Biological Psychology Flashcards
What is the CNS made up of?
The Brain, spinal cord and neurone cells
Describe the Peripheral Nervous System
Cranial nerves and spinal nerves
Describe the Autonomic Nervous System
Heart muscle, smooth muscle, glands
Describe the Somatic Nervous System
Voluntary skeletal muscles
Describe the Sympathetic Division
“Active and alert”
Automatic involuntary response to prepare the body for stressful or threatening situations
Describe the Parasympathetic Division
“Rest and digest”
What is the function of the Frontal lobe?
Higher order processing and decision making
What is the function of the parietal lobe?
Orientation, movement and sensation
What is the function of the cerebellum?
Controls fine motor skills, coordination and balance.
What is the function of the pre-frontal cortex?
Regulating emotions and social behaviour (lack of regulation can result in aggression)
What is the function of the temporal lobe?
Auditory processing
What is the function of the limbic system? (Hippocampus and Amygdala)
Controlling and regulating emotions.
The Amygdala is the centre for emotions
The hippocampus forms new memories based on past experiences
Describe the Corpus Callosum
Connects the left and right hemispheres. It ensures both sides of the brain can communicate by sending signals to each other.
Wernicke’s area
- Understanding speech
- Lower area of left frontal lobe
Broca’s Area
- Production of speech
- Upper temporal region of left hemisphere
Function of myelin sheath
White layer of insulating fat surrounding the axon, allowing the electrical signals to move more quickly
Function of schwann cells
Forms the myelin sheath
Function of the axon
Transfers electrical impulse signals from the cell body to the synapse
Function of the soma
The cell body which contains most of the cells organelles
Function of dendrites
Receives electrical impulses from neighbouring neurons
Define saltatory conduction
The propagation of action potentials along myelinated axons from one node of Ranvier to the next, increasing the speed of electrical transmission.
Describe GABA
- Inhibitor of messages
- Calming
- Low levels linked to epilepsy
Describe Norepinephrine/Noradrenaline
- Gives attention
- Prepares for fight/flight
- Can be given to treat ADHD
Describe Acetylcholine
- Memory
- Learning
Describe Dopamine
- Pleasure feelings
- Addiction
Describe Glutamate
- Cognitive function (memory and learning)
- Brain development
- Dangerous if there’s too much
Describe Serotonin
- Happiness and good mood
- Low levels give depression
Role and function of neuron
- Pass messages between neurons using neurotransmitters.
- Electrical impulses travelling down the axon trigger the release of the neurotransmitters from the terminal at the end of the axon.
- The neurotransmitters are then released into the synaptic gap, to be picked up by receptors on the dendrites of another neuron.
Difference between presynaptic and postsynaptic neuron
Presynaptic neuron sends the message, postsynaptic neuron receives the message.
Describe synaptic transmission (8)
- Action Potential (electrical impulse) arrives at presynaptic neurone.
- Calcium channels open, influx of Calcium ions into the presynaptic neurone.
- Causes vesicles carrying neurotransmitter to move to the presynaptic membrane and fuse with the cell membrane. Exocytosis of neurotransmitter into the synaptic cleft.
- Neurotransmitter diffuses across the synaptic cleft and binds to receptors on postsynaptic membrane.
- Ligand gated ion channels on postsynaptic membrane open.
- Influx of Na+ ions at postsynaptic membrane causes depolarisation.
- Action potential in postsynaptic membrane is stimulated.
- Neurotransmitter is broken down and reuptake back into synaptic vesicles occurs via receptors in presynaptic membrane.
What is an excitatory synapse?
Increases the activity of the post synaptic membrane by depolarisation due to the influx of Na+ ions, causing an action potential to be fired.
What is an inhibitory synapse?
Decreases activity of the post synaptic membrane by hyperpolarisation due to the influx of Cl- ions, causing no action potential to be fired.
How does reuptake work?
When the neurotransmitter is absorbed back into the presynaptic neuron to be reused.
It regulates the amount of neurotransmitter in the synapse and recycles the neurotransmitter so it has a useful function.
