Biopsychology

Question 1

What is the nervous system?

Answer 1

network of cells in human body, body’s internal communication system

Question 2

What is the function of the nervous system?

Answer 2

to collect, process and respond to information from the environment and to control organs and cells in the body

Question 3

What is the nervous system split into?

Answer 3

Central nervous system
Peripheral nervous system

Question 4

What is the CNS split into?

Answer 4

Brain:
-receives and processes info from senses (visual cortex processes visual info)
-initiates responses
-stores memories

Spinal cord:
-conducts signals to and from the brain
-connects nerves to the PNS
controls reflex actions (removing hand from hot plate)

Question 5

What is the role of the Peripheral nervous system?

Answer 5

sends messages to and from the CNS via neurons

Question 6

What is the PNS split into?

Answer 6

Autonomic nervous system:
-responsible for involuntary responses for vital functions (breathing/digestion)
-controls smooth and cardiac muscle and glands
-ANS control centres are in the brain stem

Somatic nervous system:
-responsible for voluntary movements (walking)
-controls skeletal muscles
-SNS controlled by motor cortex
-connects the CNS and the senses

Question 7

What is the ANS split into?

Answer 7

Sympathetic branch:
-fight or flight response

Parasympathetic branch:
-conserve and restore body energy when relaxed

Question 8

Structure and Functions of neurons

Answer 8

Dendrites- where neurotransmitter receptors found. once receptor and NT bind, causes new electrical impulse to occur

Cell body- includes nucleus which contains genetic material of cell

Myelin sheath- protects axon and helps to speed up transmission of message

Nodes of ranvier- speeds up transmission of impulses by forcing it to jump across gaps along axon

Axon- sends nerve impulse through neuron to transmit message to next neuron

Terminal button- end of neuron and send info through to next neuron, through release of NT

Question 9

What are the cells that make up a nervous system called?

Answer 9

neurons

Question 10

Sensory neuron

Answer 10

location:
-PNS in clusters knowns as ganglia

function:
-send info from senses towards brain
-receptors found in eyes, ears, tongue (attracted to skin)

structure:
-have myelin sheath
-cell body in middle

Question 11

Relay neuron

Answer 11

location:
-in brain and visual system

function:
-found in CNS
-carry nerve impulses between neurons allowing sensory/motor neurons to communicate.
-involved in analysing sensations from these neurons and deciding how to respond

structure:
-no myelin sheath
-short axons

Question 12

Motor neuron

Answer 12

location:
-cell bodies found in CNS but long axons form part of PNS

function:
-send info via long axons from brain/spinal cord through to effectors such as muscles or glands

structure:
-has myelin sheath
-cell body at the start

Question 13

What is the role of neurotransmitters?

Answer 13

chemical messengers that transmit info from one neuron to another, so a person performs an action (movement)

Question 14

process of synaptic transmission

Answer 14

1. begins in presynaptic neuron, action potentials sent down axon until they reach presynaptic terminal
2. causes neurotransmitters, which are stored in vesicles and only located in presynaptic neuron, to be released into synaptic cleft
3. neurotransmitters diffuse across synapse and then bind with their specific receptor sites that are only present on postsynaptic neuron
4. once enough NT have attached to receptor sites on postsynaptic neuron, 2 possible outcomes:

a. next neuron ready to fire impulse, depending on whether the NT has excitatory/inhibitory effect
b. NT recycled to be stored back in vesicle in presynaptic neuron in process called reuptake

Question 15

Excitatory neurotransmitter (adrenaline)

Answer 15

when EN binds to postsynaptic receptors the postsynaptic cell becomes positively charged.
makes it more likely that the postsynaptic cell will fire so impulse will travel down its axon, increasing brain activity in CNS

Question 16

Inhibitory neurotransmitter (serotonin)

Answer 16

when IN binds to postsynaptic receptor, the postsynaptic cell becomes negatively charged
preventing/reducing likelihood postsynaptic cell will fire, reducing brain activity in CNS

Question 17

Summation

Answer 17

-occurs when the excitatory and inhibitory influences are added together
- If the overall effect is mainly inhibitory it reduces the likelihood the neuron will fire an impulse down the next neuron
- If it is mainly excitatory the impulse will fire an impulse down the next neuron

Question 18

How can you change levels of neurotransmitters?

