BIOLOGICAL APPROACH

Biological Approach in General and Assumptions:

The biological approach examines the influence of genetics, neurobiology and the brain, and cognitive processes on human behavior and mental functions. The three assumptions of the biological approach are:

• Physiological factors such as neurotransmission, hormones, genes and brain structure influence behavior.

• Inheritance of genetic predispositions influence behavior and the development of disorders.

• Animal research can help to research and understand human behavior, as mammalian animal brain chemistry is similar to ours.

Research Methods in the Biological Approach:

Qualitative:

Case studies: In-depth research of individuals or groups that provide understanding into physiological factors affect behavior, such as the Milner study on HM which saw that damage to the hippocampus affect memory. Data is gathering using multiple methods.

Correlational Studies: Examine the relationship between already existing variables without manipulating them, providing understanding into how physiology affects behavior.

Twin/Family Studies: Families or Twins are observed over a period of time, along with their family history or interviews to see if a trait or disorder is an inherited trait.

Quantitative:

Experiments: Controlled animal experimental research that manipulate some independent variable to observe its effect on behavior, however there are ethics to consider here. Technology as various brain imaging techniques allow for monitoring and observation of the brain, its activity and abnormalities.

MRI: Imaging technique that provides a 3D image of brain structures. Strengths: Non-invasive and minimal potential harm, detailed image of brain structure. Limits: Only show structure not brain activity, MRI research is correlational in nature and cannot establish a cause and effect relationship.

FMRI: Imaging technique that shows brain activity. Strengths: Provides real-time images of brain activity and film that can be reviewed later, allows for imagining while a task is performed. Limits: High cost and limited accessibility, potential harm due to use of a powerful magnet, not natural environment even for cognition, loud and can cause anxiety, activity seen might not be related to behavior.

PET SCAN: Imaging technique that shows metabolic processes in the brain Strengths: Shows brain activity and changes in blood flow and glucose metabolism, can find abnormalities like tumors, and shows a more comprehensive picture of brain activity. Limits: Involves exposure to radioactive tracers so invasive, low resolution and slow.

Brain Imaging in General: Not natural environments, expensive, brain activity is random, coloring of images exaggerates brain activity, and results can be influenced by external factors, however PET and fMRI scans have identified brain patterns and predispositions seen in abnormal behaviors such as schizophrenia, alcoholism and depression.

 LOCALIZATION

Localization of function - the theory which argues that specific parts of the brain are responsible for specific behaviors or processes. However, though some parts have specific roles, the brain rarely works alone. Thus, people attempt to map the brain by exploring neural connections, and create a connectome.

HM CASE STUDY - MEMORY DAMAGE DUE TO BRAIN DAMAGE - LOCALIZATION STUDY

Aim: Investigates the extent of memory deficiency due to brain damage.

Procedure: HM, a 27 year old male underwent an experimental surgery where a neurosurgeon removed most of his hippocampus and medial temporal lobe tissues to cure him of epileptic seizures. He was observed in a longitudinal case study by Milner.

Results: HM experienced anterograde amnesia, meaning he could not transfer new information to long memory, but retained previous memories he held before surgery. However, he could still create new procedural memories.

Conclusion: The case study provided biological evidence that short memory and long memory are located in different parts of the brain, and that the hippocampus doesn't hold memory but is the site where short term become long term memories. HM being able to create procedural memories also indicates that memory is more complex than the multi store model predicts, and that the hippocampus is not the only structure involved in the processes of memory.

EUGENE PAULY - LOCALIZATION RESEARCH, CASE STUDY (Squire, 1992; 2002)

Aim: Investigate how the amygdala and hippocampus affect memory.

Design: Case study

Procedure: Series of interviews were carried out on Eugene whose amygdala and hippocampus were completely destroyed due to viral encephalitis. He was unable to draw a map of his home, but could walk home and if asked to point where he lived he did not know. In addition, if something familiar was different, such as a sidewalk getting repaired, he would get lost.

Results: Associative tasks or automatic tasks, are results of repeating behaviors and movements, thus becoming habits and they no longer require cognition. EP posessed a long-term procedural memory of how to get home, but if a familiar pattern changed he could no longer complete the task.

