Consciousness Lecture 4 PDF

Consciousness Lecture 4  Overview Are you a morning person? Or are you a night person? The field of Psychology has always been interested in the study of consciousness Like any other mental activity, the study of consciousness is essential As such psychologists h...

Consciousness Lecture 4  Overview Are you a morning person? Or are you a night person? The field of Psychology has always been interested in the study of consciousness Like any other mental activity, the study of consciousness is essential As such psychologists have found many fascinating facts Examples of these include: biological rhythms, waking consciousness, automatic and controlled processing, shift in self awareness, sleep and consciousness altering drugs  Biological Rhythms People have different adjustment periods; some people work best in the morning others have difficulty staying awake during the day These changes psychologists refer to as biological rhythms: the regular fluctuations in our bodily processes and consciousness over time When these fluctuations occur over the course of a single day then they are referred to as circadian rhythm (“carcadian” is latin for “about a day”) There are other fluctuations that are shorter such as mealtimes that could occur every 2-3 hours And there are other cycles that occur over longer periods such as the mating season of many animals which occur several times for the year  Circadian Rhythms Most of us tend to be aware of the daily fluctuations that take place in our alertness and mood these seem to be closely related to changes in underlying bodily processes These cycles seem to occur during the production of various hormones, core body temperature changes, blood pressure variations and several other processes Circadian rhythms may shift with different times of the day, or they may be affected by age (e.g., older individuals tend to have peaks earlier in the day)  Circadian Rhythms Cyclic fluctuations have been linked to task performance, not so much mental performance, but more so physical performance If we can link bodily processes, mental alertness and performance on many tasks changing throughout the course of the day, then we can assume that there is some biological mechanism that is impacting on these changes As such we can assume that we have one or more biological clocks that vary with our circadian rhythm  Circadian Rhythms Scientific research has shown that we have one structure known as the suprachiasmatic nucleus (SCN) located in the hypothalamus plays an important role in the regulation of circadian rhythms This is affected by light, as such morning light resets our internal biological clock, and therefore brings it in harmony with the outside world This is necessary as our biological clock seems to operate on an approximately 24hour cycle, if the cycle does not reset our biological rhythm would get farther and farther out of sync with the outside world  Longer Biological Rhythms The pineal gland is very important in regulating longer biological rhythms The pineal gland secretes a hormone known as melatonin in response to the input of the SCN Melatonin triggers feelings of sleepiness, impacts several structures of the brain, regulating the production of hormones and affecting many basic physiological processes. Melatonin is mostly secreted at nights, so when it is a longer night, the body secretes more melatonin Higher levels of melatonin seem to play an important role in the onset of hibernation in certain species As the days gets longer there is less release of melatonin as such animals can now spend longer time looking for a mate  Differences in Circadian Rhythm Morning individuals have more energy in the mornings and tend to be more alert Night individuals on the other hand tend to be more active in the afternoon or evening Morning individuals overall have higher level of adrenaline and experience peak of body temperature earlier in the morning than night individuals As such morning individuals therefore seem to operate on a higher overall level of activation  Disturbances in Circadian Rhythm Normally circadian rhythms do not pose a threat to us, in our day to day lives we just adjust to the fluctuation in energy and alertness However, there are factors that can disrupt our circadian rhythm, for example: Jet lag, work shifts Jet lag: when normal sleep pattern is disturbed after a long flight occurs when we fly across different time zones occurs because the body's internal clock is synced to the original time zone the more time zones crossed, the more likely you are to experience jet lag. Symptoms: daytime fatigue, an unwell feeling, trouble staying alert and stomach problems.  Disturbances in Circadian Rhythm Work shifts: when individuals are expected to work when it is time for them to sleep. occurs frequently in countries/occupations where workers are given a shift system that changes frequently May become unsettling for individuals and as such their bodies have to repeatedly reset their biological clocks becomes physically and psychologically draining to the individual  Shifts in states of consciousness Do you notice that there are times when you are talking to a friend, and they seem to be looking at you but not be in tune to what you are saying and when asked about your conversation they don’t have a clue as to what it is that you were saying? This suggests that even during our normal waking activities we have shifts between our states of consciousness This is as a result of two modes of thoughts: Controlled Automatic processing Two modes of thought Automatic processing: processing information with minimal