PSYC2800 - Sleep-related learning, eyewitness, and environmental psychology

Sleep definition prior to the 1950s

Sleep = a lapse of waking state and a loss of consciousness. Seen as a passive state caused by insufficient stimulation and little brain activity

Sleep definition after the 1950s

Sleep = body might be passive but brain is highly active with this activity being characterised by sleep cycles including NREM and REM. Sleep was linked being important for retaining and consolidating information i.e. for memory/learning

Sleep measurements

Polysomnogram, actigraphy, sleep diary, video, and self-report questionnaires (e.g. PSQI and Karolinska)

Polysomnogram

Gold standard of sleep measurement that measures electroencephalography (brain potentials - EEG), electrooculography (eye movements - EOG) and electromyography (muscle tension - EMG)

Limitations = not typical sleep environment i.e. attached to wires/electrodes, watched and in a sleep lab and it’s expensive

The 5 stages of sleep

Include 4 NREM stages + the REM stage that are distinguished by brain electrophysiology, neurochemistry and functional anatomy. The 4 NREM stages are defined by level of deepness and slow wave sleep (SWS)

NREM stages

Stage 1 = alpha and theta (3.5-7.5 waves/second (Hz))

Stage 2 = theta, sleep spindles, and K complexes

Stage 3 = delta (<3.5 Hz) and spindles

Stage 4 = delta (<3.5 Hz) > 50% of the time and increased EEG and EOG

Stage 1-4 are characterised by rolling eye movements and reduced muscle tone, heart rate, BP and temp.

REM stage

Theta, beta and gamma waves (30-80 Hz) characterised by rapid eye movements, lack of muscle tone, and increased heart rate, BP and temperature. Decreased EEG (brain potentials), rapidly increasing and decreasing EOG (eye movements) and decreased EMG (muscle) which is why you feel you can’t move in dreams. Sensation and perception is often vivid and internally generated while thought is illogical and bizzare

Awake and relaxed stage

Awake = beta activity (13-30 Hz) + irregular oscillations

Relaxed = alpha waves (8-12 Hz) + regular oscillations

Sleep cycles per night

Often 4-6 90 min sleep cycles per night with slow wave sleep existing in the first few cycles and REM + stage 2 sleep in the later cycles. People often return to stage 2 not 1 before starting a new cycle.

Actigraphy

A mini accelerometer active watch (more accurate than a smart watch) that calculates each minute as asleep or awake.

Pros: Valid, reliable, non-invasive and relatively inexpensive

Cons: no info about brain activity and can lie still while being awake and have that be recorded as sleep

Sleep diary

Participant/person close to participant records bedtime, estimated sleep onset, night wakings, wake time, time out of bed, any sleep disturbances, and helps corroborate actigraphy data

Limitations = subjective with sleep durations being overestimated and night wakings underestimated

Video sleep measurement

Night vision video surveillance cameras that provides rich info on sleep behaviours and can help corroborate sleep diary and actigraphy data

Benefits of sleep

Mood and healthy psychological functioning, restore and preserve energy (only a slice of bread), repair cell tissue, metabolic regulation, restores and strengthens immune function, moderates appetite hormones, healthy weight control, and improves attention, learning and memory

Biological rhythms

Internally generated (endogenous) patterns of behavioural and physiological change that affect temp, hormones, neurotransmitters, sleep-wake cycles, and other bodily functions. Modulated by external cues including sunlight (zeitgeber), seasons, temp and schedules.

Ultradian rhythm

Cycles within day that are less than 24 hrs e.g. 90 min REM and NREM cycles

Circadian rhythm

24hrs cycles that are endogenous (internally generated) and affected by photoentrainment that involves adjusting the clock with external cues (light). Without light the circadian cycle becomes 25 hrs with often irregular sleep wake patterns. Abnormal circadian rhythms = sleep disorder, obesity diabetes, mental health problems, and developmental disorders

Activity periods

Diurnal = active during the day e.g. humans, dogs

Nocturnal = active during the night e.g. owls, rats, possums

Crepuscular = active at dawn and dusk e.g. rabbits

Two process model

Process S (sleep drive) = homeostatic sleep drive increasing with wakefulness and decreasing with adequate sleep quantity

