Biological Flashcards
(145 cards)
1
Q
Which 2 parts make up the central nervous system?
A
Spinal cord and Brain
2
Q
What are the 2 halves of the brain called?
A
hemispheres
3
Q
What does the brain do?
A
coordination centre of sensation and intellectual and nervous activity
4
Q
What does the spinal cord do?
A
reflex actions -links the brain to the rest of the body (peripheral NS)
5
Q
Define ‘contralateral’
A
Left side of the brain controls right side of the body and vice versa
6
Q
What is the cerebral cortex?
A
outer layer of the brain
7
Q
What are convolutions?
A
folds on the cerebral surface (wrinkly)
8
Q
What are gyri and sulci?
A
ridges and valleys in the cerebral cortex
9
Q
What is lateralisation?
A
different functions for each hemisphere of the brain
10
Q
What is localisation?
A
within a hemisphere, certain behaviors are localized to one specific area
11
Q
What is the function of the frontal lobe?
A
-controls high level thinking, planning and problem solving -contains motor cortex -contains Broca’s area -one in each hemisphere
12
Q
What is the motor cortex?
A
strip along the top of the brain
13
Q
What does Broca’s area do?
A
left frontal lobe responsible for speech production
14
Q
What does the parietal lobe contain?
A
somatosensory cortex
15
Q
What does the somatosensory cortex do?
A
processes sensory information from the skin -touch, temperature and pressure -contralateral
16
Q
What does the temporal lobe do?
A
contains auditory cortex (which is contralateral) -processes location, volume and pitch of sounds -role in language
17
Q
What does Wernicke’s area do and where is it located?
A
left temporal lobe -understanding of languages
18
Q
What is the occipital lobe responsible for?
A
contains primary visual cortex -contralateral
19
Q
What does the visual cortex do?
A
interprets messages from our eyes into images we can understand
20
Q
What is the corpus callosum?
A
link of fine fibres which connect the hemispheres together -shares info between hemispheres
21
Q
What does the Thalamus do?
A
brain relay station
-receives info from senses
22
Q
What does the Hypothalamus do?
A
controls motivational behaviors (hunger, thirst, sex drive) -stress response -maintains balance in functions (body temp, hormones)
23
Q
What is the limbic system responsible for?
A
contains several structures -regulates emotional response
24
Q
What does the cerebellum do?
A
coordinates posture, balance and movement -receives and integrates info from spinal cord + other areas
25
What are the parts of the Nervous system?
- peripheral or central NS
- autonomic or somatic NS
-CNS - brain and spinal cord
- sympathetic and parasympathetic NS
26
What is the sympathetic NS responsible for?
preparing the body for fight or flight
27
What does the parasympathetic NS do?
returns the body to its normal state after fight or flight
28
What does the autonomic NS do?
-controls body's involuntary movements -controls the organs of the body
29
What does the somatic NS do?
-controls body's voluntary movement -transmits signals to and from senses and muscles
30
What is the peripheral NS?
all of the NS outside CNS
31
What is the nervous system?
The network of nerve cells and fibres which transmits nerve impulses between parts of the body
32
What are the 3 types of neuron?
Sensory, relay and motor
33
What does the sensory neuron do?
receives messages from receptors -travels along nerves in the peripheral NS to the CNS -has long dendrites and short axons
34
What does the motor neuron do?
carries messages from the CNS to effectors -along nerves in the peripheral NS -short dendrites and long axons
35
What does the relay neuron do?
connects sensory and motor neurons -only found in CNS -short dendrites and short axons
36
What are neurotransmitters?
chemical messages between neurons in the brain -allows brain to process thoughts and memories -each NT has particular function (excitatory or inhibitory)
37
Explain the 7 stages of Synaptic Transmission.
1: nerve impulse travels down an axon 2: nerve impulse reaches synaptic terminal 3: triggers the release of neurotransmitters 4: neurotransmitters fired into synaptic gap 5: neurotransmitters bind to receptors on the dendrite of adjacent neuron 6: if successfully transmitted, NT taken up by post-synaptic neuron 7: message will continue to be passed on via electrical impulses
38
What is an agonist drug?
