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PSYCH 101 Fall 2013 1/2 Course Notes

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Richard Ennis

PSYCH 101 - Introduction to Psychology Kevin James Fall 2013 Outline Psychology is the analytical study of the interactions within society and of the thoughts and behaviours of every person, giving us a less naive understanding of those aspects of our culture. An understanding of psychology helps one to gain a better understanding of oneself and of others. ABCs of Psychology The ABCs are the three most important aspects of psychology to which all topics can be brought back to or described in terms of. They include: ▯ A▯ect { feelings, moods, and states, including the study of emotional interactions. ▯ Behaviour { actions and performances. This is slightly more overt than the study of emotions, since actions are often, if not always, overt, whereas emotions can be hidden. ▯ Cognition { thoughts, decisions, attitudes. This deals with decision-making and analysis. Basic Model of Psychology We begin by looking at a person and his features, then his behaviours. We then look at the outcomes "generated" by this person, as determined by his features and behaviours, and attempt to draw infer- rences between them. We must also take into account the person’s environment { not only physically, but socially, emotionally, and mentally. In e▯ect, the basic model is person ! behaviour ! outcome. 1 Perspectives of Psychology Psychodynamic The psychodynamic approach was heralded by Sigmund Freud. This perspective deals with forces at play within the subconscious psyche of a person: these forces are said to be constantly in ux and determine one’s thoughts and behaviours. Behaviourism Mostly led by John Watson, behaviourism was originally referred to as the environmental perspec- tive. John Watson was very much in favor of the hard sciences, as opposed to Freud’s idea of psychology, and thus focused on overt behaviours { ie. things which can be measured. Thus, behaviourism deals with a person’s overt actions and behaviours. It also heavily features the "reward model", ie. that people do things because they will be rewarded in some faction. Cognitive The cognitive model of psychology, whose most famous leader was Antonia Bandura, was a more centrist view of psychology. The cognitive perspective deals primarily with thoughts and perceptions, and thus the behaviours they cause. This is very di▯erent from the psychodynamic model mainly because it deals with the conscious mind: we can actually ask "why did you come to that decision?" and ▯nd ourselves with a somewhat satisfactory answer. Students of the cognitive model tended to study animals such as lab rats, and apply their behaviour upon humans. Biological The biological perspective has been around since the time of Freud and is somewhat related to the psychodynamic approach. This approach was created by biologists studying the brain independantly of psychological studies. This perspective can be characterized by the question: "what are my neurons doing when I do or think ?". Neuropsychology, Evolution, Genetics Evolutionary psychology also comes from the study of biologiy, and deals with the question of how human thoughts and behaviours have evolved and changed over history. This tends to be highly speculative, as... well, thoughts do not fossilize. Socio-Cultural The socio-cultural approach is a more modern approach which focuses on how the environment plays a role in a person’s thoughts and behaviour. This deals heavily with the interactions between and within groups, societies, and cultures, and is expanded on by the ▯eld of sociology. 2 This approach also deals with the di▯erent perspectives of di▯erent cultures { for example, Eastern psychology is completely di▯erent from the topcs this course will cover. Science of Psychology Psychology, as a discipline, is seen as somewhat inferior when compared to the hard sciences, in that it tends not to be regarded as having as much rigour. Regardless, psychology follows the same process as any hard science: ie. observing by watching. After all, Einstein said that "the whole of Science is nothing more than the re▯nement of everyday thinking". Goals: Understand, Explain, Predict, and Control The goals of science, as layed out by Carl Poper, are to understand, explain, predict, and control a certain area of interest. Studying some topic gives us a greater understanding of said topic, which allows us to explain that topic, which can hopefully allow us to predict future events, and most ideally to control those events. Re▯nement: from Theory to Theory Re▯nement of our theories tends to follow the following cycle: develop theory, form hypothesis, carry out observation, analyze results, re▯ne theory. Repeat ad nauseum. Criteria: Empirical, Replicatible, and Falsi▯able We have certain criteria which we follow to ensure the science of psychology has any use: ▯ Our observations must be empirical, ie. quanti▯able and measurable. If all observations are subjective, then we are forming opinions, or at best we are performing philosophy. ▯ Our experiments must be replicable by other people under other circumstances. If we declare something to be true, but that result can never be repeated, then it has no use whatsoever. Again, we have simply formed a useless { and, anyway, inaccurate { opinion instead of following the scienti▯c method. ▯ Falsi▯ability is important, though this is not readily apparant. For any theory to be accepted as a scienti▯c theory, it must be possible to prove that theory wrong. This doesn’t mean that this theory must necessary be wrong, simply that there must be some potential observation which could convince us of the invalidity of this theory. "Truth is arrived at by the painstaking process of eliminating the untrue" Associations: Correlation and Causation We can have direct correlations, which imply that one variable increases as does an other, or negative orrelations, which imply the opposite relationship. Correlation, though, does not imply causation, and as such does not tell us which e▯ect is causing the other. 