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Steve Joordens

PSYA01 REVIEW CHAPTER 1 - Psychology: the scientific study of mind and behavior o Mind: private inner experience, the ever-flowing stream of consciousness that is made of perceptions, thoughts, memories and feelings o Behavior: observable actions of human beings and non-human animals , the things we do in the world, by ourselves or with others o Extremely young and complex science o Psych start to exist in its earlier format the end of primal stage of science (1660s-1680s) - Functional magnetic resonance imaging (fMRI): allows scientists to scan a brain and see what parts are active when a person does an activity PSYCHOLOGY’S ROOTS - Psychology has 2 types of camps or “schools of thought” o Structuralists: tried to analyze the mind by breaking it down into its basic components o Functionalists: focus on how mental abilities allow people to adapt to their environment Psychology’s Ancestors - Plato and Aristotle, first to struggle with fundamental questions about how the mind works - Plato argued in favor of nativism o Nativism: certain kinds of knowledge are innate or inborn - Aristotle argued for physical empiricism o Physical empiricism: all knowledge is acquired through experience From the Brain to the Mind - Dualism: how mental activity can be reconciled and coordinated with physical behaviour o In other words, there is a physical body, but it is controlled by the soul. Machine controlled by soul o Proposed by Rene Descartes o Suggested that mind influences the body through the pineal gland.  Pineal gland: tiny structure near the bottom of the brain - John Locke o Pushed Descartes idea further and said that even the mind is a machine o Tabla Rasa: born as blank slates and became who we are due to experiences we had o Empiricism: belief that accurate that accurate knowledge can be acquired through observation  Test ideas & make predictions  What makes science a science - James Mill o Materialism: notion that we do not have a soul  everything is made up of material matter that follows material laws  we are all material people living in a material world - Luigi Galvani o Made frog legs jump using electricity o Changed from us being hydraulic to having currents o From empiricism point of view, more proof that humans are like machines - Johannes Muller o When cutting bodies, realized that we had nerve fibers that deliver electrical signals to muscles, organs, etc. o Suggested that things like the brain where modular (like machines) o Doctrine of Specific Nerve Energies - Thomas Hobbes o Argued that the mind and the body are not different things at all, rather the mind is what the brain does - Franz Joseph Gall o Phrenology: specific mental abilities and characteristics, ranging from memory to the capacity of happiness, are localized in specific regions of the brain - Pierre Flourens o Removed specific parts of the brains of animals; proved Galls idea that specific parts of the brain have specific functions. Further suggesting that the brain was a machine o Ablation Studies - Paul Broca o Realized that certain patients had the same behaviour (could understand/obey him, but could not produce speech that had any meaning) o After their deaths, removed brains & found that a specific part of their brains damaged o Localization of language Structuralism - Physiology: study of biological processes, especially in the human body - Hermann von Helmholtz – measures the speed of responses or neural impulses o Stimulus: sensory input from the environment o Reaction time: amount of time taken to respond to a certain stimulus - Wilhelm Wundt – development of structuralism o Believed that psychology should focus in analyzing consciousness  Consciousness: person’s subjective experience of the world and the mind o Structuralism: the analysis of the basic elements that constitute the mind  This involved breaking consciousness down into elemental sensations & feelings o Wundt tried to analyze consciousness by using introspection  Introspection: subjective observation of one’s own experience Titchener Brings Structuralism to the United States - Edward Titchener o Brought some parts of Wundt approach to America, but with some changes - Wundt focused on relationship between elements and consciousness, Titchener focused on identifying the basic elements themselves James and the Functional Approach - Functionalism: study of the purpose mental processes serve in enabling people to adapt to their environment – it sets out to understand the functions of the mental processes - James ideas where inspired by the ideas of Charles Darwin (like natural selection) o Natural Selection: features of an organism that help it survive and reproduce are more likely than other features to be passed on to a subsequent generation THE DEVELOPMENT OF CLINICAL PSYCHOLOGY The Path to Freud and Psychoanalytic Theory - Hysteria: temporary loss of cognitive functions, usually as a result of emotionally upsetting experiences. Patients became blind, paralyzed or loss their memory even though there was no physical cause of their problem o Wundt, Titchener and other laboratory scientist did not consider them as proper subjects of scientific studies - Sigmund Freud o Unconscious: part of the mind that operates out of conscious awareness, but influences conscious thoughts, feelings & actions. This idea let him develop psychoanalytic theory o Psychoanalytic theory: approach that emphasize the importance of unconscious mental processes in shaping feelings, thoughts and behaviours.  