-imitates natural neurotransmitters -fools the brain into activating pleasure centres -much more powerful than natural occurring NT's
39
What is an antagonist drug?
boosts amount of normal neurotransmitters -triggers brain pleasure centre
40
Which 2 recreational drugs does the course focus on?
cocaine and heroin
41
How does cocaine impact the role of dopamine?
blocks reuptake of dopamine by binding with dopamine transporter molecules on terminal buttons of presynaptic neuron -synapse flooded with surplus of dopamine
42
What are effects of cocaine?
stimulant effect on the cns
dopamine receptors become downregulated -fewer receptors active, some damaged and shut down -quantity of dopamine produced decreases -tolerance increases, withdrawal, cravings
43
What are the effects of heroin?
depressant effect on CNS -processed into morphine, which binds with specific receptor
neural transmission = down regulation -receptors desensitized, tolerance increases
44
What is a strength of recreational drug research.
there support for the effect on dopamine from research using non-human animals. That is a common procedure involving mice (previously exposed to cocaine use) which deliberately damages the mesocorticolimbic pathways in the brain so the neurons cannot produce levels of dopamine normally associated with reward. After this procedure the mice did not feel the need to take the cocaine, as a control they perform lesions on other areas of the brain but they do not find that this failure to self administer occurs when this happens. The supports the view that cocaines affects are due to the activity of dopamine in the brain's reward system
45
What is a weakness of recreational drug research?
It is based off animal research, transmission processes in mammals are similar but there are differences because the human brain is more complex than the mouse brain so isolating the effects of just one neurotransmitter oversimplifies the process so therefore can be reductionistic (ignoring the effects of serotonin or noadrenaline) and ungeneralisable (animals to humans)
46
What is a counter argument to the weakness of recreational drug research?
Evidence of drug effects on the CNS transmission also comes from studies of humans. Volkow et al 1997 used pet scans to track activity of dopamine transporters during a cocaine induced high, And found that the extent to which cocaine occupied dopamine transporters correlated positively with the course of the subjective experience, supporting the view that evidence from animal models is in fact valid as human studies produce similar results
47
What is an application of recreational drug research?
It can help lead to better addiction treatments, for example heroin was identified as an agonist that binds to opiate receptors, Therefore by the addict having treatments such as naloxone, an antagonist that blocks these receptors, The reward of euphoria isn't achieved when taking heroin so the user then stops
48
What does the amygdala do?
controls emotion responses (particularly fear)
49
What does the hippocampus do?
encodes long term memories
50
What would happen if the prefrontal cortex was damaged? (Raine et al)
person would seek immediate gratification -more negative emotions
51
What are the 3 types of brain scan?
CAT, PET and fMRI
52
Outline how CAT scans work
xrays -detailed cross-section images of inside of body
53
Outline 2 advantages of CAT scans.
useful for revealing abnormal structures -high resolution, good quality images
54
outline 2 disadvantages of CAT scans
high levels of radiation -only provide structural info (still images)
55
Outline how PET scans work
measure metabolic activity in brain -radioactive glucose substance injected (radiotracer)
colour scale of activity, red/ orange is most active blue/ purple is least
56
outline 2 advantages of PET scans
shows brain in action -provide evidence of localisation of functions
57
outline 2 disadvantages of PET scans
results sometimes not easy to interpret -ethical issues, radioactive substances can damage tissues
58
outline how fMRI scans work.
-uses radiowaves to measure blood oxygen levels in brain -blood directed to active areas -picked up through radio signals which produce 3D images
59
outline 2 advantages of fMRI scans
-doesn't use radiation (safe) -extremely clear images
60
outline 2 disadvantages of fMRI scans
expensive to use -only effective if person stays perfectly still
61
what does serotonin do?
inhibitory effect on transmission between neurons -self control -regulates sleep patterns -low levels = aggression
62
What is the link between serotonin and dopamine?
serotonin underactivity stimulates dopamine overactivity, which causes a link to aggression and impulsivity
63
How is serotonin linked to aggression?
