an established connection with gender, as men are generally more aggressive than women. It can be noted since early childhood and continues through the whole lifespan. However, females prove to be more aggressive in case of strong provocations, while males tend to show better resistance to them. Impulsivity is another factor influencing the aggression outbursts, implying that temperament plays a big role in predicting violence. This trait is usually noticed since early infancy because impulsive individuals have difficulties with coping with their emotions. On the contrary, people show less aggression when they have better control over their reactions. Finally, there are assumptions about the connection between aggression and intelligence. Low IQ is supposedly linked to higher levels of aggression, especially in children. However, there is still not enough research on this hypothesis to prove it, but there is enough evidence to confirm that all the individual traits have a certain impact on the person’s reactions.

The Particularities of Aggression in Children

Aggression is an important issue when it concerns children, as violent behavior for them can be a method of shouting for help and attracting parental attention. Such a child gives signals demonstrating the lack of love and care and the feeling of neglect. In addition, it is estimated that children spending much time in front of their gadgets tend to show more signs of violent behavior than those who prefer other activities. Certain signs point that a child has problems because of their absorption with screens; they are irritability, mood swings, low tolerance, sleep deprivation, disorganized behavior, poor short-term memory, and problems with learning. In case the reason for inappropriate behavior is in gadgets, their removal for a couple of weeks solves the problem. In addition, it needs to be considered that certain mental problems such as autism, attention deficit hyperactivity disorder (ADHD), or Post-Traumatic Stress Disorder (PTSD) also impact the child’s behavior and may cause episodes of aggression. In this case, there should be a specific medical treatment which would help with managing brain processes and, thus, would discard the symptoms.

In addition, children’s behavior is directly correlated with the environment they grow in. In case a person constantly witnesses aggression and violence, there is a big chance that they will begin demonstrating the same patterns. A good example proving this thesis is a famous Bobo Doll Experiment, which exposed children to different adult models: one of them was being violent, while the other one was non-aggressive. After watching the examples of behavior, children were left in the room, where specialists observed their actions to see if they would repeat the patterns they witnessed. The experiment showed that:

  • children of both genders in the non-aggressive group demonstrated less aggression;
  • those who observed the violent model imitated the witnessed behavior;
  • boys showed more aggressive actions than girls;
  • boys who have observed adult males were more violent than those who were looking at a female model, and they were mostly involved in physical acts of violence, while girls preferred verbal aggression (Cherry, 2020b).

The experiment proved that behaviors are learned through observation and imitation. When children see adult models demonstrating violent behavior, it makes them believe that such actions are acceptable, and tend to repeat them when they have a chance. It also implies that these children may be more liable to aggression manifestation in the future. Thus, the environment, in which a person grows up, is one of the major factors, influencing the possibilities of the aggressive behavior development, impacting the whole life of this individual.

Consequences of Aggression

Health Impact of Aggression

Aggression and violence involve serious consequences for the health of the person, influencing the brain, neuroendocrine and immune systems. Such negative emotions can eventually damage many systems of the body. For example, a person may experience headaches, digestion problems, insomnia, and even mental problems. Exposure to aggression is connected with three important spheres: increased mortality, morbidity, and disability (Friborg et al., 2015). There are such common consequences as increased psychological morbidity, including depression, suicide ideas, substance abuse, or post-traumatic stress disorders. The risks of chronic functional problems and disability pension are also higher when facing violence. Negative life events, especially the presence of aggression, are associated with various health problems, such as infections, cardiovascular disease, colorectal cancer, or skin problems. The risk of mental illnesses is also higher in this case and may result in major depression or even schizophrenia. Moreover, these negative episodes may have an impact on concentration and memory and can become a reason for poor performance at school or at work.

In addition, it is suggested that women and men experience aggressiveness differently, thus, facing diverse consequences. Negative emotions have a bigger impact on women, inflicting more damage to their mental state. An analysis of domestic violence confirmed that such psychological conditions as depression are more typical for females (Friborg et al., 2015). Meanwhile, men suffer from somatic health problems more frequently than women. It shows that gender determines many possible outcomes of the aggression manifestation; however, its impact is serious in all the cases, the difference is only in the health area, which is harmed by such an experience.