Define recreational drugs
Drugs that are taken without medical justification for their psychoactive effects, in the belief that occasional use is not habit-forming or addictive
What is an agonist
Drugs that occupy receptors and activate them
Dopamine Reward Pathway
The structures and neurons in the brain associated with the neurotransmitter dopamine to cause feelings of reward
What is an antagonist
Drugs that occupy receptors but do not activate them. Antagonists block receptor activation by agonists
Euphoria & Dysphoria
Euphoria = high, intense pleasurable feeling
Dysphoria = low, intense anxiety or dissatisfaction
Define desensitisation (recreational drugs)
A higher concentration or dosage of a drug is required to cause the same feeling due to a loss of response at the synaptic level
Describe the effect of nicotine
- Stimulant
- Mimics Acetylcholine
- It attaches to nicotine/acetylcholine receptors which excite the neuron, causing it to release dopamine
- Causes depolarisation initiating an action potential, increasing neurotransmission
Describe the effect of cocaine
- Cocaine attaches to the reuptake receptor, blocking it so that dopamine cannot be re-absorbed back into the neuron
- This means levels of dopamine keep building in the synaptic gap, causing euphoria
- Causes continual depolarisation and stimulating action potentials
Evaluate the effect of Cocaine
+ Lewis et al (2020) proved the highly addictive nature of cocaine, which has been associated with dopamine receptors
+ Studied male mice
- Cannot generalise the findings from animal models to human behaviour; rats are not representative because they have a less complex CNS and brain anatomy than humans
Describe the effect of alcohol
- Alcohol increases the inhibitory effect of GABA, causing it to remain bound to its receptor for longer
- The post-synaptic neuron hyperpolarises, decreasing action potentials and neuronal transmission and slowing down reactions
Evaluate the effect of alcohol
+ Valenzuela and Harries (1997) found that alcohol’s inhibitory effect on memory could be related to GABA systems
+ This explains why consumption of alcohol causes the CNS reflex responses to slow down, decreasing memory
- Biologically reductionist as it fails to account for individual differences, e.g. some people have different tolerances for alcohol
Describe the effect of cannabis
- THC Binds to cannabinoid receptors
- Gives less neuron activity, impacts memory making
- Stops GABAergic neurons from inhibiting dopamine, thus there is excess dopamine
- Sedative effects on the cerebellum, analgesic affects in the brain stem
Evaluate the effect of cannabis
+ Manzares (2006) proved that high doses of cannabis resulted in hallucinogenic effects, but low doses were useful to treat diseases involving acute and chronic pain relief
- Correlation does not mean causation: Allen & Stevens (1994( showed that 50% of neurotransmission did not cause a response in the postsynaptic neuron. Other factors may influence the role of neurotransmitters, like genetics.
Evaluate the strengths of the argument for the effect of recreational drugs on transmission
+ The rewarding effects of drugs are linked to the increased release of dopamine
+ Benowitz found that nicotine binds to nicotinic receptors in the brain to facilitate neurotransmitter release.
+This led to the development of new treatment options for tobacco addiction, showing how the neurobiological explanation of a recreational drug can be used for the benefit of human understanding.
Evaluate the credibility of the argument for the effect of recreational drugs on transmission
- Animals are not representative because they possess a less complex CNS and brain anatomy than humans.
- Assumptions are made that we can apply the findings of animals studies to humans, so cause and effect is not established.
- Empirical research of recreational drugs and neurotransmission are not entirely falsifiable, decreasing the credibility of this explanation.
Evaluate the other expanations of the argument for the effect of recreational drugs on transmission
- Addiction to recreational drugs is not caused by neurotransmission, but instead by genetics.
Studies of monozygotic twins showed that if one twin had an addiction, the other twin is more likely to have an addiction. - Studies have consistently found that monozygotic twins are more likely to both have an addiction than dizygotic twins, who only share 50% DNA.
Evaluate the debates of the argument for the effect of recreational drugs on transmission
- Reductionist, because it ignores the addict’s motivation
- Freud suggests that recreational drug use is driven by a desire to escape from past traumatic experiences and to seek pleasure as a means of coping with emotional pain.
- The neurobiological explanation remains reductionist, as they fail to account for individual differences, like personality, free will, and learning how to use recreational drugs in the environment.
Evaluate the applications of the argument for the effect of recreational drugs on transmission
+ The binding of THC in the cerebral cortex causes cognitive effects. In the cerebellum, it causes sedative effects and, in the brainstem, analgesic effects.
+ Neurobiological research of the effects of drugs can be applied to drug replacement therapy (DRT) which involves giving users a substitute that produces a similar effect but in a controlled way
+ Although cannabis has hallucinogenic effects in high dosages, lower dosages might be useful to treat diseases involving acute or chronic pain. This shows that neurobiological explanations have important application for society as medicinal treatments.