3 If we ▯nd that A and B are directly correlated, this could mean A =) B, B =) A, or X =) A^B. Origins of Psychology It is generally believed that Willhelm Wundt was responsible for creating the ▯eld of Psychology in 1879 when an experiment of his concluded that being aware of one’s own awareness takes longer than simply allowing the awareness complete control. Schools of Thought Structuralism Structuralism was founded by Wundt’s student Edward Bradford Titchener. It focuses on breaking down one’s experiences into the most basic components by having subjects engage in introspection. Functionalism Functionalism was formed in response to Structuralism by focusing on the work of Charles Darwin and William James. This school of thought tries to explain mental processes systematically and accurately by focusing on the purpose of both consciousness and behaviours rather than the elements of said consciousness. Functionalism also takes into account individual di▯erences to a much higher degree than other schools. Behaviourism Behaviourism was formed between 1920 and 1960 by American scientists (e.g. Watson and Skinner) who dismissed introspection and reintroduced psychology as the scienti▯c study of observable behaviour. They believed in observation, and thus cared much more about poeples actions that the thoughts or feelings behind them. Humanistic Psychology Humanistic Psychology rebelled against Freudian psychology and behaviourism by emphasizing the importance of environmental in uence with regards to our personal growth. It also emphasized the importance of having our needs for love and acceptance satis▯ed. Cognitive Neuroscience By the 1960s, psychology as a ▯eld moved back toward the study of the function of the mind and various mental processes. At this point, cognitive neuroscience was developed. Cognitive Neuroscience: the interdisciplinary study of brain activity linked with cognition. 4 Psychology Today Today, we de▯ne psychology as the intesection of behaviour and mental processes. The various perspectives are as follows: ▯ Neuroscience: how the body and brain enable emotions, memories, and sensory experiences ▯ Evolutionism: how the natural selection of traits prompoted the survival of genes ▯ Behavioural Genetics: how our genes and environment in uence individual di▯erences ▯ Psychodynamic: how behavious springs from unconscious drives and con icts ▯ Behavioural: how we learn observable responses ▯ Cognitive: how we encode, process, and store information ▯ Socio-cultural: how behaviour and thinking vary cross-culture Nature vs Nurture The issue of nature vs nurture - the relative contributions of biology and experience - is an oft-discussed one. Plato assumed that character and intelligence are largely inherited and that certain ideas are inborn. Aristotle countered that there is nothing in the mind that does not ▯rst come in from the external world through the senses. John Locke rejected the notion of inborn ideas, suggesting that the mind is a blank sheet on which experience writes. Rene Descartes disagreed, believing that some ideas are innate. 20 years later, Descartes gained support from a naturalist: Charles Darwin. Three levels of Analysis The three levels of analysis form from an integrated bio-psycho-social approach. Each provides a di▯erent but incomplete view. ▯ Biological 1. Natural selection of adaptive traits 2. Genetic predispositions related to the environment 3. Brain mechanisms 4. Hormonal in uences ▯ Psychological In uences 1. Learned fears and expectations 2. Emotional responses 3. Cognitive processing and perceptual interpretations ▯ Socio-Cultural In uences 1. Presence of others 5 2. Cultural, social, and familial expectations 3. Peer and group in uences 4. Compelling models, e.g. the media A▯ective Development Psychodynamic The psychodynamic analysis of a▯ective development heavily emphasizes sex and attachment, i.e. the primary biological need is sex and the secondary emotional need is attachment. Freud was a supporter of this theory: he believed that attachment followed from sexual ful▯llment of needs. Behaviourism Behaviourists believed the primary biological need was survival, followed by the emotional need of attachment. A child would learn to associate certain people with good things, and develop a▯ectation and attachment as a side-e▯ect of the initial survival mechanism. Harry Harlow’s Monkeys Harry Harlow was a behaviourist who worked with monkeys. He initially took baby monkeys from their mother, and noted that they formed emotional bonds with whatever they had (e.g. blankets, bottles, etc). From this, he wondered if attachment was not a secondary need but a primary one. One of his studies is among the most famous in history: two surrogate mothers provide for baby animals. He divides the children into two groups: one with a cloth mother and the other with a wire mother which gives milk. The infants are then given both mothers and asked to chose. The babies preferred the cloth mothers, regardless of circumstance. In e▯ect, they chose