2024 Unit 4 AOS1 Psychology

psychological construct

models or explanations 'constructed' to describe psychological activities

what are psychological constructs used for?

to help explain and study things believed to exist, but which cannot be directly observed or measured.

Consciousness

our own personal awareness of internal and external environments (psychological construct)

how do researchers make judgements about consciousness?

~ physiological responses (such as EEG brain recordings)
~ behaviour and psychological state (eg. self-control) and
~ self-reports (eg. what the individual says).

Normal waking consciousness (NWC)

a state associated with being awake and aware of objects in the external world and of one's own sensations and existence at any given moment.

Altered states of consciousness (ASC)

those that are distinctly different from normal waking consciousness in terms of awareness and experience.

example of ASC

a person may have little awareness of the external environment or be experiencing perceptual distortions.

Altered states may be

Naturally occurring - brought on by themselves without external influence

Deliberately induced - purposefully brought on

Consciousness continuum

Visual representation of different states of consciousness that progress from low to high levels of consciousness

Sleep

a reversible behavioural state with the person removed from perceptual experience and unresponsive to the environment.

Characteristics of sleep

- Reduced ability to control behaviour
- A reduction in the control we have over thoughts e.g. lack control over what we dream about
- Less accurate understanding of the passage of time
- Perceptual and cognitive distortions

two main stages of sleep

Rapid eye movement (REM)
Non-rapid eye movement (NREM)

REM (rapid eye movement) sleep

rapid eye movement
high levels of brain activity
Low levels of physical activity
Low levels of somatic NS activity

NREM (non-rapid eye movement)

Lack of rapid eye movement
3 different stages

Sleep episode

full duration of time spent in sleep.
Made up of multiple cycles of REM and NREM cycles called sleep cycles

sleep cycle

approx. 90min period that repeats during a sleep episode in which an individual progresses through REM and NREM sleep

hypnogram

NREM stage 1

sleeper transitions from awake to light sleep.
sleeper loses awareness of themselves and surroundings but is still aware of faint sounds in the environmnent.
can be easily awaken

hypnagogic state

pre-sleep consciousness (NREM stage 1)
some people experience feelings of floating or falling

NREM stage 2

sleeper is still in relatively light sleep
spend majority of time asleep in this stage
sleeper considered 'truly' asleep, due to the types of brain waves occurring

NREM stage 3

sleeper is in a deep stage of sleep
difficult to wake sleeper
if sleeper is woken during this stage, they are likely to wake up drowsy and disorientated
sleep walking and talking are most likely to occur

Gamma waves

responsible for cognition, learning and memory, and decision making

too many gamma waves?

anxiety and stress

too little gamma waves?

causes depression and learning disruptions

what are physiological responses used for?

as a measurement tool, usually for psychological constructs such as sleep

what is an electroencephalograph?

a device that detects, amplifies and records the electrical activity of the brain (in the form of brain waves).

DARE

how does the EEG work?

1. electrical activity within neurons of the brain are detected outside the skull via small electrodes on the scalp.

2. Each electrode detects and receives signals from the many thousands of neurons in its vicinity

3. This info is then sent to a computer which records and graphs the activity

high frequency

many brain waves per unit of time

low frequency

few brain waves per unit of time

what is frequency?

number of brain waves per second

what is amplitude?

the size of the waves (difference between peaks and troughs)

high amplitude

big, tall wave height

low amplitude

small, short wave height

how does the EEG distinguish between NWC and ASC?

higher frequency, lower amplitude = NWC
lower frequency, higher amplitude = ASC

what are the 4 key brainwaves?

BATD

Beta, alpha, theta, delta

what is the frequency of a BETA wave?

high frequency, low amplitude

what is the frequency of a ALPHA wave?

high frequency (lower than BETA), low amplitude (higher than BETA)

what is the frequency of a THETA wave?

medium frequency, mixed amplitude

what is the frequency of a DELTA wave?

low frequency, high amplitude

what is the state of consciousness in a BETA wave?

normal waking consciousness and REM

what is the state of consciousness in an ALPHA wave?

relaxed and calmed states in which we are still awake (daydreaming)

what is the state of consciousness in a THETA wave?

lighter NREM sleep (1 and 2) and deep meditation

what is the state of consciousness in a DELTA wave?

deep NREM sleep (3)

what are limitations of an EEG?

not very precise and does not pinpoint or identify functional or dysfunctional areas of the brain as well as neuroimaging techniques such as fMRI

what is an electromyograph (EMG)?

a device that detects, amplifies and records the electrical activity of the muscles

how does an EMG work?

1. electrodes are attached to the skin above muscles to be monitored
2. shows muscular changes associated with different stages of consciousness, particularly different sleep stages

what is an electrooculography (EOG)

detects, amplifies and records electrical activity in the muscles surrounding the eye

how does the EOG work?

- electrodes are attached to the muscles that control eye movements
- shows eye movement changes associated with different stages of sleep (REM and NREM)

subjective

based on personal interpretation, feelings and opinions:
- open to bias
- open to personal interpretation

what are the subjective sleep measurements?

- sleep diaries
- video monitoring

what is video monitoring?

recording of sleep activities to assist with studying sleep (in particular, sleep disorders)

what are some responses that may be observed in video monitoring?

changes in posture and position, breathing problems, night terror responses, sleep walking/talking

why is video monitoring considered subjective?

more open to personal interpretation

what is a biological rhythm?

cyclic changes in bodily functional activities that repeat themselves over time

what are some examples of biological rhythms?

sleep, body temp, blood-sugar levels, menstrual cycle, alertness

what are biological rhythms controlled by?

