The Biological Approach Flashcards
Brain and Behaviour - Brain Imaging Techniques
MRI
Magnetic Resonance Imaging
Produces static image of brain and used to detect stuctural changes in the brain.
High spatial resolution (highly detailed), low temporal resolution (cannot show activity).
Helps understand cognitive processes such as Memory.
Brain and Behaviour - Brain Imaging Techniques
fMRI
Functional Resonance Imaging
Shows physiological structures in great detail - shows action and functions within brain by blood flow measurement.
Low spatial resolution, high temporal resolution.
Brain and Behaviour - Brain Imaging Techniques
Advantages/Disadvantages of Brain Imaging Technology
Advantages
Non-invasive method to look into healthy and functioning human brains (compared to exploratory surgery).
Can help with early diagnosis and treatments of disorders.
Disadvantages
Expensive.
Claustrophobic.
Loud.
Brain and Behaviour - LOF
Localisation of Function
Different areas of the brain are associated with different behaviours.
Brain and Behaviour - LOF
Hippocampus
Involved in encoding STM into new LTM (declarative/explicit memories).
Brain and behaviour - Brain Imaging Techniques, LOF, Neuroplasticity
Grey Matter
Made up of neuronal cell bodies and synapses.
More grey matter, more synaptic connections/neural networks.
Study - LOF SAQ/ERQ
Milner et al (HM case study)
RM: Case study - 5 decades
Aim
Investigates the brain’s impact due to the removal of the hippocampus.
Background information
HM sustained a serious head injury at a young age and endured serious seizures throughout his younger years.
With his and familial approval, he participated in experimental surgery for removal of temporal lobe (w/ hippocampus).
Initial observations - After operation
Remembered childhood very well.
Forgot daily events nearly as fast as they occurred.
Method
MRI scans.
Kept re-introducing himself to people.
HM underwent various strategies:
Psychometric testing.
Direct observation.
Cognitive testing
- Memory recall.
- Learning tasks (e.g. reverse mirror drawing).
Results
Diagnosed with anterograde amnesia (inability to form new declarative/explicit memories).
Psychometric testing - Hippocampus does not influence IQ.
Direct Observation - Hippocampus plays a critical role in converting STM to LTM.
Cognitive Testing (Mirror task) - Skills improved, therefore hippocampus is not responsible for procedural/implicit memories.
MRI - Almost all of HM’s hippocampus was removed.
Study - Brain Imaging Techniques SAQ, Neuroplasticity SAQ/ERQ
Maguire et al
Human Quasi experiment
Aim
Investigating whether morphological changes in the brain could be detected in relation to extensive experience of spatial navigation.
Method
London taxi drivers were chosen because they relay heavily on spatial navigation skills in working lives. Also had to undertake extensive training called “The Knowledge” to acquire vast spatial memory of roads.
Numerous right-handed male licensed London taxi drivers were compared with scans of numerous age-matched right-handed males who do not drive taxis.
Results
MRI analysis found that significantly increased grey matter volume was found in only two regions of taxi drivers’ brains: right and left hippocampi compared to control group (no other differences).
Posterior hippocampi of taxi drivers was significantly larger than control group.
Anterior hippocampi of control group was significantly larger than taxi drivers.
Positive correlational analysis between time length as taxi driver and volume of right posterior hippocampus (negative for anterior).
Critical Thinking
Strengths
Well-operationalised dependent variable - MRIs give objective data.
High external (ecological) validity - Use of real taxi drivers.
Limitations
Generalisability - Only taxi-drivers/males; general population may not have same hippocampal changes (e.g. females).
Bidirectional ambiguity (correlational research often has this):
- Experience as a taxi driver causes hippocampal changes.
- People with naturally larger hippocampi may excel at spatial navigation.
- To counter: Conducted correlational analysis. Found that longer as taxi driver = Larger posterior hippocampus.