Describe a CT/CAT scan
- Multiple X-ray radiation beams are passed at different angles rotating around the head to create a detailed cross-sectional image of the brain produced by a computer.
- It uses X-ray beams to view soft tissue, not just bones. X-ray beams are reduced in strength (attenuated) according to the density of the tissues in their path.
What are the advantages of a CT/CAT scan?
- Short procedure
- Identifies brain structures like tumors and lesions
- Non-invasive
What are the disadvantages of a CT/CAT scan?
- Low resolution
- Black & white, still images
- Only tell you about the structure of the brain
- Uses radiation which could be harmful in high doses as it can cause cancer
- Do not provide information on how brain activity functions, e.g. synaptic transmission
- Cannot be used for information processing
Describe an fMRI scan (Functional Magnetic Resonance Imaging)
- Involves exposure to radio waves and a magnetic field
- Images the water molecules in the body
- Monitors the uptake of oxygen by the cells in different brain regions. Active areas iof the brain consume more oxygen and can be visualised in an fMRI image. Active regions in the brain have enhanced blood flow and an increase in Oxyhaemoglobin
- This results in ‘lighting up’ of active brain regions on fMRI images when participants conducts cognitive tasks
Advantages of an fMRI
- Brain tissue and anatomical structure is recorded, a map of activation showing information and blood flow in neurones is recorded
- Safer than CT scanning because it doesn’t use X-rays
- Non-invasive because it doesn’t involve the injection of radioactive material like PET scans
Disadvantages of an fMRI
- Longer procedure (30 minutes)
- Not suitable for people with a cardiac pacemaker or metal surgical implant due to exposure to magnetic fields which can cause physical disruption to heart or organs
- Does not provide information on how actual receptors function in synaptic neurotransmission
- Patients who are claustrophobic may find the scanning unnerving, which could cause demand characteristics if this causes changes in brain activity
Describe a PET scan
Positron emission tomography
* PET scans are nuclear medicines involving the injection of a radioactive tracer into the patient
* FDG fluorodeoxyglucose travels in the bloodstream to active regions of the brain as the glucose is used up in respiration by neurone cells
* As glucose is used up, the radioactive tracer breaks down emitting positrons which radiate gamma rays
* Gamma rays are detected by scanner and active regions of the brain are identified
Advantages of a PET scan
- Brain activity can be investigated when a participant is conducting a cognitive task, including synaptic transmission and receptors
- Safer than CT scanning, as no exposure to X-rays
- Abnormal functioning of brain areas can be visualised, allowing scientists to identify and predict the impact on patients
Disadvantages of a PET scan
- Invasive procedure, involving the injection of radioactive glucose tracer
- Duration of the scan is 2-4 hours
- Can only be used once a year due to the danger of radioactive isotopes
Evaluate the strengths for the claim that there are brain structures that relate to aggression
+ Pardini found that over a 20 year period, 56 males consistently behaved aggressively. He took fMRI scans and found a strong correlation between aggression and amygdala volumes.
Evaluate the credibility of the claim that there are brain structures that relate to aggression
- Studies usually find links between brain structure and aggression, rather than clearly establishing cause and effect
- It’s more ethical to do correlational research rather than experiments, but it means that it’s impossible to establish whether a particular structure or function is a cause or effect of aggressive behaviour
Evaluate the applications for using brain structures to explain aggressive behaviours
+ If the nativist viewpoint is correct, then aggression is a biological predisposition and cannot be avoided.
+ It may be possible to identify people with extreme aggression at an early age (genetic screening, hormone testing, etc.). These individuals could be kept away from jobs or roles where they might present a danger to the public (e.g. working with children), and may be directed into other jobs like the Armed Forces, or contact sports.
+ Higher job satisfaction and productivity
Evaluate the other explanations for using the brain structures to explain aggressive behaviours
- There are many studies supporting the idea that aggression is a learned behaviour. Bandura’s “Bobo Doll” studies show that children imitate the aggressive behaviours they see in role models.
- Classical and Operant Conditioning both offer explanations for aggressive behaviour.
Evaluate the generalisability for using the brain structures to explain aggressive behaviours
- Animal studies: animals do not have the same pre-frontal cortex as humans and may not be capable of planning or self-awareness.
- Animals also express their behaviour through dominance or submission. It is possible that researchers are confusing dominant behaviour with aggressive behaviour. This would be a validity problem with the animal model if one sort of behaviour is being mistaken for another.
