States of Consciousness:

Transcription

1 States of Consciousness: Before the turn of the century Psychology was concerned primarily with the description and explanation of states of consciousness Because of problems with directly studying and measuring consciousness, the focus of Psychology changed to the study of observable behaviour (behaviourism). Since behaviour is directly observable, it can be measured and changes in behaviour can be attributed to intervening processes such as learning Behaviourism has been the predominant influence in North American Psychology during the past century During the last part of the century, however, interest rekindled in studying states of consciousness (response to the limitations of behaviourism) Today, contemporary psychology is concerned with both the study of behaviour as well as with the study of consciousness. What is consciousness? Today, we define consciousness as: awareness of ourselves and our environment a process which allows us to exert voluntary control over ourselves a way of communicating mental states 1

2 We direct our consciousness through attentional mechanisms Consciousness consists of several levels or layers We can obtain some insight into how the conscious mind works by looking at how humans perform certain types of tasks When we first engage in a task like driving a car, our conscious mind focuses on variables such as the traffic, pedestrians, the operation of the vehicle, the feel of the car on the road, etc. As we become more practiced at driving, the task becomes more automatic and requires less conscious effort (skilled behaviour). Becoming a skilled performer leads to the conscious mind becoming less and less burdened by the task The task becomes under the control of subconscious processes This freeing up the conscious mind allows us to parallel process e.g. daydreaming, reading while driving the car When behaviour becomes skilled, the conscious mind is free to monitor behaviour, do other things and to deal with novel situations Therefore, less familiar tasks and situations require more conscious effort or attention This division of labour (conscious / unconscious) is seen as a way that allows our mind to use it s resources more efficiently 2

3 Normal and altered states of consciousness Normal when we are awake, how we usually see the world, hear, reason and remember Altered states sleep, dreams, daydreams, hypnotic states, chemically induced states, near death experiences (NDE s). Sleep We spend approximately 1/3 (25 years) of our lives asleep Why do we sleep? Sleep helps us assimilate newly learned information During sleep, the body releases growth hormones sleep is particularly important for young growing bodies Sleep rejuvenates our bodies and promotes recovery of our immune system Our tendency to sleep at night may have helped to keep us out of harms way from predators (Coren) Studies looking at sleep deprivation in animals show that they will eventually die from lack of sleep for a long time, however, autopsies could not identify any specific physiological causes of death 3

4 More recently, it has been discovered that the lack of sleep leads to decreased efficiency of the immune system and that sleep deprivation will cause the immune system to shut down and eventual lead to death. How much sleep do we need? we need on average about 10 h of sleep per 24 h period it may not be necessary to have this much sleep in one session many societies formalize afternoon rest periods, the Spanish refer to as Siesta Evidence for needing 10 h of sleep is based on comparative psychology studies (chimps and other primates) and on summer arctic studies conducted by UBC Sleep Rhythms Sleep has its own rhythm Each night we experience 5 stages of sleep, which cycle every 90 min Other animals have different lengths to their sleeping cycles and sleep for very different lengths of time (e.g. horses 4 h) 4

5 Stage 1: Irregular EEG patterns Light sleep Lasts about 2 minutes Can experience fantastic images Feelings of expanding and contracting Feelings of falling, weightlessness Sudden jerks Stage 2: Stage 3: Deeper sleep Lasts about 20 min EEG shows rapid bursts of rhythmic brain activity called sleep spindles During Stage 2, people sometimes sleep talk but the talk is garbled nonsense speech Transitional sleep Lasts only a few minutes Brain starts to generate Delta waves (slow, high amplitude synchronous firing of neurons) 5

6 Stage 4: Lasts about 30 min Characterized by a lot of Delta waves brain activity is very rhythmic Strangely enough, this is when sleep walking occurs, also when children tend to wet the bed Also, when a truck goes by, person may not wake up but a babies cry will wake us up this suggests a selective filtering of information and possibly even a biological/genetic predisposition to respond to select frequencies of sound REM (rapid eye movement) or paradoxical sleep After being asleep for about an hour, we return to Stage 1, through Stages 2&3 We spend ½ of our sleep per night in stages 2&3 When we enter REM increase in HR, breathing becomes rapid & irregular, rapid eye movements about every 30 s REM period lasts up to 30 min If woken up, dreams are remembered REM not the only time we dream but dreams are extremely vivid and often have a surrealistic quality to them with lots of symbolic meaning 6