the mother with which they could snuggle and cling to over the one providing sustenance. Harlow’s conclusion: that we have a primary need to form bonds with members of our species, and that love is a necessity. Mary Ainsworth’s Response Mary Ainsworth wanted to know whether Harlow’s results would prove similar with humans. She thus created the strange situation. There exist two chairs in a room containing toys, one for a child’s mother and the other for a complete stranger. The children would maintain a ▯rm grip to their mother and only begin exploring the room cautiously after a period of time. When the stranger enters the room, the child would return to it’s mother. When the mother leaves, the child would cry and / or go to the mother’s chair. These results varied according to attachment patterns: ▯ Secure - the child is secure in it’s relationship with it’s mother 6 ▯ Ambivalent - the child is ambivalent about it’s situation with it’s mother ▯ Avoidant - the child is actively hostile in it’s relationship with it’s mother Note that these relationships go both ways, i.e. both of the people involved in the relationship can be in di▯erent situations. Secure Ambivalent Avoidant Secure smooth, reciprocal secure, tolerant, caring aggresive, intolerant Ambivalent x hot and cold domainant / submissive Avoidant x x power struggle, mistrust Albert Bandura Albert Bandura was a behaviouralit who noted that one way to learn is by observing associations. He called this trial and error learning. His realizations: that children acquire a massive amount of information extremely quickly, much of it through social experinces. We learn from other’s experinces, through imitative or vicarious learning. Developmental Psychology Developmental psychology focuses on three main issues: 1. Nature vs Nurture: how does genetic inheritance and experience in uence our development? 2. Continuity vs Stages: is development a gradual process or is it a sequence of discrete stages? 3. Stability vs Change: do early personality traits persist through life ot do we become a di▯erent person through aging? Developmental psychologists study the physical, mental, and social changes throughout the life span, beginning at conception. Habituation is a decrease in response with repeated stimulation. The more often a stimulation is presented, the less frequently it is used. The seeming boredom with stimuli can be used to evaluate what infants see, hear, feel, etc. This is referred to as the novelty-preference procedure, which introduces new things along with many old things. Brain Development The developing brain overproduces neurons an dneural networks which enable walking, talking, etc. Fiber pathways supporting language and agility proliferate into puberty until a pruning process shuts down excess connections and strengthens others. Maturation Deprivation or abuse can retard development, experiences of takling and reading can speed it up. Maturation sets the basic course of development to be adjusted by further experiences. 7 Motor Development The developing brain slowly enables physical coordination; in no small parts based on one’s genetics (ex: identical twins ▯rst sit up on nearly the same day). Maturation, including the rapid development of the cerebellum, allows us to walk around age one. Infant Memory Infantile Amnesia is the condition where children beneath the age of three are unable to recall otherwise memorable occasions. The earliest conscious memory forms at around age three-and-a-half. The nervous system, though, is capable of remembering what the brain cannot: children who had crossed the age-three-border provided physical responses to people they had met before that age. Cognitive Development Cognition refers to all the mental activities associated with thinking, knowing, remembering, and communicating. Developmental psychologist Jean Piaget was intrigued by children’s inability to answer certain ques- tions, and eventually concluded that children reasoned di▯erently than adults due in part to their brains being completely di▯rent than their adult counterparts. He concluded that a child’s mind develops in stages: the maturing brain builds schemas (i.e. concepts or mental molds) into which we pour our experiences. By adulthood, we have built countless schemas for each and every possible topic (e.g. animals, love, spicy food). Piaget proposed two new concepts: ▯rst, we assimilate new experiences, interpreting them in terms of our current experiences and preformed schemas. As we adjust with the world, though, we accomodate out schemas to accept the information new experiences provide. Broad views are quickly rpelaced by narrowing categoried and developing new schemas as necessary. Children, then, construct their understanding of the world slowly, and with both periods of change and cognitively stable plateaus: ▯ Age 0-2 "sensorimotor": experience the world through senses and actions. First experiences with object permanence and stranger anxiety. Infants live in the present ("out of sight, out of mind") and don’t understand that objects exist when not perceived. ▯ Age 2-7 "peroperational": represent things as words and images, uses intuition rather than logical reasoning. First experiences with pretend play and egocentrism. Children lack principles such as conservation, the idea that quantity remains the same despite changes in shape, and have di▯culty perceiving things from another’s point of view. ▯ 7-11 "concrete operational": thinking logically about concrete events, grasping conrete analogies, preforming arithmetical operations. First experiences