Study - Brain Imaging Techniques ERQ, Neurons SAQ
Arnone et al
Human True Experiment
Aim
To investigate the role of SSRIs in neurogenesis and role in reducing symptoms of depression.
Method - MRI
39 currently depressed (MDD), 25 in remission, 66 healthy controls underwent MRIs.
Results - MRI
Currently depressed patients had reduced grey matter in hippocampus compared with healthy and remission groups.
Method - Antidepressants
Most of currently depressed were treated with citolopram SSRI for 8 weeks.
After 8 weeks, patients’ hippocampi were measured again.
Results - Antidepressants
Depressed participants who were assigned to SSRI condition had increase grey matter with some experiencing decreased depressive symptoms.
Critical Thinking
Strengths
High internal validity (operationalised DV) - MRI isolated variable.
Limitations
Correlational; not causation.
Validity enhanced if there is a true control group.
- Random allocation of different groups from same depressed sample.
- May have not been done due to ethics (more ethical to give everyone treatments).
Study - Brain Imaging Techniques ERQ, LOF ERQ
Dunlop et al
Human correlational study.
Theoried that MDD is not unitary and that symptoms of depression might be better explained by underlying neural networks and ‘biotypes’ of depression.
Aim
To investigate the effectiveness of CBT and antidepressants for different biomarkers of depression.
Method
Numerous participants were assigned to SSRI or CBT condition.
Participants underwent resting-state fMRIs for baseline data.
Treated for 12 weeks and then treatment effectiveness was assessed using a depression rating scale and computer analysis using AI correlates patterns of brain connectivity with effectiveness of medications.
Results
When treatment matched biotype, 74% of participants improved.
When did not match, failed for 86%.
47.5% improved through treatment.
Critical Thinking
Helps explain why so many people with MDD struggle to find effective treatment.
Study - Neuroplasticity ERQ
Draganski et al
Human field experiment
Aim
Investigate whether juggling would affect the brain of participants.
Method
Mostly female young adult volunteers who were non-jugglers at start of study.
Separated into juggling and non-juggling (control) group.
Participants had MRI scan initially as base rate for grey matter/brain structure.
Juggling condition - Taught a three-ball juggling routine and asked to practice and notify researchers when they have mastered it.
At notification, underwent second MRI scan.
Results
Prior to juggling, no significant differences.
After second scan, jugglers had significantly larger amount of grey matter in mid-temporal area in both hemispheres (related to visual memory).
Three months after participants stopped juggling (unable to do routine), grey matter decreased.
Critical thinking
Strengths
Argues a causal relationship.
Limitations
IV manipulated under natural conditions, home environments may be different for participants affecting DV.
Generalisability - Use of volunteer; more motivated than general population.
Brain and Behaviour - Brain Imaging Techniques, Neurotransmitters.
MDD
Major Depressive Disorder.
Classified as a persistent low mood and/or anhedonia.
Other common symptoms include detrimental effects on sleep and appetite, impairment of daily functioning, and suicide ideation.
Brain and Behaviour - Neuroplasticity
Neuroplasticity
Changes in neural pathways and synapses due to changes in behaviour and environment.
Repeated activation of neural pathways make them stronger (structural changes).
Brain and Behaviour - Neuroplasticity
Neural networks
Interconnected groups of neurons that communicate with each other to carry out complex cognitive processes.
Formation of networks is dictated by neuroplasticity.
Specifically through synaptic plasticity (strengthening/weakening of synapses) and LTP (repeated activation of certain pathways lead to more efficient signal transmission).
Brain and Behaviour - Neuroplasticity
Synaptic Plasticity
Strengthening/weakening of synapses
Brain and Behaviour - Neuroplasticity
Long term Potentiation (LTP)
Repeated activation of certain neural pathways lead to a more efficient signal transmission.
Brain and Behaviour - Neuroplasticity
Neural Pruning
Brain eliminates unused synaptic connections and refines more commonly-used neural networks.
Essential for efficient brain functioning.
Can be studied by observing changes in grey matter.
