Biological Approach Studies Flashcards
Describe Maguire’s Study
A: See how cognitive processes may lead to neuroplasticty in the hippocampus by seeing whether brains of London taxi drivers may be different due to their intense mapping knowledge
M:
PPTS: 16 right handed male taxi drivers, 50 right handed regular males, a range of ages
MRI scans taken and compared
All completed ‘Knowledge’ test and must have had licence for at least 1.5 years
Correlational, researchers looked for relationship between no years driving taxi and anatomy of brai
Single-blind study
Data from MRI measured using voxel-based morphometry (to measure grey matter density) and pixel counting (counting image pixels to calculate hippocampal area)
R: Pixel counting found that posterior hippocampus was significantly larger in taxi drivers rather than the control group, VBM showed that vol of posterior hippocampus correlated directly with no of years spent as a taxi driver
C: Hippocampus may change in response to environmental demands
E:
MRI poses no health risks
Researcher bias avoided as single-blind
Appears to have sampling bias (male) however majority of London cabbies are male, yet there are issues with generalisability
Ecological validity as not asked to do anything but have a scan
No independent variable manipulated, solely correlational, causality cannot be assumed
Describe Draganski’s Study
A: See if learning a new skill would have effect on brain
M:
PPTS: 24 volunteers (21 F, 3 M) between ages of 20-24, all non-jugglers to begin
Each had MRI scan as a base rate for grey matter and brain structure
Allocated to a condition: jugglers and non-jugglers (control)
Juggling condition taught a three-ball cascade routine which they practised until mastery before a second scan
Then told not to juggle anymore before a final scan 3 months later
VBM used to see if sig diffs in neural density in brains of 2 conditions
R: No sig diffs in grey matter between 2 conditions initially, yet at end of first part of study jugglers showed larger amount of grey matter in mid-temporal area in both hemispheres (area associated with visual memory)
3 months later: grey matter in these parts decreased, as most forgotten routine, no change in non-juggling sample across duration
C: Juggling relies on visual memory (perception and spatial anticipation of moving objects)
E:
MRIs had eco val, just had to get scanned, no task
No health risks posed by MRI
Pre-test, post-test design to show diffs in neural density over time
Brain scans not that representative of males, as majority female, therefore gender bias as female brains may work in a differenceway to males
Low population validity - gender and age, MRIs can’t be used to generalise findings
Small sample size
Pot. internal validity problems as ppts at home for most of study
Describe Broca’s Case Study
Louis Leborgne (Tan) lost ability to speak at 30
He later developed gangrene - admitted to surgery by Paul Broca when could only pronounce “Tan”, typically repeated twice with expressive hand gestures
Condition same until death, unable to speak/write was his only flaw, understood everything but couldn’t communicate back
Condition now known as Broca’s aphasia
Tan died at age of 51 - autopsy revealed a lesion in frontal area of left hemisphere, a region in posterior inferior frontal gyrus now known as Broca’s area
Cautious to draw conclusion - analysed another 25 patients
Weakness: didn’t actually dissect brain so failed to see lesion broader than he documented, damage extended to surrounding regions of frontal lobe thus not strictly localised to Broca’s Area
Describe Lashley’s Study
M:
Measured behaviour before & after specific carefully controlled induced brain damage in cortex of rats
Rat was trained to run through a maze without errors in search of food, after learning occurred area of cortex removed (portion removed varied in location and size (10-50%))
Rat placed at start and behaviour change logged
Idea: if memory of a maze localised somewhere, by removing different areas, specific region responsible would be pinpointed
R: Failure: hypothesis abandoned
C: Memory widely distributed across cortex not localised, supported by…
Principle of mass action: based on correlation between % removed & learning ability observed, less cortex = slower and more inefficient learning, performance dep on % removed not location
Equipotentiality: ability of 1 part of cortex to take over functions of another
E:
Induced brain damage = vv invasive, used many rats, lasting harm caused yet no other way to do it, cost-benefit analysis needed
Describe Martinez & Kesner’s Study
A: Determine role of acetylcholine (excitatory NT) in memory formation, significant number of acetylcholine receptors in hippocampus
M:
Had mice run a simple t-maze to find food placed in one of arms of t, after having run maze but before memory could be consolidated, researchers injected mice with 1 of 3 chemicals