with conservations, mathematics, transfor- mations. Children here begin to grasp conservation and ▯rst gain the mental ability to comprehend math. 8 ▯ 12-adult "formal operational": abstract reasoning. First experiences with abstract logic, potential for mature moral reasoning. If this then that reasoning is now possible (i.e. consequentialism). Around this age, the concept of a self is discovered. Theory of the Mind Children begin to infer other’s thoughts when they form a theory of the mind (coined by David Premack and Guy Woodru▯). They can then tease, empathize, and persude others. They also begin to realise that people may hold false beliefs. Note that those with autism to not develop this. Social Development At around the age of eight months, children develop stranger anxiety. They greet strangers by crying and reaching for familiar ▯gures. This is because they have developed a schema for faces. Origins of Attachment The attachment bond is a survival impulse which keeps children near to their caregivers. Though developmental psychologists initially suggested that infants became close to those who satis▯ed their physical needs, this was eventually proven false. From Harlow’s experiments, we conclude that children become attached to those who were close to them and comfortable. Rather than nourishment, comfort and familiarity is given precedence. Familiarity Contact is only one key to attachment; another is familiarity. For many animals, these bonds must form during a certain critical period, i.e. age when these bonds can be formed. Konrad Lorenz explored the imprinting process. Even baby birds could imprint upon other species, and once formed an imprint is always di▯cult to reverse. Children, however, do not imprint, they simply become attached to what they’ve known. Attachment Di▯erences When placed in the strange situation, roughly 60% of infants display secure attachment: when the mother is present they are content, but they are distressed otherwise and welcome her return. Other infants show insecure attachment: they cling to their mother and remain severely upset when she leaves. Children have inborn di▯erences, so their behaviour is not dependant solely on parenting. While our capacity for love grows as we age and our pleasure at touching and holding never ceases, early attachment does gradually relax. Eirk Erikson concluded that securely attached children approach life with a sense of basic trust, the feeling that the world is predictable and reliable. He attributed this to early parenting: infants with loving caregivers form a lifelong attitude of trust rather than of fear. 9 Many researchers believe that our early attachments form the foundation for our adult relationships and for our comfort levels with a▯ection and intimacy. Adult styles of romantic love tend to exhibit secure, trusting attachment; insecure, anxious attachment; or avoidance of attachment. These styles a▯ect relationships with children, as avoidant people ▯nd parenting stressful and unsatisfying. Deprivation of Attachment If secure attachments lead to social competence, the deprivation of love and nurturing can lead to withdrawn, frightened, and even speechless children. Extreme trauma also seems to have an e▯ect on the mind. CHanges in the brain chemical seratonin (which calms aggressive impulses) can be noted among such cases. Stress can set o▯ a ripple of hormonal changes that permanently wires a childs brain to cope with a malevolent world. Abuse victims are at considerable risk for depression if they carry a certain gene variation which spurs stress-hormone reduction. Once again, this is a case of a particular environment interacting with particular genes. Disruption of Attachment In studies of children seperated from their caregivers, initial di▯culty tends to quickly give way to detachment. This is a process which follows from seperation distress through sadness and emotional detachment to normality. Separation distress is often di▯cult for adults as well. Day care generally has no negative e▯ects on children; regardless of the care, children need a consistent and warm relationship with people whom they can learn to trust. Parenting Styles There exist three major parenting styles: ▯ Authoritarian parents impose rules and expect obedience. ▯ Permissive parents submit to their children’s desires: they make few demands and use litte punishment. ▯ Autoritative parents are both demanding and responsive. They exert control by setting and en- forcing rules, but they also explain the reasons behind those rules. They encourage open discussion when making rules and permitting exceptions. Children with the highest self-esteem, self-reliance, and social competence come from autoritative par- ents. Authoritarian parents lead to insecurity and low self-esteem and permissive parents lead to aggression and immaturity. Adolescence Developing occurs during the entirety of one’s life, not only during childhood. During adolescence, this starts with the beginnings of physical maturity and ends with the social acheivement of independant 10 adult status. Cognitive Development Developing Reasoning Power Reasoning is initially self-focused. Eventually, we reach the intellectual peak and become more capable of abstract reasoning. Adolescents reach the point of debating human nature, absolute truth, and justice. Developing Morality A crucial task during development is acheiving a sense of right and wrong. Much of our morality is gut- level, from which we rationalize out beliefs. Lawrence Kohlberg sought to describe the development of moral reasoning, the