Vikkruken eta l 1994, compared levels of serotonin in spinal fluid of violent impulsive an violent non impulsive offenders, found a lower level in the impulsive who also reported worse sleep, linking to the idea serotonin is important for impluse control and self regulation/ relaxation
64
How is dopamine linked to aggression?
Dopamine is involved in regulating motivated behavior and our experience of reward, mainly influencing aggression through its interaction with serotonin. Seo et al 208 Serotonin underactivity (hypo function) stimulates mean overactivity (hyper function) and are both linked with impulsivity and agression
65
How is the limbic system, particularly the amygdala, associated with aggression?
coccaro at al 2007 studied people with intermittent explosive disorder (ied) a major feature of which is outburst of extreme reactive hot blooded aggression. Fmri scans were undertaken more participants were shown images of faces. The IED participants showed high levels of amygdala activity when reviewing angry faces which wasn't found in the IED controls
66
What is a strength of brain structure and aggression?
Pardini et al 2014 studied 56 males who had previously been studied as having higher aggression. Fmri scans done after 20 years found a strong correlation between aggression and amygdala activity, supporting the influence of the amygdala overactivity in aggression.
67
What is a weakness of brain structure and aggression?
Most research in this topic is often correlational therefore meaning it is impossible to establish a cause and effect relationship as to whether a particular structure or function / dysfunction is a cause or an effect of the aggressive behavior or whether a third variable is involved
68
What is a counter argument to the weakness of brain structure and aggression?
berman et al 2009 gave participants paroxetine which is a drug known to increase serotonin activity. In a similar study to milgram, they then administered fewer and less intense electric shocks to others. This is evidence of a link between serotonin and aggression that goes beyond the usual correlational findings.
69
What is an application of brain structure and aggression?
There are practical benefits for example helping to discover a drug that affects the brain serotonin system reducing aggressive behaviour, but while keeping minimal side effects. A category of serotonin agonist drugs called serenics has significant anti-aggressive effects in animals and humans (veerhoeven and tuinier 2007)
70
what is our classic study?
Raine et al 1997
71
What was the aim of Raine et al.'s study?
use brain scanning technology to identify brain impairments in people charged with murder who had pleaded not guilt by reason of insanity
72
What was the procedure of Raine et al.'s study?
-41 murderers (39 men 2 women) pled not guilty on reasons of insanity & 41 non-murderers -matched pairs design (matched by sex, age, ethnicity) -control ppts = no meds, physical examination, psychiatric interview
-PET scan of brain beforehand, then given continous performance task of identifying blurred numbers on a screen while injected with radiotracer, then were given another pet scan after half an hour of this activity to measure the brain activity
73
What was the findings of Raine et al.'s study?
murders had lower glucose metabolism in prefrontal areas, parietal areas, corpus callosum, left amygdala, left temperal lobe and hippocampus
74
What was the conclusions of Raine et al.'s study?
-murderers NGRI = impaired functioning in areas linked to violence - dysfunctions of single brain area can't explain violence -behavior only expressed when social, environmental and psychological conditions are 'right'
75
Evaluate a strength of Raine et al.'s study.
experimental controls, matched on sex age ethnicity to control pv's, also murderers were not on medication which could have altered brain function.
76
What is a weakness of Raine et al's study?
Population validity is low, sample only represents a small number of severely violent offenders as those pleading ngri are not representative of all offenders and therefore it can't be considered generalizable explanation of violence.