Served for a therapy Freud called psychoanalysis  Psychoanalysis: bringing unconscious material into conscious awareness o Both James and Freud believed that mental aberrations provide important clues into the nature of mind. o Popularized the notion of psychological disease, and linked them mostly to psychological conflict … the medical model o Invented psychoanalysis, promoted cocaine, spoke a lot about sexual and aggressive urges, popularized his notion of psychology, and drove (and still does) scientists nuts! Influence of Psychoanalysis and the Humanistic Response - Abraham Maslow and Carl Rogers pioneered a new movement called humanistic approach o Humanistic approach: approach to understand human nature that emphasize the positive potential of human beings o Focus on higher aspirations people have for themselves. Rather than viewing people as prisoners of events in their remote pasts, humanistic psychologists viewed people as free agents who have an inherent need to develop, grow, and attain their full potential o Sought to help people realize their full potential o Because of this, Freud’s ideas eventually became less influential THE SEARCH FOR OBJECTIVE MEASUREMENT - Behaviourism: study of objectively observable behaviour Watson and the Emergence of Behaviorism - Watson proposed that psychologists should focus on what people do, rather on what people experience, because behaviour can be observed by anyone and can be measured objectively o Influence by work of Ivan Pavlov - Ivan Pavlov o Carried research on the physiology of digestion o Response: action or psychological change elicited by a stimulus - Behaviourism is called “stimulus-response” or “S-R” psychology B. F. Skinner and the Development of Behaviorism - Reinforcement: consequences of a behaviour that determine whether it will be more likely or not to occur again RETURN OF THE MIND The Emergence of Cognitive Psychology - Illusions: errors of perception, memory or judgement where subjective experience differ from objective reality - Max Wertheimer – German psychologist who developed the Gestalt psychology o Gestalt psychology: psychology approach that emphasize that we often perceive the whole rather than the sum of the parts - Frederic Bartlett – British psychologist interested in memory o Memory is not a photographic reproduction of past exp & that our attempts to recall the past are influenced by our knowledge, beliefs, hopes, aspirations, & desires. - Emergence of computers led to re-emergence of interest in mental processes all across the discipline of psychology, it let to the creation of cognitive psychology o Cognitive psychology: scientific study of mental processes, including perception, thought, memory and reasoning The Brain Meets the Mind - Behavioural neuroscience: links psychological processes to activities in the nervous system and other bodily processes, also once called physiological Psychology - Cognitive neuroscience: field that attempts to understand the links between cognitive processes and brain activity The Adaptive Mind - Evolutionary psychology: explain mind and behaviour in terms of adaptive value of abilities that are preserved over time by natural selection o It thinks of the mind as a collection of specialized “modules” that are designed to solve the human problems our ancestors faced as they attempted to eat, mate, & reproduce BEYOND THE INDIVIDUAL The Development of Social Psychology - Social psychology: study of the causes and consequences of interpersonal behaviour o Tries to study bigger social issues The Emergence of Cultural Psychology - Cultural psychology: study of how cultures reflect and shape the psychological processes of their members o Study a wide range of phenomena, ranging from visual perception to social interaction, they seek to understand which of these phenomena are universal and which vary from place to place and time to time - Absolutism: holds that culture makes little or no difference for most psychological phenomena - Relativism: holds that psychological phenomena are likely to vary considerably across cultures and should be viewed only in the context of a specific culture CHAPTER 2 EMPIRICISM: How to Know Stuff - Dogmatism: tendency for people to cling to their assumptions and the world - Empiricism: belief that accurate that accurate knowledge can be acquired through observation The Scientific Method - Scientific method: set of principles about the appropriate relationship between ideas and evidence – essential element of Empiricism - Theory: hypothetical explication of a natural phenomenon - Rule of parsimony: the principle that entities should not be multiplied needlessly; the simplest of two competing theories is to be preferred - Hypothesis: falsifiable prediction made by a theory The Art of Looking - Empirical method: set of rules and techniques for observation - Method: refers primarily to technologies that enhance the power of the senses - 3 