AMRC Bio Approach Flashcards
HM study use
- localisation
- brain imaging techniques (MRI)
HM bg info
- HM fell off his bike, leading to severe epileptic seizures
- Cognitive, longitudinal case study of HM
○ HM’s anterograde and partial
retrograde - Biological part of study:
○ Correlation between brain damage and
amnesia
HM Aim
- In 1953, Scoville performed surgery on the then 27 year old to cure him of his epileptic seizures
- Surgical procedure- only became a study
once memory damage was noted
- Surgical procedure- only became a study
HM method
- During surgery, Scoville removed brain tissues
from anterior two thirds of the hippocampus - Once extent of memory loss was realised,
Scoville and Milner wrote about this and the
results of 9 similar patients in a prominent
neurological journal, and Milner started her
cognitive studying of HM
HM results
- Seizures reduces, but HM suffered with
amnesia for the rest of his life - HM lost ability to form new memories-
anterograde amnesia - Some retrograde amnesia
- HOWEVER early childhood memories stayed
intact and his IQ remained the same.
HM conclusion
The surgery which removed part of the hippocampus resulted in total anterograde and partial retrograde amnesia.
HM strengths
- Case study
- Triangulation
○ Researcher, data method
- Triangulation
- Longitudinal study- over 50 years
- Allows for the deeper, more detailed
research compared to the amount that
would have been able to be found had it
been a shorter snapshot study
- Allows for the deeper, more detailed
- Theoretical generalisability
- Can be used as a counter to lack off
generalisability - E.g. Creating a counter:
○ HM was quite “normal” and
“healthy.” Since all humans have
hippocampus, can theorise that if all
humans had their hippocampus
removed, they would experience the
same symptoms (not being able to
transfer from short to long term
memory)
- Can be used as a counter to lack off
- Qualitative data- rich, detailed
- Ecological validity
HM limitations
- Impact of medication for epilepsy
- Possible researcher bias
- Retrospective study: Type of longitudinal case
study design in which all data are collected
after the fact (i.e. After HM’s operation)- Researchers had no knowledge of HM’s
abilities prior to operation
- Researchers had no knowledge of HM’s
- Case study –> population validity –> lowered
generalisability - Debate: localisation = reductionist
- “however not holistic” is other side of
debate - must mention both bias
- “however not holistic” is other side of
Maguire et al (2000) use
- localisation (only use as second study)
- neuroanatomy
- brain imaging techniques (MRI)
Maguire aim
To see whether the brains of London taxi drivers would be different as a result of extensive training.
Maguire method
- 16 males, all healthy - compared to 50 male
non-taxi driver scans - Quasi experiment (correlational research)
○ IV not manipulated with matched-pairs
design - Average time spent training = 2 years
- Structural MRIs used to show relationship
between brain scans and length of time
drivers were licensed
Maguire results
- Taxi drivers control subjects - larger posterior
hippocampus, smaller anterior hippocampus - Hippocampal volume positively correlated
with time spend as taxi drivers
Maguire conclusion
- Plasticity occurs in response to environmental
change - Posterior hippocampus involved in spatial
skills - Implications for brain injury victims and
rehabilitation
Maguire strengths
Quasi experiment- naturally occurring
* Strong, positive correlation between
length of time driving & grey matter in
hippocampus
○ Bidirectional ambiguity
Single-blind control - avoid researcher bias
Use of MRIs
* Provide large amount of quantitative data
for statistical analysis, reduces demand
characteristics
* Scientific
Matched pairs designs - samples matched for age, sex and handedness
Maguire weaknesses
Androcentric sample
* Gender bias –> less generalisable
* Beta bias
* HOWEVER representational
generalisability as most London cabbies
are male
Use of MRIs
* Expensive
* Time-consuming
draganski et al use (2004)
neuroanatomy
brain imaging techniques (MRI)
Draganski aim
To see whether learning a new skill - in this case, juggling - would have an effect on the brains of the participants.
