In
biology
Biology is the scientific study of life and living organisms. It is a broad natural science that encompasses a wide range of fields and unifying principles that explain the structure, function, growth, History of life, origin, evolution, and ...
and
behavioural psychology, social defeat refers to the physiological and behavioral effects on the losing party in a confrontation among animals of the same species, or in any kind of hostile dispute among humans. Social defeat can potentially greatly affect an individual's control over resources, access to mates, and social position, and the term is used in both
dyadic (one-on-one) and group-individual contexts.
Background
Research on
social stress
Social stress is stress that stems from one's relationships with others and from the social environment in general. Based on the appraisal theory of emotion, stress arises when a person evaluates a situation as personally relevant and perceives ...
has accumulated a useful body of knowledge, providing perspective on the effects of detrimental social and environmental interaction on the brain. Research and experimentation suffer from many methodological difficulties: usually a lack of ecological validity (similarity with natural conditions and stressors) or are not amenable to scientific investigation (difficult to test and verify).
Social psychology
Social psychology is the methodical study of how thoughts, feelings, and behaviors are influenced by the actual, imagined, or implied presence of others. Although studying many of the same substantive topics as its counterpart in the field ...
approaches to human
aggression
Aggression is behavior aimed at opposing or attacking something or someone. Though often done with the intent to cause harm, some might channel it into creative and practical outlets. It may occur either reactively or without provocation. In h ...
have developed a multitude of perspectives based on observations of human phenomena such as bullying, mobbing, physical and verbal abuse, and relational aggression. Despite the richness of theories developed, the body of knowledge generated has not satisfied scientific requirements of
testability
Testability is a primary aspect of science and the scientific method. There are two components to testability:
#Falsifiability or defeasibility, which means that counterexamples to the hypothesis are logically possible.
#The practical feasibilit ...
and
verifiability
Verification or verify may refer to:
General
* Verification and validation, in engineering or quality management systems, is the act of reviewing, inspecting or testing, in order to establish and document that a product, service or system meets ...
.
Animal studies of within-species aggression developed in two main branches. One approach is based on laboratory experiments in controlled conditions, which allows the measurement of behavioral,
endocrine
The endocrine system is a messenger system in an organism comprising feedback loops of hormones that are released by internal glands directly into the circulatory system and that target and regulate distant organs. In vertebrates, the hypotha ...
and
neurological
Neurology (from , "string, nerve" and the suffix -logia, "study of") is the branch of medicine dealing with the diagnosis and treatment of all categories of conditions and disease involving the nervous system, which comprises the brain, the s ...
variables, but requires the application of unnatural stressors (such as foot-shocks and restraint stress) in unnatural conditions (laboratory cages rarely approximate native habitats), which potentially limits the applicability of results to natural conditions. Another is based on observations of animals in naturalistic settings, which avoids artificial environments and unnatural stresses, but usually does not allow the measurement of physiological effects or the manipulation of relevant variables.
In real life situations, animals (including humans) have to cope with
stresses generated during their interactions with other members of their own species, especially due to recurrent struggles over the control of limited resources, mates and
social positions.
Social defeat is a source of chronic
stress in animals and humans, capable of causing significant changes in behaviour, brain functioning,
physiology
Physiology (; ) is the science, scientific study of function (biology), functions and mechanism (biology), mechanisms in a life, living system. As a branches of science, subdiscipline of biology, physiology focuses on how organisms, organ syst ...
,
neurotransmitter
A neurotransmitter is a signaling molecule secreted by a neuron to affect another cell across a Chemical synapse, synapse. The cell receiving the signal, or target cell, may be another neuron, but could also be a gland or muscle cell.
Neurotra ...
and
hormone
A hormone (from the Ancient Greek, Greek participle , "setting in motion") is a class of cell signaling, signaling molecules in multicellular organisms that are sent to distant organs or tissues by complex biological processes to regulate physio ...
levels, and health.
[
]
History
The social defeat approach originated from animal experiments, using the "resident-intruder" paradigm
In science and philosophy, a paradigm ( ) is a distinct set of concepts or thought patterns, including theories, research methods, postulates, and standards for what constitute legitimate contributions to a field. The word ''paradigm'' is Ancient ...
, in which an animal was placed in the cage of another animal or group of animals of the same species, in a manner that allowed a non-lethal conflict. It has been documented to produce anxiety-like and depressive-like behavioral declines in susceptible mice.
If animals are allowed to fight on a single occasion only, it is usually regarded as a model of acute stress; if they are allowed to fight on several occasions, on different days, consecutive or not, it is regarded as a model of chronic stress.
After the defeat or in the interval between fights, the subordinate animal may also be exposed to threats from the dominant one, by having to stay in a cage or compartment beside or nearby the dominant, exposed to its visual or olfactory cues.
Later, the social defeat approach was also applied to observations of intra-species aggression in the wild, which suggested that the hypotheses generated in artificial laboratory settings can also be applied in observed in natural settings.