thinking that occurs as we consider right and wrong. He posed moral dilemmas to adults and children and recorded the results, thus determining that the following three morality schemas exist: ▯ Preconventional morality: before the age of nine, most children’s morality is centered around themselves; they obey rules to avoid punishment or to gain rewards. ▯ Conventional morality: by early adolescence, children begin to focus on caring for others and upholding laws simply because those laws exist. ▯ Postconventional morality: The third level of moral reasoning is one that some people never reach: actions are judged to be right because they follow either from people’s rights or from self-de▯ned, basic ethical principles. Social Development Each stage of development has its own psychosocial task, a crises which needs resolution. For young children, this is trust, autonomy, and initiative. Older children struggle with competence. Erikson’s Stages of Psychosocial Development 1. Infancy (0 to 1): Trust vs mistrust. Needs are dependably met, a basic sense of trust is developed. 2. Toddler (1 to 3): Autonomy vs shame and doubt. Learn to exercise their will, do things for themselves or doubt their abilities. 3. Preschool (3 to 6): Initiative bs guilt. Learn to begin tasks or feel guilty about e▯orts to be independant. 4. Elementary (6 to 12): Industry vs inferiority. Learn the pleasure of applying themselves to a task or feel inferior. 5. Adolescenxe (12 to 17): Identity vs role confusion. Re▯ne the sense of self, test roles and integrate them to form a single identity or become confused about who they are. 11 6. Young adult (17 to 25): Intimacy vs isolation. Struggle to form close relationships and gain the capacity for intimate love or feel socially isolated. 7. Middle adult (25 to 45): Generativity vs stagnation. Discover a sense of contributing to the world, usually through family and work, or feel that they lack purpose. 8. Late adult (45 to 70): Integrity vs despair. When re ecting on life, an older adult may feel a sense of success or failure. Forming an Identity TO re▯ne their sense of identity, adolescents distinguish themselves to create an identity. Social identity often forms from distinctiveness (only woman in a group, only ethnicity in a group, etc). Parent and Peer Relationships Today, delayed independance and earlier sexual maturity has widened the once brief interlude between biological maturity and social independence. FOr those still in school, the time from 18 to the mid- twenties is being increasingly referred to as emerging adulthood. Westerners typically ease their way into adulthood, returning to their parents while in school and depending on them ▯nancially. Neuropsychology Interacting with the Environment There are two requirements we have for interacting with our environment: personal and environ- mental. A process that involves bringing something inward is an a▯erent process. To detect the external world is not enough for survival, we need to be able to respond back to the environment e▯ec- tively depending on the demands of that world. Processes that are outward bound are called e▯erent processes. The Neuron A neuron is formed of the following substructures: ▯ Dendrites receive messages from other cells ▯ Axon passes message away from the cell body to other neurons, muscles, or glands. ▯ Terminal Branches of Axons form junctions with other cells. ▯ Myelin Sheath covers the axon of some neurons and helps to speed neural impulses. ▯ Cell Body is the cell’s life support center. The dendrite ▯bers receive information and conduct it toward the cell body. From there the cell’s axon passes the message to other neurons or to muscles or glands. Axons can be up to feet long within 12 the body. The myelin sheath insulates the axons of some neurons and help speed their impulses. Degeneration of the myelin sheath leads to multiple schlorosis. Neurons transmit messages when stimulated by signals from our senses or when triggered by chemical signals from neighbouring neurons. At such times, a neuron ▯res an impulse called the action potential: a brief electrical charge that travels down the axon. Neurons generate electricity from chemical events; this chemistry-to-electricity process involves the exchange of ions. The uid interior of a resting axon has an excess of negatively charged ions while the uid outside the axon membrane has positively charged ions. This positive-outside/negative-inside state is called the resting potential. An axon’s surface is selectively permeable. A resting axon has gates that block positive sodium ions. When opened, the membrane is ooded, which depolarizes that section of the axon and causes the next section to open. Each neuron is a decision making device performing complex calculations as it receives signals from other neurons. Most of these signals are excitatory, others are inhibitory. If excitatory minus inhibitory signals exceed a minimum intensity threshold, the combined signal trigger an action potential. There also exist multiple types of neurons, each of which with di▯erent functions: ▯ Sensory neurons carry messages in from the body’s sensory receptors to the CNS for processing. A▯erent direction from outside CNS to inside CNS. Quantity: 2-3 million. ▯ Motor neurons carry instructions OUT from the CNS to the body’s muscles and glands. E▯erent direction from inside CNS to outside. Qyantity: 2-3 million. ▯ Interneruons in brain/spinal cord process information between the sensory input and motor output. Within CNS Neuron to neuron. Quantity: 10-100 billion. How Neurons