This research also ignored the possibility of extraneous variables that could interfere with the findings such as Social A situational factors that may have contributed to their violent behaviour brain dysfunction or both therefore it cannot conclude whether violence is due to biology or environmental influences
77
Outline evolution by natural selection
genetic differences & spontaneous mutations cause variation -advantageous characteristic passed on (reproduction) = retained in population and become more frequent -leads to adaption
78
When does natural selection occur?
survival of the fittest -competition for scarce resources
79
explain sexual selection
choosing mates based on specific traits and then those traits will increase in the population
80
State how evolution may cause aggression
guarding your offspring -guarding your partner
81
Evaluate a strength for evolution, natural selection and aggression
explains gender differences -men more aggressive (better hunters) -cooperative females = more likely to be naturally selected, therefore = reduced aggression (manson and wrangham 1991 research with chimpanzees)
82
Evaluate an opposing argument for evolution, natural selection and aggression
any evolutionary explanation is uncertain -just correlational -may be other influencing factors, can't go back in time to see. Likely that evolution is an effect of holding certain attribute rather than a cause, also can't explain cultural differences
83
Explain how cultural differences oppose the argument for evolution in.
Wolfgang and ferricuti 1967 studied two tribes, The southern African ! Kung San people and the south-american yanomami people. The Kung san discourage aggression from childhood, With actions such as brushing past someone's shoulder having consequences of large fines. However the yanomami tribe have been described as the fierce people and aggression is encouraged in order to gain status in their Society. This shows that aggression is not biologically evolved and differs between cultures and social norms
84
What are hormones?
biochemical messengers that are transported around the body in the bloodstream
85
What is the role of hormones?
crucial in fight or flight response -helping to fuel aggressive response (e.g. increasing HR)
86
What is the role of testosterone?
-triggers aggression
-Dolan et al. = positive correlation between testosterone levels and aggressive behavior in sample of 60 male UK offenders, similar with Dabbs and Hargrove researching females
87
Explain the dual-hormone hypothesis
-cortisol: protect body against stress -high levels of testosterone = aggression only when cortisol levels are low -cortisol high = testosterone's influence on aggression blocked
88
Evaluate a strength for hormones and aggression.
-research support
gianmarco 2005 study with mice, castrated male mice at birth before testosterone came into effect, observed they were peaceful towards each other, however then injected with artificial testosterone then led to increased aggression and fighting, showing the influence of the hormone in aggressive behaviour
89
Evaluate an opposing argument for hormones and aggression.
correlational only -changing testosterone level and aggression may be result of changes of another hormone
90
Evaluate a differing theory for hormones and aggression.
difficult to determine testosterone levels -may not provide valid indicator of testosterone level in relation to aggression (carre et al 2011)
91
Evaluate an application for hormones and aggression.
controlling aggression -e.g. testosterone lowering drug reduced levels of sexually aggressive behavior in some offenders
92
Outline the 3 parts of our mind according to Freud’s psycho dynamic theory.
1: conscious = thinking which the individual is aware of 2: preconscious = readily available for access if you try 3: unconscious = main part, info we can’t access, forgotten
93
Explain Freud's psychodynamic explanation of aggression
-born with 2 major instincts: life and death -life = Eros (survival + reproduction) -death = Thanatos
94
What age are the Id, Ego and Superego developed
Id = 0-2 -Ego = 2 -Superego = 3-6
95
Explain the Id and the pleasure principle
entirely unconscious mind -instincts and impulses that satisfy immediate pleasure and gratification -makes aggression unavoidable
96
Explain the ego and the reality principle
-logical and rational thinking -mostly conscious mind -between unrealistic desires and social reality -doesn't directly fulfill id's aggressive urges -no moral sense
97
Explain the superego
-conscience and moral sense of right and wrong -aggression is destructive -opposes id's aggressive drive through guilt & shame
98
What is catharsis?
releasing aggression or aggressive thoughts -"letting of steam"
99
Which is a strength of freud's theory?
It can help explain the different types of aggression. Hot blooded aggression is impulsive, angry and has no purpose, showing its domain of the id failure of the ego's function and redirecting the id aggressive impulses. Cold blooded aggression is deliberate , rational and instrumental, Showing the outcome of the ego successful control of the ID impulses. Does matches the reality of aggressive behaviour and gives us confidence in the validity of the theory
100
What is a weakness of freud's theory?