Conclusion: Multiple different research methods including, the case study itself, interviews, IQ testing, observational studies and MRI testing were used to study EP. MRI's examined the damage to his brain and found that his Basal Ganglia was undamaged. Meaning, that the basal ganglia could be responsible for procedural memory, such as getting home.

RAINE ET AL 1997

A localization experiment that investigates structural brain differences between murderers and nonmurderers.

The brain activity of murderers and non-murdered was measured with a PET scan to show function in the brain, where the non-murderers were matched with murderers based on brain damage history to eliminate that factor.

There was a physiological difference between violent people and non-violent people, where violent people had lower prefrontal cortex activity which is linked to the lack self-control and altered or more emotion. In addition, there were brain activity differences between the two hemispheres, such as the amygdala and hippocampus.

Murderers might have stronger emotions and lack the ability to control them, which could result in violent behaviors.

PLASTICITY

Plasticity - the brain's ability to rearrange connections between neurons, thus changing brain structure through learning or experience. The effect of behaviour and environment on our brain. If we were to lose an area of the brain another area would take over easier when you're younger.

Neural pruning - the process by which extra neurons and synaptic connections are eliminated.

Dendritic branching - the increase of neurons and neural connections.

Maguire. (2000). “Taxi driver study.” Studying how drivers’ brain structures differ to that of gen pop. Distribution of grey matter between posterior vs anterior hippocampus is different.

Aim:

investigates whether the brain structures of taxi drivers could change with training. Participants must form a mental map of London.

16 right-handed male English taxi drivers participated in a quasi-experiment, MRI scans of taxi drivers and right handed non taxi drivers were taken. Participants had to have a mental map of London and have been driving for 1.5 years. The controls were taken from an MRI database and included range of ages to rid of confounding variables.

The IV occurred naturally, thus a correlational study to see whether driving taxis changes brain structure. Single-blind so researcher would not know what brain is being reviewed to rid of bias.

It was seen that the posterior hippocampi of taxi drivers were much larger than the control group and the anterior hippocampi were smaller. In addition, the volume or size of the right posterior hippocampi correlates with being a taxi driver, and no other differences were found.

Quasi-experiment, no cause and effect relationship can be established. Researchers did not manipulate IV, thus non-artificial. The brain scans were analyzed blindly and bias was avoided.

Possible that larger hippocampi participants might be more spatially talented and thus chose to be taxi drivers, but disproven by the correlation between the size of the hippocampus and the number of years driving. The MRI was used to view their brain structure, not the activity, thus not a limitation. Sample bias as most London taxi drivers are male, making it difficult to generalize the findings. MRI does not pose any health risks to the participants and all gave consent.

DRAGANSKI 2004 - PLASTICITY AND JUGGLING

A longitudinal brain plasticity field experiment that investigated whether learning a new skill - juggling, affects brain structure. A small sample of volunteering young adults participated in a field experiment. Started as non-jugglers and MRI scan was taken to view grey matter and brain structure. Participants were taught a juggling routine, and had to master it, other MRI was taken. They stopped juggling for 3 months and last MRI. The non-juggle condition acts as a control.

 MRI scans were analyzed via voxel-based morphometry to compare changes in grey matter. No significant regional difference in the amount of grey matter between conditions. However, in the second MRI scan where they had mastered juggling, more grey matter in both hemispheres of the mid-temporal lobe, associated with visual memory. Last MRI scan, the grey matter from the mid-temporal lobes decreased in the final MRI. The control group had no changes in gray matter.

Changes in gray matter indicate that juggling relies on visual memory, as one perceives and assumes where the moving ball will land, rather than procedural memory which would likely change the cerebellum or basal ganglia.

Pre-test and post-test shows differences in neural density over time. Experiment, thus argues for a cause and effect relationship. Non-jugglers served as a control group. Small sample that used averages of growth, the data may not be reliable. Low internal validity as participants were in their home environments for a great part of the study. Study would need to be replicated to establish its reliability.

 NEUROTRANSMISSION

Neurons - nerve cells and basic blocks of behavior and function, they send action potentials that travel along the axons and transmit information throughout the nervous system.