Draganski method
- 24 volunteers between ages 20 and 24
○ 21 females and 3 males - All participants non-jugglers at start of study
- Each had MRI scan at start of study to
serve as a base rate for grey matter and
brain structure
- Each had MRI scan at start of study to
- Participants allocated one of two conditions:
jugglers and non-juggler
○ Jugglers:
§ Taught three-ball cascade juggling
routing
§ Asked to practice routing and notify
researchers when they had
mastered it - at this point, jugglers
had second MRI scan
§ After scan, told not to juggle
anymore
§ 3 months later, third and final scan
carried out
§ Non-juggling group acted as control
group for duration of study
Draganski results
- Researchers used voxel-based morphometry
(VBM) to analyse MRI scans and determine if
there was significant differences in neural
density (grey matter) in brains of jugglers vs
non jugglers - From baseline scan, no significant regional
differences found in grey matter - However, jugglers showed significantly
larger amount of grey matter in mid-
temporal area in both hemispheres - an
area associated with visual memory - Three month after participants stopped
juggling - when many were no longer
able to carry out the routine - amount of
grey matter in these parts of the brain
had increased - Non-juggling sample saw no change over
duration of study - Seems that juggling relies more on visual
memory (perception and spatial anticipation
of moving objects) than on “procedural
memory” which would more likely show
change in cerebellum or basal ganglia
Draganski conclusion
- Grey matter grows in brain in response to
environmental demands (learning) and
shrinks in the absence of stimulation (lack of
practice). - This shows that there is a cause and effect
relationship between learning and brain
structure.
Draganski strengths
- The study used a pre-test, post-test design to
show differences in neural density over time. - The study was experimental, thus helping to
argue for a cause and effect relationship. - There was a control group that didn’t juggle
that served as a control group.
Draganski weaknesses
- The sample size was very small - so it is
possible that by using averages of growth, the
data may not be reliable. - The study has potential problems with
internal validity as the participants were in
their home environments for a good part of
the study. - The study would need to be replicated to
establish its reliability
Antonova et al (2011) use
neurotransmitters
brain imaging techniques (fMRI)
Antonova aim
To determine how blocking the acetylcholine receptors with scopolamine affects spatial memory.
antonova method
- 20 healthy male adults - mean age of 28
- Double blind procedure
- All participants received training about how to
use VR set up and rules before partaking in
the task - Participants randomly allocated to two
conditions
○ Group 1: injected with scopolamine
○ Group 2: injected with a placebo - Both groups injected with their respective
substances 70-90 minutes before taking part
in the experimental tasks - Participants put into fMRI while playing the
“arena task”
○ Complex virtual reality game in which the
researchers are observing how well
participants are able to create spatial
memories
§ Goal: to navigate and reach a pole
○ After reaching pole, screen went blank
for 30 seconds - in this time participants
were told to actively rehearse their route
to the pole
○ When area reappeared, they were at a
new starting point
§ Using spatial memory, they had to
get back to the pole - Brain activity measure for 6 trials
- Participants returned 3-4 weeks later and
redid the test
○ This time, received opposite treatment
(e.g. If they got placebo the first time,
they got scopolamine this time and vice
versa)
§ Repeated measures design
Antonova results
- Participants injected with scopolamine
showed significant reduction in the activation
of the hippocampus when compared to those
injected with placebo - Appears that Ach could play a key role in the
encoding of spatial memories in humans as
well as rats
Antonova conclusion
- Although there was a higher rate of error in
the scopolamine group, not a significant
difference - Difference in activity in the hippocampus,
however, is significant. - This means that the task design may not have
been best suited for showing performance
differences
- Without the use of fMRI, there would
have been no way to know that as the
biological level there were significant
differences in the two conditions
Antonova strengths
Double blind
* Controls researcher bias
○ Non-verbal cues, opinions etc
○ Therefore increases internal validity
§ Conclusions are reliable, where the
neurotransmitter Ach does not have
a role in memory encoding
* Greatly reduces demand characteristics
Random allocation
High internal validity
* Lab experiment
○ IV and DV operationalised to establish
cause and effect
○ Control over extraneous variables
Repeated measures
* Eliminates participant variability
* counter balanced - Controlled practice effects
(order)
Use of fMRI
* Scientific and therefore:
○ Objective
○ credible
Practical applications
* The results suggest drugs targeting the Ach
system, like physostigmine, may have
application in treatment of memory disorders,
like Alzheimer’s, assuming Ach plays a role in
memory function.