Answer 18

drugs can be used to increase or decrease levels of NT and work by affecting transmission of NT across synapse

Question 19

Function of the endocrine system

Answer 19

• The endocrine system provides a chemical system of communication within the blood stream to regulate the activity of cells and organs in the body
• It is slower than the nervous system but its effects are more widespread and powerful.
• These chemical messengers are hormones, which are released by the glands within the endocrine system to regulate many bodily functions.

Question 20

Adrenal Gland

Answer 20

Releases adrenaline which causes physiological changes involved in the fight or flight response such as increased blood flow to transport oxygen to the brain for rapid response planning.

Question 21

Pituitary gland

Answer 21

This secretes many different hormones that control the functions of the other glands.

Question 22

Ovaries

Answer 22

Anterior Pituitary gland releases LH & FSH which encourages the ovaries to release oestrogen and progesterone which regulate the female menstrual cycle and prepares the body for reproduction.

Question 23

The fight or flight response

Answer 23

The ANS and endocrine system plays a major role in the stress response in producing the fight or flight response. When a stressor is identified by the brain it activates the sympathetic branch of the ANS.

1. A STRESSOR is identified by the HYPOTHALAMUS, activates the pituitary gland, which triggers activity in sympathetic branch of ANS
2. ADRENALINE released by the adrenal medulla into the bloodstream
3. The “Fight or flight” response is produced, preparing the body for sudden physical action. This produces physiological reactions such as increased heart rate and blood pressure, increased respiration and reducing saliva production and digestion. (immediate and automatic response)
4. The PARASYMPATHETIC branch returns the body back to normal once the stressor has been removed. ‘rest and digest’ response, return body to homeostasis

Question 24

Role of Adrenaline

Answer 24

Adrenaline is the hormone released from the adrenal medulla. It travels through the blood stream and activates the heart and circulatory system, increasing heart rate and blood pressure.

Role: prepare body for F/F

Direct effect:
- increased heart rate/ rate of blood flow/blood pressure,
- increased blood flow to brain/ skeletal muscles (sweating)

Indirect effect: prepare body for action
-increased blood supply to skeletal muscles for physical action
- stops digestion and saliva production
-increased O2 to brain for rapid response planning

Question 25

Fight and Flight- AO3

Answer 25

:( Another issue is that it does not explain the stress response in females. For example, research has found that women are more likely to protect their offspring (tend) and form alliances with other women (befriend) than to fight or run away. This suggests there is a gender (beta) bias, as the fight or flight response assumes that men and women respond in the same way to a threatening situation prior to this research, limiting the explanation of the fight or flight response.

:( One issue with the fight or flight response is that human behaviour is not limited to two responses. Some psychologists argue that the first response to danger is to avoid confrontation altogether through a ‘freeze’ response. During the response humans consider the best course of action for the threat they are faced with. This suggests that the fight or flight response does not consider other factors such as thought processes.

Question 26

Localisation of Function intro

Answer 26

Specific areas of the brain are specialised for certain functions. E.g. the motor cortex is responsible for voluntary movement. Only this area of the brain is responsible for this job.

Question 27

Hemispheric Lateralisation intro

Answer 27

The brain is split into two symmetrical halves called the left and right hemisphere.
This is the idea that the two different hemispheres are responsible for different mental processes. E.g. Left hemisphere is responsible for language and the right is responsible for recognition and creativity.

Question 28

Holistic Theory intro

Answer 28

Before investigations into localisation and lateralisation, scientists believed that ALL parts of the brain worked together when processing information

Question 29

Localisation of Function

Answer 29

Broca’s Area (left hemisphere)
This area of the brain is involved in production of spoken and written language.
(Damage to this area can produce Broca’s aphasia where a person may show slow speech that lacks fluency or there is a complete absence of speech. They might produce short meaningful speech that requires a great deal of effort)

Motor cortex (both hemispheres)
This is involved in the creation of voluntary motor movements. (Each hemisphere controls the movement of the opposite side of the body. Damage can cause loss of control over fine movements, small movements on the opposite side of the body e.g. picking up a small objects or paralysis)