Communicate The meeting point between neurons is called a synapse. Axon terminal of one neuron is separated from the receiving neuron by a synaptic gap. When an action potential reaches the terminals at an axon’s end, it triggers the release of chemical messengers, called neurotransmitters. The neurotransmitter unlocks tiny channels at the receiving site, and electrically-charged atoms ows in, exciting or inhibiting the receiving neuron’s readiness to ▯re. Then in a process called reuptake, the sending neuron reabsorbs the excess neurotransmitters. Neuronal Connection Luigi Galvani was famous for work with electrocuting animals to discover the neural networks within their minds. Otto Loewi believed that it was a chemical which sent messages in the brain, whereas electrical impulses would arc and thus not be capable of such precision. It takes him 17 years before he comes up with his experiment (which came to him in a dream): two hearts in two beakers. He takes the liquid from the ▯rst and pours it over the second. The liquid alone caused the second heart to beat, therefore there must have been some chemical reaction: this was the ▯st neurotransmitter. 13 The Hodgkin-Huxley Model Hodgkin and Huxley presented modern "electro-chemical" theory in 1952, and received Nobel Prize in Physiology for their work. They presented the idea that there existed a chemical process between neurons and an electrical one within neurons. Neurotransmitters would accumulate on the dendrites as they pass. The dendrites check for the correct molecular structure to excite or inhibit. Agonist and Antagonist Molecule An agonist molecule ▯lls the receptor site and actives it, acting like the neurotransmitter. An an- tagonist molecule ▯lls the lock so that the neurotreansmitter cannot get in and activate the receptor site. The neurotransmitters can follow multiple potential paths after synaptic transmission: ▯ decomposed by certain enxymes ▯ taken back up into the sending neuron to be used again (reuptake) ▯ released then binded again and again (continuous binding) Neurotransmitters How Neurotransmitters In uence Us Acetylcholine is one of the best understood neurotransmitters. In addition to its role in learning and memory, it is the messenger at every junction between a motor neuron and skeletal muscle. Candace Pert and Solomon Snyder discovered that the brain creates natural occurring opiates. Endorphins help explain good feelings such as the runner’s high, the painkilling e▯ect of acupuncture, and the indi▯erence to pain in some severely injured people. Acetylcholine Involved in muscle action, learning, and memory.Deterioration of ACH neurons is implicated in Alzheimer’s disease. Dopamine In uence movement, learning, attention, and emotion. An oversupply is linked to schizophrenia; an undersupply to Parkinson’s Disease. Seratonin Infuences mood, hunger, sleep, and arousal. Undersupply linked to depression. 14 Epinephrine Norepinephrine In uence alertness, arousal, mood. Same chemical used in endocrine system (adrenaline and nora- drenaline). GABA A major inhibitory neurotransmitter. An undersupply is linked to seizures, tremors, and insomnia. Glutamate A major excitary neurotransmitter involved in memory. An oversupply can overstimulate that brain, producing migraines and seizures. Endorphins Known as nature’s painkiller, natural morphine. Also involved in various emotions in the limbic system. Foreign Chemicals When ooded with arti▯cial opiates, such as heroine and morphine, the brain stops producing its own. The brain then becomes deprived and uncomfortable. Drugs and other chemicals a▯ect brain chemistry at synapses, often by amplifying or blocking a neuro- transmitter’s activity. An agonist molecule can mimic the e▯ects of a neurotransmitter. Antagonists block a neurotransmitter’s functioning. Cocaine and amphetamines Stimulants that increase the release of norepinephrine and block reuptake of dopamine. Perceived as pleasurable and associated behaviours are reinforced. Opiates (opium, morphine, heroine, codeine) Agonists that mimic endorphins by attaching to their binding sites. Alcohol Generally depresses neural acticity throughout brain. 15 The Neurology of Addiction The brain maintains homeostasis. In other words, it increases or decreases the production of neuro- transmitters to compensate for the e▯ect of addictive substances. We thus need an increased dosage to experience the same e▯ect, once the brain learns how to compensate. The brain learns to anticipate consumption and makes pre-emptive adjustments: this leads to the potential for overdose. The Nervous System Our nervous system is the body’s electrochemical communication network. The brain and spinal cord form the central nervous system, which communicates with the body’s sense receptors, muscles and glands via the peripheral nervous system (PNS). The PNS information travels through axons that are bundled into electrical cables known as nerves. Information travels in the nervous system through sensory neurons, motor neurons, and interneurons. Peripheral Nervous System (PNS) Our peripheral nervous system has two main components: somatic and autonomic. Our somatic nervous system enables voluntary control of our skeletal muscles. Nervous System The nervous system has multiple aspects: 1. Peripheral (a) Autonomic (controls self-regulated actions of internal organs and glands) i. Sympathetic (arousing) ii. Parasympathetic (calming) (b) Somatic (controls voluntary movements of skeletal muscles) 2. Central (brain and spinal cord) Our autonomic nervous system controls our glands and the