antonova weaknesses
During debrief participants said they felt stressed, either as a result of the injection of an unfamiliar drug or being in fMRI (claustrophobia)
* This could affect the hippocampus
function as stress may interfere with
memory encoding
* Might decrease ecological validity
Small androcentric sample
* Beta bias - assuming that results can simply
be replicated for females
* Reduces reliability
Lab experiment
* Since setting is artificial, low external
validity
Small sample size
* Results must be replicated to determine if
reliable
Use of fMRI
* Decrease ecological validity
* Participants anxious in unfamiliar/closed
space
antonova ethical considerations
- Informed consent
- Deception
- Protection from harm (mental) - participants
said they felt claustrophobic
rogers and kesner (2003) use
neurotransmitters
rogers and kesner aim
To determine the role of acetylcholine in the formation of and retrieval from spatial memory.
rogers and kesners method
- 30 rats acclimate to a Hebb Williams maze by
placing food in one of the corners
○ Once rats were familiar - and no longer
afraid of the environment - the
experiment could begin - The rats were randomly allocated to one of
two conditions:
○ Scopolamine - blocks the acetylcholine
receptor sites and thus inhibits any
response
○ Saline solution was a placebo injection -
done to ensure that getting an injection
alone was not responsible for a change in
memory.
§ An injection could result in an
increase in adrenaline which would
be a confounding variable
○ Injections were made directly into the
hippocampus - 10 minutes before running the maze, the rats
were either injected with scopolamine
(experimental group) or a saline solution
(control group) - Encoding of memory assessed by average
number of errors made on the first five trials
of Day 1 compared to the last five trials of Day
1 was used to assess retrieval
rogers and kesner results
- Scopolamine group took longer and made
more mistakes in the learning maze
○ Means higher average number of
mistakes made on the last five trials on
Day 1 - However, did not appear to have an effect on
retrieval of memories that had already been
created. - Appears that acetylcholine may play an
important role in the consolidation of spatial
memories
rogers and kesner conclusion
Suggests that acetylcholine plays and important role in memory encoding, because the rats with low acetylcholine levels wandered around the maze as though lost, even though they had learned it previously
rogers and kesner strengths
- Experimental design allows for cause and
effect conclusions base on isolation of
variables in three experimental conditions - Control group allows to control for possible
confounding variables - Lab experiment - easy to replicate, control of
variables - as rodents as easy to breed.
Replication leads to reliability of theory - adds
reliability to theory of neurotransmission - Reductionist
- Scientific- can break down and identify
specific cause
- Scientific- can break down and identify
- Biological determinism
- Scientific
- Predictable
Counter argument for generalisability: rats and humans have a similar limbic system.
Practical Applications
Results suggest that drugs targeting the acetylcholine system may have applications in the treatment of memory disorders, like Alzheimer’s disease, assuming that acetylcholine plays a role in memory formation.
rogers and kesner limitations
- Difficult to generalise animals studies to
humans because results may not be wholly
applicable - Effects of neurotransmitters are difficult to
isolate, because the alteration of one
neurotransmitter may cause changes in other
neurotransmitters too. - Counter for practical applications credibility:
- Biological reductionist - therefore ignores
other potential influences
- Biological reductionist - therefore ignores
- Not free will
* Harder to suggest change or choice
kiecolt-glaser et al (1995) use
hormones
kiecolt-glaser aim
To investigate the effects of stress, caused by caring for a relative with Alzheimer’s disease, on the immune system by looking at wound healing.
kiecolt glaser method
- Participants were recruited through a
newspaper advert (volunteer samples) - Experimental group: 13 women aged 47-81
years old were carers - Control group: 13 other women were
matched with carers on basis of age and
income - matched pairs design - All participants were dressed and treated by a
nurse in the same way for every participant - Researchers also assessed biochemical
substances (such as cytokines) to regulate the
immune system - Participants were given a 10 item perceived
stress scale to assess how stressed they were
feeling.
