HL Psychology Bio Approach Studies

Detailed summary of 20+ biology studies with aims, procedure, finding, research methods, and evaluation!

Woollett and Maguire (Taxi Drivers) Aim

Test whether structural changes could be detected in the brain of people with extensive experience of spatial navigation.

Woollett and Maguire (Taxi Drivers) Sample

• All male participants (sampling bias)

• Same level of education

Woollett and Maguire (Taxi Drivers) Procedure

Group 1: Participants who passed the London Landmark knowledge test to become a qualified London taxi driver ✅

Group 2: Participants who failed the knowledge test to become a qualified London taxi driver. ❌

Group 3: Control group of non-taxi drivers with similar mean statistics as other groups. 🟡

🩻 Tested on two times with memory tests such as on their ability to recognize London Landmarks and structural scans (MRIs)

Woollett and Maguire (Taxi Drivers) Findings

✅ Group 1’s posterior hippocampi had more grey matter out of other groups. 🩶

✅❌ Groups 1 & 2 did better on London Landmark memory test.

🟡 Group 3 performed better on remembering new visuo-spatial skills. 🎨

Grey Matter - Taxi Drivers

Grey matter process and send information to different parts of the body.

Woollett and Maguire (Taxi Drivers) Supports

SUPPORTS previous research that posterior hippocampus is involved in spatial navigation (localization)

SUGGESTS that gain in one area of functioning in brain may come at the expense of another function (neuroplasticity)

Woollett and Maguire (Taxi Drivers) Research Method

Quasi Experiment

Woollett and Maguire (Taxi Drivers) Limitations

Limitation: Sampling bias because only men

Woollett and Maguire (Taxi Drivers) Ethical

Consent: Enclosed space of MRI

Scoville and Milner (HM) Aim

Examine retrograde amnesia suffered by HM after removal of his hippocampus

Retrograde Amnesia

Can't recall memories from before injury or in the past

Hippocampus

A brain structure in the temporal lobe with a major role in memory

Scoville and Milner (HM) Procedure

1. Psychometric Testing: IQ Tests

2. Direct Observation

3. Interviews with HM and Family

4. Cognitive Testing: Tracing Memory Test

Scoville and Milner (HM) Findings

• Can’t form new episodic memories, only procedural ones (performance improved on star tracing test but couldn’t remember doing it)

• Remembered childhood memories but not those a year directly before surgery

• Unchanged personality and no impairment to intellect (improved on one IQ test)

Scoville and Milner (HM) Support

Importance of hippocampus in memory processing and formation of new memories (short term memory)

Since HM could recall childhood memories, supports that the brain has memory stores across different areas (localization)

Scoville and Milner (HM) Limitations

• External Validity: Cannot generalize a single case study

• Later brain scans showed less damage than originally thought to hippocampus

• Little is known about his brain, behaviour and memory before the surgery

Scoville and Milner (HM) Ethical

Informed Consent: Difficult to consent with memory issues

Confidentiality: Name was kept confidential until after his death

Scoville and Milner (HM) Research Method

Case Study

• Can focus on experiments that may be unethical on purpose (memory loss was an unintended side effect to surgery)

• Can’t generalize one case study

Diamond (Rat Party) Aim

To investigate whether the environment (enriched or deprived) could have an influence on the development of the neurons on the cerebral cortex.

Cerebral Cortex

Outer layer of the brain's surface

Responsible for memory, problem solving and emotions.

Diamond (Rat Party) Procedure

Rats from the same litter split into 3 groups based on their environment:

• 🔬Control Group (standard lab setting)

• 🪀🐀 Enriched Environment (with toys and other rats)

• 🚫Deprived Environment (along with no toys)

Rats were given food and water, and humanely killed after 4-10 weeks to study their brain.

Diamond (Rat Party) Findings

🧠💪 Rats in the enriched environment had a heavier and thicker cerebral cortex.

• No significant differences in any other part of the brain

Rats needed both social and enriched environment in order for development to occur.

Diamond (Rat Party) SUPPORTS

Neuroplasticity and that brains can change.

Environment has an influence on neural development.

Diamond (Rat Party) Strengths

Animal model allowed intrusive methods to be used to study the brain (which were not available earlier)

Diamond (Rat Party) Limitations

External Validity: Brains of rats are not the same as human brains 

Only theoretical generalization is possible

Internal Validity: What caused neural development in the environment? Social aspect or enriched with toys?

