Aggression

Aggression: Psychology

Aggression in psychology refers to behaviours that could harm yourself and others or could affect objects in the environment. This harm can be physical or psychological.

How do we, then, measure aggression in psychology? This can be done in several ways, mainly by counting how many times a person is aggressive in response to a stimulus or trigger and the intensity of the aggression on a scale/ratio.

Types of Aggression

What kind of behaviour do scientists count as aggressive? There are a few ways aggression can be observed to be studied. To generalise, there are three types of aggression:

• Reactive-expressive (being verbally and physically aggressive).
• Reactive-inexpressive (being hostile and displaying antipathy).
• Proactive-relational aggression (being vicious towards others, impacting relationships).

Several theories on the types of aggression causes are explored using biological, social and psychological explanations.

Causes of Aggression in Psychology

According to psychology, potential reasons implicated in the causes of aggression include neuronal and hormonal mechanisms, genetic, ethological, and evolutionary explanations, and social learning theory explanations. Psychology also explores the influence of institutions on aggression and media influences.

Neural and Hormonal Mechanisms

Here, we consider the limbic system and the effects serotonin, testosterone, and cortisol have on aggression.

The Limbic System

The limbic system plays an important role in regulating emotional behaviours and includes structures such as the hypothalamus, the hippocampus, and the amygdala. The amygdala is particularly important in aggression. When stimulated in animal studies, animals show more aggressive behaviours. When removed, however, they showed less or no aggressive behaviours.

Fig. 1 - The limbic system comprises the amygdala, the hippocampus, and other notable structures.¹

Serotonin Research

Serotonin is a neurotransmitter. It has widespread inhibitory effects on the brain. When considering aggression, normal serotonin levels in the orbitofrontal cortex (OFC) correlate with greater self-control (inhibiting impulsive behaviour). Decreased levels of serotonin reduce self-control and may increase impulsivity.

This is the serotonin deficiency hypothesis: decreased serotonin levels cause a reduced inhibitory effect, affecting the OFC and causing more impulsive and aggressive behaviours.

Testosterone and Cortisol Research

Testosterone is an androgen, a hormone controlling the development of male characteristics. It is produced in the gonads (male testes and female ovaries) and the adrenal cortex. It is suggested that testosterone is linked to aggression due to the correlation between men having higher testosterone levels and committing more aggressive acts than women.

Cortisol is a stress hormone. Nearly every cell in the body has receptors for cortisol, so its effects vary. Usually, it aids in the body’s response to chronic stress, affecting the immune system, muscles, and so on. The Fearlessness Theory suggests stress induced by cortisol can inhibit aggression through fear.

Genetic, Ethological, and Evolutionary Explanations

Aggression is affected by hormones and neurotransmitters. So, where genetics are concerned, genes play an important role in affecting the production of these components, which, in turn, affects aggression.

Genetic Explanations for Aggression

According to Popova (2008), behaviours such as attacking, defending, and other aggressive traits that apply to animals and humans are specifically related to serotonin as it modulates these behaviours. Namely, the functioning of a serotonin system relies on:

• Synthesis (making) and appropriate degradation (scrubbing away) of serotonin. Serotonin uptake.
• Serotonin 5-HT receptors/degradation.
• Genes such as the PET-1 gene (covered in more detail elsewhere).

Monoamine oxidase A (MAOA; the warrior gene) gained notoriety in a 2006 study by Dr Rod Lea on New Zealand Māori men. It was suggested that those with the warrior gene exhibit higher levels of aggressive behaviours in response to provocation.

The MAOA gene codes for the production of the enzyme involved in breaking down neurotransmitters in the synapses between neurones. This is especially true for serotonin. When variants of this gene occur, it can result in lower enzyme production, causing neurotransmitters to remain in the synapse for longer, resulting in brain and behaviour dysfunction.