things make people difficult to study o Complexity: people are complex o Variability: people are as varied as their fingerprints o Reactivity: people often think, feel, and act one way when observed and a different way when not. OBSERVATION: Discovering What People Do - To observe means to use one’s senses to learn about the properties of an event Measurement - Defining and detecting o Operational definition: description of a property in concrete, measurable terms o Measure: device that can detect the conditions to which an operation definition refers o Electromyography (EMG): device that measures muscle contractions under the surface of a person’s skin - Validity, reliability and power o good measures have 3 properties: o Validity: extent to which a measurement and a property are conceptually related o Reliability: tendency for a measure to detect the concrete conditions specified in the operational definition o Power: the ability of a measurement to detect the concrete conditions specified in the operational definition - Demand characteristics o Demand characteristics: those aspects of an observational setting that cause people to behave as they think they should  Makes it hard to measure behaviour as it normally unfolds o Naturalistic observation: technique for gathering info by unobtrusively observing people in their natural environment  It is not always a viable solution to the problem of demand characteristics - Observer bias o Expectations can influence observations o Expectations can influence reality o To avoid these influences, psychologists use double bind observation o Double bind observation: an observation whose true purpose is hidden from both the observer and the person being observed Descriptions - Graphic representations o Frequency distribution: graphic representation of measurement arranged by the number of times each measurement was made o Normal distribution: also known as Gaussian distribution, mathematically defined frequency distribution in which most measurements are concentrated around middle - Descriptive statistics o Descriptive statistics: brief summary statements that capture the essential info from a frequency distribution. 2 important kinds of descriptive statistics  Central tendency of a frequency distribution: statements of the value of the measurements that tend to lie near the center or midpoint of frequency distributions. 3 most common descriptions of central tendency:  Mode: value of the most frequently observed measurement  Mean: average value of all the measurements  Median: the value that is “in the middle” – i.e. >= half the measurements and <= half of the measurements  Variability of a frequency distribution: statements about the extent to which measurements differ from each other  Simplest description of variability is range  Range: value of largest measurement in frequency distribution minus the value of the smallest measurement  Standard deviation: statistic that describes the average difference between measurements in a frequency distribution and the mean of that distribution EXPLANATION: Discovering Why People Do What They Do Correlation - Patterns of variation o Measurements can only tell us about properties of objects and events, but we can learn about the relationships between objects and events by comparing the patterns of variation in a series of measurements o Variables: properties whose values can vary across individuals over time o Correlation: or pattern of covariation, when variations in the value of one variable are synchronized with variations in the value of the other  Every correlation can be described in two equally reasonable ways:  A positive correlation describes a relationship between two variables in “more-more” or “less-less” terms  A negative correlation describes a relationship between two variables in “more-less” or “less-more” terms. - Measuring correlation o Correlation coefficients: measure of the direction and strength of a correlation, symbolized by the letter r  Value of r can range from -1 to 1, # outside this range are meaningless  Perfect positive correlation: If every time the value of one variable increases by a fixed amount the value of the second variable also increases by a fixed amount, r = 1  Perfect negative correlation: If every time the value of 1 variable increases by a fixed amount, value of the second variable decreases by a fixed amount, r = -1  Uncorrelated: If every time the value of one variable increases by a fixed amount the value of the second variable does not increase or decrease systematically, r = 0 Causation - The third variable problem o Natural correlations: correlations we observe in the world around us o Third variable correlation: two variables are correlated only because each is casually related to a third variable  Match sample technique: technique whereby the participants in two groups are identical in terms of a third variable  Matched pair technique: technique whereby each participants is identical to one other participant in terms of a third variable o Third variable problem: causal relationship between 2 variables cannot be inferred from the naturally occurring correlation between them because of the ever-present possibility of third-variable correlation – we cannot