Process C (circadian clock) = the circadian clock modulating sleep and waking

The larger the distance between sleep drive and circadian clock = the greater the urge to sleep. Both are heavily influenced by light exposure

Retinophypothalamic pathway

Light travels through retinal ganglion cells (modulate sleep wake cycle even in blind mammals) → retino-hypothalamic tract → suprachiasmatic nucleus → pineal gland → melatonin. Diseases of the retinal ganglion cells e.g. glaucoma can affect circadian rhythm and cause sleep disturbance

What causes changes in circadian rhythms

Any factors that desynchronise internal rhythms from external environmental cues e.g. jet lag, shift work, blue light, and countries with midnight sun. This desynchronisation can be treated with light and melatonin

Two-process model applied to depression

People with depression have an increase in the low buildup of sleep drive which contributes to sleep deprivation. There are also differences in light exposure and activity levels that messes with sleep. Improving sleep is a key part of mental health treatment which often involves planned/optimal light exposure.

How does temperature and exercise affect sleep

Excessive temp negatively impact sleep with too hot being worse than two cold. There are difficulties regulating body temp during REM sleep + increase in temp during stage 3 sleep which can lead to night wakings. Hot baths/shower 1-2hrs prior to sleep reduces sleep latency. Exercise increases body temp and reduces sleep.

The effects of screen-time on sleep

Blue light decreases melatonin especially when peoples eyes are close to the device. Engagement with the device also increases cognitive engagement rather than winding down. Children are more sensitive to blue lights than adults. Screen time also affects sleep indirectly through increased sedentary time → reduced homeostatic drive for sleep → poorer sleep → greater sedentary behaviour

Prevalence of human sleep difficulties

• Approx. 30% of ppl regularly under sleep and have daytime sleepiness

• 23% experience concentration difficulties due to sleepiness and 11% experience driving difficulties

• 33% get less than 7 hrs of sleep

Benefits of sleep for the brain

Energy conservation = neurons depend on glycogen for energy → NREM sleep uses less energy = restores brain glycogen

Brain growth = REM sleep is high during critical periods of brain maturation in infants

Brain plasticity = sleep promotes synaptic connections

Toxin cleansing = space between brain cells increase during sleep suggesting brain flushed out toxins built up during waking hours

Recommended sleep durations

Infants (0-3mths) = 14-17 hrs and (4-11mths) = 12-16hrs

Toddlers = 11-14hrs

Preschoolers = 10-13hrs

Primary school-aged = 9-11hrs

Teens = 8-10hrs

Adults = 7-8hrs

Primate sleep duration

A lot of sleep = bats (19.9hrs), armadillo (18.5hrs), and cats (14.5hrs)

Moderate sleep = fox (9.8hrs), rhesus monkey (9.6hrs), rabbit (8.4hrs), and humans (8hrs)

Little sleep = cow (3.9hrs), sheep/goat (3.8hrs) and horse (2.9hrs)

*larger animals may have less sleep because they have less ability to hide (evolutionary)

What did the study comparing sleep in western communities to sleep in Hadza community

Hadza community had shorter sleep duration, poorer sleep quality, but stronger circadian rhythm. If Hadza community is indicating typical sleep this suggests that poor sleep may not be that much of an epidemic i

Affects of drugs and alcohol on sleep

Benzodiazepines suppress stages 3 and 4, tricyclic antidepressants suppress REM sleep and alcohol increases stage 3 and suppresses REM

How does caffeine and adenosine interact

Caffeine promotes alertness and is similarly shaped like adenosine so it can bind with adenosine receptors. Adenosine promotes sleep and increases with sleep drive and decreases during sleep. Caffeine binds to adenosine receptors → blocks adenosine from binding → reduces feelings of sleepiness → adenosine is still present in the brain so once caffeine wears off → feelings of sleepiness returns.