kiecolt-glaser results
- Complete healing took on average 9 days
(24%) longer in carers than control group - Cytokine (protein) levels, which are important
for wound healing, were lower in carers than
control group - Carers reported feeling more stressed on
perceived stress scale
kiecolt-glaser conclusion
- Chronic stress (increased cortisol) suppresses
functioning of the immune system. - The behaviour is the stress response but how
it affects the immune system- E.g. Chronic stress leads to increased
corticosteroids in the blood stream –>
lowers T cells –> lowered immune system
–> takes longer to heal
- E.g. Chronic stress leads to increased
kiecolt-glaser strengths
Application:
* Research provided good evidence to medical
staff and emphasised the effects that stress
can have on recovery after surgery. It is
important to reduce stress before surgery
Experimental design
* Quasi experiment - matched pairs (can be
countered with the weakness)
kiecolt-glaser weaknesses
Matching of participants was not exact
* Participants not matched on other factors
e.g. Relationship status or smokers
* Both these variables associated with
stress levels
* Carers more likely to be married
* Social support known to lower support
* Results in sample bias which suggests
that carers should have a better
functioning immune system and so
strengthens the validity of the study
findings
kiecolt glaser ethical issues
- Protection from (physical) harm - couldn’t
guarantee that the wound wouldn’t re-open
and cause the participants any pain - Deception - could go into full informed
consent
newcomer et al (1999) use
hormones
newcomer aim
To look at the impact of stress on memory
newcomer method
The researchers carried out a double blind laboratory experiment in which the participants were matched for age and gender to one of three conditions:
* Condition 1: high level of cortisol
○ Given a tablet containing 160 mg of cortisol on each day of the four-day experiment
○ Dose of cortisol produces blood levels similar to those seen in people experiencing a major stress event
* Condition 2: low level cortisol
○ Given a tablet containing 40 mg of cortisol per day
○ Dose is similar to amount of cortisol circulating in the bloodstream of people undergoing minor surgical procedures such a having stitches
* Condition 3: placebo group
○ Participants in this condition were given placebo tablets
§ A tablet that looked like the other tablets but with no active ingredient
○ This was done in order to have a control group
* All participants were asked to listen to and recall a prose paragraph ○ Each day given a different piece of prose with same level of difficulty ○ Tested three times * Participants tested again one day after taking the pill and then again four days later * There was a test again six days later to ensure that there were no long-term effects of the treatment on the participants
newcomer results and conclusion
- Results indicated that high cortisol levels impaired performance in the memory task since the participants who received the highest level of cortisol also showed the worst performance in the verbal declarative memory
- Researchers were also able to verify that the effect was not permanent
○ Performance of participants in high cortisol condition returned to normal after they stopped taking the hormone tablet - According to researchers, these results demonstrate a clear link between levels of cortisol and remembering
- Appears that high levels of cortisol interfered with the recall of the prose passage, whereas moderate levels of cortisol may have actually assisted in the recall of the passage
This is supported by the fact that there are cortisol receptor sites on the hippocampus, which is responsible for the transfer of information from STM to LTM and vice versa
- Researchers were also able to verify that the effect was not permanent
newcomer evaluation
- Experimental, therefore researchers could establish clear cause and effect relationship between IV and DV
- Carried out baseline test in order to eliminate the possible confounding variable of individual differences between groups
- Counterbalanced use of tests
- As different texts were used for days 1 and 4, counterbalancing acted as a control that the difficulty of the text did not play a role in recall
newcomer weaknesses
- Researchers did not have full control over extraneous variables
- Experiment ran over several days and participants were not in the lab the whole time
- Variables e.g. Individual stressors in lives of participants
- MINI COUNTER: despite this weakness, clear relationship between amount of cortisol ingested and performance on memory test established
- Generalisability
- Memorising a piece of prose not the most authentic memory experience - may explain student exam stress, but ability to generalise to other situations may be limited
newcomer ethical considerations
Participants ingested cortisol which affected memory negatively, however, participants had signed informed consent and damage was not permanent
lundtrom and olsson (2005) use
for pheromones
L&O aim
To test the hypothesis that androstadienone (derivative of testosterone and one of the chemical components of sweat) exposure would modulate participating women’s mood and corresponding behaviour as measured by a sustained attention task.
L&O method
- 37 women participated
- Repeated measures design, within-group experiment
- Tested by either a female or a male experimenter
- Effects on mood, psychophysiological arousal, sustained attention, and rating of male facial attractiveness were assessed
- Sensory detection of the experimental substance was rigorously controlled for by psychophysical testing
L&O results
- Shown that exposure to a non-detectable amount of androstadienone modulated women’s psychophysiological arousal and mood in a positive direction, but did not change attention performance or rating of facial attractiveness
- Moreover, mood effects only evident when an experimenter of the opposite sex conducted the testing
L&O conclusion
Androstadienone as a pheromone intensifies women’s reactions to men and that social context is important for mood effects of androstadienone exposure in women.