Social Outcomes of Aggression

Aggression and violence are not normal for society, as they lead to loss of trust in other people, difficulties in concentrating and performing at school or work. For example, for children, self-evaluation usually depends on their peers and social identification among them. Thus, aggression manifestation tends to lower self-esteem, which leads to a further decrease of performance and social exclusion. However, for adolescents, there are two possible patterns of the outcome, as some aggressive individuals remain lonely because they are rejected by their peers, while others can become leaders among their friends. In order for aggressive children to become successful, they need to master many skills and prove their peers they are reliable and capable of controlling themselves. Thus, adolescents demonstrating signs of aggression can have both advantages and disadvantages depending on the situation and context of certain relationship.

From a social perspective, aggression may also lead to criminality, thus, influencing the life of the whole community. Violence is typically characterized by destructive consequences, which often may involve illegal activities, contradicting the existent norms and rights. However, there is a concept of constructive violence, implying actions, violating the current laws, but not ruining society’s expectations, for example, when an individual attacks another person when saving their family. Thus, aggression is a complex concept, often difficult to estimate, and always depending on the norms of morality set in certain community.

Treatment Opportunities

Aggression and violence should always be under control as they are the most destructive emotions causing much damage and, in many cases, leading to criminal deeds. For adults, treatment involves the use of medications and psychotherapy. One of the most effective measures for helping an individual susceptible to aggression manifestation is various types of therapy, such as cognitive-behavioral therapy, applied behavior analysis, and electroconvulsive therapy. According to the estimations of experts, these practices lead to positive outcomes, including “the alliance between the client and the therapist, as well as the therapist’s empathy, listening skills, and positive regard for the client” (Rathus, 2016, p. 350). Moreover, there is a concept of behavior therapy, also known as behavior modification, directly influencing the patient’s performance by helping them fight destructive patterns (Rathus, 2016). In addition, people susceptible to aggression need support and encouragement from others to be able to control their behavior and not allow negative emotional outburst. It is always useful to be aware of the triggers, which make an individual show signs of aggression, trying to eliminate them, and develop strategies which could help.

In addition to therapy, there are numerous opportunities for pharmacological treatment of aggressive behavior, involving “different classes of medications, such as typical and atypical antipsychotics, antidepressants, benzodiazepines, alpha 2 agonists, mood stabilizers, and anticonvulsants” (Gouveia et al., 2019, para. 7). Typical antipsychotics include dopaminergic antagonists, which proved to be effective for children with conduct disorders, psychotic patients, and cognitively impaired individuals. Atypical antipsychotics, for example, risperidone, act on multiple neurotransmitter systems and can also be effectively used for treating those groups of patients. Antidepressants are commonly prescribed in order to reduce the signs of aggression and irritability in patients with such diseases as depression, Alzheimer’s, autism, psychosis, and personality disorders. For individuals with intellectual and physical disabilities and for children with conduct-disorder, mood stabilizers, such as lithium, are also widely used. The treatments with medications should always be carefully controlled by doctors, and the curative scheme may be changed according to the needs of a certain patient. In some cases, it is required to lower or increase the dose, while in others, the change of the drug or a combination of different medications may be required.

Moreover, in case the conditions concern children, there are more ways for fighting signs of aggression with psychological methods and therapies. One of the best ways to cope with violence is to serve as a good example, be consistent with demands and praise good behavior. In addition, a limitation for screen time may be required in most of the cases. Moreover, there are different types of art therapy which can be helpful with violent behavior, such as drawing, sand, dancing, and others. With children, medical treatment can be recommended by doctors in cases of serious mental disorders. The treatment scheme usually includes such antipsychotics as risperidone, olanzapine, quetiapine, ziprasidone, and aripiprazole, aimed at discarding symptoms of mental problems. Thus, the medicine of the 21st century has many ways of helping people with various mental problems, including those, which are manifested through symptoms, such as aggression. It gives an opportunity for people with these conditions to have a normal life in society.


For a long time, psychologists have been researching human aggression, which resulted in the appearance of important knowledge about the types of factors, increasing the risks for aggression development. It is proven that aggression and violence are widespread emotions, which are encountered every day. Moreover, it is established that this state is a connection of humans with animals, representing a big problem as such behavior is not appropriate for life in society as it causes many damages. Experts proved that the feeling of anger is connected with certain parts of the brain, which control negative feelings and typically stop people from demonstrating signs of aggression. However, there are health conditions, external factors, and personal issues, which can impact these brain areas and lead to the loss of emotional control. In order to cope with this problem, modern therapy offers different opportunities for receiving psychological help in combination with medications. Today, science has unique techniques for helping both children and adults by providing them with a qualified therapy aimed at supporting patients and aiding them in overcoming the symptoms of a disease. Thus, it allows people with such problems to live a normal life in the community.


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