conduct infinite studies - Experimentation o Experiment: technique for establishing the casual relationship between variables o Best ways to understand how experiments eliminate the countless differences between groups is by examining 2 key features: manipulation and random assignment - Manipulation o Manipulation: creation of an artificial pattern of variation in a variable in order to determine its causal powers o Doing an experiment involves 3 critical steps:  First, perform manipulation  Independent variable: variable that is manipulated  When we manipulate an independent variable, 2 groups of participants are created: o Experimental group: group of people who are treated in a particular way o Control group: group of people who are not treated in this particular way  Second, after manipulating one variable, we measure the other variable  Dependent variable: variable whose value “depends” on what the person being measured says or does  Third, check to see if manipulation produces changes in variables we measured - Random assignment o Self-selection: problem that occurs when anything about a person determines whether he/she will be included in the experimental or control group o Random assignment: procedure that uses random event to assign people to experimental or control group - Significance o Statistically significant: when the odds that random assignment failed are less than 5% o Inferential statistics: tells scientists what kinds of conclusions or inferences they can draw from observed differences between the experimental and control group Drawing Conclusions - Internal validity: characteristic of an experiment that establishes the causal relationship between variables - Representative variables o External validity: property of an experiment in which variables have been operationally defined in normal, typical or realistic way  Most psychology experiments are externally invalid, they don’t attempt to mimic the real world, but to test hypotheses derived from theories - Representative people o Population: complete collection of people o Sample: partial collection of people drawn from a population o Case method: method of gathering scientific knowledge by studying a single individual o Random sampling: technique for choosing participants that ensures that every member of a population has an equal chance of being included in the sample THE ETHICS OF SCIENCE: First, Do No Harm Respecting People - Few of the most important rules that govern the conduct of psychological research: o Informed consent: written agreement to participate in a study made by an adult who has been informed of all the risks that participation may entail o Freedom of coercion o Protection from harm o Risk-benefit analysis o Deception o Debriefing: verbal description of the true nature of a study o Confidentiality CHAPTER 3 NEURONS: The Origin of Behavior - Neurons: cells in the nervous system that communicate with one another to perform information-processing tasks Components of the Neuron - Cell bodies: largest components of the neurons that coordinates the information-processing tasks and keeps the cell alive – also called the soma o Functions such as protein synthesis, energy production and metabolism take place here o Cell body contains nucleus (structure that houses chromosomes that contain DNA) - Dendrites: receive information from other neurons and relay it to the cell body - Axon: transmits information to other neurons, muscles or glands. o In many neurons, the axon is covered by a myelin sheath o Myelin sheath: insular layer of fatty material  This myelin sheath is composed of glial cells  Glial cells: supports cells found in the nervous system o Axons covered in myelin sheath can more efficiently transmit signals to other neurons o Synapse: the junction or region between the axon of a neuron and the dendrites or cell body of another o Demyelinating disease: disease like sclerosis deteriorates the myelin sheath, slowing the transmission of info from one neuron to another. Leads to a variety of problems Major Types of Neurons - Sensory neurons: receives info from outside & conveys this info to the brain via the spinal cord o Have specialized endings on their dendrites that receive signals for light, touch, sound, taste and smell - Motor neurons: carry signals from the spinal cord to the muscles to produce movement o These neurons have long axons that can stretch to muscles at our extremities - Interneurons: connect sensory neurons, motor neurons or other interneurons o Most of the nervous system is composed of this kind of neuron o Some interneurons carry info from nervous system to motor neurons, and still others perform a variety of information-processing functions within the nervous system Neurons Specialized by Location Neurons are differentiated according to the functions they perform. The three major types of neurons - Purkinje cells: type of interneuron, carry info from cerebellum to rest of the brain & spinal cord o Have dense, elaborate dendrites that resembles bushes - Pyramid cells: found in the cerebral cortex, have a triangular cell body and a single, long dendrite among many smaller dendrites - Bipolar cells: type of sensory neuron found in the retinas of the eyes, have a single axon and