Somatosensory Cortex (both hemispheres)
It processes information from the senses. This includes touch, pain and temperature from all areas in the body.
(Damage can produce problems in perceiving touch, failure to recognise object by touch)

Visual cortex (both hemispheres)
This area of the brain receives information directly from the eyes. RVF – LH, LVF – RH.
(If this becomes damaged it can produce blindness, hallucinations (seeing things which aren’t there) or an inability to see colour or motion)

Wernicke’s area (left hemisphere)
This is the area that is involved in the understanding
of language.
(Damage to this area can cause Wernicke’s aphasia whereby individuals cannot understand spoken language or where a person produces nonsense words as part of their speech. (fluent but meaningless speech)

Auditory cortex (both hemispheres)
This area is associated with analysing speech based information e.g. hearing. (Damage could produce partial hearing loss through to full hearing loss).

Question 30

Locating structures of the brain

Answer 30

Middle = auditory
go around clockwise - alphabetical order

Question 31

Localisation of Function- AO3

Answer 31

:) research to support localisation of function in the brain was by Broca. He reported the case study of man who lost the ability to speak, except for one word Tan’, even though he could understand language. Post-mortems showed damage in one area in the left hemisphere, which is now named Broca’s area. This shows that language production is localised to one specific brain area as the theory predicts.

:( In addition, research to contradict localisation of function further comes from a case study on a patient named EB. EB suffered from brain damage that resulted in the removal of his left hemisphere and therefore his language centres. Despite this, after some time EB managed to regain some of his language ability that would not be possible if the language centres were completely localised to the left hemisphere, within Broca’s and Wernicke’s area. This demonstrates that language must be in more areas than just the left hemisphere suggesting a holistic explanation of brain functioning is more appropriate than localisation of function/language centres.

:( However, both case studies lack population validity. It may not be appropriate to generalise the findings on the localisation of function to the typical population, as these are unique case studies where brain damage may have affected the way in which the brain functions and some individuals may be able to process language in other areas of the brain. for example, some research has suggested that Broca’s area is not solely located in the left hemisphere but is found in the dominant cerebral hemisphere which is commonly found to be opposite to the dominant handedness. Therefore, suggesting that more research is needed with more diverse samples before firm conclusions on the localisation of language areas are possible.

8 marks:
* Define
* 1 area
* 2 AO3

16 marks:
* Define
* 3 areas
* 3 AO3

Question 32

Hemispheric Lateralisation

Answer 32

Hemispheric lateralisation is the idea that the left and right hemispheres of the brain are responsible for different functions
The two hemispheres each have different functions and roles

left hemisphere: responsible for language, as two main language centre’s, Broca’s area responsible for speech production and Wernicke’s area responsible for understanding language, are located in left hemisphere.

right hemisphere: responsible for recognition of faces, places and objects and creativity and can only produce rudimentary words and phrases but contribute to emotional context of what is being said.

many functions not lateralised, such as vision, motor and somatosensory areas as they occur in both hemispheres

Brain has contralateral wiring:
- The LEFT hemisphere receives information from the RIGHT visual field and controls the RIGHT side of the body
- The RIGHT hemisphere receives information from the LEFT visual field and controls the LEFT side of the body

Question 33

Hemispheric Lateralisation- AO3

Answer 33

:) Research to support hemispheric lateralisation was conducted by Sperry (1968) using split brain patients with a severed corpus collosum. He found that when participants were shown an image of an Object to their right visual field, the patient could name it verbally, but when presented to the left visual field they could not name it verbally but could identify the object through pointing. This supports that the brain is lateralised and that the hemisphere’s are responsible for different functions such as left being responsible for language abilities. Therefore, split brain research supports the theory of hemispheric lateralisation.

:( Moreover, research to contradict hemispheric lateralisation of the brain comes from a case study on a patient named EB. EB suffered from brain damage that resulted in the removal of his left hemisphere and therefore his language centres. Despite this, after some time EB managed to regain some of his language ability which would not be possible if the brain was completely lateralised. This demonstrates that language must be in more areas than just the left hemisphere, arguing against lateralisation of function in the brain.

