1. Ecological Theory
*Why do we sleep? → we have evolved to stay awake when we
are most successful and sleep vournarable and least active
*Meddis 1997
-Sleep is an instinctive behavior that has evolved to keep us out of
-For humans being out of in the dark is dangerous, and are more
successful during the days → so we sleep at night
trouble.
*Emerson 1993
-Ecological Theory aka ‘WASTE TIME THEORY’
-Animals are simply biding their time until the environment is more
suitable
-The reduction in brain activity ensure that the hiding animal is not
motivated to seek out sources of stimulation
-Being totally inactive is even better because a motionless animal
are less likely to attract the attention from the predator
*Evaluation
(+)Explain why different species sleep at different times
(+)Can be accounted for the reduction in the cognitive activity
during
sleep
(-)Does not adequately explain why there is such a huge variation
in sleep
requires between different species
(-)can not be accounted for the absolute necessity to sleep even
when it
is maladaptive
(-)Excludes sleep cycle and dream
2. Restoration Theory
*Why do we sleep?
→ In order to conduct growth and repair functions. The processes
of restoration and activity are mutually exclusive.
(We can not recharge our battery energy while we are still running
on them)
→ Bodily inactive during REM sleep maybe important for the
restoration of muscles.
*Oswald 1980
-High level of ATP is found during sleep.(Because we are
constantly using up our ATP while we are awake)
-Especially to the brain. Although it is only 5% of our body by
weight, it is uses 20% of our energy →” Quiet maybe neededto
allow brain to recuperate.”
*Adam1977
-Correlation between the weight of participant with length of REM
sleep.
-More energy is needed when person weigh more
*Shapiro
-Shown that body wirght also relates with time in n REM sleep
*Dement 1960
-Tested Restoration Theory by depriving young volunteers of REM
or nREM sleep for 5 nights
-REM deprivation showed irritable, nervous, and unable to
concentrate even hallucination. When uninterrupted, individuals
went straight to REM and spent 60% of time in REM
-PET Scan showed bases low emotional senses
*Evaluation
(+)Growth hormone is more active during at night
(+)Account for the cyclical nature of sleep as we cannot persist
without regular restoration
(+)Athletes and drug overdose sleep more
(-)Can’t be accounted for our preference for sleeping at night
(-) Does not explain the cause of dream
3.Reorganization Theory
4. Genes as they effect behavior
*Why do we sleep?
→ To have a chance to recuperate from the past day’s activities
prepare for the next
* Offers the MIND what restoration theories offer to the body.
*Crick and Mitchison 1986
- Proposed a neurobiological Theory of Reorganization
- They suggested that dreams are the result of random firing of
neutral networks which hold memories
-These memories can be accessed by activation any part of the
network
-These memories can be accessed by activation any part of
network → random activation serves to debug the net works,
removing un wanted connections.
-Reverses learning: Storage of important information is enhanced
by the removal of cognitive debris
-Mice deprived of REM sleep either slectivelt or by total deprivation
were equally bad at maze learning compared to nREM and nondeprived mice
*Smith 1995-1996
-Invested the effects of learning on REM sleep requirement
-When they were deprived of REM they only remembered half of
the skills
-If the sleep deprivation was delayed for more than 20 hrs after
training, the rats showed not decrement in learning
→the rates seemed to need REM sleep to consolidate their
memories
*Roffword 1983
More use of mind required more REM sleep
*Tilley and Empson 1978
Deprived REM sleep showed low performance of memorization
*Evaluation
(+)Studies have proved that cognitive functioning is impaired when
People are deprived of REM sleep
(+)Explains the role of dreams as neurons are fired and cognitive
debris is dealt with
(-) Craik and Mitchison’s theory does not explain why dreams are
such an intense subjective experience or why they hold so much
personal meaning for dreams
(-)Doesn’t explain the difference of REM and nREM dreams
* Research in human genetics aims to identify particular genes
involved in hereditary diseases.
*Genetic arguments of behavior are based on the principle of
‘inheritance’. Genes and DNA are passed down from parents to
their offspring.
-Human have 24 distinct chromosomes, with approximately
20000-25000 genes.
*Psychologists argue that an individual may have a genetic
predisposition towards a certain behavior
(HOWEVER, without the appropriate environmental stimuli, this
behavior will not be manifested.)
*Research Methods
-Twin Studies (Note card # 15)
-Family Studies:
More reprehensive sample of the general population than twin
studies. A child inherits half its genes from the mother and half
from the father. It follows that ordinary brother ands and sisters
will share 50% of their genes with each other. In family studies ,
the different degrees of genetic relatedness are compared with
behavior, The notion is that concordance rated will increase if
heritability is high and vice versa.
EX)if the heritability of IQ is high, there should be a strong
correlation in IQ b/wn children and their mothers.
-Adoption studies (Note card # 16)
5. Neuron as they effect behavior
9. Neurotransmitters
*Neurons
-Aprox. 10and 100 billion neurons in the nervous system
-Sends electrochemical messages to the brain so that people can
respond to stimuli(either from the environment or from internal
changes in the body)
*Kasamatsu &Hirai(1999)
-Neurotransmitter’s effect on behaviour
-Aim: to see how sensory deprivation affects the brain.
-Studied groups of monks who went of a 72- hour pilgrimage to a
holy mountain in Japan. The researchers took blood samples
before the monks ascended the mountain and than again
immediately after the monks reported having hallucination.
-They found that serotonin levels had increased in the monks’
brains. These higher levels of serotonin activated the parts of the
brain called the hypothalamus and the frontal cortex, resulting in
the hallucinations.