Half and quarter life of caffeine

Half-life = 5-7 hrs for caffeine to leave the body by 50%

Quarter-life = 10-14 hrs and 25% of caffeine is still in body

Sleep and neurodegeneration

Sleep plays a role in preventing the onset of neurodegenerative diseases i.e. Parkisons’s and Alzheimers. This may be because damaging molecules associated with neurodegeneration are cleared out during sleep

Insufficient sleep’s affect on weight

Insufficient sleep increases the release of appetite increasing hormone (ghrelin) and decreases appetite suppressing hormones (leptin)

Sleep memory consolidation

An automatic and subconscious process distinct from conscious rehearsal and memorisation. Suggests that consolidation continues to evolve and consolidated information can still change during recall and recognition

Memory stages

Encoding/acquisition (information/action) → integration + consolidation (leads to greater interference resistance) which includes stabilisation and enhancement → recall → reconsolidation

• Stabilisation = mostly while awake

• Enhancement = during sleep and can involve restoring “lost” memories + additional learning

Brain areas for explicit vs implicit memory

Explicit = medial temporal lobe and hippocampus

Implicit = diverse brain parts but includes cerebellum and basal ganglia

Factors involved in sleep-related memory consolidation

Demographic (e.g. children, elderly, and psychiatric patients), learning material (e.g. task difficulty, declarative vs procedural), learning mode (explicit vs implicit), retrieval (recall vs recognition), and sleep factors (e.g. timing, circadian rhythm, amount, stages)

Bi-directional relationship between sleep and learning

Types of learning alters the type of sleep and the type of sleep alters the types of memories formed e.g. intense foreign language learning involve declarative memory which increases REM and REM increases learning

Homeostatic response

Performing a task that is REM dependent → increases REM demands → increased REM sleep = improved learning

Sleep deprivation

Involves chronic sleep loss which is the cumulative increase in objective sleepiness and accumulated sleep debt. Difficult to subjectively determine as subjective perception of sleepiness poorly correlatives with objective measures

Sleep deprivation and accidents

Sleep deprivation increases accidents due to attention lapses and delayed response time at critical moments with 20% of accidents occurring during 12-6am with 2/3 drivers falling asleep. Medical residents working over 24 hours are 2-3x more likely to crash after their shift. Sleep deprivation is also a significant contributor to many disasters e.g. Chernobyl and Challenger space shuttle.

Sleep deprivation and task performance

Task performance after 24 hrs awake is comparable with 0.1% blood alcohol (driving BAC must be <0.05). Greater affect for speed related tasks and newly learned skills compared to accuracy and familiar tasks. Impaired executive functions (e.g. planning, emotion regulation, memory and attention) and motor functions (e.g. hand-eye coordination, verbal fluency and articulation)

Brain areas affected by sleep deprivation

• Pre-frontal cortex and parietal lobe activity increases

• Medial temporal lobe (LTM) activity decreases

Following sleep deprivation PFC and parietal lobe overcompensate for lower activity in other areas i.e. medial temporal lobe

Encoding of emotional words during sleep deprivation

Sleep deprivation group had overall lower word retention for recognition tasks however they had a greater memory for negative words → maybe greater memory for overall negative experiences

Sleep deprivation and emotional expression

Sleep deprivation causes greater activity in amygdala to emotional stimuli with stimuli being classified as threatening at higher rates than non-sleep deprived. Anterior cingulate responded to highly to threatening and non-threatening stimuli showing that brain was unable to distinguish between the stimuli.

Effects of moderate sleep extension and restriction in children 9-12 years

Extension (+30 mins) = greater memory, attention and reaction time

Restriction (-30 mins) = improved sleep quality but decreased alertness

Non-declarative procedural memory (finger tapping)

Finger tapping involves repeatedly typing a 5-digit numeric sequence as fast as possible. After a night of sleep, problematic transitions improved with most significant improvement after a night of sleep. Improvement was correlated with stage 2 sleep and sleep spindles

Texture discrimination task

Discriminating between T or L and Vertical or Horizontal textures. After sleep, participants showed significant improvement which was correlated with slow wave sleep in 1st quarter of the night and REM sleep in the last quarter = SWS is important for initial consolidation and REM for later enhancement. Disruption during these stages = disrupted sleep-related improvement