7 During REM, motor cortex is very active but brain stem blocks activity to the body and the body is extremely relaxed and immobilized 80% of people who claim that they don t dream remember dreams if they are woken up during REM If someone is deprived of REM, there is a rebound effect in subsequent sleep Biological Rhythms and Sleep In addition to sleep having its own 90 min biological rhythm, overall sleep is regulated by biological rhythms we call circadian rhythms (24h cycles) Sleep is regulated by 2 types of biological rhythms endogenous and exogenous rhythms Endogenous rhythms are the stronger of the two and are controlled by an internal body clock (RAS), but are calibrated or adjusted by means of exogenous time cues Endogenous rhythms control body functions including core temperature and metabolism Exogenous rhythms are rhythms controlled by external time givers (Zeitgbers) light/dark being prominent but social cues (dinner time) also act as external time givers. 7

8 Endogenous rhythms change to 25 h cycles in the absence of exogenous time cues cave studies, flying across time zones, night shifts If we fly across time zones and try to sleep according to new light/dark cycle, we have problems sleeping until exogenous cues recalibrate endogenous rhythms Easier to fly from east to west than west to east Ideally people will adapt (re-entrain) to a night shift but it rarely happens Easier for people to adapt to shifts that rotate forward We need to sleep when body temperature is falling in order to experience proper sleep periods If exogenous cues continue to change, temperature rhythms flatten out once this happens, deep sleep can t be obtained Deep sleep is critical for our bodies to recuperate Estimates are that a lifetime of work causing flattened body temperature rhythms will decrease life expectancy by up to 20% Sleep Debt Because we need 10 h of sleep our 24 h society suffers from sleep debt (Coren) Daylight savings/ single car accident studies (spring forward lose 1 h increase accidents by 7%) 8

9 Cost of sleep debt in the US is estimated between 3 and 4 hundred billion dollars per year (accidents, decreased work efficiency, absenteeism) Lack of sleep: Impairs creativity & concentration and vigilance (consciousness and attention) Mood changes irritability Tremor Slowed performance (blocking) Misperceptions on monitoring tasks (vigilance and attention) Cherynobl, Exon Valdez, 3 Mile Island, Challenger, Bopal All monitoring tasks, people who have been working the night shift, accidents around 3:00 AM. Sleep Disorders Newborns sleep about 16 h per 24 h Adults sleep 7.5 h per 24 h Insomnia Difficulty getting to sleep affects 10-15% of the population 9

10 Quick fixes such as sleeping pills or alcohol reduce REM and leave the person feeling tired the next day Best strategies are: Relax before bed Avoid caffeine within 5 h of sleep Drink milk helps produce serotonin Sleep according to a regular cycle Avoid naps Don t eat before bed Restrict sleep time Narcolepsy Falling asleep uncontrollably regularly overcome with the need to sleep affects 1 in 1000 Extremely dangerous condition Sleep apnea breathing stops while asleep affects 1 in 25 decrease in blood oxygen levels arouse sleeper condition often associated with snoring excessive weight (peripheral sleep apnea) condition can also be brainstem dysfunction (central sleep apnea) 10

11 Dreams REM dreams are more vivid, emotional and bizarre than dreams experienced during other stages of sleep Manifest content - the story line - often follows events experienced during the day Latent content meaning of the dream according to Freud, our unconscious adjusting our psyche through experience Information processing, assimilation and learning Hypnosis An altered state related to subconscious mind Subconscious brought forward conscious mind put into suspension (dissociation) Some people are more susceptible than others Harvard Hypnotic Susceptibility Scale Hypnosis can help with some memory problems and with the alleviation of pain 11

12 Drugs Psychoactive: Alter states of consciousness Depressants - calm neural activity, slow CNS Stimulants - excite neural activity, arouse CNS Hallucinogens evoke sensory images without stimulation Depressants: Inhibition of inhibition State dependency Degrade performance and judgment Alcohol reduces self awareness Opiates brain stops producing endorphins pain on stopping, REM rebound from heroin withdrawal and nightmares Stimulants: Stimulate CNS sympathetic Increases energy and self confidence Improves performance Weight loss Keeps people awake alert Hallucinogens: PCP (angel dust) LSD Generation of internal stimulation 12

13 Marijuana short term memory effects, decreasing dose response, stored in fatty tissue for up to 30 days Near death experiences: Light Tunnel Helpers Common across cultures other 13