What was the aim of Raine’s study?
- To investigate whether there was a difference in the structure of brain activity in murderers who pleaded not guilty by reason of insanity (NGRIs) and non-murderers.
- Specifically looked at the prefrontal cortex, corpus callosum, amygdala, medial temporal lobe and thalamus.
- Wanted to see if the studies linking aggressive behaviour to brain structure on animals could be generalised to humans.
Describe the participants of Raine’s study
- 41 offenders pleading NGRI. 39 men and 2 women.
- 41 controls. People of the same age and sex with no history of crime or mental illness, other than 6 schizophrenics.
- Matched for sex and similar age
- Opportunity sampling
What was the IV and DV for Raine’s study
IV:
- Type of participant: the experimental group (murderers who pled NGRI) were compared to the control group (non-murderers)
DV:
- PET scans of brain anatomy and activity measuring a radioactive glucose tracer
What was the methodology of Raine’s study
Natural quasi experiment: brain damage was naturally occurring
Describe the procedure of Raine’s study
- All pps injected with a glucose tracer
- They all performed a continuous performance task (CPT) for 32 minutes and were then given a PET scan
- They were allowed to practice the task for 10 minutes before the injection to make sure they were all familiar with it.
- All pps were taken off any medication 2 weeks prior to the experiment
Describe the results of Raine’s study
- NGRIS showed less activity in the frontal lobe, especially the pre-frontal cortex (responsible for rational thinking, self-restraint and memory)
- Less activity in the parietal lobe (responsible for abstract thinking like morality and justice)
- Less activity in the corpus callosum (long-term planning)
- More activity in the occipital lobe
- Less activity on the left and more on the right in the amygdala and thalamus (these are associated with aggression in animals)
Evaluate the reliability of Raine’s study
STRENGTH
+ PET scans are easily replicable and can be checked for consistency by comparing results
+ CPT was 32 mins long with 10 mins of practice } demonstrates standardised procedures
- However, PET scans in the 1990s were unclear and had to be interpreted
Evaluate the generalisability of Raine’s study
WEAKNESS
- The sample of NGRI participants wasn’t representative of other criminals like thieves.
- Most of the murders committed were non-violent crimes, so it can’t be generalised to violent crime either
- 39 males, 2 females = androcentric
Evaluate the applications of Raine’s study
WEAKNESS
- The study suggests that aggression-causing brain structures can be identified, and therefore ‘treated’ through medication or surgery
- Can’t be used as a full explanation; Raine et al argue that the findings only offer a partial explanation
- Environmental factors influence it
Evaluate the ethics of Raine’s study
+ Informed consent given
- Pps were taken off mediation 2 weeks prior to the experiment
- Pps exposed to potentially harmful radioactive isotope in the PET scan
What are hormones?
Chemical messengers produced from the endocrine glands that are carried in the blood where they bind to receptors, initiating a response.
Evaluate the ecological and task validity of Raine’s study
WEAKNESS
- Low task validity, low mundane realism
- CPT with 10 mins of practice is not reflective of everyday life
- Laboratory setting = low ecological validity
Define Behavioural Endocrinology
The scientific study of interaction between hormones and behaviour.
This interaction is bidirectional – hormones can influence behaviour, and behaviour can sometimes influence hormone concentrations.
Define the endocrine system
A group of glands which secrete hormones into the blood to regulate the function of distant target organs
Define the endocrine glands
Glands which secrete hormones directly into the bloodstream rather than through a duct. There are 10 major glands
Define negative feedback
A regulatory system where a stimulus causes the output of the endocrine system to be lessened (hormone secretion) in order to maintain homeostasis.
Describe testosterone and its influence on aggression
- Produced in testes in males, ovaries/adrenal glands for women
- Males have 20x more. Androgen
- Influences areas of brain development in the pre-frontal cortex, amygdala and hypothalamus, which are associated with aggression
- Increased testosterone = increased aggression
Describe cortisol and its influence on aggression
- Flight or flight response
- Produced in the adrenal glands
- Fearlessness theory: Cortisol normally inhibits aggressive behaviour
- Less cortisol = more aggressive behaviour.
Describe adrenaline and its influence on aggression
- Fight or flight response
- Adrenal gland
- Increased cardiac output, heart rate, endurance and strength
- Increased adrenaline = increased aggression
Describe the supporting research for testosterone influencing aggression
Wagner et al’s 1979 results showed that castration in mice reduced the aggressive behaviours and testosterone replacement therapy caused the aggressive behaviour to return back to pre-castration levels.