Brain and behaviour - Neurotransmitters
Neurotransmitters
Neurotransmitters are chemical messengers that neurons use to communicate.
Mediates the events at the synapse between neurons.
Affected by agonists (amplies their effects) and antagonists (reduces their effects).
Brain and behaviour - Neurotransmitters
Serotonin
Serotonin (5-HT) is a neurotransmitter which modulates mood, sleep and appetite.
Brain and behaviour - Neurotransmitters
Excitatory neurotransmitters
Excites (activates) the neuron.
Brain and behaviour - Neurotransmitters
Inhibitory neurotransmitters
Prevents a neuron from firing.
Brain and behaviour - Neurotransmitters
Neuron
Basic building blocks of the nervous system and are responsible for transmitting information in the form of electrical impulses throughout the brain.
Neurons work together to produce many effects, resulting in a complex repertoire of behaviours.
Neurons communicate across synapses through neurotransmitters, which influence behavior by either exciting or inhibiting postsynaptic neurons.
Brain and behaviour - Neurotransmitters
Agonist
Substances that bind to synaptic receptors and amplify effect of neurotransmitter.
One are SSRIs.
Brain and behaviour - Neurotransmitters
SSRIs
Selective Serotonin Reuptake Inhibitors.
Based on the serotonin hypothesis.
Prevents re-absorption of serotonin back into pre-synaptic neuron, increasing amount of serotonin in the synapse.
Does not block receptors.
Brain and behaviour - Neurotransmitters
Antagonist
Bind to synaptic receptors but decreases effect of neurotransmitter.
One is ecopipam (dopamine antagonist).
Brain and behaviour - Neurotransmitters
Ecopipam
Dopamine Antagonist
Stops dopamine binding with receptors in post-synaptic neuron, prevents usual feelings of reward/pleasure from occurring.
Study - Agonist SAQ, Neurotransmitters SAQ/ERQ
March et al
Human true experiment.
Aim
Looking into the Serotonin hypothesis and the most effective treatment for MDD.
Method
Adolescent MDD patients from various USA clinics participated in three stages (12 week treatment administration intervals with depression assessed at end of each interval).
Assigned randomly to 4 treatment conditions: Fluoxetine (SSRI) alone, CBT alone, fluoxetine and CBT combined, Placebo (no therapuetic effect).
SSRIs were controlled using a double blind design (no-one knew what patient was receiving).
CBT were unblinded as therapy environment is obvious.
Depression was assessed using a clinical rating scale.
Results - First Stage
Response and reduction in depression symptoms:
35% of placebo group (expectancy effect and benefit of placebo). Discontinued from here.
61% of fluoxetine (better short term)
44% of CBT.
71% of combined (best when both).
Results - Third Stage
Response and reduction in depression symptoms:
81% of fluoxetine.
81% of CBT (as effective long term).
86% of combined (still the best).
Critical Thinking
Strengths
High external (population) validity - Patients taken from different clinics in US.
Limitations
Correlational; not causation.
Study - Antagonist SAQ
Romach et al
Aim
Investigates role of ecopipam in treatment of cocaine (dopamine) addiction.
Method
Self-selecting adults were cocaine addicts.
Two weeks where participants were hospitalised (ensures experimental controls) and used a randomised double-blind design into 4 conditions: placebo, 10mg, 25mg, 100mg of ecopipam orally on 4 separate occasions.
Two hours after taken, participants were injected with 30mg of cocaine.
Assessed for biological measures of cocaine (blood pressure, heart rate) and psychological measures (feelings of being ‘high’ or anxiety, confusion, etc).
Asked about desire to take cocaine (important in effectivity of reducing cravings).
Results
Participants in ecopipam group reported reduced feelings of euphoria and feeling ‘high’.
Reduces anxiety associated with taking cocaine.
Ecopipam group also expressed less desire to use cocaine than placebo group. Most effective between 25-100mg.
Hormones/Pheromones and Behaviour - Hormones
Hormones
Chemical messengers that are transported through the blood due to activation of different glands in endocrine system.
