PSYC1101 Chapter Notes - Chapter 6: Slow-Wave Sleep, Circadian Clock, Circadian Rhythm
PSYC1101 Chapter Notes
Chapter 6
The puzzle of consciousness
• Consciousness refers to our moment-to-moment awareness of ourselves and the environment.
It is subjective, dynamic, self-reflective, central to our sense of identity and linked to selective
attention. Scientists use self-report, behavioural and physiological measures to measure states
of consciousness.
• Freud viewed the unconscious mind as a reservoir of unacceptable desires and repressed
experiences. Cognitive psychologists view it as an information-processing system and
distinguish between controlled and automatic processing. Research on visual agnosia, blind
sight and priming reveals that information processed unconsciously can influence people's
behaviour and emotions.
• Consciousness has adaptive value. It facilitates planning and decision making, helps us cope
with novel situations and lets us override impulsive and automated behaviours. The brain
contains at least several separate neural circuits for conscious versus unconscious information
processing
• Global-workspace models propose that the mind consists of separate but interacting
information-processing modules. Consciousness arises from the unified activity of multiple
modules located in different brain areas.
Circadian rhythms: our daily biological clocks
• Circadian rhythms are 24-hour biological cycles that help regulate bodily processes and
influence our alertness. The suprachiasmatic nuclei (SCN) are the brain's master circadian
clock. Free-running circadian rhythms are about 24.2 hours. The day-night cycle and other
environmental factors reset our daily clocks to a 24-hour schedule.
• Circadian rhythms influence our tendency to be a morning or night person. Cultural factors
may also play a role
• In general, our alertness is lowest in the early morning hours. Job performance errors, major
industrial accidents and fatal car accidents peal during these hours
• Jet lag, night-shift work and seasonal affective disorder (SAD) involve circadian disruptions.
Treatments include controlling one's exposure to light, taking oral melatonin and regulating
one's daily activity schedule.
Sleep and dreaming
• Sleep has five main stages. Stage 1 and 2 are lighter sleep; stages 3 and 4 are deeper, slow-
wave sleep. High physiological arousal and rapid eye movement characterise stage-5 REM
sleep. Several brain regions regulate sleep, and genetic, psychological, and environmental and
social factors affect sleep duration and quality
• Sleep deprivation negatively affects mood and performance
• The restoration model proposes that we sleep to recover from physical and mental fatigue.
Evolutionary/circadian models state that each species developed a sleep-wake cycle that
maximised its chance of survival.
• Insomnia, narcolepsy, REM-sleep behaviour disorder, sleepwalking, night terrors and sleep
apnoea can have serious consequences. Sleepwalking typically occurs during slow-wave sleep,
whereas nightmares most often occur during REM sleep. Night terrors create a near-panic
state of arousal and typically occur in slow-wave sleep.
• Dream occurs throughout sleep but are most common during REM periods. Our cultural
background, current concerns, and recent events influence what we dream about.
• Freud proposed that dreams fulfil unconscious wishes. Cognitive-process dream theories view
dreams and waking thoughts as products of the same mental systems. Activation-synthesis
theory views dreaming as the brain's attempt to fit a story to random neural activity.
Document Summary
The puzzle of consciousness: consciousness refers to our moment-to-moment awareness of ourselves and the environment. It is subjective, dynamic, self-reflective, central to our sense of identity and linked to selective attention. Scientists use self-report, behavioural and physiological measures to measure states of consciousness. Freud viewed the unconscious mind as a reservoir of unacceptable desires and repressed experiences. Cognitive psychologists view it as an information-processing system and distinguish between controlled and automatic processing. Research on visual agnosia, blind sight and priming reveals that information processed unconsciously can influence people"s behaviour and emotions: consciousness has adaptive value. It facilitates planning and decision making, helps us cope with novel situations and lets us override impulsive and automated behaviours. The brain contains at least several separate neural circuits for conscious versus unconscious information processing: global-workspace models propose that the mind consists of separate but interacting information-processing modules. Consciousness arises from the unified activity of multiple modules located in different brain areas.