Describe the refuting research for testosterone influencing aggression
Research using mice cannot be generalised to the human population as they are two different species.
Describe the supporting research for cortisol influencing aggression
Van Goozen et al (2007) found a link between cortisol hormone levels and aggressive behaviours. Low levels of the stress hormone cortisol in the saliva are associated with persistent aggression in boys.
Describe the refuting research for cortisol influencing aggression
The influence of hormones on the body’s response is correlational so we cannot be certain which hormone is responsible for human aggressive behaviour. Correlation does not mean causation.
Describe the supporting research for adrenaline influencing aggression
Immature Adrenaline Systems Over-reactivity is a treatment used in children with autism and bipolar disorder who suffer from episodes of rage and outbursts.
Describe the refuting research for adrenaline influencing aggression
Immature Adrenaline Systems Over-reactivity is an informal label and there have been no empirical clinical trial to support this treatment. This reduces the scientific credibility of the IASO explanation.
Also biologically reductionist. Fails to account for learning aggressive behaviour.
Define zygosity
The degree of similarity in the alleles for a trait in an organisms
Define monozygotic
Identical twins developed from one zygote which separates and forms 2 embryos. 100% shared DNA.
Define dizygotic
Fraternal twins, developed from a separate egg fertilised by individual sperm cells. 50% shared DNA
Define concordance
A positive or negative correlation between the IV/DV
Define genotype
The complete genetic heritability, for example the alleles inherited Bb.
Define phenotype
The physical characteristics, for example brown or blue eyes.
What were the aims of Brendgen’s study?
- To examine the contribution of genes and environment to social vs physical aggression
- To examine whether the correlation between physical and social aggression can be explained by genetic or environmental factors or by a directional link between phenotypes
Who were the participants in Brendgen’s study?
- 234 twin pairs
- Opportunity sampling. Cluster sampling. All pps were taking part in the Quebec Newborn Twin Study
- Population-based
- Recruited at birth
- Montreal Canada
Describe the procedure of Brendgen’s study
- Zygosity was assessed at 18 months using the zygosity questionnaire for young twins
- A sixth wave of data collection was completed at 6 years of age to assess children’s social adaptation in kindergarten
- Kindergarten teachers rated the children’s level of social aggression and physical aggression using items based on the Preschool Social Behavior Scale (PSBS – T; Crick et al., 1997) and on the Direct and Indirect Aggression Scales (Bjoerkqvist, Lagerspetz, et al., 1992).
- Peer ratings were done with matching pictures
- Responses were given on a 3 point scale
Describe the results of Brendgen’s study
- About 50-60% of physical aggression can be linked to genetic factors
- Social aggression mostly explained by non-shared environmental factors, only 20-23% of social aggression explained by genetics
- Moderate but significant correlation between physical and social aggression - more PA = more SA
- Higher concordance rates for physical aggression in MZ twins compared to DZ
- Similar concordance rates for social aggression between MZ and DZ.
Describe the conclusions of Brendgen’s study
- Strong genetic component to physical aggression but not social aggression
- As child grows more social aggression as social convention on physical aggression
- Genes may lead to a general predisposition towards aggression which becomes social aggression if they have an environment that encourages it
Evaluate the generalisability of Brendgen’s study
+ As it includes nearly an equal number of males and females therefore results of the study can be representative of populations of both genders
- Ethnocentric
- All participants being from/ the same place (Quebec)
- May not be representative of populations in other places eg. Collectivist societies
Evaluate the reliability of Brendgen’s study
- Brendgen used the zygosity questionnaire when all the twins were 18 months old. This demonstrates standardised procedures and is easily repeatable for other scientists in the future. This increases the reliability.
- However, the zygosity questionnaire is potentially objective, and should have been replaced by a DNA test instead, which would have been easier to measure and therefore replicable by other researchers.