Regulates long-term ongoing processes (e.g. growth, metabolism, reproduction).
One is testosterone.
Hormones/Pheromones and Behaviour - Hormones
Testosterone
Potential reason for male aggression.
Major sex hormone produced by body in (largely) men and women.
Produced in testes or ovaries/placenta.
Special interest as it influences brain in archetypical situations such as fight and flight and search and struggle for status.
Recent developments argue for causal role of testosterone as social hormone (influences social behaviour).
Study - Hormones/Pheromones and Behaviour
Dabbs et al
Human correlational research.
Debriefing, informed consent.
Aim
Investigates the role of testosterone in aggression.
Method
Took saliva samples of 89 male inmates.
Also interviewed inmates in cohabilitation housing unit.
Results
Found that 10/11 men with highest testosterone concentration were convicted of violent crimes.
Contrasted with 9/11 males with lowest concentration were convicted of non-violent crimes.
Qualitative - Interviews found that inmates rated ‘toughest’ and ‘most aggressive’ by peers had highest levels of testosterone.
Inmates who received parole for good behaviour had lowest concentrations.
Similar with women.
Critical Thinking
Strengths
Relationship is bidirectional.
Limitations
Testosterone is not deterministic - plenty of males with extremely high levels of testosterone who do not commit violent crimes.
- Behaviour is not determined by testosterone.
- Rather increases likelihood of behaviour.
Study - Hormones/Pheromones and Behaviour
Radke et al
Human True Experiment.
Informed consent, debriefing.
Aim
Investigating whether testosterone administration leads to enhanced amygdala reactivity to angry faces.
Method
54 healthy females (half were given small dose of testosterone, other half with placebo.)
While in fMRI, participants were shown happy or angry faces one at a time.
Participants had to avoid or approach the face with a joystick (picture becomes closer/bigger for approach and further/smaller for avoid).
Amgydala and prefrontal cortices were measured.
Results
Increased activation in right amygdala during threat approach after testosterone administration compared to approaching happy face and placebo group.
Amygdala activity differed between approach/avoidance of angry faces after testosterone but not after placebo.
Testosterone administration increased amygdala activity during approach and decreased during avoidance.
Critical Thinking
Strengths
Internal validity - Isolation of variable through fMRI.
Limitations
Ecological validity - To what extent does a face moving closer/further on a screen represent a social threat in reality.
- Environment is not representative.
- Narrow definition of what contitutes a social threat; more research needed on variety types and amygdala activation to generalise results.
Correlational studies can establish a statistical link between testosterone and aggression.
- Research like this alone is not particular insight to understand complexity behind relationship.
- Although no causation, correlational may be good enough for complex relationship.
Genetics and Behaviour - Genetics Similarities
Genetics similarity argument
Genetics based on principle of inheritance (50% of genetics from each parent).
Referred to as relatedness.
- Greater the genetic similarities, the higher the degree of relatedness.
If a behaviour is heritable then the more genetically similar two individuals are, the more common that behaviour should be.
Purely correlational.
Genetics and Behaviour - Genes and Behaviour
Genes
A unit of heredity, a region of DNA that encodes a specific trait or function.
Building blocks to complex behaviours.
Genetics and Behaviour - Genes and Behaviour
MAOA Gene
Monoamine oxidase A gene - Warrior Gene
Produces the protein MAOA enzyme - that breaks down neurotransmitters in the synapse involved in regulating mood, emotion and stress.
- Helps maintain balanced levels of mood/behaviour in the brain.
- Abnormal levels may lead to psychological effects.
Some humans have low expression variant of this gene
(MAOA-L).
If they have low expression variant, less MAOA produced.
- Affects neurotransmitter levels and therefore brain activity.
Both protective (H) and harmful (L)
Study - Genes and Behaviour SAQ/ERQ
Caspi et al
Human Case study
Shows gene-environment interaction.
Aim
To investigate the MAOA gene.
