Flashcards in L3 - Neurobiological Risk Factors for Antisocial and Violent Behaviour Deck (58):
What are two types of genetic influence?
1. Behavioural genetics (identical twin studies, adoption studies, twins separated at birth)
2. Molecular genetics (candidate genes)
What percentage of the population are twins?
What is another name for dizygotic twins?
What percentage of twins are fraternal/dizygotic?
In dizygotic twins, how many eggs are fertilised by how many sperm cells?
2 eggs are fertilised by 2 separate sperm cells
In monozygotic twins, how many eggs are fertilised by how many sperm cells?
1 egg is fertilised by 1 sperm. The fertilised egg later splits into two identical eggs.
In twin studies, the contribution of 3 factors to antisocial behaviour is worked out. Which 3 factors are they?
- Genetics (heritability) h^2
- Shared environment c^2
- Non shared environment e^2
Heritability for ASB ranges between what across all different studies?
Between around 0.4-0.5.
What are the heritabilities for aggressive and non aggressive ASB?
0.65 for aggressive
0.48 for non-aggressive
What are the heritabilities for reactive and proactive aggression?
Reactive - 0.39
Proactive - 0.50
Heritability for early-onset ASB is ______ , especially when it occurs across many settings, is persistent and severe and involves psychopathic tendencies. These children have a heritability of _______.
What is the typical design of most adoption studies?
Experimental group involves foster children who's biological parents are criminals.
Control group are foster children who's biological parents are not criminals.
What results would have to be shown to conclude a significant genetic influence of ASB in twin studies and why?
If the experimental group shows higher levels of ASB than the control group.
Because the experimental group's biological parents are criminals.
What did Mednick et al., (1984) find about the heritability of property crimes?
Significant positive correlation between adoptees and their biological parents for convictions of property crimes.
No such correlation found for violent crimes.
Adoption studies have robust findings despite differences in what?
- age of participants
- study periods
- measures of ASB
- study design
Caspi et al., (2002) found gene-environment interactions between the low activity MAOA allele and childhood maltreatment for which aspects?
- conduct disorder
- conviction for violent offences
- disposition towards violence
- antisocial personality disorder symptoms
The low allele of the MAOA gene has been shown to be linked to what?
- higher levels of aggression following provocation (McDermott et al., 2009)
- greater brain response following social exclusion (Eisenberger et al., 2007)
Raine studied which biosocial effects on violent crime?
Birth complications and maternal rejection.
What did Raine find when studying the biosocial influences on violent crime?
Significant interaction between biological (birth complications) factors and social factors (maternal rejection) increased the rate of violent crime convictions.
Why might birth complications lead to increased violent behaviour?
Those exposed to hypoxia have decreased neural densitiy, believed to lead to learning, decision making and emotion regulation deficits.
Why might maternal rejection lead to increased violent behaviour?
Lack of love, care and a nurturing environment may bring out cold, aggressive traits.
Which factors were accounted for in studies which still found a link between smoking during pregnancy and antisocial behaviour?
- Low socio-economic status
- parental crime and ASB
- low maternal education level
- bad parenting
- mother's age at child's birth
- family size
- bad parenting
- family problems
- parental psychiatric diagnoses
- genetic influences
What might be the mechanisms behind smoking during pregnancy and increases in antisocial behaviour?
Babies, infants or adolescents exposed to nicotine found to have deficits in gray matter volume in key cortical and subcortical areas involved in emotion regulation.
When nicotine passes through the placenta, a reduction of uterus blood flow eventuates. This leads to a decrease in the nutrients and oxygen delivered to the foetus, (hypoxia), which can cause death of neurons.
Which indirect measure of brain development was used by Jaddoe et al., (2007) to suggest effect of nicotine exposure on brain development?
Head circumference. Reduced circumference in babies exposed to nicotine prenatally.
Adolescents exposed prenatally to nicotine show what? (+studies)
- lower amygdala volume (Haghighi et al., 2013)
- lower cortical thickness of the orbitofrontal cortex (Toro et al., 2008)
- Increased drug experimentation (Loftipour et al., 2009)
Deficits in brain regions as a result of nicotine exposure leads to what impairments?
Neuropsychological impairments in:
- executive functioning
What does FAS stand for?
Foetal Alcohol Sydrome
What are some physical characteristics of FAS?
- small head
- folds of skin between eyes and nose
- smooth area between nose and upper lip
- thin upper lip
- small eye openings
- short nose
- flat upper part of the nose
- underdeveloped jaw
What are some symptoms of FAS?