L&O debate
reductionism
L&O strengths
Lab experiment
* Has controls and accounts for extraneous variables such as:
○ Pregnant?
○ Heterosexual?
○ Menstrual cycle?
* Therefore increases validity
Repeated measures design
L&O weaknesses
Lab experiment
* Has controls and accounts for extraneous variables such as:
○ Pregnant?
○ Heterosexual?
○ Menstrual cycle?
* Therefore increases validity
Repeated measures design
- Construct validity
- Difficult to operationalise
- What is the researcher was attractive?
- Reliability
- Lack of consistent findings
hare et al use
against pheromones
Hare aim
To investigate if androstadienone and EST signal gender and affect mate perception
hare method
- 140 heterosexual participants
- Repeated measures design
- Participants completed two computer-based tasks on two consecutive days
- On one day exposed to putative pheromone (AND or EST) masked with clove oil; On other day exposed to control scent (clove oil alone)
- Order of conditions was counterbalanced
○ Task 1: participants shown five “gender neutral facial morphs” and had to indicate the gender (male or female)
Task 2: they were shown photographs of the opposite sex and asked to rate their attractiveness on a scale from 1 to 10.
- Order of conditions was counterbalanced
hare results
- There was no difference in gender assigned to the faces in the pheromone versus control condition
There was no difference in the average attractiveness ratings of the photographs of the opposite sex
hare conclusion
- The two chemicals (AND and EST) do not act as signals of gender or attractiveness
- Based on this result, researchers concluded that these chemicals do not qualify as human pheromones
hare strengths
- Lab experiment
- Variables are operationalised
- Scientific and measurable
- Repeated measures design
- Eliminates participant variability
- counter balanced - Controlled practice effects (order)
- Single blind design
- Control of demand characteristics, which increases internal validity
hare weaknesses
- Construct validity
- Attractiveness, while used as a measurement in the experiment, is subjective
- Low reliability
Lack of consistent findings
hare debate
reductionism
caspi aim
to investigate why some children who are maltreated grow up to develop antisocial behaviour, whereas others do not & to investigate whether antisocial behaviour would be predicted by an interaction between a gene (MAOA) and an environment.
caspi participants
- large sample (442 male children) followed from birth to adulted
assess every 2 years from 3-15, then at 18, 21 and finally at 26
caspi method
- Sample was genotypes
- environmental factors (forms of maltreatment) were assessed- maltreatment groups did not differ in MAOA activity
- 3-11 y.o.: 154 children maltreated
§ 8% severe maltreatment
§ 28% probably maltreatment
§ 64% no maltreatment - Maltreatment was considered to include:
§ physical abuse resulting in injury
§ sexual abuse
§ rejection by mother
§ frequent changes of primary caregiver
- 3-11 y.o.: 154 children maltreated
- antisocial behaviour measured using clinical diagnosis conduct disorder:
- personality checklists to measure antisocial personality traits
official conviction records for violent offences (assault, robbery, rape, domestic violence, homicide)
- personality checklists to measure antisocial personality traits
- environmental factors (forms of maltreatment) were assessed- maltreatment groups did not differ in MAOA activity
caspi results
- 85% of males having low-activity MAOA gene genotype who were severely maltreated developed some form of antisocial behaviour
males with high MAOA activity did not have elevated antisocial scores. even when they had experiences childhood maltreatment
caspi strengths
Biological determinism
* Predictable (incl education)
* Treatment
Biological reductionism
* Can be operationalised
Longitudinal researcher (vs snapshot)
Scientific method - methodological consideration
* Little bias
High ecological validity
caspi weaknesses
Biological determinism
* Irl applications - the court views all actions as free will
Biological reductionism
* Disregards extraneous variables
Correlational research - 3rd variable
* Limited control
Impossible to replicate
caspi applications
- Useful when ensuring that adoption agencies place children (with low-activity MAOA gene genotype) into safe, nurturing homes
Justifies the reason from social services to complete regular check-ups in the homes of violent families to protect children
caspi conclusion
‘nature loads the gun, nurture pulls the trigger’
* partly explain why not all victims of maltreatment group up to victimise others
provide epidemiological evidence that genotypes can moderate children’s sensitivity to environmental results
caspi alternative explanations
Although the participants were assessed every few years, the study did not take into account an array of confounding variables and other major life events which may have triggered aggressive behaviour.