First group: injection with scopolamine, which blocks acetylcholine receptor signs thus inhibiting any response (antagonist)
Second group: injection with physostigmine, which breaks down enzyme acetylcholinesterase which breaks down acetylcholine in synapse (agonist)
Final group: placebo injection of saline sol to ensure memory change wasn’t due to getting injection alone
Placed back in maze to see how long it would take them to find food previously located
R: Scopolamine group took longer & made more mistakes, physostigmine group learner faster & made fewer mistakes (comp to control)
C: Acetylcholine may play important role in memory consolidation and retrieval
E:
May be harming animals, may not represent human behaviour
Animal research, can use same litter and can inject with physostigmine which is toxic for humans
Aids us with human research
Describe Antonova’s Study
A: Role of neurotransmitter on behaviour
M:
PPTS: 20 healthy male adults, mean age of 28 randomly allocated to 1 of 2 conditions
Double-blind
Injected with scopolamine or a placebo 70-90 mins before taking part in task
Put in fMRI - scanned playing ‘Arena task’ (complex virtual reality game where researchers observing ability to create spatial memories)
Goal for ppts is to reach pole in arena
After learning pole’s location, screen goes black for 30s where ppts told to actively rehearse how to get to pole, spatial memories then used to locate pole
When arena reappeared, ppt at a new starting point, needed to use spatial memory to determine how to reach pole
R: When injected with scopolamine - sig reduction in activation of hippocampus compared to when received placebo and they also took longer to find pole
C: Appears acetylcholine plays key role in encoding of spatial memories in humans as well as rats
E:
Just men - gender bias, cannot be generalised as women’s brains may work diff
Controlled - random allocation (increases validity), double-blind (researcher bias eliminated)
Invasive injection
Claustrophobic
Describe McGaugh & Cahill’s Study
A: Study role of emotion on creation of memories
M:
Ppts divided into 2 groups, each saw 12 slides with either a boring story about a woman and son who visited father in hospital and witnessed staff in a disaster preparation drill of a simulated accident victim or a story where a boy was involved in a car accident where his feet were severed, he was quickly brought to hospital where surgeons reattached limbs, he stayed in hospital for few weeks then went home with mother
After viewing slides, rated how emotional they found story on scale from 1-10
2 weeks later, ppts came back and their memory for specific details about story was tested through a recognition task with a series of questions
Follow up study: above procedure repeated but ppts in traumatic story condition injected with a beta-blocker called propranolol (which prevents amygdala activation) or placebo
R: In original version: ppts who heard more emotionally arousing story had better recall of details from story & slides, yet in follow up those who had beta-blocker did no better than those who heard mundane story
C: Amygdala plays sig role in creation of memories linked to emotional arousal
E:
Application: treatment of PTSD patients
Could block adrenaline allows cause-effect relationship between adrenaline and amygdala activation to create emotional significance
Lab experiment - artificial, didn’t actually see something traumatic & highly controlled, concern about ecological validity
Easily replicated, reliability can be tested
Recognition task only had 3 options so may not be valid memory test yet significant difference between ppts recall in different conditions so internal validity is shown
No bias as double blind
Describe Pitman et al’s Study
M:
Randomised, double-blind experimental study where patients coming into emergency rooms within 6 hours of traumatic injury were given a 10-day course of beta-blockers (n=18) (40mg propranolol) or placebo (n=23)
Propranolol reduces amount of adrenaline produced, therefore not stimulating amygdala so traumatic memories not formed as adrenaline improves memory, helps us remember details
R: One month later, mean score on clinical administered PTSD scale for patients who received beta-blocker = lower than those who received placebo
C: Suggests post-trauma propranolol may have preventative effect on subsequent PTSD
E:
Field study, real life not artificial
Double-blind
Small sample
All had different traumatic events - only similarity is beta-blocker or not, all other things e.g. injury, support systems may impact, many variables
Describe Cutler et al’s Study
A: Investigate whether synthesised male pheromone (AND) added to aftershave lotion would increase sociosexual behaviour of men
M:
PPTS: 38 males volunteered
Selection criteria…