Bushman 2002 angered students by getting a confederate to criticize their essays one randomly allocated group then were able to vent their Anger by hitting a punch bag while thinking about the Confederate. In a later interaction these students then blasted the Confederate with longer and louder noise compared to controls who didn't vent anger, opposing Freud theory and suggesting catharsis will actually increase Anger by keeping the emotion going.
101
What is a counter argument of the weakness of freud's theory?
Graham et al 2008 suggest that there are different types of catharsis, ranting or venting. Ranting involves considering the reasons for anger, whereas venting is an uncontrolled expression of Anger in general. Ranting allows the individual to gain control over the root of their feelings and therefore can help extinguish aggressive behaviour and anger.
102
Who is our contemporary study?
Li et al 2013
103
What was the aim of Li et al 2013?
To investigate the involvement of the posterior cingulate Cortex (pcc) in heroin dependence, Aiming show that the activation in this area is abnormally stronger in heroin addicts than in healthy controls, showing a sign of brain dysfunction in addiction
104
What was the sample of Li et al 2013?
14 males in the detoxifying stage of heroin addiction recovery, had use heroin for 19 to 182 months but now heroin free symbolised from a urine test, compared to a control of 15 healthy males with no history of drug use or head injuries/ psychiatric disorders.
105
What was the procedure of Li et al?
Each participant underwent three brain scans
1. Structural MRI to identify the standard brain areas
2. 5-minute resting state fmri
3. Reactivity trial another MRI in test of the brain's response to 24 heroin related images for example syringes or 24 neutral images, each shown for 2 seconds with a gap of 4 to 12 seconds in between. Participants were then asked on a self-report zero to ten scale to assess their craving for heroin
106
What were the findings of li et al?
Heroin uses had a significantly higher subjective craving scores than the controls after the cue induced craving, raging from 2.31 to 3.21. There was stronger functional connectivity in the PCC in heroin users that in controls, and the insula/ dorsal straitum were also strongly connected to the pcc in the ex herion addicts. those who have been addicted to heroin for longer also had stronger connections in the brain between these areas.
107
What are the conclusions of Li et al?
Drug related queues are predictors of reward for heroin addicts, and the PCC is linked to neural circuits in drug cravings. The neural dysfunction affects the individuals ability to process external stimuli related to drug taking. Strong positive relation between the length of Hero independence and the strength of the functional connectivity of the PCC.
108
What is a strength of Li et al?
The study had standardized procedures. For instance each participant saw the same heroin related and neutral images all of which represented for two seconds. The fmri scans also followed the same protocol for example the resting state scan taking five minutes. The procedure was identical for every participant therefore researchers controlled potentially confounding variables so the study has greater internal validity.
109
What is a weakness of Li et al?
Nicotine may have been a potentially confounding variable that was not controlled. All of the participants including the controls were smokers. This means that could have been an interaction between nicotine and heroin in the user group and there is evidence that these two do interact by a chemically (kohut 2017) Therefore this would then mean there could be an effect from a confounding variable as it was a systematic difference between the two groups as to whether the nicotine and heroine in their system would have interacted
110
Why is there possibility of a Type 1 error in li et al?
The sample was very small, only 14 heroin users were studied, Increase the possibility of finding a significant result when none-exists.
111
What is an application of Li et al's research?
It can help lead to improve diagnosis of brain damage, functional connectivity of the pcc could be used as a biomarker of brain damage and addicts, Helping to establish the severity of the brain damaged and might be the first step in providing treatment or at least preventing further damage.
112
What is our twin study?
Gottesman and Shields 1966
113
What did Gottesman and Shields study?
The concordance rate (percentage prbablitiy) of one twin being diagnosed with schizophrenia if the other is already diagnosed
114
What were Gottesman and Shields findings?
They found a concordance rate of 42% in identical twins who share 100% of DNA, whereas in fraternal twins who share 50% of DNA the concordance rate was only 9%.