REM sleep and semantic memory

Semantic priming task with varying related words. Weakly related pairs had fastest RT’s before sleep and after REM sleep which demonstrates that REM facilitates associative learning for declarative memories = since REM occurs mostly at last quarter → short sleepers have poorer memory consolidation

Naps and finger tapping task

Nap group had 16% improvement and further 7% improvement after a nights sleep and non-nap group had low improvement during the day BUT 24% improvement after a nights sleep = both groups had similar level of improvement

Naps and texture discrimination task

No-nap groups performance deteriorated by 7-m, 60 min nap (mostly SWS) had slight deterioration and 90 min nap (SWS + REM) had significant improvement. Nap group had further improvement over night that was similar to improvement after 2 nights of sleep

Nano naps

Extremely short naps (6 mins) and longer naps (60 mins) which showed that most word recall improvement occurs within 6.3 minutes which very gradually increasese

Caffeine and performance

Caffeine increases mood, alertness, vigilance, attention, information, processing speed, motor speed and reaction time. 70-200mg is best for performance while >400 mg is detrimental to performance

Caffeine vs Naps in learning study

Study shows that naps produced higher performance in 7hr delay word recall and recognition tasks, 20 min recall tasks and texture discrimination tasks. Naps and caffeine had similar performance in the 20 min delay word recognition task.

Adolescent sleep patterns

Increasingly later bed times with later wake times during the weekends. Daytime sleepiness and decrease in sleep duration across cohorts over time. Need for sleep increases due to biological predisposition, hormonal changes, increasing demands, and device use. Evidence based education has meant some schools allow later start times.

Adolescent nap-related learning for declarative memory

Tested adolescents declarative memory using an unexpected test across 1, 2, or 5 days later. Day 1 = both nap and no-nap had 10% gain; Day 2 and 5 = nap group had sustained retention while no nap had significant memory decay

Infancy and early childhood sleep patterns

Infants have a greater proportion of days asleep (2-6 yrs = 10-12 hrs) with significant development occurring during these years. Sleep is decreasing across cohorts as sleep is not given the same regard of importance.

Amount and quality of sleep and learning for infants

Insufficient sleep and frequent awakenings = lower language and spatial performance, higher impulsivity, hyperactivity, and weight and lower scores on mental/motor development in infancy AND later in development. Children with <10 hrs of sleep at 2.5 yrs where 3x more likely to have low receptive language scores and 2.4x more likely to score low on block test.

Naps and infants abstraction of grammar

Infants learn abstraction of grammar (e.g. general rules derived from specific examples) more quickly after a nap. Infants were able to discriminate between two recently exposed languages which demonstrated grammar abstractions and more flexible implicit learning

Naps and infant visuo-spatial learning

Naps in infants contribute to higher visuo-spatial recall even after both nap and no nap group had a full night sleep. This was dependent on whether napping was habitual of not.

Naps and toddler word learning using storytelling

Study compared novel word learning in same story repeated or different stories + nap vs no-nap. Results found that repeated stories had higher performance for different stories and nap had higher performance than no nap. Overall the highest performance was for same repeated stories and nap-group however children who did nap and have different stories where still able to recall the same words as the same story no nap group

Naps and toddler fast mapping

Compared performance in ostensive (assigning names to things by directly linking them) and non-ostensive (not being obvious in name assignment) naming and found that nap group in non-ostensive naming condition maintained accuracy while no-nap went back to chance. For ostensive naming, no nap and nap group had same performance.

How can sleep and short naps enhance memory

Develops new synaptic connections, strengthens relevant connections and weakens irrelevant connections. Neuronal plasticity allows for constant changes with synaptic networks being optimised, organised and connected to other networks

Proteins during sleep

Brain waits for a period where interference is limited to consolidate most info. During sleep the brain releases higher levels of proteins which aid in memory consolidation and while waking these proteins are reduced to inhibit disruption to memory consolidation

Two-stage memory system

Suggests that information is initially stored in the hippocampus (efficient and temporary) and during sleep info is transferred into the neocortex (long-term storage) during consolidation.