Method
Over 1000 children in Dunedin had their genes, blood pressure and private lives monitored and measured every few years.
Results
MAOA-L gene moderated effects of experiencing child abuse on adult aggression.
- 85% with gene and were abused as children were more likely to be antisocial/aggressive adults compared with those with just the gene.
Critical Thinking
Strengths
Credibility - Multiple data sources.
Longitudinal.
Limitations
Absence of free will
- Young people do not have free will (parents control their environment).
- Genes cannot be controlled.
Cannot be replicated.
Study - Genes and Behaviour ERQ
Meyer-Lindenberg et al
Human quasi experiment
Aim
Investigates how the MAOA gene influences antisocial behaviour in the brain.
Method
Compared brain activity of two groups of healthy participants.
- One with MAOA-H, other with MAOA-L.
Results
When shown angry/fearful faces while in an fMRI, MAOA-L group had significantly increased activity in amygdala and reduced activity in ventromedial prefrontal cortex (VMPFC).
- VMPFC inhibits impulsive behaviour and allows us to think through actions.
- Reduced activity may lead to impulsive aggression.
Genetics and Behaviour - Genes and Behaviour
VMPFC
Ventromedial prefrontal cortex
VMPFC inhibits impulsive behaviour and allows us to think through actions.
Reduced activity may lead to impulsive aggression.
Genetics and Behaviour - Genetic Similarities
Relatedness
Extent to which two individuals have a genetic similarity.
Genetics and Behaviour - Genetic Similarities (Twins)
MZ twins
Monozygotic twins
Twins with 100% genetic similarity
Genetics and Behaviour - Genetic Similarities (Twins)
DZ twins
Dizygotic twins
Twins with 50% genetic similarity
Genetics and Behaviour - Genetic Similarities (Twins)
Heritability
Estimation of extent to which a character’s variance within a population is due to genetics.
Calculated using concordance rates.
Genetics and Behaviour - Genetic Similarities (Twins)
Concordance rate
Extent to which a given trait is shared by a pair of individuals expressed as a percentage.
Genetics and Behaviour - Genetic Similarities (Twins)
Twin studies
Concordance rates measures twin similarities (probability that one twin with trait and that other will have it)..
Relies on MZ twins have 100% genetic material and DZ have 50%.
Also based on equal environment assumption.
Genetics and Behaviour - Genetic Similarities (Twins)
Equal environment assumption
Belief that twins are raised in the same culture by the same parents and attend the same school and socialise with the same friends (allows for ignoring environment).
- Results in environmental factors affecting genetic expression of behaviour development would be equal.
Criticised as erroneous as differences can have significant effects on behaviour (e.g. nutrition, peer groups, treatment by parents, etc).
Genetics and Behaviour - Genetic Similarities (Twins)
Anti-social Behaviours
Actions that harm/lack consideration for well-being of others.
Major component is aggression.
Study - Genetic Similarities (Twins) SAQ, Genetic SImilarities ERQ
Gottesman and Goldsmith et al
Aim
Investigate the concordance rates of juvenile deliquencies and adult criminal conviction in monozygotic/dizygotic twins.
Method - Part 1
Studied numerous sets of young twins.
Results - Part 1
0.91 (91%) concordance rate for MZ twins.
- If one twin broke the law, 91% chance the other will.
0.73 (73%) concordance rate for DZ twins.
Genetics is a factor (but not not fully due to <100%).
Method - Part 2
Studied over 500 adult twins.
Results - Part 2
0.52 concordance rate for MZ twins.
0.23 concordance rate for DZ twins.
Inability to generalise.
- Not a lot of family dynamics have siblings are raised at equal environment. Twins may have aspects that are not repersentative.
- Families a more broader sample and more generalisable.
Study - Genetic Similarities (Kinship) SAQ, Genetic Similarities ERQ
Natsuaki et al
Aim
Investigate genetic influence on behaviour in a kinship sample.
Method
Compared a large sample of sibling pairs (MZ, DZ, step-siblings).