115
What did Gottesman and Shields conclude?
Since the concordance rate is higher in genetically identical twins rather than genetically different twins, they concluded as a strong likelihood that there is a genetic element that explains why people develops schizophrenia.
116
What is our adoption study?
Cadoret and Stewart 1991
117
What was the aim of cadoret and stewart
To investigate the relationships and genetic background environmental factors beyween ,ADHD aggressivity and adult anti-social personality
118
Who did cadoret and stewart study?
283 male adoptees
119
What were cadoret and stewart's findings?
adopted boys version increased rescue ADHD or aggressive behaviour as children if they had a biological parent convicted of crime in adulthood. They also found that the risk of ADHD in aggression was higher if there were psychiatric problems in the adoptive family. ADHD is likely to lead to aggression which therefore leads to adult anti-social personality.
120
what was cadoret and stewart's conclusion?
ADHD in aggression is influenced by both genetics and environment and isn't attributable to fully one or the other.
121
what is a strength of gottesman and shields?
The study has a relatively large sample of 62 pairs of twins, ranging from teenagers to being in their 50s, and with a 50/50 split of gender, thereofre can be argued to have good population validity.
It is also reliable; This study is a replication of 11 smaller scale studies, which had similar results to those found in gottesman and Shields
122
What is a weakness of gottessman and shields?
There are issues of participant variables within the sample, some twins had been admitted to psychiatric wards after struggling with PTSD in World War II, this may have been an extraneous variable contributing to the detriment of their mental health
123
What is an application of gottesman and shields?
It can help people with a family history of schizophrenia understand their risk, and allow them to know to avoid triggers such as drugs or alcohol
124
What is a strength of cadoret and Stewart?
It takes into account both genetics and environment, so can be argued to be holistic in its approach
125
What is a weakness of cadoret and stewart?
It can be argued to be unethical, as some of the adoptive Sons were not in contact with their family but knowing the researchers are could have caused stress
126
Explain two strengths of twin studies in general
The international twin registry means that there is a large representative sample readily available for any research
they are particularly useful for studying genetic elements in behaviour, as the two different types of twins can act as two different levels of the IV
127
Explain a weakness of twin studies. in general
There is evidence that parents treat identical twins more similarly than fraternal twins, death or concordance rates maybe influenced by an uncontrollable extraneous variable, for example the environment
128
Explain a strength of adoption studies in general
Adopted individuals are often exposed to different environments to their biological parents which makes it easy for scientists to tease apart the environmental and biological effects. Taking account into environment also shows how twin studies can often overestimate the genetic effect
129
Explain a weakness of adoption studies in general
May be incomplete information about the biological families
Placement for adoption isn't random, some agencies may match children with a family similar to their biological family so the extent to which the environments are different may sometimes be questioned
130
What was the aim of our biological practical?
to investigate whether there is a relationship between aggression (measured through the Buss Perry questionnaire) and the level of pre natal testosterone exposure (as measured by digit ratio).
131
what did we need to control in our biological practical?
with the questionnaire, there might be social desirability bias. the ps may change their answers to appear less or more aggressive to impress peers. we controlled this by removing them from their friends and making it anonymous.
with the digit ratio, we made sure to draw around their hand accurately.
132
state the research hypothesis of our practical
there will be a significant negative correlation between aggression and digit ratio
133
how did we operationalise our variables in our biological practical?
testosterone —> digit ratio. lower ratio = higher testosterone, longer ring finger indicative of higher T (2D:4D)
aggression —> Buss Perry 1992 aggression questionnaire
134
what was our sample in our biological practical?
opportunity sample 16-18 year old male sixth form students
135
what was the conclusion of our biological practical?
from our findings from the spearmans rho test, we can conclude we should reject the research hypothesis and accespt the null hypothesis that there is no significant correlation between self reported agression and digit ratio (as a measure of prenatal exposure to testosterone) except by chance. this provides evidence to counter the idea that the higher a persons testosterone exposure as a baby does alter the organisation of their brain, making them more aggressive.