conscious awareness For example, includes activities such as driving and listening to the radio Requires less cognitive energy and because this is well practiced it can be done without conscious intention  Two modes of thought Controlled processing: requires more effort and conscious control of thought and behaviour. The individual pays more direct careful attention to what you are doing and concentrate on it. This requires significant cognitive resources as such only one task can be performed at a time. According to Daniel Wegner we do this by: intentional operating process which is effortful and consciously guided, it searches for mental contents that will produce the state we desire Ironic monitoring processes which is less demanding and unconscious, it searches for mental contents that signal our failure to achieve the desired state  Sleep Early to bed, and early to rise, makes a man healthy, wealthy, and wise." --- Benjamin Franklin, 1758 (in Poor Richard's Almanack)  Sleep We spend about 8 hours/day, 56 hours/week, 240 hours/month and 2,920 hours/year SLEEPING. We apparently spend one third of our lives doing nothing. But is sleep really doing nothing? It looks like it...our eyes are closed, our muscles are relaxed, our breathing is regular, and we do not respond to sound or light. If you take a look at what is happening inside of your brain, however, you will find quite a different situation - the brain is very active. You are doing something!  Study of sleep Sleep is defined as a process in which important physiological changes and slowing basic bodily functions are accompanied by major shifts in consciousness Psychologists gain knowledge of sleep by using a scientific sleep laboratory, where they observe participants and monitor the changes that occur as individuals fall asleep These changes are monitored through the electrical activity of the brain by means of electroencephalogram (EEG), electrical changes in various muscles with the electromyogram (EMG) and changes in electrical potentials in the eyes with the electroculogram (EOG). Study of sleep  Stages of sleep When you are awake and alert your EEG contains many beta waves (high frequency and low voltage activity) As you get into bed and turn off the light your beta waves are replaced by alpha waves where your EEG activity is somewhat lower in frequency but higher in activity As you fall asleep it goes into theta activity where you have even lower frequency and higher activity  Stages of sleep Stage 1: the border between waking and sleep Stage 2: is marked by: sleep spindles (may represent the brain’s reduction of sensitivity to sensory input and so help us to enter deeper stages of sleep) K complexes (involved in helping us to remain asleep) Stage 3: marked by delta activity where there is high amplitude of waves less than 3.5 hertz Stage 4: portion of delta activities increases; some researchers believe that delta activities represents a synchronization of neurons in which increasingly large number of neurons fire together  REM Sleep About 90 minutes the individual enters a distinctive phase known as REM (rapid eye movement sleep). Associated with vivid dreaming. In this phase the electrical activity of the brain changes rapidly and now closely resembles people in their wake stage. Delta activity disappears and low voltage returns The sleeper's eyes begin to move about rapidly beneath their closed eyes and there is total suppression of muscles during this stage Muscles are inactive to prevent us from acting out our dreams. This also means that sleepwalkers are not in REM sleep and are not acting out their dreams.  REM Sleep It has been suggested that most dreaming occurs during REM sleep. Sleep researchers discovered this when they woke people up during REM sleep. Often when people in REM sleep wake up, they say that they were just dreaming. REM sleep continues to fluctuate with other stages of sleep throughout the night REM periods seem to increase toward morning REM sleep is a relatively light sleep, despite the vivid dreaming  EEG Rate EEG Size Stage (Frequency) (Amplitude) Awake 8-25 Hz Low 1 6-8 Hz Low 4-7 Hz 2 Occasional "sleep spindles" Medium Occasional "K" complexes 3 1-3 Hz High 4 Less than 2 Hz High REM More than 10 Hz Low  Stages of sleep While we are asleep, our brains are on a bit of a "roller-coaster" through different stages of sleep. As we drift off to sleep, we first enter stage 1 sleep. After a few minutes, the EEG changes to stage 2 sleep, then stage 3 sleep, then stage 4 sleep. Then it's back up again: stage 3, stage 2, then a period of REM sleep...then it's back down again, and back up again, and down again.... The figure below, depicts an 8-hour period of sleep, the brain cycles through these stages about 4-5 times.  The function of sleep Sleep acts as a restorative and an adaptive function Restorative: slow wave sleep (stages 3 and 4; the deepest sleep) allows us to rest from the rigors of everyday life Vigorous physical exercise seems to increase slow wave resting sleep but only if such exercise raises the brain’s temperature. There has been findings to support this argument as PET scans have revealed that the sections in the brain with the most delta activity seems to be the area that had experienced the most intense activity during the day  Just Sleep On It! Sleep May Enhance Memory and Learning Sleep (especially REM sleep) plays an essential role in learning and memory; it allows us to consolidate memories of the preceding day or perhaps to eliminate unnecessary memories and other mental clutter from our brains "Researchers have found evidence that sleep improves memory!"