brunner et al (1993)
A study of violence in a family with genetic abnormality
brunner aim
Brunner and his colleagues wanted to explain the behaviour of a large
family in the Netherlands where the males are affected by a syndrome of borderline intellectual disability and abnormal violent behaviour
brunner method
- the study was based on five affected males from the family
- data were collected from analysis of urine samples over a 24-hour period
case study
brunner results
- test showed disturbed monamine metabolism associated with a deficit of the enzyme MAOA
in each of five males a point mutation was identified in the X chromosome of the gene responsible for the production of MAOA
brunner conclusion
- MAOA is involved in serotonin metabolism
- Defect in gene that leads to impaired serotonin metabolism is likely to be responsible for the intellectual disability in this family
○ In turn, may account for the violent behaviour
Brunner concluded that the MAOA deficiency in this family was associated with a recognisable phenotype that accounted for their inability to regulate their aggression
brunner strengths
Deterministic
* Means that it is out of the control of the individual
* Can establish cause and effect - help develop a universal treatment for those in the same situation
Case Study
Allows for rich, qualitative data
brunner weaknesses
Applications
In the court, all actions are considered as free will and the individual is held accountable regardless
Low population validity and generalisability
Aggression being expressed is from a recessive allele, meaning only the minority have it`
kendler et al (2006)
correlational twin study
kendler aim
to carry out a twin study of twins from the Swedish national twin registry (has over 42000 set of twins registered) to determine the level of heritability of depression.
kendler method
Lifetime major depression was assessed at personal interview by modified DSM-IV criteria on15,493 complete pairs of twins, from the national Swedish Twin Registry.
kendler results
They found that the average concordance rate for MZ male twins was 31 per cent and for MZ female twins 44 per cent, while for DZ twins it was 11 and 16 per cent respectively.
kendler conclusion
Overall, Kendler concluded that heritability of depression is estimated to be 38%.
While the study agreed with the argument of depression being genetically inherited, the fact that the concordance rate for MZ twins is far below 100 percent indicates that depression maybe the result of a genetic predisposition- also known as genetic vulnerability. This means that inheriting the gene does not automatically result in the person developing depression. Additionally, the results for the DZ twins being lower than the MZ twins supports the theory of genetic inheritance because fraternal twins are much less likely to have the same gene makeup.
kendler eval
A strength of this study is that there was a large sample size, meaning that it can be easily generalised to the amongst the population. However, this in contradicted by the fact that twins are a very small part of the global population, reducing the overall generalisability of the study.
kendler additional issue
Another issue, this time with ethics, is the self-fulfilling prophecy. Given the study, this means that as identical twins may think that they are more likely to develop depression, they might start to exhibit more symptoms. This also causes questions into issues of undue stress or harm, both because the study may contribute to the onset of depression, but also because it could leave participants in fear that they too will develop the illness.
Therefore, while the study supports the idea that depression is genetically inherited, it also indicated that the expression of the illness may be affected by external influences.
weissman (2005)
kinship study
weissman intro
One of the ways in which genetic research is carried out is through a technique called ‘family studies.’ In such studies, researchers look at the incidence of a behaviour over a number of generations. Usually, this is limited to three generations in most populations. These studies look at the genetic similarity between familial relationships, that is, the chance that if one member is diagnosed with a certain disorder, another will have it as well. Concordance rates are the percentage of this similarity. One behaviour commonly studies is Major Depression Disorder, or MDD.
weissman aim
To study the potential genetic nature of Major depressive disorder
weissman method
· carried out a longitudinal family study over 20 years
· sample of 161 grandchildren and their parents and grandparents, looking at families at high and low risk for depression. The original sample of depressed patients (now grandparents) were selected from an outpatient clinic with a specialisation in the treatment of mood disorders, and non depressed participants from same local community.