muscles of our internal organs, in uencing functions such as glandular activity, heartbeat, and digestion. The sympathetic nervous system arouses and expends energy. If something alarms, enrages, or challenges you, the sympathetic system will accelerate your heartbeat, raise your blood pressure, slow your digestion, etc. When stress subsides, your parasympathetic nervous system produces opposite e▯ects. It conserves energy as it calms you by decreasing heartbeat, lowering blood sugar, etc. 16 The Central Nervous System The spinal cord is an information highway connecting peripheral nervous systems to the brain. Ascend- ing neural ▯bers send up sensory information and descending ▯bers send back motor-control info. The neuropathways governing our re exes, our automatic responses to stimuli, illustrate the spinal cord’s work. The hand jerks away from hot surface before we feel pain because the pain re ex pathway runs through spinal cord to our nervouss ystem but takes longer to get to brain. Endocrine System Interconnected with the nervous system is endocrine system, the glands of which secrete hormones. Some hormones are chemically identical to neurotransmitters. While nervous system mesages move quickly, the endocrine system take several seconds or more. The messages linger, however, such as when a person is upset. In moments of danger, adrenal glands release epinephrine, norepinephrine (adrenaline), and nora- drenaline. These hormones increase heart rate, blood pressure, etc, providing us with a surge of energy. The most in uential endocrine gland is the pituitary gland. Controlled by the hypothalamus, this gland releases hormones that in uence growth and the release of hormones. It is the master gland which triggers sex glands to release sex hormones. The Brain’s Electrical Activity An electroencephalogram (EEG) is an ampli▯ed read-out of the electrical activity in the brain’s billions of neuron sweeps. It identi▯es the electrical wave evoked by a stimulus. Neuroimaging Techniques The PET (Positron Emission Tomography scan) depicts brain activity by showing each brain area’s consumption of sugar glucose. After consuming radioactive glucose, a PET tracks the glucose throughout the brain. This shows which areas of brain are most active as a person performs mathemat- ical calculations, looks at images of faces, or daydreams. An MRI (Magnetic Resonance Imaging system) puts the head in a strong magnetic ▯eld, aligning the spinning atoms of brain molecules. A radio wave disorients the atoms, and when they return to their normal spin, signals are released which outline the brain’s soft tissue. The Brainstem The brainstem is the brain’s oldest and innermost region. It begins where the spinal cord swells, called the medulla, and controls heartbeat and breathing. Just above the medulla is the pons, which helps to coordinate movement. 17 The brainstem is a crossover point where nerves from each side of the brain connect with the body’s opposite side. Inside the brainstem, between ears, is the reticular formation, a ▯nger-shaped network of neurons that extends from the spinal cord right up to the thalamus. The reticular formation is involved in arousal, incites a coma if severed, and produces alertness when stimulated. Thalamus The thalamus sits at top of brainstem and acts as brain’s sensory switchboard. Receives information from all senses except smell and routes it to the higher brain regions. Directs higher brain replies, sending them to medulla and cerebellum. Cerebellum The cerebellum (little brain) extends from the rear of the brainstem and enables one type of non- verbal learning and memory. Helps us judge time, modulate our emotions, discriminate sounds and textures. These functions all occur without conscious e▯ort, our brain processes most information outside of our body’s awareness. The Limbic System At the border between the brain’s older parts and the cerebral hemispheres is the limbic system. One limbic system is the hippocampus, which processes memory. The amygdala in uences aggression and fear. 0.1 The Hypothalamus The hypothalamus (below the thalamus) is an important link in the chain of command gov- erning bodily maintenance. Some clusters in uence hunger, others thirst, body temperature, sexual behaviour... The hypothalamus monitors blood chemistry and takes orders from other parts of the brain. For example, thinking about sex could cause hormones to be released, illustrating how the brain in uences the endocrine system, which in turn in uences the brain. Stimulating the hypothalamus of animals can trigger their reward system and thus release dopamine or speci▯c centers associated with eating, drinking, sex. Cerebral Cortex A thin surfance of interconnected neural cells, the cerebral cortex is the brain’s thinking crown, the ultimate control and information processing center. 