Measured for externalising problems (antisocial behaviour towards environment - physical aggression, vandalism, stealing).
Results
MZ twins were most similar (correlation between similarity of twins and correlation coefficient score)
Research has evolved past twins and kinship studies.
Looking into genotypes and particular genes (Caspi)
Genetics and Behaviour - Evolutionary Explanations
Charles’ Darwin’s Natural Selection (Sexual Selection)
The evolutionary explanation to explain mate choice.
Human attraction originates from the desire to find the best mate that can produce and protect the healthiest offspring possible.
Genetics and Behaviour - Evolutionary Explanations
MHC genes
Major histocompatibility complex genes; An important group of genes of the immune system.
General
Biological explanations
Aims to explain psychological phenomena due to biological etiology where every psychological process originates from internal physiological processes.
Study - Evolutionary Explanations SAQ, ERQ
Wedekind and Furi et al
Human quasi experiment.
Aim
Investigates the relationship between MHC gene signatures and attraction.
Method
Numerous female and male participants.
Males were given a clean cotton t-shirt and asked to keep in open plastic bag when not worn.
T-shirt worn for 2 nights during sleep.
Asked to abstain from spicy foods and other odour-affecting activities.
Females were asked to rate pleasantness of t-shirts.
Results
Females gave higher ratings of pleasantness to MHC-dissimilar t-shirts compared to MHC-similar t-shirts.
Odour assessment was reversed when women took contraceptives.
Critical Thinking
Strengths
Increased internal validity - Actual smell of person affects attraction.
- Controls extraneous variables (e.g. Spicy foods/Perfume/not wearing during day/no smoking)
Limitations
Low mundane reality - rating t-shirt smells does not reflect mate selection scenarios.
Low external (ecological) validity - People interact with odour-changing activities.
Spiral
Evolution is for species level.
- To be fully supportive, research needs to be replicated/reproduced cross-culturally in a universal setting (does not explain non-hetero r/s) - does not test it.
- Can be spiral to Buss (almost universe sample)
Study - Evolutionary Explanations ERQ
Buss et al 1989 Bio Analysis
Looks at parental investment theory (females are choosier as more vulnerable and greater investment)
Cross-cultural survey.
Hypothesis
Females favour mates who:
- Can invest resources in her and her children.
- Can protect her and her children.
Aim
Investigation into mate preferences and evolutionary explanations for mate selection.
Method
Over 10000 participants across 37 cultures.
Cross-cultural survey collected data on partner/spouse age preferences.
- Rated different mate characteristics on 0-3 scale (irrelevant-indispensible).
- Ranked characteristics in order of most desired.
Characteristics included - good financial prospects, chastity, ambition and industriousness, physical attractiveness.
Results
Females rated ‘good financial prospects’ and ‘ambition and industriousness’ significantly higher than males did.
Males generaly preferred spouse to be younger (females preferred older spouses).
Sex specific differences irrespective of culture.
- Evolution is to some extent as unconscious/more accurate explanations may explain mate choice (socio)
Study - Evolutionary Explanations ERQ
Buss et al 1990 Socio Re-Analysis
Cross-cultural survey.
Hypothesis
Females favour mates who:
- Can invest resources in her and her children.
- Can protect her and her children.
Aim
Investigation into cultural effects on mate preferences.
Method
Over 10000 participants across 37 cultures.
Cross-cultural survey collected data on partner/spouse age preferences.
- Rated different mate characteristics on 0-3 scale (irrelevant-indispensible).
- Ranked characteristics in order of most desired.
Characteristics included - good financial prospects, chastity, ambition and industriousness, physical attractiveness.
Results
Each culture had its own distinct mate preferences.
Most evident for chastity.
Formulation of dimensions (Not Hofstede); traditional vs modern and how each culture rated ‘traditional’ mate characteristics (e.g. chastity, desire for home and children, etc).
Traditional cultures placed highest preferences for such characteristics, while modern placed lowest