• Missing condition with alone rat and toys

Diamond (Rat Party) Research Method;

Experiment

Diamond (Rat Party) Ethical

• Rats were euthanized quickly: After predetermined periods of time (4 to 10 weeks), rats were killed humanely in order to study their brains

• Food and water given

• Provide justification for use of animals

Radke (Joystick) Aim

To investigate how testosterone influences the amygdala when someone is responding to a threat.

Amygdala

Associated with emotional processes located in temporal lobe.

Radke (Joystick) Procedure

Approx. 50 female participants

🎮 Trained on a computer game controlled with a joystick while a fMRI being conducted

• 😊😡 Shown happy or an angry face and instructed to either approach or avoid the person using the joystick provided

🍹 After training, participants were consumed either a placebo drink or a testosterone drink before the actual experiment began

🧠 Researchers observed brain activity during the game

Radke (Joystick) Findings

Testosterone group showed more activity in their amygdala while they approached the angry face, but not a significant difference if they avoided it.

Radke (Joystick) Supports

When testosterone is high, aggression can increase.

Shown when testosterone group had more activity in amygdala approaching the threat due to the increased emotional arousal and flight or fight response.

Radke (Joystick) Strength

Sampling bias (only female participants - allowed baseline testosterone levels to be similar)

Radke (Joystick) Limitation

Low Ecological Validity:

• Participants were not actually under threat (playing a joystick game) and were having brain activity observed

Sampling Bias: Only female participants

Radke (Joystick) Research Method

Experiment

Radke (Joystick) Ethical

• 😷 Protection from harm

  • Medical history would be important as testosterone being consumed

• 💵 Use of inducements

  • Compensated for their time as the study took about 6 hours to complete in order to allow time for testosterone levels in the body to be significantly increased

Pucilowski (Killer Rats) Aim

To determine the role of serotonin in aggression in rats through injections of serotonin and quipazine (serotonin agonist)

Agonist

Substance amplifying effect of neurotransmitter

Pucilowski (Killer Rats) Sample

🔪🐭 Sample was screened to included “killer rats”

• Those that would attack/kill a mouse in their cage within 10 minutes

Pucilowski (Killer Rats) Procedure

• 🧠🌱 “Killer rats” had brain implants so that injections could be directly made to the amygdala

• 💉 After the implant was made, they began injecting the rats

• Three conditions: 

  • Serotonin 😊😊

  • Quipazine (serotonin agonist) 😀😀

  • Placebo

• 10 minutes after the injection, a mouse was placed in their cage to test their tendencies to kill or attack

• After an hour, they are tested again.

Pucilowski (Killer Rats) Findings

• 10 minutes after the injection:

  • Quipazine (the serotonin agonist) blocked the killing response 😀❌

  • High dose of serotonin decreases the killing response 😊📉

• 60 minutes after injection:

  • No significant difference between groups, all showed tendency to attack

Pucilowski (Killer Rats) SUPPORT

SUPPORTS the hypothesis that serotonin has a link to aggression as rats who had an increase in serotonin, whether through an agonist or serotonin, showed less aggression.

Pucilowski (Killer Rats) Strength

Placebo used - increases internal validity

Pucilowski (Killer Rats) Limitations

• Sampling bias (only “killer rats” were used)

• Likely not direct correlation, serotonin may reduce anxiety (therefore decrease aggression)

• Only theoretical generalization

Pucilowski (Killer Rats) Research Method

Experiment

Pucilowski (Killer Rats) Ethical

Justification for the use of animal research

Moore (Antisocial) Aim

Determine if there is a correlation between (5-HIAA) and antisocial behaviour by analyzing 25 years of research

Moore (Antisocial) Procedure

16 studies were used in the analysis

Main Criteria for Inclusion:

• 👨 Studies had to be on humans

• 🧬 Include measure of 5-HIAA from a lumbar puncture and a measure of antisocial behaviour

📈 Studies were weighted differently based on their findings and participants numbers. The overall statistics were computed.

What is 5-HIAA?

5-HydroxyIndoleAcetic Acid

Waste product of serotonin. It’s levels can be measured through a lumbar puncture to get an indicator of someone’s serotonin levels.

Moore (Antisocial) Findings

Found negative correlation between serotonin levels (5-HIAA) and antisocial behaviors

Low levels of serotonin have the greatest effect on antisocial behaviour in people younger than 30 years old.