18 The larger the cortex, the greater the capacity for learning and thinking, enabling them to be more adaptable. What makes us distinctively human mostly arises from complex functions of our cerebral cortex. Structure of the Cortex Supporting the billions of nerve cells in the cortex are nine times as many spidery glial cells, or glue cells. Glials work for neurons, providing nutrients and insulating myelin, mopping up ions and neurotransmitters. Einstein had more glial cells than the average person. Each hemisphere of the cortex is divided into four lobes, geographic regions separated by prominent ▯ssures. There are the frontal lobes, behind the forehead, parietal lobes, at the top and to the rear, and the occipital lobes, at the back. Just above ears, ▯nd temporal lobes. The arch-shaped region at the back of the frontal lobe, running from ear-to-ear across the top of the brain is the motor cortex. Body areas requiring precise control require greatest amount of cortical space. Sensory Functions The area at the front of the parietal lobes, parallel and just behind motor cortex, is called the sensory cortex. The more sensitive the body region, the larger the sensory cortex area devoted to it. We also have auditory cortex in temporal lobes, and visual cortex in occipital lobes. Association Areas Three quarters of the thin, wrinkled layer are a part of the association areas whose neurons integrate information. They link sensory inputs with stored memories. We don’t only use a tenth of our brains, rather these association areas interpret and act on info processed by the other areas. Association areas are found in all 4 lobes, enabling judgement, planning, and processing of new memories in the frontal lobes. With ruptured frontal lobes, we become less inhibited and more judgments seem unrestrained by normal emotions. The parietal lobes enable mathematical and spacial reasoning. An area on the underside of the right temporal lobe enables us to recognize faces. The Brain’s Plasticity Brains are sculpted by our experiences. Neurons do not usually regenerate when severed, rather they can reorganize in response to damage. Constraint-induced therapy forces the brain to rewire to use a bad limb when the good limb is made unavailable. 19 Damaged brain functions can migrate to other brain regions, as in the case of those who have lost one of their senses. If a blind person uses one ▯nger to read Braille, the brain area dedicated to that ▯nger expands as the sense of touch invades the visual cortex that normally helps people see. Adjacent regions in the brain, such as the arm and hand invade one another if one is lost. Touching an arm when a person has lost a hand may cause them to feel as though their hand has been touched as well. The arm area had invaded the space vacated by the hand. Neurogenesis is the process of generating new neurons. Natural promoters of neurogenesis include exercise, sleep, and non-stressful but stimulating environmnents. Our Divided Brain In 1960, it was believed that the left hemisphere was the dominant or major hemisphere and the right was subordinate or minor. In 1961, neurosurgeons speculated that epileptic seizures were caused by an ampli▯cation of abnormal brain activity bouncing back and forth between the two cerebral hemispheres. They tried to end this by severing the corpus callosum, the wide band of axon ▯bers connecting the hemispheres and carrying messages between them. After severed, people were surprisingly normal, operating ▯ne with these split brains. With a split brain, both hemispheres can comprehend and follow an instruction simultaneously. These studies revealed that the left hemisphere is more active when a person deliberates over decisions. The right hemisphere understands simple requests, easily perceives objects, and is more engaged when quick, intuitive responses are needed. The right side is skilled at perceiving emotion and portraying emotions through the more expressive left side. Right/Left Di▯erences in the Intact Brain Perceptual tasks increase glucose consumption in the right side. Speaking or calculating increases activity in the left side. If the left side is disabled, we lose control of right arm and speech. Sign language, like hearing using the left side to process speech, also uses left hemisphere for sign language. Language is the same to the brain, whether spoken or signed. While the left side is adept at making quick, literal interpretations of language, the right excels in making inferences. Gien the word foot, the left brain will quickly associate it with heel. But given foot, cry, glass, the right would more quickly associate it with cut. The right hemisphere also orchestrates the sense of self. After right brain damage, we have di▯culty perceiving who other people are in relation to oneself. People had di▯culty recognizing themselves in photos with the right brain disabled. 20 Brain Organization and Handedness Almost all right-handed people process speech primarily in the left hemisphere, which tends to be larger. Behaviour Genetics and Evolutionary Psychology Behaviour geneticists study our di▯erences and weigh the e▯ects and interplay of heredity and environment. Identical twins who develop from a single fertilized egg that splits in two are genetically identical. Fraternal twins develop from seperate fertilized eggs; they share a fetal environment but they are no more genetically similar than any two siblings. Biological vs Adoptive Relatives Adoption creates two groups: ▯ Genetic relatives are biological parents and siblings ▯ Environmental relatives are adoptive parents and siblings The ▯nding from studies of adoptive families show that people who grow up together, whether biologi- cally related or not, do not resemble one another much in personality. In traits such as extraversion and agreeableness, adoptees are more similar to their biological parents than to their caregiving adoptive parents. The environment shared by a family’s children has virtually no discernible impact on their personalities. Two adopted children are no more likely to share personalities with each other than with the children down the street. While genetics may limit the family’s environment’s in uence on personality, parents do in uence their children’s at
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