Evaluate the applications of Brendgen’s study
- Since social aggression is more socially linked than physical aggression, Social aggression can be prevented using early intervention, educating children on the effects of verbal bullying
- Parents can be educated on ways to deal with children displaying social aggression, monitoring their children
- Physical aggression could be used as an early indicator to parents and teachers that a child’s behaviour could become problematic later on
Evaluate the internal validity of Brendgen’s study
- The study was low in internal validity as it was subjective and was subject to bias as:
- The twins were sorted into MZ and DZ based off physical appearances, not a DNA test
- The children were all rated by peers and teachers, but it was subjective
- Natural experiment, so cause and effect cannot be established. E.g one of the twins might influence the other’s behaviour, leading them astray
Evaluate the ecological validity of Brendgen’s study
+ Naturalistic classroom setting, likely to reflect everyday behavior
+ High task validity - observing natural behavior of the twins in terms of their social or physical aggression
Evaluate the ethics of Brendgen’s study
- Strength: Informed consent - presumptive consent was given by parents of the children, teachers
- Weakness: No protection from psychological harm and it could negatively impact the children as they were studied for such a longer period of their lives
Define evolution
The process by which inherited characteristics in living organisms change over generations
Define survival of the fittest
Organisms that are better adapted to their environment (have the most favourable characteristics) are best suited to survive and successfully reproduce
Define natural selection
Process by which organisms that are better adapted to their environments produce more offspring to transmit their genetic characteristics
Define genetic variation
The difference in DNA sequences between individuals within a population, usually caused by a genetic mutation
Define genetic mutation
Sudden variation in one or more characteristics caused by a change in a gene or chromosome.
Define selection pressure
Environmental or Social factors which determine which characteristics are favorable, e.g. aggressive behaviour may have evolved due to competition over scarce resources such as mates, prevention of infidelity, access to otherwise inaccessible partners, hierarchies and social status.
Define epigenetic
How your behaviors and environment can cause changes that affect the way your genes work
Define genetic drift
A loss of phenotypes which are not favorable to the survival of the organism, causing a reduction in the gene pool
Define kin selection
When an animal engages in self-sacrificial behaviour that benefits the genetic fitness of its relatives
Outline evolution of aggressive behaviour
- Genetic variation is caused by genetic mutations, resulting in differences in both observable and unobservable traits like aggression
- Selection pressures in the environment cause aggressive behaviours to occur as a solution to their adaptive problem
- Survival of the fittest causes organisms with advantageous characteristics that make them better adapted to defending territory and maintaining mates to survive and reproduce
- Genes coding for aggressive behaviour are inherited by offspring
- Epigenetic process occurs which involves the interaction between genes and the environment leads to aggression being an observable phenotype
Outline sexual selection
- The influence of evolution acting on the success of reproduction rather than foremost for survival
- Explains why some characteristics that appear disadvantageous actually confer an advantage
Evaluate supporting research for evolution and aggression
+ Thornhill and Palmer hypothesise humans have evolved adaptions to rape to obtain otherwise inaccessible partners, arguing that the behaviour of rape evolved over millenia of human history, along with courtship and sexual attraction related to the production of offspring
Evaluate research supporting genetic links and aggression (MAOA-L)
+ Chester et al found that the low-functioning MAOA-L genotype was linked to greater aggression. It caused the lack of breakdown of neurotransmitters, increasing synaptic transmission and resulting in a grater reactivity to negative experiences such as a tendency to act impulsively.
Evaluate research supporting genetic links and aggression (MAOA-H)
+ Metins et al found that the high functioning MAOA-H genotype was associated with greater prosocial behaviour.
Describe refuting theories for evolution and aggression
- Bandura’s Social Learning Theory says that aggressive behaviours may be observed by in the environment by same-sex role models and then imitated by observers
- Freud said that violence exists within everyone due to a basic instinct to dominate. Aggressive energy is an instinctive drive that builds up until it needs to be released.
Evaluate refuting ideas for evolution and aggression (MAOA-L)
- Against: Henian et al (2013)
- Refutes the idea of low MAOA-L genotype is linked to aggression instead proposes that low MAOA-L is linked to human happiness in females
What are twin studies?
An investigation into the role of nature (genes) and adoption studies investigate the role of nurture (upbringing) in behavioural, physical and medical traits.
What is the biology behind twin studies?
Monozygotic twins share 100% DNA. Dizygotic twins share 50% DNA.
This allows psychologists to determine the likelihood of both, or one twin inheriting a particular trait by comparing concordance rates between the twin pair.
Why are twin studies important to studying disease?
They have helped psychologists investigate whether psychological behaviours like human aggression are ‘hard-wired’ into humans the same way as genetic factors like a person’s phenotypic eye colour or whether behaviour is learned due to environmental influences (nurture).