:( However, the case study of EB lacks population validity. It may not be appropriate to generalise the findings on the lateralisation of function to the typical population, as these are unique case studies where brain damage may have affected the way in which the brain functions and some individuals may be able to process language in the right hemisphere. (A* only for example, some research has suggested that language is not solely lateralised to the left hemisphere but is found in the dominant cerebral hemisphere which is commonly found to be opposite to the dominant handedness). Therefore, suggesting that more research is needed with more diverse samples before firm conclusions on the lateralisation of language is possible.

8 marks:
* Define
* Left (1 function)
* Right (1 function)
* 2 AO3

16 marks:
* Define
* Left (2 function)
* Right (2 function)
* contralateral
* 3 AO3

Question 34

What is Split Brain?

Answer 34

• Split brain patients have had surgery to cut the area that connects the two hemispheres of the brain (corpus callosum).
• While the surgery may relieve epilepsy, it has a major side effect: the two hemispheres become functionally separate (they act as two separate, independent brains

Question 35

Split Brain Research

Answer 35

Aim: To investigate the effect of severing the connection between the two hemispheres of the brain (corpus callosum) on functioning
Method: Natural experiment
Participants: studied 11 individuals who had had their
corpus callosum severed due to surgery

Procedure:
1. Participants sit in front of a screen, while fixating their gaze on a spot in the middle of a screen
2. Participants were presented with visual information to either their right visual field or left eye visual field for 1/10th of a second (this is so there is not enough time for the other visual field to switch focus to the visual image).

Results:
-Objects seen in right visual field can be named verbally and in writing as the image would be processed by the language centres in the left side of the brain
-If objects are only seen in the left visual field then they can only be identified though pointing but cannot be named by the participant

Conclusion
-The two hemispheres of the brain have different abilities and functions; but only the left is able to produce language.
-The right hemisphere can recall and identify information, but cannot verbalise this

Question 36

Split Brain Research- AO3

Answer 36

:) A strength of the research into hemispheric lateralisation is that it uses scientific methods. This is because it is based on objective and empirical techniques such as controlled laboratory settings. These are used to identify which hemisphere of the brain is responsible for which task, for example the split-brain patients were only able to say what they saw when the image was presented to the right visual field, which suggests the left hemisphere is activated during language tasks. Arguably, this increases the overall internal validity of hemispheric lateralisation research, therefore, raising Psychology’s scientific status.

:( One limitation of the research is individual differences in the participants, in relation to how lateralised their brain was. The degree to which the corpus callosum was severed for each participant varied greatly with some having a greater disconnection between the two hemispheres than others. This is a weakness because the research may not be measuring the effects of lateralisation effectively which reduces the internal validity of split-brain research.

:( Moreover, research to contradict hemispheric lateralisation of the brain comes from a case study on a patient named EB. EB suffered from brain damage that resulted in the removal of his left hemisphere and therefore his language centres. Despite this, after some time EB managed to regain some of his language ability which would not be possible if the brain was completely lateralised. This demonstrates that language must be in more areas than just the left hemisphere, arguing against lateralisation of function in the brain.

8 marks:
* Brief outline on procedure
* Finding
* 2 AO3

16 marks:
* When surgery done
* Where
* Procedure / findings / conclusion
* 3 AO3

Question 37

What is Plasticity?

Answer 37

This is the brain’s ability to change and adapt its structures and processes as a consequence of experience and new learning.

Question 38

What is synaptic pruning?

Answer 38

• During infancy the brain experiences a rapid growth in the number of synaptic connections it has, peaking at approximately 15,000 at the age of 2-3 years. This is around twice as many as an adult brain.
• As we age, connections that are not used regularly are deleted and ones that are used regularly are strengthened – this is called synaptic pruning.
• Research suggests that at any time in life existing neural connections can change, or new neural connections can be formed between neurons as a result of learning and experience. It used to be believed that these changes only happened in infancy.

Question 39

Research investigating plasticity – Maguire et al

Answer 39

• The brains of London taxi drivers were studied.
• There was a greater volume of grey matter in the posterior hippocampus in those who had been a taxi driver for a long time in comparison to those who had only been a taxi driver for a short time.
• This difference was due to their greater knowledge of the roads which suggests the structure of their brain has been altered by their experience = plasticity.

Question 40

What is functional recovery?

