Gazzaniga • Heatherton • Halpern Psychological Science FOURTH EDITION Chapter 5 Consciousness ©2013 W. W. Norton & Company, Inc.
Consciousness • Erik Ramsey is “locked in…” • Suffered traumatic injury to his brain as the result of an automobile accident • He can see, hear and feel, but he cannot move or communicate with the outside world…at least not yet
Consciousness • In a coma, but aware • Patterns of brain activity in a coma sufferer were similar to patterns found in those not in a coma (Owen et al., 2006) • Communication may be possible with coma patients previously believed to be unreachable
5.1 What Is Consciousness? Learning Objectives • Define consciousness. • Identify varied states of consciousness. • Summarize research findings on consciousness and “the interpreter” among individuals with split brain. • Discuss how unconscious processes influence thought and behavior.
What Is Consciousness? • People can be conscious even when they appear not to be • All conscious experience is associated with brain activity • Variations in consciousness occur naturally • Consciousness can be manipulated • Conscious experience varies from person to person
Consciousness Is a Subjective Experience • Consciousness: The subjective experience of the world, resulting from brain activity • The brain and the mind are inseparable • Each of us experiences consciousness personally • We cannot know if two people experience the world in exactly the same way
There Are Variations in Conscious Experience • Sleep/wake cycle • Automatic tasks • Driving, walking, catching a baseball • Controlled processing • Helps us perform in complex or novel situations
Extreme States • Conditions of impaired consciousness provide useful points of contrast to “normal” (fully-functioning) consciousness • Persistent vegetative state • Full coma that lasts more than a month • Terri Schiavo • Minimally conscious state • Deliberate movement and communication are possible • Jan Grzebski
Brain Activity Gives Rise to Consciousness • Psychologists can examine and measure consciousness (e.g., fMRI) • Consciousness arises from brain circuits’ activity
The Global Workplace Model • In some cases brain-injured patients are unaware of their deficits (“hemineglect”) • Consciousness arises through brain processes that are active at any point in time • No single area of the brain responsible for general “awareness”
The Split Brain • Awareness of the world is associated with functioning in different parts of the brain
The Split Brain • Corpus callosum removed • Two halves of the brain cannot receive information directly from each other • Studies show the relation between specific brain regions and conscious experience • Early observations were that split-brain patients had no discernable problems • Sperry & Gazanniga’s (1960s) research proved otherwise
The Split Brain • Language center located in left hemisphere • Split brain patients cannot report on an object presented in their left visual field • They could correctly choose the object (with their left hand) • Right hemisphere handles spatial tasks • Split-brain patients could not arrange blocks correctly when using their right hand • Left-handed, the task was effortless
The Interpreter • The left hemisphere attempts to make sense of right-hemisphere actions
The Interpreter Speculates • The left hemisphere tries to make sense of the world (e.g., imposing narrative structure, seeking patterns) • The right hemisphere simply experiences the world • Brain hemispheres work together to construct our experience of the world
Unconscious Processing Influences Behavior • We are aware of some mental processes and unaware of others • Subliminal perception: Processing information by sensory systems without conscious awareness • Freudian slip: An unconscious thought expressed at an inappropriate moment • Stereotype activation: Is it automatic? • Bargh et al. (1996) found research participants primed with stereotypes about the elderly unconsciously behaved in ways consistent with those stereotype
The Smart Unconscious • Good advice: “You’d better sleep on it.” • Unconscious processing of problems can lead to superior solutions (Dijksterhuis, 2004) • Even conscious thinking can undermine good decision- making (Wilson & Schooler, 1991)
5.2 What Is Sleep? Learning Objectives • Describe the stages of sleep. • Identify common sleep disorders. • Discuss the functions of sleep and dreaming.
What Is Sleep? • Sleep is biologically regulated • Circadian rhythms • Melatonin secretion linked to light-dark cycles • Some adults report needing 7-9 hours a night • 70-year-old “Miss M.” gets by on one hour per night!
Sleep Is an Altered State of Consciousness • Sleep: Awareness of the outside world is turned off (mostly) • So why don’t we fall out of bed? • EEG: The brain is active in sleep
Stages of Sleep • Sleep is not an “on-off” event • Sleep stages • Historically: 5 distinct stages • Currently: Stages 3 & 4 are now joined
REM Sleep • The sleep cycle reverses after about 90 minutes • Enter REM (paradoxical) stage • Most dreaming occurs in REM sleep • Amount of time spent in REM increases • Cycle through this pattern around 5 times per night
Sleep Disorders • Insomnia: Difficulty falling or staying asleep • Obstructive Sleep Apnea: Breathing may stop hundreds of times per night • Narcolepsy: Sufferers unexpectedly fall asleep • REM Behavior Disorder: Sufferers act out their dreams • Somnambulism: Sleep walking
Sleep Is an Adaptive Behavior • Sleep serves important biological purposes: • Restoration • Circadian rhythms • Facilitation of learning
Restoration and Sleep Deprivation • Restorative Theory: Sleep allows the body to rest and repair itself • The evidence: • Sleep increases after strenuous physical activity • Growth hormones secreted in sleep • Replenishes the brain’s energy stores • Strengthens the immune system
Restoration and Sleep Deprivation Effects of sleep deprivation: • Mood problems (e.g., irritability) • Decrements in cognitive performance (e.g., attention and short-term memory lapses) • May compromise the immune system • Falling asleep for a few seconds to a minute (microsleeps) can impair ability to perform critical tasks (e.g., driving)
Circadian Rhythms Circadian rhythm theory: • Many creatures are quiet and inactive during the night because darkness is the time when danger is highest • Reduced risk of exposure to predators • Humans: Are adapted to sleep at night because our early ancestors were more at risk in the dark
Facilitation of Learning Sleep: Strengthens neural connections needed for learning to occur • Research shows memory in participants who slept was greater than those who didn’t (Drosopoulos, Schulze, Fischer, & Born, 2007) • REM and slow-wave (stages 3 & 4) important for learning to take place • Participants who completed a complex task and later dreamed about it subsequently performed better on the task than non-dreaming participants (Wamsley, Tucker, Payne, Benavides, & Stickgold, 2010) • Students spend more time in REM during exam periods
People Dream while Sleeping • Dreams: Products of an altered state of consciousness in which images and fantasies are confused with reality
REM Dreams and Non-REM Dreams • REM dreams: More likely to be bizarre and include intense emotions, visual and auditory hallucinations, and uncritical acceptance of illogical events • Non-REM dreams: Relatively dull (e.g., what sweater should I wear?)
REM Dreams and Non-REM Dreams Explanation: • Non-REM: General de-activation of many brain regions • REM: Brain structures associated with motivation, emotion, reward, vision are active; pre-frontal cortex is not