In humans
It has been proposed that animal models of social conflict may be useful for studying a number of mental disorders, including major depression
Major depressive disorder (MDD), also known as clinical depression, is a mental disorder characterized by at least two weeks of pervasive low mood, low self-esteem, and loss of interest or pleasure in normally enjoyable activities. Intro ...
, generalized anxiety disorder
Generalized anxiety disorder (GAD) is an anxiety disorder characterized by excessive, uncontrollable and often irrational worry about events or activities. Worry often interferes with daily functioning. Individuals with GAD are often overly con ...
, post-traumatic stress disorder
Post-traumatic stress disorder (PTSD) is a mental disorder that develops from experiencing a Psychological trauma, traumatic event, such as sexual assault, domestic violence, child abuse, warfare and its associated traumas, natural disaster ...
, drug abuse
Substance misuse, also known as drug misuse or, in older vernacular, substance abuse, is the use of a drug in amounts or by methods that are harmful to the individual or others. It is a form of substance-related disorder, differing definitions ...
, aggressive psychopathologies, eating disorders
An eating disorder is a mental disorder defined by abnormal eating behaviors that adversely affect a person's health, physical or mental health, mental health. These behaviors may include eating too much food or too little food. Types of eatin ...
and schizophrenia
Schizophrenia () is a mental disorder characterized variously by hallucinations (typically, Auditory hallucination#Schizophrenia, hearing voices), delusions, thought disorder, disorganized thinking and behavior, and Reduced affect display, f ...
.
The social defeat model has been extended to include observations of human aggression, bullying
Bullying is the use of force, coercion, Suffering, hurtful teasing, comments, or threats, in order to abuse, aggression, aggressively wikt:domination, dominate, or intimidate one or more others. The behavior is often repeated and habitual. On ...
, relational aggression
Relational aggression, alternative aggression, or relational bullying is a type of aggression in which harm is caused by damaging someone's relationships or social status.McGrath, Mary Zabolio (2006). ''School Bullying: Tools for Avoiding Harm a ...
, chronic subordination and humiliation
Humiliation is the abasement of pride, which creates mortification or leads to a state of being Humility, humbled or reduced to lowliness or submission. It is an emotion felt by a person whose social status, either by force or willingly, has ...
. The social defeat model attempts to extend animal studies to include human behaviour as well, in contrast to the study of aggression in social psychology, in which comparisons are drawn exclusively from experiments involving humans.[
Bullying has interesting parallels with animal models of social defeat, the bully being equivalent to the dominant animal and the victim the subordinate one. Similarly at stake are possession of and access to resources, social position in the group through in-group prestige, and the potential consequential lack of access to mates, including for socio-sexual behaviors like copulation. Human victims typically experience symptoms like low self-esteem (due to low regard by the group), feelings of depression (due to unworthiness of efforts), social withdrawal (reduced investments in the social environment), anxiety (due to a threatening environment), and they can also be shown to experience a plethora of physiological effects such as increased corticosterone levels, and a shift towards sympathetic balance in the autonomic nervous system.][
Research about human aggression, usually conducted by psychologists or social psychologists, resembles to a great extent the research about social defeat and animal aggression, usually conducted by biologists or physiological psychologists. The different disciplines use different terminologies for similar concepts however, which hinders communication between the two bodies of knowledge.][
Similarly, research on depression has employed similar constructs, such as ]learned helplessness
Learned helplessness is the behavior exhibited by a subject after enduring repeated aversive stimuli beyond their control. It was initially thought to be caused by the subject's acceptance of their powerlessness, by way of their discontinuing att ...
, although that theory is focused on the perceived inability to escape any sort of negative stimuli rather than on social factors.
Behavioral and physiological effects
Social defeat is a very potent stressor
A stressor is a chemical or biological agent, environmental condition, external stimulus or an event seen as causing stress to an organism. Psychologically speaking, a stressor can be events or environments that individuals might consider dema ...
and can lead to a variety of behavioral effects, like social withdrawal (reduced interactions with conspecifics), lethargy (reduced locomotor activity), reduced exploratory behavior (of both open field and novel objects), anhedonia (reduced reward-related behaviors), decreased socio-sexual behaviors (including decreased attempts to mate and copulate after defeat), various motivational deficits, decreased levels of testosterone in males (due to a decline in the functionality of the Leydig cells of the testes), increased tendencies to stereotyped behaviours and self-administration of drugs and alcohol.
Research also implicates that the referred behavioral effects are moderated by neuroendocrine phenomena involving serotonin
Serotonin (), also known as 5-hydroxytryptamine (5-HT), is a monoamine neurotransmitter with a wide range of functions in both the central nervous system (CNS) and also peripheral tissues. It is involved in mood, cognition, reward, learning, ...
, dopamine
Dopamine (DA, a contraction of 3,4-dihydroxyphenethylamine) is a neuromodulatory molecule that plays several important roles in cells. It is an organic chemical of the catecholamine and phenethylamine families. It is an amine synthesized ...