Synapse - the link between two neurons, which action potentials travel through by diffusion

Neurotransmission - the process of sending electrochemical messages via electrical impulse

Agonist - a chemical that amplifies the effect of neurotransmitters, all neurotransmitters are agonists for receptor sites, lets a message get transferred

Antagonist - a chemical that reduces the effect of neurotransmitters, chemical that blocks the receptor site and does not allow the neurotransmitter to do its job

Action potential - the electrical charge that travels down the axon

Neurotransmitter - chemical messengers that send signals between neurons through synaptic gaps.

Receptor site - specific site on the dendrites of the receiving neuron which given neurotransmitters bind to

Reuptake - the process after the neurotransmitter has completed its function where it is taken back into the neuron in came from

The limbic system - consists of 5 parts, but in general responsible for emotion, and mainly studied for how emotion affects memory.

Amygdala - responsible for the formation of emotional memory and fear responses.

Basal ganglia - responsible for habit formation and procedural memory.

Hippocampus - responsible for short-term memory transfer to long-term memory.

Hypothalamus - responsible for homeostasis, emotion, thirst, hunger, circadian rhythms, and the autonomic nervous system, and the pituitary gland.

Nucleus accumbens - responsible for addiction and motivation.

NEURON STRUCTURE

• Dendrite - collects information about surrounding environment

• Cell body/Soma - the genetic material of the nerve cell containing genes

• Nucleus - contains genes

• Axon - carries electrical action potentials and transmits them

• Myelin sheath - fatty tissue sleeve that protect the neuron

• Schwann cell

• Axon terminal - small branch at

• Node of Ranvier

NEUROTRANSMITTERS

Caffeine - an antagonist that binds to adenosine receptor sites, while stimulating brain activity so movements and thoughts are faster.

Adenosine - a neurotransmitter in the brain that is responsible for sleepiness

Acetylcholine - a neurotransmitter that is responsible for consolidation of memory in the hippocampus

Dopamine - a neurotransmitter that controls the brain's reward and pleasure centers, responsible for motivation, low levels are linked to addiction

Norepinephrine - a neurotransmitter that is responsible for arousal and alertness

Serotonin - a neurotransmitter that is responsible sleep, arousal levels, and emotion

Antonova et al. (2011). “Neurotransmitters and behaviour.” Effect of blocking acetylcholine receptors on spatial memory. Those with blocker showed less activation of hippocampus.

Atri et al. (2004). “Acetylcholine and memory formation.” In all 3 conditions, overlapping pairs scored lower and scopolamine did the worst.

Rogers and Kesner. (2003). “Acetylcholine and the formation in spatial memories.” Rats with blocker took longer in maze.

HORMONES

Hormones - chemical messengers secreted by the endocrine system that control bodily functions from hunger to emotions and mood. Hormones can also act as neurotransmitters by attaching to post-synaptic receptor sites.

Adrenaline - Secreted by the adrenal glands; responsible for arousal and the "fight or flight" response. Plays a role in emotional memory formation. Adrenaline increases oxygen flow and blood to the brain by increasing heart activity and dilating blood vessels.  It is appears to play a role in the creation of flashbulb memories.

Cortisol - Secreted by the adrenal glands and involved in the "fight or flight" response; helps control blood sugar levels, regulate metabolism, reduce inflammation and assist with memory formation. Cortisol interferes with moving STM to LTM.

Melatonin - Secreted by the pineal gland; signals the relaxation and lower body temperature that help with a restful sleep. It is secreted when we are in the dark.

Neuropeptide Y - Produced by the hypothalamus; acts as a neurotransmitter in the brain. Stimulates food intake, reduces anxiety and stress, reduces pain perception, affects the circadian rhythm. Higher levels of NPY appear to be linked to higher levels of resilience.

Oxytocin - the "love" hormone produced by the hypothalamus and secreted by the pituitary gland. When it affects the brain, it acts as a neurotransmitter. Plays a role in mother-child attachment; believed to play a role in social bonding and trust between people.

Testosterone - Produced by the testes; plays a facilitative role in aggressive behavior - that is, it doesn't cause aggression, but higher levels of testosterone result in higher levels of aggression.

McGaugh and Cahill (1995). “The role of adrenaline and the amygdala on emotional memory.” Emotional vs boring story. People with emotional story did better. Follow-up-study gave beta-blockers.