Answer 40

this is a type of plasticity and refers to recovery of abilities and mental processes (such as movement or language) that have been affected as a result of brain damage or disease.

Question 41

How does functional recovery work?

Answer 41

brain is able to rewire itself by forming new synaptic connections close to damaged area of brain. secondary neural pathways that would not typically be used to carry out certain functions activated to enable functioning to continue, often in some way as before

process creates number of structural changes:
1. axonal sprouting- growth of new nerve endings which connect with other undamaged nerve cells to form new neural pathways
2.recruitment of homologous area- areas from opposite side of brain take over function of damaged area of brain e.g. if brocas damaged in LH, right sided equivalent would cary out its function

Question 42

What affects recovery after trauma?

Answer 42

1. perseverance- lose function due to believing unrecoverable
2. age- younger people more likely to recover than older (40+) as deterioration of brain in old affects extent/speed of recovery
3. gender- evidence mixed, females more likely to recover
4. education- more time spent in education greater chance of disability free recovery
5. stress/alcohol- makes more difficult for recovery

Question 43

Plasticity and Functional Recovery- AO3

Answer 43

:) Research to support comes from a case study on a patient named EB. EB suffered from brain damage that resulted in the removal of his left hemisphere and therefore his language centres. Despite this, after some time EB managed to regain some of his language ability, which would not have been possible if the brain was completely lateralised. This suggests that EB’s brain has experienced recruitment of homologous areas and demonstrates the brain can adapt to produce language even when the left hemisphere is not present or functioning,

:( However, this research lacks population validity as the case study only involves one participant, EB who had severe brain damage. This is an issue as it may have caused unique changes in the brain that may have influenced the plasticity and functional recovery of the brain. This limits how well the research can be generalised to the wider population as different genders or age groups may experience different levels of plasticity in the brain. Thus, this lowers the external validity of the research into plasticity and functional recovery.

:) A strength of the research investigating plasticity and functional recovery is that it has practical applications. This is because the principles of the theory that it is possible for an individual’s brain to recover from damage through axonal sprouting has led to the development of neurorehabilitation. This where the patient practises repeatedly using the affected side of their body e.g., an arm, whilst restraining the unaffected arm (constraint induced movement therapy) Therefore, this is as an important area of applied psychology as it helps to treat people in the real / world.

Question 44

fMRI

Answer 44

works by:
- Identifying changes in the levels of oxygen in blood that occurs due to brain activity in specific areas
- When a brain area is more active it leads to more oxygen being used so there is an increase of blood flow to this active area
- fMRI produces a 3D image showing which part of
the brain is active, called an activation map.
- It has been used to identify which specific parts of the brain are active in particular mental processes (showing localisation)

Question 45

fMRI AO3

Answer 45

fMRI is a much safer technique to measure brain activity as it is non-invasive and doesn’t use radiation to identify the differences in brain area. Unlike the use of PET scans which uses radiation. Therefore, fMRI is a more appropriate technique to use that could reduce the risk of potential harm to individuals.

fMRIs have higher spatial resolution than EEG and ERP which is an important feature of brain scans because it can accurately identify specific brain areas involved in behaviour, depicting detail by the millimetre, and providing a clear image of how the brain is localised. However, fMRI has poorer temporal resolution as there is around a 5 second time lag behind the image on the screen and the initial firing of neuronal activity. Therefore, fiMRIs may not truly represent moment-to-moment brain activity.

Question 46

EEG

Answer 46

works by:
- Electrodes being placed on the scalp using a skull cap
- They detect small electrical changes resulting from the activity of brain cells
- The electrical signals are graphed over a period of time to see a person’s general brain activity
- EEGs are used to detect sleep patterns and states such as sleep or arousal
- It is used as a diagnostic tool to help diagnose conditions such as brain tumours and epilepsy

Question 47

EEG AO3

Answer 47

A strength of the use of an EEG is that it is high in temporal resolution, this enables the researcher to take a real time recording of brain activity rather than a still image of the brain, as is the case with the use of an fMRI or post-mortem. This means that the researcher can gain a more accurate measure of brain activity in a particular task. Therefore, providing a greater insight into the processes of the brain, such as the activity of the brain during sleep, increasing its validity as a way of studying the brain.