Slow wave sleep (SWS)

During SWS, neuronal activation occurs which involves cells firing in the same sequence that occurred when information was encoded during wakefulness. SWS includes large amplitudes and slow oscillations which move synaptic connections to long-term storage and enhance retrieval. SWS is especially important for declarative memory consolidation

Transfer from hippocampus to cortex

during SWS, sharp wave ripples in the hippocampus influence the slow oscillations in the cortex which reactivates memories repeatedly and transfers them to the cortex. These ripples occur alongside thalamocortical spindles which are important for synaptic plasticity

Picture recognition study

Longer SWS duration during the post-encoding nap = less hippocampal activation for successful and confident retrieval of remote memories. Overtime the study showed an exponential increase in activity in the ventral medial prefrontal region and exponential decrease in hippocampal activity (as the task got more practiced)

Procedural memory study

After sleep the brain demonstrated increased activity in motor control areas (relative to the hand used i.e. left → increased right motor areas) and decreased activity in the insular cortex and temporal areas due to a reduced need for conscious spatial monitoring and emotional task burden

Synaptic homeostasis theory (two process model)

Suggests that there is a rising synaptic potentiation during waking alongside homeostatic sleep drive and then synaptic downscaling during sleep that results in reduced synaptic weight after sleep.

Downscaling

During encoding the weight of synapses (synaptic saturation) increases which places demands on energy and tissue volume → brain downscales synaptic strengths with weak connections and noise removed while stronger connections are maintained and sharpened = better signal to noise ratio + energy conservation

Effects of sleep deprivation on the synaptic connections

Decreased synaptic connections while after recovery sleep there was increased synaptic connections and density of neuronal connections in the hippocampus

Effects of sleep deprivation on attention

Demonstrates reduced activation in intraparietal suculus (control of eye movements and visual attention) and inferior frontal gyrus (impulse control) (only for vulnerable populations) while the visual cortex only had decreased activity when stimuli was lower contrast = that decreased attentional performance after sleep deprivation is due to decreased attentional control NOT decreased vision

Environmental psychology

Studies the interplay between humans and the built + natural environment. Focus on environmental affects on human experience, behaviour and wellbeing, how humans affect the environment and how do we encourage pro-environmental behaviours.

History of environmental psychology (Brunswick and Lewin)

Brunswick and Lewin were founding fathers of environmental psychology with Brunswick focusing on physical environment and Lewin on social environment. Both advocated for real-life studies.

Interactive approach

Our ability/desire to be sustainable depends on multiple factors e.g. infrastructure or education → affects whether we engage in sustainability → affects environment → affects human behaviour and so on.

Interdisciplinary collaboration

Main disciplines include architecture & geography (physical/spatial), social & cognitive psychology (theoretical), environmental science, neuroscience and biology.

Problem-focused approach

Combination of theoretical development applied to solve real-world problems including local, regional, national and global problems.

Methods used in environmental psychology

Questionnaire studies, laboratory experiments & computer simulation studies (artificial setting) and case studies & field studies (real setting). Each has external and internal validity trade-offs.

Three perspectives for understanding colour

Biology (e.g. brain areas and rods/cones), physiology (affect on emotion and mood)< and culture/society (how our understanding of colour is shaped)

Theoretical aspects of colour and design

• Colour is used in branding and symbolism to convey certain messages (these messages can be cultural different)

• Colour-coding facilitates wayfinding through universal symbolism

• Colour helps us understand the nature of a built environment e.g. white = hospitals

• Colour can signify fashion and historical style trends

Wayfinding

Process of orientation and navigation within physical spaces that involves the development of cognitive maps and use of landmarks. Wayfinding can be improved through visual access, architectural delineation, signage, numbering systems and building layout. Colour can improve development of cognitive maps, recall ability (e.g. parking floors), and help us follow paths (e.g. train maps)

Segmentation bias

The mental division of paths/journey’s into smaller segments to make travelling longer distances easier. Design can harness this by breaking up spaces using colour, lighting and material changes.

