VCE Psychology Unit 4 AOS 1 - How does sleep affect mental processes and behaviour?

consciousness

the level of awareness an individual has of their thoughts, feelings, perceptions and existence

is a psychological construct

psychological construct

an agreed upon description and understanding of psychological phenomena that cannot be overtly measured or observed

normal waking consciousness (NWC)

a state of consciousness in which an individual is awake and aware

altered state of consciousness (ASC)

a state of consciousness that is distinctly different from normal waking consciousness in terms of quality of experience and levels of awareness

naturally occurring ASC

a type of ASC that occurs without intervention

e.g. sleep, daydreaming

induced ASC

a type of ASC that occurs due to a purposeful action or aid

e.g. meditation, hypnosis, influence of drugs/alcohol

consciousness continuum

a visual representation of the different states of consciousness that progress from lower levels of awareness to higher levels of awareness

sleep

a regular and naturally occurring altered state of consciousness that involves a loss of awareness and disengagement with internal and external stimuli

is a psychological construct

NREM sleep

a type of sleep characterised by a lack of rapid eye movement and is subdivided into three different stages

REM sleep

a type of sleep characterised by rapid eye movement, high levels of brain activity, and low levels of physical activity

sleep episode

the full duration of time spent asleep

sleep cycle

an approximately 90-minute-period that repeats during a sleep episode in which an individual progresses through stages of REM and NREM sleep

NREM Stage 1

a transitional phase between wakefulness and sleep

called the hypnogogic state and individuals can experience hypnic jerks (reflex muscle contraction)

considered light sleep - physiological responses slow down (brain activity, heart rate, breathing rate, body temp etc.) and easiest to wake a person.

NREM Stage 2

relatively light sleep

individuals spend the majority of their time asleep in NREM stage 2

considered to be truly asleep due to the brain waves in this stage

NREM Stage 3

considered to be deep sleep, and a person is difficult to wake and is likely to feel disoriented and drowsy if they are woken

most likely for sleep-waking and talking to occur in this stage.

slow-wave sleep b/c brain activity is at its slowest

experiences of stages across sleep episode

NREM3 is experienced more in the first half of the night than the second half. May not be experienced at all in the last one or two sleep cycles

NREM1 is experienced less as a sleep episode progresses as a person quickly moves to NREM2

REM characteristics

highly active brain and less active body

virtually paralysed

sleepers can be woken fairly easily

vivid dreaming

20-25% of a sleep episode for most

amount increases as a sleep episode progresses

NREM characteristics

less active brain than NWC

physical movement is possible but tends to decrease as stages progress

non-vivid dreams that are unlikely to be recalled

becomes shorter with each sleep cycle

makes up 75-80% of a sleep episode

Electroencephalograph (EEG)

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

Electromyography (EMG)

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

Electro-oculography (EOG)

a device that detects, amplifies, and records the electrical activity of the muscles responsible for eye movement

sleep diaries

a record containing self-reported descriptions from an individual about their sleeping periods, including an estimated time spent sleeping and judgements they might have about the quality and nature of their sleep

video monitoring

the use of camera and audio technologies to record an individual as they sleep

objective physiological measures

EMG, EOG, and ECG

they provide reliable, unbiased, quantitative data that can indicate someone's state of consciousness.

subjective measures

sleep diaries and video monitoring

information is provided by an individual and is related to their personal experiences.

amplitude

the intensity and height of brain waves

frequency

the number of brain waves that occur per second

EEG, EMG, and EOG describing activity

EEG - high frequency low amplitude signals alertness and low frequency high amplitude signals low alertness

EMG and EOG - low/high/medium activity when applicable

more muscle tension indicates

greater alertness

sleep diary strengths

inexpensive and simple way for researchers to gain insight into sleep patterns

gives participants the opportunity to express how they are feeling

sleep diary limitations

accuracy of recording and therefore reliability due to self-reported nature of report

people may neglect to report things due to fear or embarrassment

video monitoring strengths

footage is recorded and therefore can be viewed at any time after a period of sleep

it can be given to several people to interpret and can be shown to the participant

video monitoring limitations

results may be inconclusive

interpretations may be subjective

the artificial environment and attachment of extensive monitoring equipment may affect the person's ability to sleep normally.

biological rhythms

repeated biological processes that are regulated by internal mechanisms

Circadian rhythms

biological and behavioural changes that occur as part of a cycle that lasts around 24 hours

Sleep-wake cycle

a 24-hour-cycle that is made up of time spent sleeping and time spent awake and alert

Ultradian rhythms

biological and behavioural changes that occur in a cycle that lasts less than 24 hours

The suprachiasmatic nucleus (SCN)

an area of the hypothalamus that is responsible for regulating an individual's sleep-wake patterns

External cues

involve information from the environment, such as the presence or absence of light.

Internal cues

involve information that originates within the body (such as the expression and suppression of particular genes, known as clock genes).

Pineal gland

a gland in the brain responsible for the production and release of melatonin

Melatonin

a hormone released by the pineal gland typically at night-time to induce sleep as part of the sleep-wake cycle

Process of SCN regulating the sleep wake cycle

1. The SCN receives external cues. The SCN also receives internal cues.

2. After receiving both internal and external cues, the SCN sends neural messages (signals) to the pineal gland to produce and release melatonin.