However, a limitation of the use of an EEG is that it is low in spatial resolution, therefore can only provide information on general activity in the brain. It cannot pinpoint the exact source of neural activity that is involved in behaviour, unlike the use of Event Related Potentials (ERPs) which enable a researcher to identify specific brain activity in a particular task. Therefore, findings may be less valuable in developing our understanding than by using alternative ways of scanning the brain such as ERPs.

Question 48

ERP

Answer 48

• Like with EEG, electrodes are placed on the scalp
• Unlike EEG (which shows general activity) ERP shows specific brain activity as all extraneous brain activity from the original EEG recording is filtered out leaving only those responses that link to the presentation of the stimulus.
• A stimulus is presented to a participant many times and specific electrical responses to that stimulus in the brain are measured
• The readout means that the researcher is able to measure brain function at any given moment
• Used to study attention and perception.

Question 49

ERP AO3

Answer 49

ERPs also have high temporal resolution, especially when compared to an fMRI. This means ERPs can identify brain activity every millisecond so researchers can see brain activity in real time. However, ERPs have poorer spatial resolution than fMRI as they can only detect brain activity in general brain areas rather than identify the specific location of brain activity.

It can be hard to obtain meaningful data from the use of Event Related Potentials because they can be affected by external factors such as background noise which means that it can take many trials to obtain meaningful data as it hard to control these other factors. This limits the validity of ERPs as a means of studying the brain for a range of brain processes

Question 50

Post-mortems

Answer 50

• The brain of a dead patient is examined and dissected to see if there are any physical/structural abnormalities.
• The brain can be compared with a brain that does not show this particular behaviour or mental process.
• It is mainly used on people who have a rare disorder or defects
• One area of research has been the identification of Broca’s area as an important brain areas for speech production

Question 51

Post-mortems AO3

Answer 51

This is the only invasive way to study the brain which means that it is possible to get a more detailed examination of the brain than would be possible through solely using brain scanning techniques such as EEG and ERPs. For example, it has meant researchers have been able to study deeper areas of the brain such as the hypothalamus which has helped understand brain functioning in many different behaviours.

It is hard to establish cause and effect with post-mortem studies as there are many confounding variables which cannot be easily controlled such as how long a person has had a particular disorder, age at time of death or whether they have received drug treatment for their disorder. Therefore, it limits the internal validity of the findings of these studies and therefore the appropriateness of using post-mortems to study the brain.

Question 52

What are the biological rhythm?

Answer 52

Circadian Rhythms – This is a cycle that lasts for 24 hours e.g. body temperature, and the sleep wake cycle

Infradian rhythms – This is a cycle that lasts longer than 24 hours e.g. the female menstrual cycle which operates approximately on a 28 day cycle

Ultradian rhythms – This is a cycle that is less than 24 hours e.g. the stages of sleep which last approximately 90 minutes.

Question 53

Circadian rhythms

Answer 53

One example of a CR is the sleep wake cycle which is controlled by the master endogenous pacemaker, the suprachiasmatic nucleus found in the hypothalamus

our eyes notice change in light as it gets dark and less light received by retina

sends info to SCN, stimulates pineal gland to release melatonin and promote sleep

when our eyes detect light (exogenous zeitgerber) the SCN is reset which maintains the sleep wake cycle to around 24 hrs so that we can be in synchrony with the outside world

Question 54

Circadian rhythms AO3

Answer 54

:) Research to support circadian rhythms lasting around 24 hours was conducted by Siffre. He isolated himself in a cave for six months where his biological clock was able to be free running and unaffected by exogenous factors such as clocks and natural light. It was found that within a few days he had developed a consistent 25-hour cycle and continued to fall asleep and wake up on a regular schedule. Therefore, this supports that the sleep wake cycle is a circadian rhythm which is mainly controlled by an endogenous pacemaker, the SC, to maintain a circadian rhythm.
DISCUSSION:
However, some may argue that because Siffre’s sleep wake cycle did adjust to longer than 24 hours that exogenous factors are important in maintaining circadian rhythms.

