Biopsychology: Paper 2 (16 markers) Flashcards
A01: Outline the full process for acute stress in the fight or flight response
- In acute stress, the amygdala processes fearful and threatening stimuli.
- The amygdala sends a stress response to the hypothalamus , which activates the sympathetic nervous system (SNS), which delivers more blood to areas of the brain that require oxygen.
- The SNS then triggers the adrenal medulla to secrete the hormones called adrenaline and noradrenaline.
- The realise of adrenaline triggers the body’s fight or flight response by increasing the heart rate and expanding the air passages of the lungs.
- Also, the noradrenaline constricts blood vessels which maintain blood pressure in times of stress.
- Lastly, after the threat has passed, the parasympathetic nervous system is activated, which calms the body down after the fight or flight response. For example, it slows down the heart rate and restores digestion.
A01: Outline the full process of the fight of flight response to chronic stress
- A major component of the chronic stress response is the hypothalamic-pituitary-adrenal axis (HPA axis).
- When a chronic stressor (an example could be exam stress) is perceived, the hypothalamus secretes CRH: a hormone that is the main organiser of the body’s response to stress.
- Next, the hormone CRH causes the pituitary gland to release a hormone called ACTH, which plays a role in maintaining blood pressure.
- The release of ACTH then triggers the adrenal cortex to produce cortisol, which is known as the stress hormone, which regulates the stress response of the body by keeping inflammation down.
- Lastly, the hypothalamus then maintains the levels of cortisol keeping it stable by utilising a negative feedback loop.
- For example, if cortisol levels get too high then a signal is sent to the hypothalamus, which inhibits ACTH, inhibiting the release of cortisol.
- Therefore, this reduces the cortisol levels back down to normal.
A03: Why does the fight of flight response not tell the whole story?
- Gray argues that the first response to danger is to avoid confrontation.
- This is demonstrated by the ‘freeze response’, in which humans are hyper alert as they assess the situation and determine the best action to take for the particular threat that is imposed on them.
- Therefore, the ‘fight or flight response’ does not show an accurate representation of the body when faced with a threat.
A03: Why is the fight of flight response not required in modern life?
- While the fight or flight response may have been a useful survival mechanism for our ancestors, who faced genuinely life-threatening situations (e.g. from predators), modern day life rarely requires such an intense biological response.
- The problem for modern humans arises when the stress response is repeatedly activated. E.g. increased blood pressure that is characteristic of the SNS activation can lead to physical damage in the blood vessels and eventually to heart disease.
- This suggests that the fight or flight response is a maladaptive response in modern-day life.
A03: Why does research into the fight of flight response suffer from beta bias?
- Early research into the fight or flight response was typically conducted on males (androcentrism) and this meant researchers assumed that the findings could be generalised to females. This means research into the fight or flight response suffers from beta bias as psychologists assumed that females responded in the same way as males.
A03: What research shows that women actually have a different fight or flight response?
- The fight or flight response is typically a male response to danger and more recent research suggests that females adopt a ‘tend and befriend’ response in stressful/dangerous situations due to the release of oxytocin in response to stress (which is associated with maternal bonding and a mother’s natural protective urges)
- According to Taylor et al. (2000), women are more likely to protect their offspring (tend) and form alliances with other women (befriend), rather than fight an adversary or flee.
- Furthermore, the fight or flight response may be counterintuitive for women, as running (flight) may put their offspring at risk of danger.
- Therefore, women deal with stress through different system responses than fight or flight responses, in which they are more likely to ‘tend and befriend’ due to the excretion of oxytocin.
A03: How does genetic data show that it is unlikely women have the same flight or fight response as men?
- In fact, this is supported by genetic data.
- Lee and Harley (2012) found the SRY gene, exclusively on the male Y chromosome, associated with aggression and priming for a fight-or-flight response to stress.
- They conclude that the absence of this gene in females, together with the action of oestrogen and oxytocin, mean that the response is not likely to occur in females - showing that the fight or flight response is not an adequate explanation for female responses.
A03: How does contradictory research show that men actually go through the same ‘tend and befriend’ response as women?
- However, a strength of the fight or flight response is that there is evidence for positive rather than ‘fight or flight’ behaviours.
- Von Dawans et al (2012) challenge the view that, under stress, men respond only with fight or flight, whereas women are more prone to ‘tend and befriend’.
- It was found that acute stress can actually lead to greater cooperative and friendly behaviour, even in men. This could explain the human connection that happens during times of crisis such as the 9/11 terrorist attacks.