3. The pineal gland releases melatonin into the bloodstream, which promotes feelings of calm and relaxation, therefore promoting sleep

Cortisol (sleep)

a hormone that is responsible for increasing alertness and maintaining heightened arousal

released by adrenal glands (adrenal cortex) in the morning to promote wakefulness and alertness.

Neonatal period (1-15 days) characteristics

highest sleep duration (approx 16 hours)

50% REM 50% NREM due to rapid brain development

14-17 hours required

Infancy (3-24 months) characteristics

13.5 hours approx

35% REM 65% NREM

12-15 hours required

Childhood (2-14 years) characteristics

11 hours approx

NREM around 80% REM 20% due to pace of brain development steadying

Variations about duration and proportion of sleep types due to large time period - REM and duration generally reduce

10-14 hours required

Adolescence (14-18 years) characteristics

9 hours approx

80% REM 20% NREM

biological delayed sleep onset 1-2 hours and social factors

8-10 hours required

Young adulthood (18-30 years) characteristics

approx 7.75 hours

20% REM 80% NREM

7-9 hours required

Middle adulthood (30-75 years) characteristics

7-8 hours approx

20% REM 80% NREM

7-9 hours required

Old age (75+ years) characteristics

6 hours approx

20% REM 80% NREM

ASPD, shift forward + reduced growth/ill health

7-8 hours required

sleep deprivation

inadequate quantity and/ or quality of sleep

full sleep deprivation

when an individual has no sleep within a 24-hourperiod

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

Affective effects

the changes in emotions and emotional responses that arise from sleep deprivation

these include:

irritability/moodiness

reduced empathy towards others

amplified emotional responses

Behavioural effects

the changes in actions and the ability to control them that arise from sleep deprivation

these include:

sleep inertia (sense of disorientation after waking)

fatigue/lack of energy

slowed reaction time

Cognitive effects

the changes in mental processes that arise from sleep deprivation

these include:

reduced concentration

lapses in attention

irrational and/or illogical thinking

Blood alcohol concentration

a measure of how much alcohol is in a person's bloodstream

BAC of 0.05 (cognitive motor impacts)

roughly equivalent to 17 hours of sleep deprivation

BAC of 0.10 (cognitive motor impacts)

roughly equivalent to 24 hours of sleep deprivation

affective effects of SD vs BAC

alcohol can make a person feel happy and excited, angry or sad in the short term, long-term it has a dulling effect as a depressant.

sleep deprivation generally makes a person more irritable or sensitive

Sleep disorders

disturbances to typical sleeping and waking patterns

Circadian rhythm sleep disorders

sleep disorders that interfere with the typical regulation of the circadian rhythm of sleep, leading to a change in the sleep-wake cycle

CRSD causes

a disruption to the typical sleep-wake cycle. This can be due to a biological issue, such as the sleep-wake shift that occurs in adolescents, or lifestyle changes, such as shift work.

Delayed sleep phase syndrome (DSPS)

a type of circadian rhythm sleep disorder in which sleep and waking occur later than usual

caused by a misalignment between external and internal cues that regulate the circadian rhythm

Advanced sleep phase disorder (ASPD)

a type of circadian rhythm sleep disorder in which sleep and waking occur earlier than usual

caused by a misalignment between external and internal cues that regulate the circadian rhythm

Shift work

an occupation that involves working at unusual hours, such as working overnight

Bright light therapy

a method used to adjust a person's circadian rhythm through exposure to a high-intensity light source

BLT factors

Appropriate timing of exposure sessions

The right amount of light

Safe exposure

Sleep hygiene

the practices and habits that promote an individual's sleep patterns

Mental wellbeing

an individual's psychological state, involving their ability to think, process information, and regulate emotions

linked to sleep and sleep hygiene

Zeitgebers

external cues from the environment that influence the circadian rhythm

Daylight zeitgeber

the typical light an individual is exposed to during the day, and is mostly natural blue light

Blue light zeitgeber

a type of light that can be emitted both naturally and artificially

Temperature zeitgeber

the degree of external heat in the environment that can influence the quality and quantity of sleep

Eating and drinking patterns zeitgeber

what, when, and how much food and drink is consumed by an individual

Time sleep hygiene

sleeping and waking at a consistent time each day

sound sleep hygiene

sleeping in a fairly quiet space

light sleep hygiene

sleeping in a dark space and reducing bright light exposure close to sleeping time

comfort sleep hygiene

sleeping in a comfortable space

technology sleep hygiene

avoiding bright screen use close to sleeping time

association with bed sleep hygiene

avoiding doing activities other than sleeping in bed

food and drink consumption sleep hygiene

avoiding large meals, caffeine, alcohol before bed

exercise sleep hygiene

engaging in exercise early in the day and avoiding exercise close to sleeping time

biological mechanisms regulating the sleep wake cycle

SCN

ultradian/circadian rhythms

melatonin production and release

quality of sleep

refers to the proportions of NREM and REM sleep attained, as well as the number of awakenings or disruptions to the sleep-wake cycle