Moore (Antisocial) SUPPORTS

Strong correlation between low levels of serotonin and antisocial behaviour but does not provide an explanation

Moore (Antisocial) Strengths

Data triangulation of findings from many studies

Moore (Antisocial) Limitations

Reliant on accuracy of 5-HIAA that may not reflect actual serotonin in brain

Reductionist to believe 5-HIAA directly connected to serotonin levels

Bidirectional ambiguity: Which variable is influencing which?

Moore (Antisocial) Research Method

Correlational Research (meta-analysis)

• Combines results of individual studies with statistical methods

Banks and Dabbs (Delinquent) Aim

See correlation between testosterone and delinquent behavior

Banks and Dabbs (Delinquent) Procedure

Two groups compared:

1. US College Students

2. Delinquent group characterized by drug use and violence

Participants interviewed by participant researcher who was already known to the delinquents.

Salivary testosterone measure taken.

Banks and Dabbs (Delinquent) Findings

Delinquent group had a significantly higher measure of salivary testosterone.

• But measure of aggression & testosterone had no significant correlation in the delinquent group

• Aggression score determined by whether participant answered yes to question such as:

  • Frequent alcohol use, been arrested, killed someone

Banks and Dabbs (Delinquent) SUPPORTS

Positive correlation between testosterone levels and delinquent behavior

Banks and Dabbs (Delinquent) Strengths

Low Participant Bias

• Researcher known to group, less pressure to lie

Banks and Dabbs (Delinquent) Limitations

Questionable Internal Validity

• Lack of correlation between testosterone and aggression may be due to the scale used to measure aggression

Banks and Dabbs (Delinquent) Ethical

Confidentiality

Informed Consent

Banks and Dabbs (Delinquent) Research Method

Correlational

Semi-Structured Interview (questionnaire)

Albert (Alpha Male Rats) Aim

See the role of testosterone in aggression of alpha male rats

Albert (Alpha Male Rats) Procedure

👪 Rats were kept in small colonies as families

🐀 Single male rats were introduced as intruders so aggressive behavior of the rats could be recorded.

💉 Once an “alpha male” was established in the family, a surgery was performed (three options)

→ Castration and insertion of testosterone tubes

→ Castration and insertion of empty tubes

→ Sham castration and insertion of empty tubes

💢 Intruder rats was introduced again after surgery and behaviour was recorded again

💉☯ A second surgery was completed and castrated rats with empty tubes had tubes with testosterone inserted, those with testosterone had them emptied.

Albert (Alpha Male Rats) Findings

Attacks decreased in rats who had been castrated with empty replacements

Aggression reinstated in rats when the testosterone replacement occurred.

Castrated rats lost their status as the alpha male in the family

Albert (Alpha Male Rats) SUPPORTS

Testosterone causes aggression in alpha male rats and plays a role in social dominance.

Albert (Alpha Male Rats) Strengths

Internal validity (sham surgery, insertion of tubes for controls)

Albert (Alpha Male Rats) Limitations

Sampling bias (only alpha rats studied)

• Could this happen in less socially dominant rats?

Theoretical generalization

Albert (Alpha Male Rats) Ethical

Need to justify scientific purpose of research

After the research, if the rats could no longer be used for another experiment, they need to be euthanized quickly

Albert (Alpha Male Rats) Research Method

Experiment

Rabbit Pups Aim

Determine the chemical identity of the substance involved in rabbit pup feeding, seeing if it fits criteria of a pheromone.

Rabbit Pups Procedure

🧪 Researchers separated 21 different volatiles from rabbit milk to identify the one that rabbit pups respond to

👃Pups exposed to volatiles one at a time through sniffing device

🐰 Response measured if pups were turning towards the device or trying to orally grasp it

🥛Tested with milks of other animals

Pups of other species were also tested with 2MB2 (suspected pheromone in rabbit milk)

Rabbit Pups Findings

Reactivity to one volatile, 2MB2, was evident

Pups responded to 2MB2, despite never being fed before.

Pups did not respond to milk from other species.

Rabbit Pups SUPPORTS

Researchers concluded that 2MB2 is a pheromone, fits criteria: obvious behavioral response.

Rabbit Pups Strengths

Researchers were able to break down rabbit milk into its different components in order to be tested.

Rabbit Pups Limitations

Internal Validity: Substances were deodorized so milk would have no detectable scent

Only theoretical generalization to humans

Rabbit Pups Ethical

Specific ethical guidelines are used during animal studies:

As rabbit pups were not harmed, they would likely be used in other experiments

Mares were euthanized and samples were taken.