Original sample (parents/children) interviewed 4 times during this period, and children (now adults with own children - allowing for 3rd gen study). Data collected from clinicians blind to past depression.
weissman results
researchers found high rates of psychiatric disorders in the grandchildren with 2 generations of MDD. By age 12, 59% grandkids already showing signs of a psychiatric disorder (commonly anxiety disorders). Kids had increased risk of any disorder if depression was observed in both grandparents and parents, compared to kids where parents weren’t depressed. Also, severity of parent’s depression was correlated with increased rate of mood disorder in the children. However, if a parent was depressed but there was no history of depression in grandparents, there wasn’t significant effect of parental depression on grandkids.
weissman conclusion
The association between parental MDD and child diagnosis is moderated by grandparental MDD status. The rates of psychopathology are highest in grandchildren of parents and grandparents with a moderately to severely impairing depression.
weissman strengths
- Longitudinal
- Increases reliability of data
- Researcher triangulation - increases credibility
Large sample - 161
weissman weaknesses
- Confounding variable - amount of time a child spent with a healthy grandparent
- Association between parental MDD and child diagnosis is moderated by grandparental MDD
- Large sample, but more research needed to confirm reliability of findings
Although kinship studies indicate a potential genetic link to behaviour, no actual genotype is studies
weissman ethical considerations - implications of findings
If there was a gene for aggression, would people stigmatise those who posses the gene?
informed consent in genetic research
Particularly in genetic research, it must be ensured that participants truly understand what the study means
weissman undue stress or harm
○ When one finds out that his identical brother has bipolar disorder and that there is a high concordance rate for this disorder, this may lead to stress in the healthy twin
May even lead to a self-fulfilling prophecy in which relatively normal behaviour is interpreted by the participant as “symptoms” of bipolar disorder
weisman confirmation bias
If confirmation bias takes place because of earlier research, it can lead to complications in diagnosis where the incorrect diagnosis of bipolar disorder may happen
confidentiality genetic research
○ Important to ensure that the samples are anonymised and that confidentiality is maintained. This means that the names are not given to the researcher who is carrying out the research
§ This is a blind control
○ Results of such testing should not be given to people outside of the study
§ May lead to:
□ Confirmation bias by practitioners
□ Stigmatization in society
□ (in some cultures) - denial of employment or health/life ensurance
curtis et al (2004)
- Argues that there are 6 categories of disgust:
- Poor hygiene
- Animals that are vectors disease (such as rats of cockroaches)
- Sexual behaviours
- Atypical appearance
- Lesions and visible signs of infection
- Food that shows signs of decay
- What they all have in common: elicit ‘disgust response’ which is all about avoiding infection
Thus, disgust as a behavioural strategy that reduces the likelihood of contact with potentially harmful pathogens
curtis aim
What (things) elicited a disgust response
curtis method
- Carried out research on the internet via BBC to test whether there were patterns in people’s disgust responses
- Online survey where 77,00 respondents from 165 countries (mostly European) were shown 20 images
- For each image they were asked to rank their level of disgust
Among 20 images were 7 pairs in which one was infectious or harmful to the immune system. The other was similar but not infectious
curtis results/conclusions
The findings confirmed that the disgust reaction was most strongly elicited for those images which threaten one’s immune system
curtis strengths
- Large-scale cross-cultural survey with many participants
- Unlikely responses were excluded (all 1s in the answers or all 5s)
Data therefore robust and seems that the significant differences found in 6 of the 7 pairs between the levels of disgust when looking at the disease-irrelevant picture and the levels of disgust shown at the disease-relevant picture are reliable findings
curtis weaknesses
- 75% of participants were between 16 and 65 years of age, with only 10% over 65 years old
○ Age range shown on graph is misleading, and the responses for under-16s and over 65s come from a much smaller groups of people - Sample also skewed towards those who have a computer and those who answer surveys of this kind
- 78% of respondents were from Europe, and majority of them from the UK
Research was not as cross-cultural as it might seem - affects validity and reliability
fessler aim
To investigate the nausea experienced by women in their first 3 months of pregnancy when the infusion of hormones lowers immune system
fessler method
- 496 pregnant women were asked (web based survey) to think about 32 stomach-turning scenarios (i.e. fishhook through their finger) and then were to rank the scenarios
Fessler then asked questions to determine whether they were experiencing morning sickness
fessler results
Women in their 1st trimester scored higher in their sensitivity test than the women in later stages
fessler conclusion
- Natural selection may have helped compensate for the increased susceptibility to disease during the risky period of pregnancy by increasing the urge to be picky about food
Sensitivity seems to decrease as the risk of disease decreases.
fessler strengths
- Methodological strength
○ Although there was a correlation between disgust and nausea, researchers also measured each independently
§ Found that the phase of the pregnancy and feelings of nausea contributed separately to disgust sensitivity
Essentially, it is impossible to feel nausea without disgust and the level of disgust felt decreased considerably throughout the pregnancy
