Consciousness, Sleep, and Meditation: Key Concepts and Theories in Psychology

Consciousness

Awareness of internal and external stimuli; constantly changing (a "stream of consciousness").

Examples of conscious thoughts

Imagining events, thinking/speaking words, feeling emotions, focusing on sensory details.

Mind wandering

Task-unrelated thoughts not related to what you're doing at the moment.

Frequency of mind wandering

Between 15-50% of the time.

Consciousness and brain structure

No — it arises from activity across distributed neural networks.

EEG (Electroencephalograph)

Records electrical activity from the cortex via scalp electrodes.

Beta waves

13-24 cps (active alert states).

Alpha waves

8-12 cps (relaxed wakefulness).

Theta waves

4-7 cps (light sleep).

Delta waves

<4 cps (deep sleep).

Circadian rhythms

24-hour biological cycles regulating sleep, temperature, hormone and blood production.

Chronotypes

Morning chronotype: Sleep earlier, wake earlier. Nocturnal chronotype: Stay up late, wake later.

Pathway of the biological clock

Light → Retina → Suprachiasmatic nucleus (hypothalamus) → Pineal gland → Melatonin secretion → Adjusts biological clock.

Disruptors of circadian rhythms

Shift work and irregular sleep schedules.

Consequences of ignoring circadian rhythms

Poor sleep quality, reduced productivity, impaired social relations, poor mental health, higher risk of physical diseases (cancer, diabetes, ulcers, high BP, heart disease), increased mortality.

Tools to measure sleep

EEG: brain electrical activity, EMG: muscle activity, EOG: eye movements, also observe heart rate, breathing rate, and temperature.

Stage 1 of sleep

Light sleep (1-7 mins), transition from alpha → theta waves, may experience hypnic jerks.

Stage 2 of sleep

30-60 minutes, sleep spindles (bursts of higher-frequency waves).

Stage 3 of sleep

Deep sleep (~30 mins), dominated by delta waves.

REM sleep

Rapid Eye Movement sleep — EEG similar to wakefulness, vivid dreaming, and body paralysis. REM periods get longer as the night goes on.

Sleep changes with age

Newborns: sleep 16+ hours/day, ~50% REM. Adults: sleep less, ~20% REM. Older adults: less sleep overall, but less daytime sleepiness.

Brain structures involved in sleep

ARAS (Ascending Reticular Activating System), pons, medulla, thalamus, hypothalamus, limbic system.

Neurotransmitters regulating sleep

Acetylcholine, serotonin, norepinephrine, dopamine, and GABA.

Hypotheses for why we sleep

Energy conservation, safety/adaptive immobilization (reduces danger), restoration of energy and resources.

Importance of REM and slow-wave sleep

Memory consolidation, integrating new memories, problem solving and creativity, insight development.

Complete sleep deprivation effects

Usually limited to 3-4 days before serious effects.

Effects of partial sleep deprivation

Impaired attention, reaction time, coordination, and decision making.

Selective sleep deprivation

Experimental deprivation of REM or slow-wave stages; leads to REM rebound.

Health impacts of sleep loss

Poor emotional regulation, increased hunger, lower immune function, more inflammation.

Insomnia

Difficulty falling or staying asleep.

Narcolepsy

Sudden, uncontrollable sleep attacks.

Sleep apnea

Reflexive gasping for air during sleep.

Nightmares

Anxiety-arousing dreams during REM sleep.

Night terrors

Panic and intense arousal during NREM sleep.

Somnambulism

Sleepwalking; linked to stress, genetics, or medication.

REM sleep behavior disorder (RBD)

Acting out dreams due to lack of REM paralysis.

Dreams

Mental experiences during sleep; usually familiar content with 'day residue' from waking life.

Lucid dreaming

When the dreamer is aware they are dreaming.

Freud's theory of dreaming

Wish fulfillment — dreams express unconscious desires.

Manifest content

Surface storyline of a dream.

Latent content

Hidden meaning of a dream.

Rosalind Cartwright's theory

Cognitive problem-solving — dreaming enhances learning and helps solve waking problems.

Hobson & McCarley's theory

Activation-synthesis model — dreams are by-products of random neural activity, and the brain tries to make sense of it.

Hypnosis

A systematic procedure that increases suggestibility.

Percentage of people highly susceptible to hypnosis

About 15%.

Effects of hypnosis

Anesthesia (pain treatment), sensory distortions and hallucinations, disinhibition (doing things you normally wouldn't), posthypnotic suggestions and amnesia.

Role-playing theory

People act out a role during hypnosis.

Divided consciousness (dissociation)

Consciousness splits into separate streams.

Meditation

Practices that train attention to heighten awareness and increase voluntary control over mental processes.

Common forms of meditation

Yoga, Zen, and Transcendental Meditation (TM).

Two main types of meditation

Focused attention: concentrating on a single object or sensation; Open monitoring: observing all aspects of experience without attachment.

Benefits of mindfulness meditation

Better attention, working memory, problem solving, emotional regulation; lower blood pressure; higher self-esteem, well-being, and social interactions.

Psychoactive drugs

Chemicals that modify mental, emotional, or behavioral functioning.

Six categories of psychoactive drugs

Narcotics (opioids/opiates): relieve pain; Sedatives: induce sleep; Stimulants: increase CNS activity; Hallucinogens: distort sensory and perceptual experience; Cannabis: produces mild, relaxed euphoria; Alcohol: produces relaxed euphoria and reduces inhibition.

Examples of other psychoactive drugs

MDMA (Ecstasy): warm, friendly euphoria; Oxycodone: narcotic pain reliever.

Cocaine

Blocks reuptake of dopamine, norepinephrine, and serotonin.

Amphetamines and cocaine influence on dopamine circuits

They increase activity in dopamine reward pathways.

MDMA

Causes large serotonin release → positive affect and euphoria.

THC

Activates cannabinoid receptors, leading to endorphin release.

Personal factors influencing drug effects

Age and body weight; mood and motivation; personality and expectations; experience and tolerance.

Environmental factors influencing drug effects

Setting; dose; potency of the drug.

Physical dependence

Needing a drug to avoid withdrawal symptoms.

Examples of drugs with high physical dependence potential

Opioids, alcohol, stimulants.

Psychological dependence

Continuing to use a drug to satisfy emotional or mental cravings.

Type of dependence more common

Psychological dependence, though rare for hallucinogens.

Drugs most linked to overdose deaths

Depressants, stimulants, and opioids (especially combinations).