Aim: Investigates the role of adrenaline and amygdala on emotional memories.

Procedure:

In an independent research design participants were divided into two groups. Group one were shown 12 slides of a boring story about a women and her son who went to see the father in a hospital, but saw the staff preparing a simulated accident drill.

Whereas, the second group saw 12 slides of an emotional story where the boy's feet were severed in a car accident and were reattached at the hospital. However, some of the emotional group was injected with propranolol which is an adrenaline antagonist to prevent the activation of the amygdala and prevent the formation of emotional memory.

Participants who heard emotional stories recalled the specific details story better. However, participants that received the antagonist which blocked the secretion of adrenaline did no better than the control group.

Adrenaline and activation of the amygdala play a significant role in the creation of emotional memories.

Highly standardized, thus easy to repeat. Cause and effect relationship established as blocking secretion of adrenaline which is responsible for creating flashbulb memories prevented the creation of flashbulb memories. Unlikely demand characteristics as you cannot remember better or ignore the adrenaline antagonist. Results help explain how flashbulb memories happen and are applicable as propranolol can prevent traumatic memories, and it is being tested to prevent the onset of PTSD.

Newcomer et al. (1999). “Cortisol and verbal declarative memory.” Ppl with the highest levels of cortisol had worst performance. Ppl with normal levels of cortisol performed well in the task.

Aim: Investigates whether cortisol affects verbal declarative memory.

Verbal declarative memory refers to facts and events that can be stated or recalled. In a double blind match group design participants aged 18-30 matched for age and gender were assigned to one of three conditions: high level of cortisol - ingested 160mg of cortisol equivalent to a major stressful event, low level of cortisol - ingested 40mg of cortisol equivalent to a minor stressful event, and placebo - ingested empty tablet.

Participants then listened and recalled a prose paragraph to measure their verbal declarative memory. Each day they were given different prose pieces of the same difficulty and were tested three times. Participants were tested first before taking cortisol to acquire a baseline.

High cortisol levels showed impaired performance in the memory task as participants with highest cortisol levels performed worst in the verbal declarative memory test. Low-level group showed no overall decrease in memory.

High levels of cortisol impair the recall of prose paragraphs, whereas moderate levels of cortisol may assist recall. This is because cortisol receptor sites in the hippocampus are responsible for the transfer of STM to LTM. Thus, high levels of stress affect verbal declarative memory.

A cause and effect relationship between cortisol and verbal declarative memory was established. A baseline level of cortisol was acquired to eliminate individual differences between groups. Double-blind method, thus less likely to be biased. The experiment took multiple days, thus researchers did not fully control any extraneous variables, such as daily stressors, but still provided a clear relationship. Different texts, but the same difficulty were used to assure that difficulty did not affect recall. Memorizing prose pieces is not a realistic memory experience, but could explain exam stress, however limited to generalize to other situations. Participants ingested cortisol which impaired their memory, however they signed an informed consent form and damage was not permanent.

➢ The reductionist nature of attributing complex human behaviors to a single hormone

➢ Hormones are often measured indirectly, difficulty of measuring hormones naturalistically

➢ If experiments are not used then correlations are decided, which may be based on assumptions

PHEROMONES

Pheromones - a chemical substance produced by animals and humans that may affect the behavior and physiology of others. It is not clear whether pheromones affect human behavior, but they may play a role in human attraction - MCH hormone.

Wedekind et al. (1995). “Smelly t-shirt study.” Does a difference in MHC genes affect female mate attraction? Females preferred the dissimilar MHC genes compared to similar ones.

Investigates whether similar or dissimilar MCH pheromones can be differentiated, and influence female attraction to potential mates.

Major histocompatibility complex genes may influence body odor and mate choices, in which individuals choose mates with different immune systems to produce offspring with stronger immune systems.

In a double-blind experiment 44 Male and 39 female Swiss participants from 18-40 were analyzed for their MHC genes. Male participants wore clean shirts and avoided factors that could affect odor, like fragrance, deodorant, spicy food, or sex for two days to reduce interference with natural odors. Shirts were put into sealed boxes until the females were asked to smell them. Females were asked to rate the shirt for attractiveness of the odor from 0-10.

Female participants rated the odors more attractive if they came from a male with a dissimilar set of MHC genes.