:( However, one limitation of the research by Siffre is low population validity. It was conducted as a case study with Siffre as the only participant so it may not be appropriate to generalise findings on the sleep wake cycle beyond Siffre due to individual differences in the sleep/wake cycle and circadian rhythms. For example, some people’s circadian rhythms may be slower and more easily influenced by exogenous zeitgebers, as even in one of Siffre’s later replications he found that his own circadian rhythm had slowed. Therefore, lowering the external validity of the research investigating circadian rhythms.

:) The strength of the research into circadian rhythms is that it uses scientific methods. This is because it is based on objective and empirical techniques such as heart rate monitors and EEGs to measure brain activity. These scientifically measure the length of the circadian rhythm with the absence of exogenous zeitgebers. Thus, psychologists would argue that this increases the overall internal validity of research investigating circadian rhythms, therefore, raising Psychology’s scientific status.

Question 55

Disruption to biological rhythms

Answer 55

• Decreased attention which can lead to accidents
• Digestive problems
• Tiredness and poorer reasoning skills
• Increased anxiety and irritability

How could we maintain our sleep wake cycle?
* Keep to local times for eating
* Keep to local times for sleeping e.g. sleeping when it is
dark and forcing yourself to get up when it is light.
* Stimulate yourself during the day by being social and
active, such as talking and eating.

Question 56

Infradian rhythm

Answer 56

IR are biological rhythms that last longer than 24hrs. One example is the female menstrual cycle, which operates on a 28 day cycle

-the MC is an endogenous system which typically lasts between 28-35 days
-begins on the first day of period, when womb lining is shed, to day before next period
-in brain, pituitary gland stimulates releases FSH which activates release of oestrogen from ovaries, causes egg to mature
-increased oestrogen, increases level of LH which promotes release of egg
-oestrogen develops lining of womb and progesterone helps it grow thicker, readying womb for pregnancy
-if pregnancy does not occur, egg absorbed by body, womb lining comes away and leaves body and cycle begins again
-although cycle mainly endogenous system that maintains infradian rhythm, it can be affected by exogenous factors like stress and pheromones

Question 57

Infradian Rhythms AO3

Answer 57

:( Research to contradict that infradian rhythms such as the menstrual cycle are mainly governed by an endogenous system was conducted by Russell (1980). They asked a sample of women to wear cotton pads under their arm. The pads were then rubbed on the upper lip of 5 sexually inactive women. This process was repeated daily for five months. They found that 4 out of the 5 women developed menstrual cycles that synchronised to within one day of the donor cycle. Therefore, suggesting that the infradian rhythm of the menstrual cycle can be affected by exogenous factors as well as controlled by endogenous factors which may influence the length of the infradian rhythm.

:( However, Russell’s research into the effect of exogenous zeitgebers on the menstrual cycle was a field experiment and so has low control over extraneous variables. The research took part in the participant’s natural environment, where other exogenous factors, such as light, changes in diet and stress, could also have affected the infradian rhythm. Therefore, it is difficult to establish cause and effect between the influence of pheromones on maintaining an infradian rhythm. This weakens the extent to which Russell’s research can contradict the importance of endogenous pacemakers on maintaining infradian rhythms.

:) However, despite the methodological flaws in infradian synchronisation studies, the research findings can be explained by evolutionary psychologists. It would have been advantageous in our evolutionary past for a social group to synchronise pregnancies so that many women would be breast feeding at the same time so one mother could take over caring for an orphaned child, to improve chances of survival. Therefore, showing that synchronisation of infradian rhythms, such as the menstrual cycle, is an adaptive strategy and supports exogenous factors influencing infradian rhythms.

Question 58

Ultradian Rhythm

Answer 58

An ultradian rhythm is a biological rhythm that occurs more frequently than once every 24 hours
One type of ultradian rhythm is the sleep cycle. This cycle lasts approximately 90 minutes and consists of 5 stages and alternates between REM sleep and NREM sleep.
It is known as the sleep staircase, a person can experience up to 5 cycles per night that repeat in a rhythmic pattern.