-Conclusion: the sensory deprivation triggered the release of
serotonin, which actually altered the way that the monks
experienced the world
*Martines and Kesner(1991)
-Aim: determining the role of the neurotransmitter acetylcholine on
memory.
-Rats were trained to go through a maze and get to the end. Once
the rats were able to do this, one group of rats were injected with
scopolamine, which blocks acetylcholine receptor sites thus
decreasing available acetylcholine. Second groups were injected
with physostigmine, which blocks the production of cholinesterase.
Cholinesterase which does the ‘clean up’ of acetylcholine from the
synapse and returns the neuron to its ‘resting state’. Third was a
control group, not given any injection.
-Result: Scopolamine were slower than physostigmine group.
-Conclusion: acetylcholine played an important role in creating a
memory of the maze
*Evaluation on explaining behavior only w neurotransmitter
(+)experimental method with a control group able to establish
cause and effect relationship(Martines and Kensner)
(+)Increase of acetylcholine producing in the early stage of
Alzheimer
(-) complex human behaviour can not be explained by
neurotransmitter alone
(-)might not be gene realized to human
*Body’s natural chemical messengers which transmit information
form one neuron to another.
*When an electrical impulse travels down the body, or axon, of the
neuron, it releases neurotransmitters which then cross the gap,
synapse, between two neurons.
*Neurotransmitters underlies behaviour as varied as mood,
memory, sexual arousal, and mental illness.
-Acetylcholine: Effects muscle contraction, and a role in the
development of memory in the hippocampus
-Dopamine: Effects voluntary movement, learning, and feelings of
pleasure
-Norepinephtine (noradrenalin):Arousal, alertness, and stimulation
of the sympathetic nervous system.
-Serotonin: Sleep, arousal levels, and emotion
*Kasamatsu and Hirai 1999’s study on how the neurotransmitter
serotonin can affect behaviour(Note card #5)
12. Melatonin/Serotonin
15. Twin Studies
*Melatonin
-Melatonin is a hormone concealed by the pineal gland in the brain.
It helps regulate other hormones and maintains the body's
circadian rhythm. When it is dark, your body produces more
melatonin; when it is light, the production of melatonin drops. Being
exposed to bright lights in the evening or too little light during the
day can disrupt the body' s normal melatonin cycles. For example,
jet lag, shift work, and poor vision can disrupt melatonin cycles.
-Some researchers also believe that melatonin levels may be
related to aging
-Some people think lower levels of melatonin may explain why
some older adults have sleep problems and tend to go to bed and
wake up earlier than when they were younger..
-EX)young children have the highest levels of nighttime melatonin.
Researchers believe these levels drop as we age.
*Types of twins
-Monozygotic (MZ): genetically identical because they are formed
from one fertilized egg that split into two. These twins are the same
sex and should look very much alike
-Dizygotic (DZ): not any closer genetically than brothers and
sisters(50% common genes). They are forms two separate
fertilized eggs.
*The higher the genetic relationship, the more similar individuals
will be in the particular characteristic being investigated is
inherited.
*Concordance rate is the correlation found in the twin studies
*Serotonin
-Effects sleep, arousal levels, and emotion
-Kasamatsu &Hirai(1999)(Note card #5):
Neurotransmitter serotonin effect on behaviour
13. Dopamine
*Effects voluntary movement, learning, and feelings of
Pleasure
* helps control the brain's reward and pleasure centers. Also helps
regulate movement and emotional responses, and it enables us
not only to see rewards, but to take action to move toward them.
*Dopamine deficiency results in Parkinson's Disease, and people
with low dopamine activity may be more prone to addiction. The
presence of a certain kind of dopamine receptor is also associated
with sensation-seeking.
16. Adoption Study
In principle, it allows the most direct comparison of genetic and
environmental influences of behavior. Adopted or foster children
generally share none of their genes with their adoptive parents,
but they do share 50% of their genes with their natural mother. It
would be reasonable to suppose that if the heritability of
behavior of adopted children should correlate more strongly with
the behavior of their natural mother than their adoptive mother.
(-) not representative of the general population.
(-) selective placement
17. Correlation methodology
* Genetic research in human is to a large extant based on
correlational studies.
*Researchers look at how different variables may co-vary.
*Correlational study establishes that there is a relationship
between variables, but the researcher does not manipulate an
independent variable as in an experiment
*CORRELATION DOES NOT MEAN CAUSATION.
26. SAD(Seasonal Affective Disorder)
*SAD is a condition experienced in the short days of winter by as
many as 10% of the population
-EX)In Shetland the shortest day lasts just 5 hrs and 53 min b/w
sunrise and sunset, with no guarantee of any sunshine in
between December brings 15 of sunshine in the whole month
*Symptoms: severe depression, craving for high carbohydrates
foods and sleepiness.
*Therapy
-Ferenzi(1997)
Suggested that it may either reset the circadian cycle or increase
the secretion of serotonin, which is implicated in mood disorders.
Light therapy isn’t effective at all. The key factors of light therapy
are duration of exposure and amount of exposure.
-Illnerova et al(1993)
>Light Therapy
>If light therapy raised mood by affecting the pineal gland,
reduced level of melatonin would be expected following
treatment.
>Illnerova showed a shifting in the melatonin cycle using bright
lights to extend the day. Non SAD participants were exposed to
3 hrs of bright lights morning for 5 consecutive days during
winter. Their circadian clocks moved 1-3 hrs, and took 3 days
to regain(showing an effect on melatonin levels)
*Evaluation
(-)Stiles (1990) had suggested that SAD isn’t what we think
response of people to publicity. He suggests that people see
psychiatrists less in summer because they’re on vacations.
(-)Light therapy seems effective only to SAD who suffer from
sleepiness and high carb food craving