Gender and Aggression

Considering the association certain hormones have on aggression, Gender may play a role in aggressive behaviour tendencies. The super-male hypothesis, established by Sandberg (1961) suggests the mutation of the XYY chromosome in males would lead to more aggression. Multiple studies indicate that gender does have some role in aggression.

Fig. 2 - Aggression can come down to a person's DNA.

Ethological Explanations of Aggression

Aggression can be studied and explained by analysing non-human animal behaviours and comparing them to humans. This kind of study is known as ethology.

Konrad Lorenz suggested that aggression in animals is innate, an instinctual process to help species maximise their resources (food, space, and other necessities). Fights within species occur till one backs down, not to death, to avoid killing off their own species. This is why some animals growl or snarl as a warning first, known as an innate releasing mechanism (IRM).

IRMs lead to Fixed Action Patterns (FAPs), which are an ethological term used to describe instinctive behaviours in a species, usually an action in response to a stressor.

The animals have a fixed action pattern when faced with a particular releasor. In effect, an IRM is where a neural sensorimotor interface links and creates a response between a stimulus and the fixed action pattern (Ewert, 2013). Once the IRM occurs, the FAP will occur after and cannot be stopped.

Evolutionary Explanations of Aggression

Evolutionary explanations of aggression cite natural selection as a large part of why aggression has developed the way it has in humans. Therefore, aggression is an adaptive response that serves a purpose in both survival and reproduction. If an animal's last piece of meat is being fought for by a competing animal, an aggressive act to secure it will increase each animal’s chance of survival if they choose to fight for it and win.

It is essentially us vs them.

The behaviour the outgroup exhibits is undesirable to the ingroup.

Social Learning Theory of Aggression

Social-psychological explanation of aggression includes social learning theory, including reference to Bandura's study, the Bobo Doll Experiment, deindividuation and the influence of media. Social-psychological explanations of aggression suggest children learn by observing others.

Bandura and the Bobo Doll Experiment

The social learning theory of aggression claims aggression is learned through observation, imitation, and reinforcement (positive or negative, direct or vicarious). The Bobo Doll experiment supported Bandura’s claims, showing that children can learn behaviours through observation alone.

In this experiment, in contrast to the control group, the children exposed to aggressive behaviours tended to exhibit aggressive behaviours themselves as a result.

Institutional Theories of Aggression in the Context of Prisons

Institutional theories of aggression in the context of prisons involve the situational approach and the dispositional approach.

The situational approach (Sykes, 1958) is that prisons make people more aggressive due to the deprivation of their liberties, rather than the prisoners being at that level of aggression before sentencing (the pains of imprisonment). This is where the manifestation of aggression is placed on the institution and organisation, focused on the hierarchy in place.

The dispositional approach uses the importation model and focuses on the behaviour and beliefs of prisoners before they enter prison. Irwin and Cressey (1962) argued that prisoners were often violent and aggressive before prison and, therefore, naturally inclined to behave this way inside prison.

Fig. 3 - Aggression was high in the Stanford Prisoner Experiment.

Media Influences on Aggression

Media use has risen considerably in recent years. As a result, some have hypothesised that this increase has caused issues with aggression. The blame for aggression has often been pinned on different media sources. The common trend today is to target computer games that use violence.

Different theories support and disprove this idea. Learning Theories are referenced (i.e., Skinner, Anderson and Drill, Bandura), alongside the general aggression model and the neurological effects of media influences on aggression.

Media influences consider:

• Cognitive Priming
• Desensitisation
• Disinhibition

Each suggests that prolonged exposure to violent media influences people's reactions to feeling angry and seeing aggressive behaviour in real life, normalising aggression.

Frustration-Aggression Theory

The frustration-aggression theory states that frustration leads to aggressive behaviours resulting from an inability to do a certain action or reach a certain goal. Due to this, a need to release this energy occurs and the frustration is released as aggression, sometimes to a source that isn’t the main cause of the frustration.