Relationship between physical space and healthy populations

Urban and suburban environments can encourage sedentary lifestyle and overall poor health through lack of green spaces, ‘third spaces’, healthy grocery stores, walkable cities, and public transport. Asthma and obesity are two main disease with key environmental links e.g. reliance on cars and pollutants from cars.

5 main legal pathways to improve built environment

Environmental regulation, zoning & related developmental requirements, building & housing codes, taxing power, and spending power.

10 factors that can improve design (especially in hospitals)

1. Natural views = improves healing outcomes and release of endorphins

2. Natural light = encourages circadian rhythm

3. Green spaces

4. Space for family/community and important items e.g. art

5. Safe spaces for staff members

6. Effective wayfinding = reduces stress e.g. colour coding

7. deinstitutionalisation by providing choice = e.g. Langer & Rodin study that gave residents plants to take care of and layout decision-making

8. Artistic and colourful architecture

9. Clean and well-lit spaces = odour can affect brain chemicals

10. Flexibility and options within the layout

Effects, prevalence, and risk factors of acute climate events

Increased anxiety, mood disorders, acute stress reactions, PTSD, sleep disruption, suicide and ideation, decreased sense of self due to loss of home and grief. 25-50% prevalence of negative mental health outcomes. Risk factors = magnitude of events, injury/death of a loved one, women/children, and lower SES. E.g. Hurricane Maria.

What are the overall impacts of climate events

Direct e.g. heat stress and indirect impacts e.g. negative wellbeing. Overall, it is associated with poor mental health.

Subacute climate events (heatwaves)

Shifts in temp above 30 degrees lead to increased mental health problems, aggression, homicide, crime, suicide, and higher hospitalisation/mortality especially for people with dementia, schizophrenia and substance-use disorders as they have poor thermoregulation caused by medication + heat-related cognitive impairment

Hormone and heat waves

Heat suppresses the thyroid hormone which causes hypothyroidism = fatigue, low mood, and cognitive impairment. Heat stimulates growth hormone and prolactin = fatigue.

Long-lasting climate events

Economic losses (especially for poorer countries), psychological distress about future e.g. exoanxiety, exoparalysis and solastagia especially for young people in 1st world countries.

What does the increase in climate events mean for health services?

We need to develop new mental health services which includes planned relocation, public health education, violence prevention, risk communication and personal conservation engagements.

Summary of the healing power of gardens

Nature plays a key role in emotional, spiritual, physical, and neurological health especially for urban/city neighbourhoods and healthcare institutions. Patient examples:

• Tourettes = tics lessened due to calming effects of nature

• Parkisons = was able to move through varied landscape in the garden

• Alzheimers = felt more oriented doing nature based tasks

What do healthy built neighbourhoods look like

More walkable neighbourhoods with well constructed/repaired side walks that have mix of destinations, attractive surroundings and perceived safety leads to higher physical activity and lower obesity/overweight.

What types of physical activity lowers depression and alcohol abuse and increased social connections.

Leisure-oriented and destination driven physical activity

5 characteristics of dementia-friendly spaces

1. Avoid repetitive layouts = lack of colour/texture variation causes disorientation

2. Having unique landmarks = salient and stable items

3. Use colour to break up and connect spaces = visible colour contrast but avoiding to much which can cause perceptual errors

4. Reducing background noise = people with dementia have higher noise sensitivity

5. Good access to toilets = clear signage and accessibility

Autism design index

International guidelines that considers acoustics, spatial sequencing (follow routine/predictability), escape areas (when overstimulated), compartmentalisation, transition, sensory zoning (organise spaces based on stimulation), and safety.

allostatic load

Long-term physiological costs of the organism’s adaptations to repeated or chronic stressor exposure; an index of general wear and tear on the body.

spillover effect

The negative affect, strained interpersonal relationships or fatigue, produced by exposure to an environmental stressor in one setting that carries over into another setting.

Environmental stressors

Can be acute e.g. pollution levels in a tunnel or chronic e.g. noise pollution. Chronic stressors are hard to escape and more consequential as they are are linked to immunological responses.