Male, heterosexual, 25-42, good health, not taking medication, regular appearance, shaving regularly, adequate social skills with women
Screened with personality questionnaires to ensure fitted criteria
Divided into 2 groups
Researchers examined ppts aftershave lotions, asking them to use it after each shave at least 3x per week
In 2 week baseline period ppts filled out behavioural calendar daily indicating occurrence of:
Affection, sleeping next to romantic partner, sexual intercourse, informal and formal dates, masturbation
Returned to lab & technician added either ethanol/pheromone with ethanol to aftershave lotion which they used for a further 6 weeks whilst filling out calendar
R: More men in pheromone condition had increase over baseline in first 4 behaviours, 47% had increase in frequency of sexual intercourse compared to 9% in placebo
C: Applying synthetic pheromone led to increase of sociosexual behaviours where willingness of femal partner plays major role, behaviours e.g. masturbation didn’t increase, thus evidence that synthetic pheromone actually increased attractiveness of men to women not just libido
E:
Attractiveness = subjective despite being one of criteria
Only done on males in certain age range may not be generalisable to older/younger men
Small sample size, different pattern may be seen if larger group
Baseline measure allowed difference in behaviour to be observed between groups
Volunteered, somewhat informed of what study aimed to measure, only sign up if had certain level of sexual activity or may enhance behaviour to look certain way yet this social desirability bias should be cancelled out by control
Cultural differences in how affection displayed not accounted for
Describe Hare et al’s Study
A: Whether androstadienone (AND) & estratetraenol (EST), best known candidates for human sex pheromones, signal gender & affect male perception
M:
PPTS: Heterosexual
2 computer based tasks on 2 consecutive days
One day: exposed to putative pheromone (AND or EST) masked with clove oil, other day: control scent of clove oil only
Administered via cotton ball taped under nose during task
Some had pheromone and some control on each day
Task one: ppts required to assign a gender to 5 gender neutral facial morphs
Task two: ppts shown opposite sex photos, rated attractiveness 1-10
Gender of experimenter was alternated
R: Both tasks: no difference between control and putative pheromone, no effect, experimenter gender had no effect either
C: AND & EST don’t act as signals of gender or attractiveness so aren’t sex pheromones
E:
Repeated measures
Lab - high internal validity and repeatability yet low in ecological validity and generalisability as difficult to ensure same results in real life as potential pheromone synthesised instead of having ppt face to face with an individual
Double blind (good validity)
Very high concentration of potential pheromone as right under nose, not realistic imitation
Very binary, looking at field from very basic level
Tasks subjective, personal perception of what is attractive, confounding variable
Describe Caspi et al’s Study
A: Examine the role of the 5-HTT gene in depression
M:
PPTS: 847 New Zealand 26 year olds
Longitudinal study, all members of cohort that had been assessed for mental health every other year until age of 21
Divided into 3 groups based on 5-HTT alleles
Group 1: 2 short alleles
Group 2: 1 short, 1 long
Group 3: 2 long
Participants asked to fill in stressful life events questionnaire that asked them about frequency of 14 events including financial, health & relationship stressors between age 21-26
Participants assessed for depression
R:
Those who inherited 1 or more short versions demonstrated more symptoms of depression & suicide ideation in reponse to stressful life events
Those with 4+ stressful life events, 33% of those with short allele developed depression vs 17% of those with 2 long alleles
Acknowledges interaction between biological & environmental factors - more holistic approach, not reductionist
C: Simply inheriting gene not enough to lead to depression, but genes interacting with stressful life events increased one’s likelihood of developing depression, evidence for gene-environment interaction
E:
Correlational, no cause & effect relationship can be determined
Assumption made that serotonin causes depression
Information about stressful life events self reported, salience of negative life events may play a role in depression, such that those who recalled them easily may have a tendency towards depression
Some participants who didn’t carry gene mutation became depressed so can’t say that gene expression alone can cause depression
Describe Kendler et al’s Study
A: Investigate…
Past studies suggest a 35-45% heritability of MDD, true in large Swedish sample?
Are there significant gender differences in heritability of MDD?
Is there evidence that genetic & environmental factors in MDD differ over time?