, epinephrine
Adrenaline, also known as epinephrine, is a hormone and medication which is involved in regulating visceral functions (e.g., respiration). It appears as a white microcrystalline granule. Adrenaline is normally produced by the adrenal glands a ...
, norepinephrine
Norepinephrine (NE), also called noradrenaline (NA) or noradrenalin, is an organic compound, organic chemical in the catecholamine family that functions in the brain and human body, body as a hormone, neurotransmitter and neuromodulator. The ...
, and in the hypothalamic-pituitary-adrenal axis, locus ceruleus and limbic system
The limbic system, also known as the paleomammalian cortex, is a set of brain structures located on both sides of the thalamus, immediately beneath the medial temporal lobe of the cerebrum primarily in the forebrain.Schacter, Daniel L. 2012. ''P ...
s. In separate studies, defeat behaviors can be modulated by acetylcholine.
A useful concept in understanding the causal relationship between these behavioral and neuroendocrine effects is that of the 'causal chain', in which recurrent evolutionary events, in this case intra-specific competition, generate selective pressures that influence a whole species. Physiological phenomena may therefore evolve to facilitate adaptive patterns of action by individuals. According to this framework, selective pressures generated by intra-specific competition can be considered as the ultimate cause, the neuroendocrine phenomena can be considered to be the proximate causes (sometimes also called mechanisms or moderators) and the observed behavioral alterations are considered the effects (the end events in the causal chain).
Both animal and human studies suggest that the social environment has a strong influence on the consequences of stresses. This finding seems to be especially true in the case of social stresses, like social defeat. In animal studies, animals housed collectively showed reduced symptoms after defeat, in comparison with those housed alone; and animals that live in more stable groups (with stable hierarchies, less intra-group aggression) exhibit reduced effects after a defeat, in comparison with those housed in a more unstable group.[ Similarly, in human studies individuals with greater support seem to be protected against excessive neuroendocrine activation, thereby reducing the adverse effects of stresses in general, and especially stresses of social origin.
]
Potential evolutionary causes
Some authors, for example Randolph Nesse, warn that patterns of behavior commonly considered inappropriate or even pathological may well have adaptive value. Evolutionary psychology
Evolutionary psychology is a theoretical approach in psychology that examines cognition and behavior from a modern evolutionary perspective. It seeks to identify human psychological adaptations with regard to the ancestral problems they evolved ...
provides several possible explanations for why humans typically respond to social dynamics in the way that they do, including possible functions of self-esteem
Self-esteem is confidence in one's own worth, abilities, or morals. Self-esteem encompasses beliefs about oneself (for example, "I am loved", "I am worthy") as well as emotional states, such as triumph, despair, pride, and shame. Smith and Macki ...
in relation to dominance hierarchies. Various behaviors related to intra-species competition or predator-prey relationships seen in a number of different animal species may have played a role in the evolution of human abilities. For example defensive immobilization is hypothesized to have played a role in the evolution of both human parent-child attachment and the development of theory of mind
In psychology and philosophy, theory of mind (often abbreviated to ToM) refers to the capacity to understand other individuals by ascribing mental states to them. A theory of mind includes the understanding that others' beliefs, desires, intent ...
. Human behaviors considered abnormal may in fact be part of an adaptive response to stressors that evolved in early humans, for example social stressors from chronic subordination or interpersonal conflicts.[
]
See also
* Bullying
Bullying is the use of force, coercion, Suffering, hurtful teasing, comments, or threats, in order to abuse, aggression, aggressively wikt:domination, dominate, or intimidate one or more others. The behavior is often repeated and habitual. On ...
* Social determinants of health
The social determinants of health (SDOH) are the economic and social conditions that influence individual and group differences in health status. They are the health promoting factors found in one's living and working conditions (such as the dist ...
* Social determinants of mental health
* Social exclusion
Social exclusion or social marginalisation is the social disadvantage and relegation to the fringe of society. It is a term that has been used widely in Europe and was first used in France in the late 20th century. In the EU context, the Euro ...
* Social rejection
Social rejection occurs when an individual is deliberately excluded from a social relationship or social interaction. The topic includes ''interpersonal rejection'' (or peer rejection), ''romantic rejection'', and ''familial estrangement''. A pe ...
* Social stigma
Stigma, originally referring to the visible marking of people considered inferior, has evolved to mean a negative perception or sense of disapproval that a society places on a group or individual based on certain characteristics such as their ...
References
General references
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* {{cite journal , last=Van Reeth , first=O , author2=Weibel, L. , author3=Spiegel, K. , author4=Leproult, R. , author5=Dugovic, C. , author6=Maccari, S. , title=Physiology of sleep (review) - Interactions between stress and sleep; from basic research to clinical situations , journal=Sleep Medicine Reviews , volume=4 , issue=2 , pages=201–219 , year=2000 , doi=10.1053/smrv.1999.0097
External links
*https://academic.oup.com/ilarjournal/article/55/2/221/642069/Social-Defeat-as-an-Animal-Model-for-Depression
Animal cognition
Power (social and political) concepts