- One reason stress may lead to greater cooperative behaviour is because human beings are fundamentally social animals and is the protective nature of human social relationships that has allowed our species to thrive.
A01: What is localisation of function?
Localisation of function refers to the principle that specific functions have specific locations within the brain. According to this theory, if a certain area became damaged, the function associated with that area will also become damaged.
A01: How has research found that different locations of the brain are associated with different functions?
Provide an example and what they found.
- Scientists such as Broca and Wernicke discovered that certain parts of the brain are associated with particular physical and psychological functions using case studies.
- For example, Broca used postmortem to study the speech area of the brain. He had a case of a patient called Tan who had a speech difficulty who was found to have a lesion in the left hemisphere of his brain due to Syphilis.
- This led Broca to conclude that this area was responsible for speech production, calling it the Broca’s area and that the left side of the brain had been responsible for language and speech.
Before these discoveries, scientists supported the holistic theory of the brain – that all parts of the brain were always involved.
A01: Where is the Somatosensory Area located and what is its function?
- The somatosensory area is located in the parietal lobe and receives incoming sensory information from the skin to produce sensations related to pressure, pain, temperature, etc.
- Different parts of the somatosensory area receive messages from different locations of the body.
A03: What is evidence to support the existence of the somatosensory area performing its designated function?
Robertson (1995) found that this area of the brain is highly adaptable, with Braille readers having larger areas in the somatosensory area for their fingertips compared to normal sighted participants, showing that the somatosensory area has a specific function for sensory information within the brain.
Case studies such as Broca’s are limited as they are based on a small and unique sample…
A03: Localisation of Function
One limitation is that case studies are based on a small and unique sample. This is a limitation because these results cannot be generalised to other people as case studies are unique to the individual and cannot be replicated for verification. Therefore, we cannot be sure if the brain works to the localisation theory in all individuals.
Functional recovery limits the idea of the brain being localised…
A03: Localisation of Function
One limitation of localisation is the notion of functional recovery. This is a limitation because after brain trauma, the brain is able to rewire and reorganise itself in order to recover lost function, which can involve another part of brain taking over that function.
This is illustrated in the case study of Jodie Miller, who had hemispherectomy. While she had almost all of her right hemisphere removed, she was able to walk within 10 days.
Therefore, this suggests localisation is not fixed to specific areas for specific function; functional recovery supports holistic theory suggesting the brain is working as whole unit.
Contradictory evidence on Broca’s findings…
A03: Localisation of Function
Although there is evidence from case studies to support the function of the Broca’s area, more recent research has provided contradictory evidence.
Dronkers et al. (2007) conducted an MRI scan on Tan’s brain, to try to confirm Broca’s findings. Although there was a lesion found in Broca’s area, they also found evidence to suggest other areas may have contributed to the failure in speech production.
This is a limitation because these results suggest that the Broca’s area may not be the only region responsible for speech production and the deficits found in patients with Broca’s aphasia could be the result of damage to other neighbouring regions.
Biologically reductionist…
A03: Localisation of Function
One limitation is that critics argue that theories of localisation are biologically reductionist in nature and try to reduce very complex human behaviours and cognitive processes to one specific brain region.
This is a limitation because critics suggest that a more thorough and holistic understanding of the brain is required to truly understand complex cognitive processes like language.
Different areas of the brain interact with each other rather than act independently..
A03: Localisation of Function
One limitation is that some psychologists suggest that it is more important to investigate how the brain areas communicate with each other, rather than focusing on specific brain regions. Wernicke claimed that although the different areas of the brain are independent, they must interact with each other in order to function.
An example to demonstrate this is a man who lost his ability to read, following damage to the connection between the visual cortex and the Wernicke’s area, which was reported by Dejerine.
This is a limitation because this suggests that interactions between different areas produce complex behaviours such as language.
Therefore, damage to the connection between any two points can result in impairments that resemble damage to the localised brain region associated with that specific function. This reduces the credibility of the localisation theory.
A wide range of evidence to support the idea that different areas of the brain have different functions…
A03: Localisation of Function
Furthermore, advances in brain imaging techniques such as PET scans have led scientists to be able to discern and describe the neurological basis of mental processes. For example, in Tulving et al’s research involving tasks that required the use of episodic and semantic memory were able to show how these different types of long-term memory may be located on opposite sides of the pre-frontal cortex, whilst procedural memory may have been located in the cerebellum.