Rabbit Pups Research Method

Experiment

Doucet (Newborns) Aim

If secretion from areolar glands gets a response in infants.

Doucet (Newborns) Procedure

Group of newborns:

• Some exclusively breastfed 🤱

• Some bottle fed 🍼

📺😴 Exposed to different stimuli in random order while sleeping

Stimuli

• Secretions of areolar glands

• Sebum (oils from human skin)

• Human milk

• Cow milk

• Formula milk

😯⏺ Physiological data recorded along with facial reaction.

Doucet (Newborns) Findings

Breastfed and non-breastfed infants reacted the longest to secretions of areolar glands

• Reactions like pursed lips, preparing to feed

Indicates that it was not a learned response as infants with no previous exposure to secretions from the areolar glands reacted in the same way.

Doucet (Newborns) SUPPORTS

Existence of human pheromones as infants who had never been breastfed reacted the same way to exposure to secretion than those who did.

Doucet (Newborns) Strengths

Data triangulation

• Supported by existence of pheromones for feeding in other mammals

Double-blind procedure

• Researchers did not know which stimuli they were exposing the infant to

Doucet (Newborns) Limitations

Difficult to determine causation

Reductionist approach

Doucet (Newborns) Ethics

Informed consent:

• Parent consented on behalf of infant

Protection from harm:

• Parent was present while infant was participating

• Infants with “unstable reactions” were withdrawn

Doucet (Newborns) Research Method

Experiment

Weissman (Grandparents and Parents) Aim

Examine the potential genetic influence of (MDD) on psychiatric disorders

Weissman (Grandparents and Parents) Procedure

Large group of grandparents, parents and children:

📅 Data collected over 20 years.

Data collected from clinicians, who were blind to past diagnosis of depression.

Sample of original depressed patients (now, grandparents) selected from clinic with a specialization in treatment of mood disorders

• Non-depressed participants selected from same community.

🧠🎤 Assessments during interviews included diagnosis of psychiatric disorders, IQ, overall functioning and impairment.

Weissman (Grandparents and Parents) Findings

🧓🏻👩🏽 High rates of psychiatric disorders (ex. Anxiety or mood disorders, substance abuse) in grandchildren with two generations of MDD

🤱😔 If parent was depressed but there was no history of depression in grandparents, there was no significant effect of parental depression on grandchildren

👶😱 Severity of a parent's depression was correlated with an increased rate of a mood disorder in children

Weissman (Grandparents and Parents) SUPPORTS

Genetic influence of MDD on psychiatric disorders and overall functioning in grandchildren.

(?) Impairment is factor that should be studied when looking at familial transmissions.

Weissman (Grandparents and Parents) Strengths

Longitudinal study

Non-biological children were removed from analysis (increasing internal validity)

Researcher triangulation increases the credibility of the

Weissman (Grandparents and Parents) Limitations

Although family (kinship) studies indicate a potential genetic link to behaviour, no actual genotype studied.

Grandchildren avg age 12 years (not past age of risk for developing depression)

Weissman (Grandparents and Parents) Ethical

Informed consent was obtained

• Difficult with children who may change their mind (or not make the decision)

Confidentiality will be very important as genetic research increases

Weissman (Grandparents and Parents) Research Method

Semi-structured interview

Kendler (Twin Study) Aim

To investigate a difference in the heritability of (MDD) between men and women

Kendler (Twin Study) Procedure

👨🏻‍🤝‍👨🏻 Over 40K individuals were interviewed including over 15K complete set of twins.

📞 Major lifetime depression was assessed in a personal telephone interview according.

💊🩺 Participants who stated that they had taken antidepressants were not asked the questions related to MDD but were given the “diagnosis” for this study.

Kendler (Twin Study) Findings

Heritability of major depression was 38%

Correlations for major lifetime depression were higher in MZ twins than DZ twins

👭 Correlations for female-female (due to environmental, cultural) twins were higher than male-male twins.

Kendler (Twin Study) SUPPORTS

🧬😢 Supports a genetic influence on MDD

🚹🚺 Supports hypothesis that there are sex differences in the genetic risk factors for major depressive disorder

Kendler (Twin Study) Strengths

Large, representative sample of Sweden

Provides data triangulation for findings of other twin studies

Kendler (Twin Study) Limitations

Interviews were conducted at one point and time (not at the end of the participants life)

• Participants might experience depression later in their lives

Differences between female and male participants may be related to culture rather than actual prevalence of depression