Stages 1&2:
- light sleep, easily woken
-stage 1= alpha waves
-stage 2= alpha waves, sleep spindles and k complexes

Stages 3&4:
-deep sleep, slow wave sleep
-brain waves are delta waves
-difficult to wake someone in this stage

Stage 5 (REM):
-body paralysed
-brain produces theta waves
-eyes occasionally move around
-dreams experienced

Question 59

Ultradian Rhythms AO3

Answer 59

:) A strength of research investigating ultradian rhythms is that it has practical applications in understanding age-related changes in sleep. The knowledge that growth hormone is produced during stage 4 of sleep (slow wave sleep) has been associated with sleep deficit in old age as research has found older people experience less stage 4 sleep. As a result of this research, medication and relaxation techniques have been developed to increase stage 4 sleep in older individuals and therefore, prevent some issues associated with old age such as reduced alertness. Therefore, research investigating ultradian rhythms is an important part of applied psychology.

:) In addition, a further strength of research into ultradian rhythms is that it uses scientific methods. This is because it is based on objective and empirical techniques such as EEGs to measure brain activity and controlled lab settings. These scientifically measure the activity of the brain throughout the five stages of sleep to identify the length of the rhythm and how many times the rhythm occurs throughout the duration of sleep whilst excluding extraneous variables that may affect sleep such noise and temperature. Thus, psychologists would argue that this increases the overall internal validity of research investigating ultradian rhythms, therefore, raising Psychology’s scientific status.

:( However, the research may have low ecological validity. Research on ultradian rhythms is conducted in an artificial setting and so the sleep experienced by participants in these studies may not reflect their genuine sleep patterns due to the unfamiliar surroundings and because they are attached to electrodes. This may alter the length of the ultradian rhythm, making it difficult to generalise findings to explain how ultradian rhythms work in real life.

Question 60

The Effect of Endogenous Pacemakers and Exogenous Zeitgebers on the Sleep Wake Cycle

Answer 60

Endogenous pacemakers are internal factors which help us to maintain our biological rhythms. It is also thought that our rhythms are entrained (synchronised) by exogenous zeitgebers (external factors) such as light and meal times.

1. The sleep wake cycle is controlled by the master endogenous pacemaker, the suprachiasmatic nucleus (SCN)
2. Our eyes notice a change in light as it gets dark and less light is received by the retina
3. This sends information to the SCN which stimulates the pineal gland to release melatonin and promote sleep.
4. When our eyes detect light again (exogenous zeitgeber) the SCN is reset which stimulates the SCN and pineal gland, which inhibits the release of melatonin to promote wakefulness. This suggests the sleep wake cycle is controlled by endogenous factors

Question 61

The Effect of Endogenous Pacemakers and Exogenous Zeitgebers on the Sleep Wake Cycle AO3

Answer 61

Research to support the role of endogenous pacemakers on the sleep wake cycle was conducted by Michel Siffre (1975). He lived in a cave isolated from all exogenous zeitgebers e.g. clocks and the light dark cycle for six months. It was found that within a few days he had developed a consistent 25 hour cycle and continued to fall asleep and wake up on a regular schedule. This suggests that the sleep wake cycle is controlled by an endogenous pacemaker. This supports the theory that the sleep wake cycle is primarily governed by endogenous pacemakers rather than exogenous zeitgebers. DISCUSSION: However, some may argue that because Siffre’s sleep wake cycle did adjust to longer than 24 hours, that exogenous factors are important in maintaining the sleep wake cycle.

However, research, such as Siffre’s, lacks ecological validity as they are highly controlled and do not reflect how endogenous pacemakers and exogenous zeitgebers interact in real life. Only in exceptional circumstances are endogenous pacemakers free-running and unaffected by the influence of exogenous zeitgebers. In real-life, pacemakers and zeitgebers work together and it makes little sense to separate the two for the purpose of research. Therefore, this reduces the external validity of the findings and cannot be generalised to explain how endogenous pacemakers impact the sleep wake cycle in real life.

Research to support the effect of endogenous pacemakers on the sleep wake cycle was conducted by DeCoursey et al (2000). They destroyed the SCN connections in the brains of 30 chipmunks who were then returned to their natural habitat and observed for 80 days. The sleep/wake cycle of the chipmunks disappeared and by the end of the study a significant proportion of them had been killed by predators. This may be because they were awake and vulnerable to attack when they should have been asleep. This supports the influence and importance of endogenous pacemakers, such as the SCN on the maintenance of the sleep wake cycle, as exogenous zeitgebers alone were not able to maintain the sleep wake cycle of the chipmunks.