Higher Psychology - Sleep and dreams

What hormone makes us feel sleepy and is affected by light?

Melatonin

Which chemical builds during waking hours and causes sleep pressure?

Adenosine

Which hormone boosts alertness in the morning?

Cortisol

What did Michel Siffre's study suggest about circadian rhythms?

They are internally regulated and persist without external cues.

How many stages are in a full sleep cycle?

Five stages: 1-4 (non-REM) and REM

Which sleep stage is associated with dreaming?

REM sleep

What is atonia and when does it occur?

Temporary paralysis during REM sleep to prevent acting out dreams.

What is the key idea of Oswald's restoration theory?

Non-REM restores the body; REM restores the brain.

What was the key finding of Dement and Kleitman's study?

Dreaming is most likely to occur during REM sleep.

What does the cognitive approach say about the purpose of sleep?

It helps consolidate different types of memory.

What does Crick & Mitchison's theory suggest about dreams?

They help 'unlearn' unnecessary information through reverse learning.

What was Czeisler's study about?

Improving night shift adaptation using bright light and controlled sleep conditions.

How does caffeine affect sleep?

It blocks adenosine, reducing sleep pressure and increasing alertness.

Why does alcohol reduce sleep quality?

It reduces REM sleep, which is crucial for feeling rested.

What is blue light's effect on melatonin?

It suppresses melatonin production, delaying sleep onset.

How does Czeisler et al.'s study challenge the belief that shift work adaptation is fixed?

It shows that exposure to bright light and controlled sleep conditions can reset circadian rhythms, suggesting they are malleable, not fixed.

In what way does Crick & Mitchison's theory conflict with the cognitive theory of sleep?

Crick & Mitchison view dreams as a by-product of 'reverse learning', while cognitive theory sees them as purposeful for memory consolidation.

Why does Freud's theory lack scientific credibility, despite its historical significance?

Because it is based on subjective interpretation and untestable concepts like the unconscious mind and symbolic dream meanings.

Why is the suprachiasmatic nucleus (SCN) considered an endogenous pacemaker, and what real-world implications does this have?

It regulates circadian rhythms independent of external cues, influencing treatments for jet lag and sleep disorders.

Why is Oswald's restoration theory considered reductionist by some critics?

It focuses solely on biological repair functions and ignores cognitive and environmental influences on sleep.

How does sleep deprivation affect REM rebound and what does this imply about its function?

After REM deprivation, individuals spend more time in REM during recovery sleep, implying it serves a vital psychological function.

How does the EEG pattern differ between REM and non-REM sleep, and what does this suggest about brain activity during sleep?

REM shows beta-like (high frequency, low amplitude) waves similar to wakefulness, suggesting the brain is highly active during this phase.

What is a methodological strength of using case studies like Michel Siffre's in sleep research?

They offer in-depth, longitudinal insights into circadian rhythms in the absence of external zeitgebers.

How do individual differences affect sleep research findings, and what does this mean for generalisability?

Factors like age, genetics, and chronotype influence sleep patterns, making it difficult to apply findings universally.

What are zeitgebers and how do they influence sleep?

External cues like light and temperature that help regulate the circadian rhythm.

What does the term 'circadian rhythm' refer to?

A natural 24-hour cycle regulating sleep-wake patterns and other physiological functions.

What is the role of the pineal gland in sleep?

It produces melatonin, which regulates sleepiness based on light exposure.

How is REM sleep different from deep non-REM sleep in terms of brain activity?

REM sleep shows high-frequency, low-amplitude waves similar to wakefulness, while deep sleep shows slow, high-amplitude delta waves.

What effect does shift work have on the circadian rhythm?

It disrupts the natural sleep-wake cycle, often leading to sleep disorders and decreased alertness.

What is sleep hygiene?

Habits and practices that are conducive to sleeping well on a regular basis.

Why is the 'first-night effect' important in sleep research?

People often sleep poorly the first night in a lab setting, which may affect the validity of results.

How do state-dependent cues affect memory retrieval?

We recall information better when our internal state during recall matches the state during encoding.

What is the purpose of the visuo-spatial sketchpad according to the WMM?

It temporarily holds visual and spatial information, such as the layout of a room.

How can the cognitive theory explain differences in dream content?

Dreams reflect current concerns, memories, and problem-solving efforts of the sleeper.

What is Freud's theory of dreaming?

Dreams allow unconscious desires to be expressed in a disguised form through symbolic content.

What is displacement in Freud's dream theory?

Shifting emotional significance from an important object to a trivial one in dreams.

What is condensation in Freud's theory of dreams?

Combining multiple ideas or images into a single dream symbol.

What is manifest content of a dream?

The literal storyline or surface content of the dream.

What is latent content of a dream?

The hidden, unconscious meaning behind the dream.

What does Crick & Mitchison's Reorganisational Theory of dreaming suggest?

Dreams help the brain 'unlearn' unnecessary or parasitic memories during REM sleep.

What are 'parasitic memories' according to Crick & Mitchison?

Useless or harmful memories that interfere with efficient cognitive functioning.

What are 'adaptive memories' in the Reorganisational Theory?

Useful, relevant memories that are retained during the unlearning process in REM sleep.

How does the Reorganisational Theory view dreaming?

As a biological mechanism to protect mental efficiency by clearing unnecessary data.

What is one strength of the Reorganisational Theory?

It is supported by the observation that REM sleep increases after learning, suggesting memory processing.

What is one criticism of the Reorganisational Theory?

It lacks direct empirical evidence and cannot explain meaningful or recurring dreams.

What is a circadian rhythm?

A natural internal process that regulates the sleep-wake cycle, roughly every 24 hours.

What is the primary endogenous pacemaker in humans?

The suprachiasmatic nucleus (SCN) located in the hypothalamus.

What is the role of the SCN in circadian rhythms?

It receives light signals from the retina and helps regulate melatonin production via the pineal gland.

What are zeitgebers?

External cues, like light and temperature, that help regulate biological rhythms.

What hormone does the pineal gland secrete to promote sleep?

Melatonin.

How does light influence circadian rhythms?

Light suppresses melatonin production, promoting wakefulness and helping reset the biological clock.

What did Michel Siffre's cave study demonstrate?

That circadian rhythms persist in the absence of external cues but may become slightly longer than 24 hours.

What is the impact of shift work on circadian rhythms?

It disrupts natural rhythms, leading to poor sleep quality and increased health risks.

How does jet lag relate to circadian rhythms?

It results from misalignment between the internal body clock and the external environment when changing time zones.

What are some consequences of circadian rhythm disruption?

Sleep disorders, reduced cognitive performance, mood disturbances, and increased risk of chronic illnesses.