Evaluate the internal validity of twin studies
Cause and effect can easily be established by sequencing their DNA and find out the MZ and DZ concordance.
Evaluate the generalisability of twin studies
They are very unique
The results might not be able to represent the wider population due to the research only being representative of twins that either share 50% or 100% DNA
What was the aim of Heston’s adoption study?
To test the genetic contribution of developing schizophrenia between adopted children and their schizophrenic biological mothers
What was the sample for Heston’s adoption study?
- Participants born between 1915 and 1945 to schizophrenic mothers who were in the Oregon State psychiatric hospital. Selected if they had been separated from birth and put up for adoption
- 47 experimental participants (30 males + 17 females).
- 50 controls (33 males + 17 females).
What was the IV and DV for Heston’s adoption study?
IV:
- Whether ppt was born to schizophrenic mothers where mother and child were permanently separated after the first two postpartum weeks, or ppt was born to a normal, healthy mother
DV:
- Psycho-social disability (numerical score 100-0)
- Based on MHSRS (mental health sickness rating scale)
Describe the procedure of Heston’s adoption study
- All possible original subjects were located and their background informationw as looked into.
- School records, criminal status, civil information and newspaper files were gathered of the subjects
- Personal interviews were conducted, a Minnesota Multiphasic Personality Inventory (MMPI), an IQ score, social class of the subjects first home and current social status were obtained
- Interview was standardised (general medical and environmental questionnaire). Nearly all interviews were conducted in the subjects homes
- Social class values were rated from 1-7 (7 being the worst social status)
3 Psychiatrists independently rated the subjects
What were the results of Heston’s adoption study?
- The probability of children born with schizophrenic or sociopathic mothers developing these disorders in the future was 0.05
- 5/47 people born to schizophrenic mothers, compared to 0/50 in control group, were schizophrenic
- Half of all people in the study who were diagnosed with other psychiatric conditions, and people discharged from the Armed Forces for psychiatric or behavioural reasons were born to schizophrenic mothers.
- The other half of the people born to schizophrenic mothers were successful adults + demonstrated imaginative adaptions to life and artistic talents which were uncommon in the control group
What were the conclusions of Heston’s adoption study?
- The results of this study support a genetic causation of schizophrenia as schizophrenia was only found in the offspring of schizophrenic mothers
- The probability of this segregation being affected by chance is less than 0.025
- Also, half of the experimental group exhibited major psycho-social disability
- They had disorders other than schizophrenia
Evaluate the generalisability of Heston’s adoption study
- Ethnocentric: 47 participants for Oregon. Individualist culture that can’t be generalised to collectivist culture
- Androcentric: 30 males vs 17 females
- Most of the population isn’t adopted so not generalisable to whole population
Evaluate the reliability of Heston’s adoption study
- Personal interviews were conducted, the Minnesota Multiphasic Personality Inventory (MMPI), an IQ score, social class of the subjects first home and current social status were obtained. The interview was standardized, allowing for replicability.
- Primary data was collected
- Inter-rater reliability - 2 psychiatrists and Heston
Evaluate the internal validity of Heston’s adoption study
- MMPI used and IQ score
- Social classes rated from 1-7
- Quantitative data is objective, reducing bias and increasing internal validity
Evaluate the ecological validity of Heston’s adoption study
The interviews were conducted in the home, which is a natural environment. This means that the participants behaviours would reflect their everyday life because of the familiar setting, which increases the ecological validity because the findings can be applied to real-life.
Evaluate the applications of Heston’s adoption study
+ Useful for families with a history of schizophrenia who are looking to adopt children - it is not caused by upbringing
+ Clear genetic link for schizophrenia so this information can be used to develop research in order to prevent schizophrenia being passed on
+ Prevent children with genetic predispositions for schizophrenia from developing it in the future by changing lifestyle factors and avoiding stressful careers, drugs to prevent it from being triggered.
Evaluate the ethics of Heston’s adoption study
- Parents of adopted pps or adoption agency gave consent for children
- Pps were lost from the study over time, indicating a right to withdraw
- The study pries into the personal lives of the pps, like their private medical records
- Goes against the social responsibility of the researcher
What are adoption studies?
- An informative approach for understanding the nature vs nurture debate and how it affects behavioural, physical and medical traits.
- Adoption studies look at the impact of nurture on children who are raised by foster/carer parents who are not their biological parents.
What is the biology behind adoptions studies?