For example, Paterson used brain scans to demonstrate how Wernicke’s area was active during a listening task (where people had to understand what’s being said) and Broca’s area was active during a reading task.
These are strengths because there is a wide range of evidence to support the idea that different areas of the brain have different functions.
Individual differences are not taken into account…
A03: Localisation of Function
One limitation is that some psychologists argue that the idea of localisation fails to take into account individual differences.
Research for this comes from Herasty who found that women have proportionally larger Broca’s and Wernicke’s areas than men, which can perhaps explain the greater ease of language use amongst women.
This is a limitation however because it suggests a level of beta bias in the theory: the differences between men and woman are ignored, and variations in the pattern of activation and the size of areas observed during various language activities are not considered.
What is Hemispheric Lateralisation?
A01: Lateralisation and Split-Brain Research
Hemispheric lateralisation refers to the fact that one side of the brain controls the opposite side of the body, and each hemisphere of the brain is responsible for different functions.
Research has shown that the left hemisphere of the brain is responsible for language and speech whereas the right hemisphere of the brain is responsible for recognition and visual-motor tasks.
What is an easy way to remember the functions of each hemisphere?
Left hemisphere of the brain– processes Language
Right hemisphere of the brain– processes Recognition; identification of something (such as faces and objects)
What is the difference between what the left and right hemisphere control?
(in terms of body and visual fields)
The left hemisphere receives information from and controls the right-hand side of the body and receives information from the right visual field.
The right hemisphere receives information from and controls the left-hand side of the body and receives information from the left visual field.
Why were split-brain patients used in Sperry and Gazzaniga’s Split Brain Research and why had they been different from normal people in terms of information processing in their hemispheres?
A01: Lateralisation and Split-Brain Research
In split-brain patients, the corpus colosseum (which normally allows for communication between the left and right hemispheres) was cut out due to seizures.
They took advantage of the fact that information from the left visual field went to the right hemisphere and information from right visual field went to the left hemisphere of the brain.
As their corpus collosum had been severed, communication between these two hemispheres had been prevented meaning that information can only be processed in the hemisphere that received it.
What happened in Sperry and Gazzaniga’s Split Brain Research and what did they find?
A01: Lateralisation and Split-Brain Research
Sperry presented them with information on the right and left visual fields, ensuring a barrier was put between the patient’s eyes so that the hemisphers processed information individually.
When he presented information on the right visual field, which is sent to the left hemisphere of the brain, they weren’t able to recognise what they seen but could speak what they had seen.
When presented information on the left visual field, which is sent to the right hemisphere of the brain, they could recognise what they seen, but cannot speak what they had seen.
Therefore, research has shown that the left hemisphere of the brain has a specific localised function for language whereas the right hemisphere of the brain has a specific localised function for visual-motor tasks and recognition.
Age affects hemispheric lateralisation
A03: Lateralisation and Split-Brain Research
One limitation is that research has found that hemispheric lateralisation decreases with age. As we grow up our brain becomes more lateralised as the left hemisphere is used more for speech production.
However, as we pass the age of 25, we become more bilateral, and the functions of each hemisphere not limited to one half of the brain.
This is a disadvantage to the theory as it shows that lateralisation is not constant throughout our lives and specific functions of the separate hemispheres become less important over time.
Brain is plastic –> lateralisation (hemispheres performing different functions from each other) not fixed.
A03: Lateralisation and Split-Brain Research
However, one limitation of split-brain research is that research has found language may not be restricted to the left hemisphere.
Turk et al discovered a patient who suffered damage to the left hemisphere but developed the capacity to speak in the right hemisphere, eventually leading to the ability to speak about the information presented to either side of the brain.
This is a limitation as it suggests that perhaps lateralisation is not fixed and that the brain can adapt following damage to certain areas.
Low mundane realism
A03: Lateralisation and Split-Brain Research
- The experimental procedure used in split brain patients is unlike how these individuals would process information and act in normal day to day life (Tasks are artifiical and lack mundane realism) resulting in low external validity.
- In real life, both hemispheres would have access to information by moving the head.
Split-brain patients are a unique and rare small sample size.
A03: Lateralisation and Split-Brain Research
Unfortunately, much of the research into lateralisation is flawed because the split-brain procedure is rarely carried out now, meaning patients are difficult to come by.
Such studies often include very few participants, and often the research takes an idiographic approach.
Therefore, any conclusions drawn are representative only of those individuals who had a confounding physical disorder that made the procedure necessary. This is problematic as such results cannot be generalised to the wider population.