- Craniofacial abnormalities
- Growth retardation
- CNS dysfunction, leading to learning disabilities and low IQ.
What did Popova's (2016) meta-analysis show about the main disorders caused by FAS?
ASB and conduct disorder is the most common in individuals with foetal alcohol syndrome.
Define maltreatment according to the World Health Organisation.
All forms of physical and/or emotional ill-treatment, sexual abuse, neglect or negligent treatment or commercial or other exploitation, resulting in actual or potential harm to the child’s health, survival, development or dignity in the context of a relationship of responsibility, trust or power.
Name 4 types of maltreatment.
What is neglect?
A persistent failure to meet a child’s basic physical and/or developmental needs.
All types of maltreatment are linked with what?
- Poorer mental health
- Elevated levels of delinquency
The majority of maltreated children experienced how many types of abuse?
More than one
How do maltreated children react when they see angry faces, compared to children who have not been maltreated?
The amygdalae of maltreated children are hyperactive - far more active than those of 'normal' children.
According to De Brito et al., (2013), what were maltreated children more likely to have?
Conduct disorder and (amygdala?) hyperactivity.
Why might maltreated children be more likely to turn to violence?
Increased activity in amygdala when shown angry faces --> when experiencing disagreements in life, they may be more emotionally unstable and therefore react much more than they should.
De Brito et al., (2013) says that child maltreatment leads to decreased gray matter volume in which regions?
Medial orbitofrontal cortex
Left middle temporal gyrus
Kelly et al., (2015) linked decreases in gray matter volume in maltreated children to what?
Peer problems. Maltreated children have decreased gray matter in areas needed for emotion and decision making, which impairs their ability to interact effectively with peers.
How do maltreated children react when they see happy faces, compared to children who have not been maltreated?
Hyperactivity in amygdalae. Seems that the amygdalae of maltreated children activate immediately in response to any information about imminent danger.
How do reactions of amygdala activity in maltreated children tell us about the nature of their maltreatment?
The more sensitive the amygdala is in response to happy/angry faces, the longer the duration of abuse
What is the left middle temporal gyrus important for, and what does this mean for maltreated children with reduced gray matter volume in this area?
Autobiographical memory. Possible that the maltreatment has decreased the encoding of autobiographical memories - easier for children to forget/harder for them to clearly remember what has happened to them.
Did maltreated children show overt symptoms whilst at mainstream schools? What does this show about the effects of maltreatment on overt symptoms
No. Maltreatment may be a pre-disposition to overt psychological symptoms later in life.
Which disorders does maltreatment increase the risk of later in life?
Depression and substance abuse among others.
What did Glenn and Raine (2014) show about the (almost causal) link between ventral prefrontal cortex dysfunction and paedophilia?
When the vPFC was displaced by a tumour in 40 year old schoolteacher Michael, his overt paedophilic behaviour emerged. Whenever the tumour was cut out (resected) his behaviour returned to normal.
What does ASPD stand for?
Antisocial personality disorder
What is ASPD?
A personality disorder that indexes a life-long pattern of antisocial behaviour
What are the symptoms of ASPD?
- repeated criminality
- consistent irresponsibility
- repeated fights/assaults
- lack of remorse
According to Andersen et al., (1999) and Meyers et al., (1992), lesions in vmPFC leads to changes in what in individuals with acquired antisocial personality disorder?
What is the vmPFC?
Ventromedial Prefrontal Cortex
What is the vmPFC important for?
Processing of risk and fear
Children with conduct problems show reductions in which brain regions?
Decreased gray matter in the orbitofrontal cortex is associated with what?
Substance use disorders
What are the two theories linking low resting heart rate with ASB?
Fearlessness Theory (Raine, 1993)
Sensation-Seeking Theory (Quay, 1965; Eysenk, 1997)
How does the Fearlessness Theory explain the link between low resting heart rate and antisocial behaviour?
Low resting heart rate is associated with low fear, meaning early fear conditioning may not have developed normally. This would mean consequences of ASB are not feared/aversive, increasing the likelihood of engagement in AS behaviour.
How does the Sensation-Seeking Theory explain the link between low resting heart rate and antisocial behaviour?
Low resting heart rates are linked with with low autonomic arousals, which is an unpleasant physiological state. Therefore, activities which increase heart rate and arousal are engaged in to avoid/reduce the uncomfortable state