- Biological parents can pass on 50% of their DNA from the mother and father to their offspring. Non-biological foster parents are not related or linked to the child.
- If there is no biological connection between the foster parent and the child, the child’s shared trait with the parents must be due to nurture rather than nature
Why are adoption studies important to studying disease?
- Helped psychologists to investigate whether clinical disorders like schizophrenia are caused by nurture and upbringing.
- This has helped society to move away from blaming/stigmatising parents and moving towards considering genetics and biology as root causes
Evaluate the internal validity of adoption studies
+ Adoption studies are made more valid if the researchers have information about the child’s biological parent. If the child grows up with these traits that resemble the adoptive parent more than the biological parent, this is stronger evidence that these traits are due to nurture, Psychologists conduct adoption studies with large samples, so that statistical analysis can be assessed, which increases validity.
- Correlation does not always mean causation when studying concordance rates for adoption studies, as psychologists may be failing to account for confounding factors.
Evaluate the generalisability of adoption studies
- This is a group that may not be very representative of other children.
- These children have been separated from the biological parents, perhaps through tragic circumstances or because their biological parents “gave them up” due to difficult circumstances. - Child Psychologists like John Bowlby argue that children are badly affected if they are separated from their mother during a critical period in infancy. If this happens to adopted children, it would make them even less representative of children in general.
What are the three forms of the ‘psyche’
- Conscious
- Preconscious
- Unconscious
Describe the conscious
- Includes thoughts and perceptions we are aware of and have control over
- What we are currently thinking of
Describe the preconscious
- Includes thoughts and perceptions we are occasionally aware of
- Memories that can be recalled
Describe the unconscious
- The majority of the mind which we are totally unaware of
- Repressed childhood memories, instincts, desires, fears, dreams
Define neurosis
Neurosis: A mental disorder marked by anxiety or fear; less severe than psychosis because it does not involve detachment from reality (e.g., hallucination)
Describe the ID
- First part to develop
- Exists only in unconscious mind
- Urges, instincts and desires
- Impulsive and selfish
- Instant gratification
- Denial results in frustration
2 instincts: Eros (life), Thanatos (death)
Describe the Ego
- Second to develop. 2 years
- Exists in conscious mind
- Logic, decision making, self-control
- Mediator between ID and Superego
- Triggers defense mechanisms to defend itself
Describe the Superego
- Last to develop. 3-5 years old
- Exists in conscious and unconscious mind
- Morals and values of society
- Challenges ID’s impulses
2 systems:
1. Conscience. Causes feelings of guilt
2. Ego-Ideal. Feelings of pride due to acting as a ‘good’ member of society
Describe Repression
ID demands are repressed back into the unconscious mind
Describe Denial
Conscious mind refuses to admit that the ID instincts are real
Describe Sublimation
ID instincts satisfied, but are transformed into something socially acceptable, e.g. boxing to relieve aggression
What is Catharsis?
The process of releasing negative energy in the mind.
Why is Catharsis important?
Catharsis is important to relieve the conflicts of the unconscious mind and symptoms of distress, anger and anxiety
How does the psychodynamic theory explain personality development?
- Personality is based on the interactions between the tripartite system (ID, Ego and Superego)
- Ego strength is the ability to function normally despite the conflict between the 3 systems
- Healthy personality types are maintained by balance between the ID, Ego and Superego
How does the psychodynamic theory explain aggression?
- Aggressive behaviour develops because the ID is dominant over the Ego and Superego
- ID drives the impulsive and instinctive behaviours to be satisfied
- The ID’s Eros energy is libido (sexual impulses), this can explain aggressive behaviours observed in sex offenders
- Thanatos drives the death instinct: this could explain aggressive behaviours observed in violent criminals
- Ego develops at 2 years of age, and the superego develops at 3-5 years of age. This could explain why young children display tantrums or aggressive behaviours towards other children as the ego and superego are underdeveloped and children cannot distinguish between right and wrong.
What is the Key Question for Biological Psychology?
What are the implications for society if aggression is found to be caused by nature, not nurture?
Why is the Key Question relevant to today’s society?
If aggression is found to be caused by nature, there might be measures put into place to promote early intervention of potential criminals, such as genetic screening and DNA testing for biological predispositions like the MAOA gene or abnormally high levels of testosterone/adrenaline.
How many offences in March 2022 involving a knife or sharp instrument?
45,000 in Wales and England
How many homicides using a sharp instrument in the year ending March 2022?
261