M:
PPTS: 15,493 twin pairs born between 1886-1958 listed on Swedish Twin Registry
Trained interviewers carried out telephone interviews between March 1998 & Jan 2003
Interviewers assessed lifetime MDD by using modified DSM-IV criteria
8,056 twins met criteria for MDD diagnosis at some point in life & 322 twins discussed history of antidepressant treatment
Interviewers asked questions about twins shared environment when living in same household & their individual-specific environment i.e. their adult personal life events
R:
Concordance rates of MDD significantly higher in women than men
Concordance higher for monozygotic than dizygotic twins
Estimated heritability for MDD = 0.38
Suggests genetic influence = 40% & environmental influence = 60%
C: Heritability for MDD higher in women than men
Correlational, no cause & effect - no particular genes isolated & tested
Appears to confirm previous research
Self-report, may be gender differences in reliability e.g. men less reliable in reporting
Interviewers didn’t diagnose twins, accepted diagnoses made my clinicians - not highly reliable
Very large sample size helps to minimise concerns
Describe Weissman et al’s study
A: Investigate potential genetic nature of MDD
M:
PPTS: 161 grandchildren & their parents & grandparents
Longitudinal study over 20 year period, looking at families with high & low risk for MDD
Original sample of depressed patients (now grandparents) selected from outpatient clinic & non-depressed ppts selected from same local community
Original sample of parents & children interviewed 4 times during this period, children now adults & have children of own allowing for 3rd generation for study
Data collected from clinicians blind to past diagnoses of MDD & data from past interviews
Researcher triangulation used to establish credibility
Children evaluated by 2 experienced clinicians (one child psychiatrist & one psychologist)who had an inter-rater reliability of their diagnoses for MDD of 0.82
R:
High rates of psychiatric disorders in grandchildren with 2 generations of MDD
By 12, 59.2% of grandchildren already showing signs of a psychiatric disorder
Children had increased risk of any disorder if MDD was observed in grandparents and parents compared to children where parents not depressed
Severity of parent’s depression correlated with increased rate of mood disorder in children
If parent depressed but no history of MDD in grandparents, there was no significant effect of parental depression on grandchildren
C: Genetic influence on MDD observed
Longitudinal, increasing reliability of data
Association between parental MDD & child diagnosis is moderated by grandparental MDD status, amount of time child spent with a healthy grandparents may be confounding variable in study
Researcher triangulation increases credibility of findings
Large sample but more research should be conducted to confirm reliability
Although family (kinship) studies indicate potential genetic link to behaviour, there is no actual genotype studied
Describe Buss et al’s Study
A: Investigate if evolutionary argument for formation of relationships is universal
M:
PPTS: 10,047 participants from 37 cultures & 33 countries
Samples collected using different techniques
2 surveys
1 collected biographical data, asked ppts what age they preferred to marry, preferred age difference between self and spouse, who should be older and how many children they want
Other asked ppts to rate 13 characteristics in terms of desirability in a mate
Surveys given in language of ppts & back-translated to ensure no discrepancies
R:
36/37 samples - women view financial prospects more than men
Mean age of women desired by men = 24.83, close to peak fertility
Females prefer older men
34/37 samples - men value physical attractiveness more than women
C: Supports universality of the evolutionary argument for formation of relationships
E:
Surveys possess high internal validity, as test mate preference regardless of culture, however concern of variability of personal interpretation of the traits - minimised by back-translations used to help account for cultural differences
Large, cross-cultural sample used, so easier to generalise to wider population on global scale, however samples can’t be viewed as representative of populations from each country as those from rural, less educated and lower socioeconomic status backgrounds underrepresented - caution needed in assuming nationalities have standardised norms
Assumed heterosexuality through the study
Difficulties with construct validity as not all marriage structure accounted for e.g. polygamy
Describe the case study of HM
Longitudinal case study
HM was hit by a cyclist while crossing the street & sustained serious head injury leading to epileptic fits
Neurosurgeon William Scoville performed experimental surgery where removed tissue from medial temporal lobe & hippocampus on both sides of his brain
Neuropsychologist Brenda Milner studied HM until he died & conducted interviews & memory tests following surgery
His personality remained unchanged
Procedural memories intact but could not form new episodic & semantic memories
HM had issue transferring information from short term to long term memory - anterograde amnesia, e.g. could not remember faces of people met following operation
The study was a case study. The strength of this study is that it was longitudinal - over 50 years! This means that change could be observed over time. In addition, case studies use method triangulation.
The limitation of case studies is that they cannot be easily replicated. However, there are several other case studies of patients like HM - for example, Clive Wearing - which confirm the findings.
Some of the study was retrospective in nature. This means that we do not have a lot of data on HM’s actual cognitive abilities before the accident.
The medication taken to treat epilepsy may have resulted in some of the damage, but this is not highly relevant as it is the damage to specific parts of the brain that is important.
High ecological validity, no variables were manipulated and HM was observed in his natural environment.
Milner’s research met high ethical standards of consent, confidentiality and protection from harm.