Very scientific —> high internal validity & can be replicated.
A03: Lateralisation and Split-Brain Research
One strength is that Sperry’s procedure was closely controlled
This is a strength because Sperry’s research used scientific methods and empirical data that were not affected by any extraneous variables.
For example, Patients were given eye patches, and images were flashed up for a very brief time (fractions of a second), meaning there was no possibility of looking over and using the other visual field. This strengthens the internal validity of the studies.
Research support from brain scans in normal participants.
A03: Lateralisation and Split-Brain Research
One strength is research shows that even in normal brains, the two hemispheres process information differently. For example, Fink et al used PET scans to identify which brain areas were active during a visual processing task.
When ‘normal’ participants were asked to attend to global elements of an image (such as looking at a picture of a whole forest) regions of the right hemisphere were much more active.
When required to focus in on the finer detail (such as individual trees) the specific areas of the left hemisphere tended to dominate. This suggests that, at least as far as visual processing is concerned, hemispheric lateralisation is a feature of the normal brain as well as the split-brain.
Research support from animal studies regarding multi-tasking
A03: Lateralisation and Split-Brain Research
Gazzaniga and Sperry’s research is supported by a study from Rogers which found that brain lateralisation improves our ability to multi-task.
He saw that chickens were able to both gather food and be aware of predators at the same time. Using only one hemisphere to engage in a task leaves the other hemisphere free to engage in other functions.
This shows that brain efficiency is improved by brain lateralisation and our hemispheres being able to work simultaneously.
Animal studies cannot be generalised to humans.
A03: Lateralisation and Split-Brain Research
However, because this research was carried out on animals, it is impossible to conclude the same of humans.
This is because chickens do not have a corpus collosum and have a different structure of their brains from human.
This is therefore a limitation because research from animals cannot be generalised to humans. In fact, despite animal studies, very little empirical evidence has been provided to show that lateralisation provides any advantage to the functioning of the brain in humans.
What is Brain Plasticity?
A01: Plasticity and Functional Recovery of the Brain
Brain plasticity refers to the brains ability to change and adapt in both its structure and function because of experiences and new learning.
These changes could be as a result of damage, or to meet the cognitive needs of learning new skills
What is synaptic pruning?
A01: Plasticity and Functional Recovery of the Brain
This means nerve pathways that are used frequently develop stronger connections whereas neurones that are rarely or never used eventually die in a process called synaptic pruning.
Thus brain plasticity makes the brain a more efficient communication system over time.
Why do children learn a language faster than adults?
A01: Plasticity and Functional Recovery of the Brain
This process of synaptic pruning is highly active in the brains of newborns and children
In fact, infants have the highest amount of neural synapses as an infant than any other period of an individual’s lives meaning that their brain is more plastic.
Many of these synaptic connections are pruned meaning fewer but stronger connections are formed as we grow older.
This explains why children find it easier to learn languages than adults due to this higher plasticity.
How does the Brain recover function after trauma?
A01: Plasticity and Functional Recovery of the Brain
Stroke victims have been able to regain functioning.
Although some parts of the brain may be damaged or even destroyed because of trauma, other parts of the brain appear able to take over the functions that were lost as the brain re-wires itself over time.
These regenerative developments in the brain arise from the brain’s plasticity.
What is Neural Unmasking?
Fully outline this process.
A01: Plasticity and Functional Recovery of the Brain
Wall discovered ‘dormant synapses’ in the brain—connections that exist anatomically but remain inactive due to low neural input.
Surrounding brain damage can increase input, activating these dormant synapses.
This activation leads to connections in normally inactive brain regions, creating a lateral spread of activation which fosters new structure development in the brain over time.
Brain Plasticity can also have negative consequences…
A03: Plasticity and Functional Recovery of the Brain
However, brain plasticity can be negative. This is a limitation because the brain’s ability to rewire itself can sometimes have maladaptive consequences. For example, research from Medina shows that prolonged drug use has shown to result in poorer cognitive functioning as well as an increased risk of dementia later in life.
Support for the existence of negative brain plasticity comes from the existence of pornography…
A03: Plasticity and Functional Recovery of the Brain
Overuse of pornography can lead to creating negative functional and structural changes in the brain due to the damaging of dopamine receptors, leading to negative effects such as desensitisation to rewards.
For example, Max Planck Institute for Human Development found a negative correlation between pornography use and the volume of the striatum, an area of the brain that makes up part of the reward system.