'biological clocks' in the brain but also influenced by external environmental factors such as light, noise and diet

circadian

biological rhythms that follow a 24 hour cycle

ultradian

biological rhythms that follow a cycle of less than 24 hours

what is circadian in relation to sleep-wake cycle?

governs when we feel sleepy and when we wake up.
most adults have a period of wakefulness and a period of sleep that follows a basic 24 hours cycle (full asleep at 10, wake at 6)

how is circadian controlled?

by an internal biological clock, but also external cues ('zeitgebers') in particular light

what is ultradian in relation to sleep-wake cycle?

we move between REM and NREM sleep in cycles 90 minutes long, typically 4-5 per night

sleep episode

full duration of time spent asleep, from falling asleep to waking up

sleep cycle

repeated approximate 90 minute period in which an individual progresses through the stages of REM and NREM.
therefore, a sleep cycle is an ultradian rhythm

what are the biological functions that regulate the sleep-wake cycle?

- Suprachiasmatic nucleus
- Melatonin
- Cortisol

what is the suprachiasmatic nucleus?

our inbuilt biological clock.
area of the hypothalamus that is responsible for regulating an individuals sleep-wake cycle

what is the suprachiasmatic nucelus made of?

two nuclei that have approximately 10000 neurons each and are located above the optic chiasm (intersection of optic nerve fibres between each eye)

how does the process of the SCN work?

receives info from external and internal cues to help modulate the circadian rhythm

external cues

info from the environment such as absence or presence of light

internal cues

info that originates from within the body

eg. expression or suppression of clock genes

clock proteins process

clock genes expressed = produce clock proteins
clock genes suppressed = do not produce clock proteins

Clock genes are expressed or suppressed at certain times during the 24 hour period, which generates the circadian rhythm

melatonin in relation to the SCN

internal and external cues dictate the messages the SCN sends to the pineal gland which produces and releases melatonin

melatonin in relation to light

low light = higher melatonin = more sleepy.

In low light, the SCN signals the pineal gland to produce more melatonin to make us feel sleepy.
In higher light, the SCN signals the pineal gland to produce less melatonin to make us less sleepy.

melatonin artificial light

artificial light such as our phones can also interrupt/delay melatonin release

what is cortisol?

hormone responsible for increasing alertness and maintaining heightened levels of arousal

what produces cortisol?

released by adrenal glands to promote wakefulness and alertness

sleep wake cycle process

morning: low levels of melatonin in the body, high levels of cortisol in the body
night: high levels of melatonin in the body, low levels of cortisol in the body

what characteristics of sleep change throughout the lifespan?

- sleep onset
- sleep duration
- awakenings during sleep
- proportion of REM and NREM sleep

why do sleep requirements change over time?

because of their physical and cognitive needs changing over time.

what is REM sleep important for?

has been suggested to be important for the brain and cognitive development

what is NREM sleep important for?

has been suggested to be important for physiological rest and development

Neonatal period (1-15 days)

- sleep duration highest it will ever be (approx. 16 hours)
- approx 50% REM
- approx 50% NREM

Neonatal period (1-15 days) why?

time spent in REM sleep is significantly high because newborns and infants are experiencing rapid brain development

Infancy (3-24 months)

- decreases to approx 13.5 hours
- 35% REM
- 65% NREM

Childhood (2-14 years)

- decreases to approx 11 hours (slight variations as childhood is significant period of time)
- 20% REM
- 80% NREM

Childhood (2-14 years) why?

time spent in REM sleep starts to reduce as the pace of brain development steadies

adolescence (14-18 years)

- decreases to approximately 8.5 hours.
- REM and NREM sleep are fairly consistent (20:80)

What is the biological phenomenon experienced by adolescents in relation to sleep onset?

They experience a biological delayed sleep onset by 1-2 hours, making them more likely to become sleepier and wake up later.

adolescence (14-18 years) why?

sleep patterns change due to various societal factors.
more prone to delayed circadian phase disorder in which their biological clocks are not in alignment with the demands of their environment

young adulthood (18-30 years)

- decreases to approx 7.75 hours
- REM and NREM fairly consistent

middle adulthood (30-75 years)

sleep duratiom approx 7-8 hours

middle adulthood (30-75 years) why?

lower levels of sleep tend to be attributed to ill health and an increase in the prevalence of sleep disorders as well as reduced amount of cognitive and physical growth within this age group

old age (75+ years)

decreases to approx 6 hours.
tend to experience advanced sleep phase syndrome, which is a biological shift forward in their sleep-wake cycle, meaning they become sleepier earlier and wake up earlier

old age (75+ years) why?

lower levels of sleep tend to be attributed to ill health and an increase in the prevalence of sleep disorders as well as reduced amount of cognitive and physical growth within this age group

notable characteristic of sleep during old age

increased brief awakenings during the sleep episode (also occurs for newborns as they have very long sleep durations but do not sleep through the whole night without waking at certain stages)

sleep deprivation

inadequate quantity and/or quality of sleep

full sleep deprivation

when an individual has no sleep within a 24 hour period

partial sleep deprivation

when an individual sleeps for some duration within a 24 hour period, but the sleep duration is too short, or the quality of sleep is poor

how can sleep deprivation influence functioning?

can impact affective function, behavioural function and cognitive function

affective

changes in emotions and emotional responses

behavioural

changes in actions and ability to control them