136
what was the procedure for our biological practical?
Draw round participants hand and measure the index and ring finger lengths
move participant away from pairs and get the participant to take the questionnaire
In analyzing the data, the 2d4d digit ratio is calculated by dividing the length of the index finger by the length of the Ring finger
137
What are some strengths of our biological practical?
We have relatively high objectivity, there is a strict binary scoring system for the analyzing the questionnaire, and there are no opinions needed in drawing around the Hand and using the ruler to measure the digit ratio
we also have high reliability as finger lengths won't change between tests due to the age of our participants (stopped growing) and also the closed questions on the questionnaire would Funnel people into similar boxes each time.
138
What are some weaknesses of our biological practical?
Our population validity was low, are target population is adult men and our sample what's 16 to 18-year-old boys, answers on the question there may have been exaggerated because social status is likely a concern for this age and it is seen to refelct toughness.
our construct validity is also low, as the 2D 4D digit ratio is a very rough measure of prenatal testosterone levels, and the self-report style of the questionnaire may have led to exaggeration or participants named may not be aware of how aggressive they actually are
Our ecological validity is also low as aggression is more of a spontaneous reaction rather than pre-considered. A questionnaire does not replicate a situation where aggression would be triggered.
139
What is our key question?
To what extent is aggressive behaviour down to nature versus nurture?
140
Describe the issue of nature versus nurture in violent behaviour (key question)
Nature reflects the influence of genetics and nurture reflects the influence of environment. I discovering which has the largest impact on violent behaviour we can find a way to tackle violence in early life and prevent murderers. Murders are very detrimental to a large group of people, it affects the victim who has been killed, the victims family who are left without a loved one, and the murders themselves who now have life in prison and their life is ruined. Therefore by tackling violent behaviour at a young age we can help prevent the lives of many people being ruined
141
Nature is to blame: evolution (key question)
Evolution by natural selection is where traits that increase the chance of survival are genetically passed on to Offspring. When life is tough small differences between individuals who possess characteristics that help them survive and pass on the next generation is vital. The evolutionary theory by Darwin 1859 can be used to help explain aggression; It becomes an Instinct in sense of protecting yourself, a partner or your offspring, enhancing your survival and therefore leading you to reproduce. This means that aggression may be a biological response when under stress or attack
142
Nature is to blame: genetics, twin studies: (key question)
gottesman and shields show high concordance rates between genetically identical twins (48%) compared to fraternal twins who share 50% of DNA (9%)In the development of schizophrenia, showing the importance of genetics in terms of determining behaviour or illnesses.
Similarly a twin study by Christiansen 1977On 500 twins in Denmark found higher concordance rates of criminal behaviour in identical twins (35% in males 24% in females) as opposed to non identical twins (13% male 8% females). These twins studies help show that large proportion of behaviour is attributed to genetic traits
143
Nurture is to blame: cultural differences (key question)
Evolution can't explain changes in aggression that take place over shorter time periods. Wolfgang and fercutti 1967 Studied the South African kung San tribe and the south-american yanomami tribe. With the Kung san, aggression is discouraged and punished, however with the Yanomami, it is encouraged as a form of gaining status. This means that the evolutionary approach can be challenged, as these tribes are genetically similar but the influence of their cultural norms is stronger than their biological instinct.
144
Nurture is to blame: issues with Christiansen 1977 (key question)
There are low concordance rates even in the identical twins, and even lower in the non identical twins. This suggested that there may be more of a role with the environment, as even though the genetics are the same, the likelihood that one twin will behave the same as the other is still lower than would be expected if it was solely down to genetics.
145
what is the conclusion of our key question?
Nature does play a role however there seems to be more of an influence from nurture. Even if you do have the aggressive genes, the environment can either enhance or dampen the of behavior effects
Bonus: with raine et al, there is no evidence for why the amygdala activity is high and prefrontal cortex activity is low, suggesting it maybe to do with the environment the person grew up when rather than biological differences.