Individuals are more likely to choose mates with dissimilar MHC genes, or different immune systems to produce offspring with stronger immune systems. However, sweat does not consist of just MHC, and human attraction and mate selection is influenced by other factors.

Zhou et al. (2014). “Pheromone stick figure study.” Do female and male pheromones affect human sexual behaviour? Pheromones influence communication of gender information in a sex-specific manner.

Aim: Investigates whether potential human pheromones affect sexual behavior/attraction.

Androstadienone found in semen and sweat, and Estratetraenol found in female urine are potential human pheromones. In a repeated measures design, Heterosexual men and women, homosexual men and women, watched walking stick figures on a screen and were asked to determine their gender while being exposed to the smell of cloves. In the first condition the cloves were mixed with Androstadienone, and in the second with Estratetraenol, for control only cloves were used.

Androstadienone biased heterosexual females and homosexual males, but not heterosexual males, to perceive the stick figures as more masculine. Whereas, Estratetraenol influenced heterosexual males and homosexual women in perceiving the stick figures as more feminine.

Human pheromones influence the communication of gender information in a sex-specific manner. Pheromones may communicate opposite gender information that is effective or not based on sexual orientation.

Doucet. (2009). “Pheromones and breastfeeding.” Does secretion of the areolar glands affect suckling infants? Infants only began suckling when exposed to the secretions, and they also get an increased breathing rate.

McClintock. (1971). “Pheromones and menstrual synchronicity.” Do females living together experience menstrual synchronicity? The data suggests so, but otherwise there is no concrete data to support it.

EVALUATION OF PHEROMONES

 GENETICS

GENETICS AND BEHAVIOR

Behavioral genetics explores how genetics and one's environment produce variations in human behavior. Psychologists argue that people have genetic predisposition towards specific behavior or disorders inherited from their parents, but without specific environmental stimuli the gene will not be expressed and the behavior will not occur.

Diathesis stress model states that depression may be a result of an inherited genetic predisposition and an interaction with environmental stress. Argues that individuals with certain genes that are exposed to a stressful environment are more likely to develop depression.

GENETIC STUDIES

Genetic research relies on correlational studies in which a researcher finds a relationship between genetic and behavioral variables based on concordance rate - the probability that the same trait will be present in related individuals.

Twin studies compare monozygotic and dizygotic twins and evaluate how their genes and environment influence a specific trait by measuring the concordance rate, the probability that the same trait will be present in both. It assumes that heritable traits will be more likely in identical twins, and lower in non-identical twins and even lower in siblings.

However twins are rarely raised apart and tend to live in the same environment, in addition twins are not representative of the general population

Family studies compare different family members and evaluate how their heritage percentage influences a specific traits or behaviors, assuming that concordance rate will increase if members are more related.

Prospective studies observe a family member that is genetically vulnerable to certain behaviors or disorders to see if they develop them, major ethical concerns.

Weissman et al. (2005). “MDD, family study”. 20-year longitudinal. investigated the genetic nature of Major Depressive Disorder. Increased risk for depression in children with depressed grandparents and/or parents.

A longitudinal kinship/family genetics study that investigates whether genetics influence the development of Major Depressive Disorder.

161 participants consisting of grandparents, parents and grandchildren were observed longitudinally for twenty years. Participant families had either a high or low risk for depression, in which the grandparents of high risk families were selected from an outpatient facility, and low risk participants were not. Participants were interviewed four times, clinical data was collected and children were evaluated by psychologists and psychiatrists.

High rates of psychiatric disorders were found in children with two generations of depression. At 12 more than half of the children showed signs of mental disorders.

Children had increased risks of any disorders if depression was observed in both the grandparents and the parents. In addition, a parents depression severity was correlated with increased rates of mood disorders in children. However, if a parent was depressed but the grandparents had no history of depression, there were no significant effects on the grandchildren.

EVALUATION OF FAMILY STUDIES

• Limit overall genetic variability of the sample which increases statistical power of any discovered gene

• Controlled more than studies of unrelated people, similar environments

• It is difficult to obtain reliable data that goes back more than one generation

• Rely on anecdotal data with regard to grandparents or great-grandparents

• Only recently have we been able to get diagnoses, in the past we can only make assumptions