a single dendrite THE ELECTROCHEMICAL ACTIONS OF NEURONS: Information Processing - The communication of information within and between neurons proceeds in two stages o Conduction: conduction of an electric signal over relatively long distances within neurons, from the dendrites, to the cell body, then throughout the axon o Transmission: transmission of electric signals between neurons over the synapse - These stages are what scientists generally refer to as the electrochemical action of neurons Electric Signaling - Resting potential: difference in electric charge between the inside and outside of a neuron’s cell membrane + + o K molecules flow freely across the membrane, but Na molecules are kept out o Resting potential is negative, inside of the neuron has a charge of about -70milivolts - Action potential: electric signal that is conducted along the length of a neuron’s axon to synapse o Action potential occurs only when the electric shocks reach one level, or threshold + + o Electric stimulation of the neuron shuts down the K channels and opens the Na channels, allowing Na to rush in and increase the positive charge inside the axon relative to outside - Refractory period: time following an action potential during which a new action potential cannot be initiated o After action potential reaches its maximum, the membrane channels return to their original state, and K returns to its resting potential. + + o Leave a lot of Na ions inside the axon, and a lot of K ions outside the axon o During this period when the ions are imbalanced, the neuron cannot init other Act Pot + + o Imbalance in ions is eventually inversed by chemical pump that move Na outside and K inside the axon - Myelin Sheath facilitates transmission of the action potential. o Nodes of Ranvier: little break points between the myelin sheath o When an electric current passes down the length of myelinated axon, the charge jumps from node to node rather than having to traverse the entire axon.  This process is called salutatory conduction, it helps speed the flow of info down the axon Chemical Signaling - Axons usually end in terminal buttons or bags that contain neurotransmitters. o Terminal buttons: knoblike structures that branch out from an axon o Neurotransmitters: chemicals that transmits info across the synapse to a receiving neuron’s dendrites - The dendrites of the receiving neuron contains receptors o Receptors: parts of the cell membrane that receive neurotransmitters and either initiate or prevent a new electrical signal + + - As K and Na flow across a cell membrane, they move a presynaptic neuron (sending neuron), from a resting potential to an action potential. o The action potential travels down the axon to the terminal buttons, it stimulates the release of neurotransmitters from vesicles into the synapse. o These neurotransmitters float across the synapse and bind to receptor sites on a nearby dendrite of the postsynaptic neuron (receiving neuron).  Neurotransmitters will bind with specific receptors sites on the dendrites o New electric potential is initiated in that neuron and process continues down that neuron’s axon to the next synapse and the next neuron. This electrochemical action is:  Synaptic transmission: it allows neurons to communicate with one another and ultimately underlies your thoughts, emotions, and behavior. o Neurotransmitters leave the synapse through 3 methods after the chemical message is relayed to the postsynaptic neuron  Reuptake: occurs when neurotransmitters are reabsorbed by terminal buttons  Enzyme deactivation: neurotransmitters are destroyed by enzymes in synapse  Autoreceptors: neurotransmitters bind to receptor sites on presynaptic neuron Types and Functions of Neurotransmitters - Different types of neurotransmitters can activate different kinds of receptors, like lock and key. - Acetylcholine (ACh): neurotransmitter involved in# of funct including voluntary motor control o Found in neurons of the brain & in synapses where axons connect to muscles & organs o Activates muscles to initiate motor behaviour, but it also contributes to regulation of attention, learning, sleeping, dreaming and memory o Alzheimer is a disease involved with severe memory impairments, is associated with the deterioration of ACh-producing neurons - Dopamine: neurotransmitter that regulates motor behaviour, motivation, pleasure, and emotional arousal o Because of its role in basic motivated behaviour, such as seeking pleasure or associating actions with rewards, it plays a role in drug addiction o High levels of dopamine linked to schizophrenia while low level linked to Parkinson - Glutamate: major excitatory neurotransmitter involved in info transmission throughout brain o It enhances the transmission of info o Too much can overstimulate the brain, causing seizures o GABA (gamma-amynobutyric acid): primary inhibitory neurotransmitter in the brain  They stop the firing of neurons, also contributes to the function of the organism  Too little GABA, like too much glutamate can cause neurons to be overactive - Norepinephrine: neurotransmitter that influences mood and arousal o Involved in states of vigilance or heightened awareness of danger in the environment o Serotonin: involved in regulation of sleep & wakefulness, eating, & aggressive behaviour  Serotonin elevates mood o Since both affect mood and arousal, low levels of each are implicated in mood disorders - Endorphins: chemicals that act within the pain pathway and emotion centers in the brain o Contradiction of endogenous morphine, o Morphine: synthetic drug that has a calming and pleasurable effect o Endorphin is an internally produced substance that has similar properties to morphine, like dulling the experience of pain and elevating moods - Imbalance (too much or too little of one neurotransmitter) can affect behaviour How Drugs Mimic Neurotransmitters - Agonists: drugs that increase the action of a neurotransmitter - Antagonist: drugs that block the function of neurotransmitter - Methamphetamine – affect pathway for dopamine, serotonin, and norepinephrine at neuron’s synapses, making it hard to interpret how it works - Amphetamine – popular drug that stimulates the release of norepinephrine and dopamine o Both amphetamine and cocaine prevent the reuptake of norepinephrine and dopamine  Combination of processes results in the increase activation of their receptors o Both are agonists o Increase in either norepinephrine and dopamine results in euphoria, wakefulness and a burst of energy – norepinephrine also increases heart rate o Overdose of amphetamine and cocaine can cause fainting and sometimes death - Prozac: drug commonly used to treat depression. o Another example of agonists o Blocks the reuptake of serotonin, making it part of a category of drugs called serotonin reuptake inhibitors or SSRI o By blocking reuptake, more of the neurotransmitter remains in the synapse longer and produces greater activation of serotonin receptors. Serotonin elevates mood THE ORGANIZATION OF THE NERVOUS SYSTEM - Nervous system: interactive network of neurons that convey electrochemical info to the body Divisions of the Nervous System - Central nervous system (CNS): composed of the brain and spinal cord o CNS receives info from the outside world, processes and coordinates info, and sends commands to the skeletal and muscular systems for action - Peripheral nervous system (PNS): connects the central nervous system to the organs & muscles. It is divided into 2 major subdivisions: o Somatic nervous system: set of nerves that convey info into and out of the CNS  People are conscious about this system and use it to perceive, think and coordinate behaviour o Autonomic nervous system (ANS): set of nerves that carry involuntary and automatic commands that control blood vessels, body organs, and glands. 2 major subdivisions:  Sympathetic nervous system: set of nerves that prepares the body for action in threatening situations  Parasympathetic nervous system: helps body to return to normal resting state Components of the Central Nervous System - Spinal cord can do some basic behaviors such as spinal reflexes without input from the brain - Spinal reflexes: simple pathways in nervous system that rapidly generate muscle contractions - More elaborated movement may require collaboration between the brain and the spinal cord STRUCTURE OF THE BRAIN The Hindbrain - Lower part of the brain - Hindbrain: area of the brain that coordinates info coming into and out of the spinal cord There are 3 anatomical structures that make up the Hindbrain: o Medulla: extension of the spinal cord into the skull that coordinates heart rate, circulation and respiration. Inside the medulla, there is a cluster of neurons called reticular formation  Reticular formation: regulates sleep, wakefulness, and levels of arousal o Cerebellum: large structure of the hindbrain that controls fine motor skills o Pons: structure that relates info from the cerebellum to the rest of the brain The Midbrain - It is relatively small, but it is a central location for neurotransmitters involved in arousal, mood, and motivation and the brain structures that rely on them - Sits on top of the hindbrain, and contains 2 main structures: o Tectum: orients an organism in the environment o Tegmentum: involved with movement and arousal The Forebrain - Forebrain: highest level of the brain, controls complex cognitive, emotional, sensory, and motor functions. Divided into 2 main sections: o Cerebral cortex: outermost layer of the brain, visible into the naked eye and divided into 2 hemispheres o Subcortical structures: areas of the forebrain housed under the cerebral cortex near the very center of the brain. Thalamus, hypothalamus, and pituitary gland are located in the center of the brain, interact with other brain structures. Relay & regulate signals to & from these structures  Thalamus: relays & filters info from senses & transmit them to cerebral cortex  Receives inputs from all major senses except smell  Blocks the pathway of incoming sensations during sleep, has function of not allowing info to pass to the rest of the brain  Hypothalamus: regulates body temperature, hunger, thirst, and sexual behavior  Located below the thalamus, plays important role in food intake and triggers the release of hormones for sex  Pituitary gland: “master gland” of the body’s hormone producing system, releases hormones that direct the functions of many other glands in the body - SUBCORTICAL STRUCTURES  Limbic system: group of forebrain structures, including the hypothalamus, the amygdala, and the hippocampus, involved in motivation, emotion, learning and memory. o It is where the subcortical structures meet the cerebral cortex o Hippocampus: critical on creating new memories and integrating them into a network of knowledge so that they can be stored indefinitely in other parts of the cerebral cortex  People with damage in this can store new memories for a few sec, but as soon as they are distracted they forget them o Amygdala: located at the tip of each horn of the hippocampus, plays a central role in many emotional processes, particularly the formation of emotional memories  Attaches significance to events associated with fear, punishment or reward  Basal ganglia: set of subcortical structures that directs intentional movements o Located near the thalamus and the hypothalamus, receives input from cerebral cortex and sends output to the motor centers in the brain stem o Striatum: part of basal ganglia, involved in the control of posture and movement - CEREBRAL CORTEX o Gyri: Smooth surfaces of the cerebral cortex (ind. gyrus) o Sulci: indentations or fissures in the cerebral cortex (ind. sulcus)  Functions of the cerebral cortex can be understood in 3 levels: o Organization across hemispheres: Separation of cortex into 2 hemispheres (left-right)  Contralateral control: each hemisphere controls functions and perceives stimuli from opposite side of the body  Commissures: bundles of axons that make possible the communication between parallel areas of the cortex in each half. Largest is corpus callosum  Corpus callosum: connect large areas of the cerebral cortex on each side of the brain & supports commu of information across hemispheres o Organization within hemispheres: Functions of each hemisphere.  Each hemisphere is divided into 4 areas or lobes, from back to front they are:  Occipital lobe: process visual information. Located at the back of the cortex  Damage to the primary visual areas of occipital lobe can cause partial or complete blindness  Parietal lobe: process information about touch. Located in front of occipital lobe  Contains somatosensory cortex (strip of brain tissue running from the top to the sides of the brain). Different parts of the somatosensory cortex corresponds to different parts of the body  Temporal lobe: responsible for hearing and language, located on the lower side of each hemisphere  Primary auditory cortex is analogous to the somatosensory cortex  It receives info from the ears based on the frequencies of the sounds  Second areas process info into meaningful units such as speech & words  Frontal lobe: has specialized areas for movement, abstract thinking, planning, memory, and judgement. Located behind the forehead  Contains the motor cortex (parallel strip of brain tissue) which is in front of somatosensory cortex. Same as somatosensory cortex, different parts correspond to different parts of the body. o It initiates voluntary movement and sends messages to the basal ganglia, cerebellum and spinal cord o Organization within specific lobes: Role of specific cortical areas  Association areas: composed of neurons that help provide sense and meaning to info registered in the cortex Brain Plasticity - Plasticity: ability that the sensory cortex has to adapt to changes in sensory inputs o Functions that where assigned to certain areas of the brain may be capable of being reassigned to other areas of the brain to accommodate changing input of the enviromnt o Neurons can be shaped by exp and the environment, making the human brain plastic. THE DEVELOPMENT AND EVOLUTION OF NERVOUS SYSTEMS Prenatal Development of the Central Nervous System rd - Nervous system begins to forms after the 3 week after fertilization - Ontogeny of the brain – how it develops within a given individual - Phylogeny of the brain – how it developed within a particular species Genes and the Environment - WHAT ARE GENES?  Genes: unit of hereditary transmission. Sections on a strand of DNA organized into larger threads called Chromosomes  Chromosomes: strands of DNA wound around each other in double helix configuration o Comes in pairs and humans have 23 of each o Chromosomes that determine sex are X and Y chromosomes, Female XX Male XY  Degree of relatedness: probability of sharing genes o Monozygotic twins: (identical twins) most genetically related people share 100% of their genes o Dizygotic twins: (fraternal twins) share 50% of the genes, same as 2 siblings born separately - ROLE OF ENVIRONMENTAL FACTORS  Heritability: measure of the variability of behavioural traits among individuals that can be accounted for by genetic factors  Bboth genes and the environment work together to influence behavior. Genes set the range of variation in populations within a given environment, but they do not predict individual characteristics; experience and other environmental factors play a crucial role as well. INVESTIGATING THE BRAIN Learning about Brain Organization by Studying the Damaged Brain - Split brain procedure: surgical severing of the corpus callosum, to alleviate severity of seisures o This helps patients with epilepsy, but it also produces unusual or unpredictable behavior Listening to the Brain - Electroencephalograph (EEG): device used to record electrical activity in the brain Brain Imaging - Structural brain imaging: provides info about the basic structure of the brain and allows clinicians and researchers to view abnormalities in brain structure o Computer axial tomography (CT) Scan: scanner rotates a device around a person’s head and takes a series of X-rays photographs from different angles  one of the first neuroimaging techniques o Magnetic resonance (MRI): involves applying brief but powerful magnetic pulses to the brain and recording how these pulses are absorbed throughout the brain - Functional brain imaging: provides info about the activity of the brain where people perform various kinds of cognitive motor skills o Positron emission topography (PET): harmless radioactive substance is injected into a person’s bloodstream. The brain is then scanned by radiation detectors as the person performs perceptual cognitive tasks, such as speaking or reading o Functional magnetic resonance imaging (fMRI): detects the twisting of hemoglobin molecules in blood when they are exposed to magnetic pulses. Mapping the activity of the brain.  Both fMRI and PET allow to localize changes in the brain  fMRI is better than PET since: 1. Does not require exposure to any radioactive substance 2. Can localize changes in brain activity across briefer periods than PET, + useful when analyzing psychological process that occur extremely quick CHAPTER 4 SENSATION AND PERCEPTION - Synesthesia: perceptual experience of one sense that is evoked by another sense OUR SENSES ENCODE THE INFORMATION OUR BRAINS PERCEIVE - Sensation: simple stimulation of a sense or organ o Basic registration of light, sound, odour, pressure or taste as parts of body interact with the physical world - Perception: organization, identification and interpretation of a sensation in order to form a mental representation - Transduction: occurs when many sensors in the body convert physical signals from the environment into encoded neural signals sent to the central nervous system o Senses all depend on the process of transduction Psychophysics - German psychologist Gustav Fechner developed an approach to measure sensation and perception called psychophysics - Psychophysics: methods that measure the strength of a stimulus and the observer’s sensitivity to that stimulus Measuring Thresholds - Transition from not sensing to sensing is gradual - Psychophysics measures absolute threshold and Just Noticeable Difference (JND) - Absolute threshold: minimal intensity needed to just barely detect a stimulus o Threshold is a boundary o Useful in assessing how sensitive we are to faint stimuli, but most everyday perception involves detecting differences among stimuli that are well above the Absolute threshold - Just noticeable difference (JND): minimal change in a stimulus that can just barely be detected o Fechner proposed JND as a way to measure this difference threshold o JND is not a fixed quantity, it depends on how intense the stimuli is and on the sense being measured - Weber’s law: JND of a stimulus is a constant proportion despite variations in intensity Signal Detection - Signal detection theory: response for a stimuli depends both on the person’s sensitivity to the stimulus in the presence of noise and on a person’s decision criterion  If there is a stimulus and the person answers yes correctly, it is a hit  If there is a stimulus and the person answers no, it is a miss  If there is no stimulus and the person answers that there is, it is a false alarm  If there is no stimulus and the person answers no, it is a correct rejection o Approached that was used before absolute threshold was developed o Allows researchers to distinguish (or measure) between an observer’s perceptual sensitivity to a stimulus and criteria for making decisions about the stimulus o Perceptual sensitivity: how effective the perceptual system represents sensory events Sensory Adaptation - Sensory adaptation: sensitivity to prolonged stimulation tends to decline over time as an organism adapts to the current conditions o It responds more strongly to changes in stimulation, than to continuous stimulation o It occurs because sensitivity to lengthy stimulation tends to decline over time VISION I: How the Eyes and the Brain Convert Light Waves to Neural Signals - Visual acuity: ability to see fine detail o Smallest line in the Snellen chart (eye exam thingy), measures Visual Acuity at 20 feet Sensing Light - Light can be seen as waves of energy. There are 3 properties of light waves: o Length: hue or what we perceive as color o Intensity or amplitude: brightness o Purity: saturation or richness of color - HUMAN EYE  Cornea: smooth transparent outer tissue. Bends light and sends it through the pupil  Pupil: hole in the colored part of the eye  Iris: colored part, doughnut shaped muscle that controls the size of the pupil, and the amount of light that passes through it  Muscles inside the eye control the shape of the lens to bend the light again and focus it onto the retina  Retina: light sensitive tissue lining in the back of the eyeball. Images appear inverted  Accommodation: process by which the human eye maintains a clear image on the retina o Nearsightedness (myopia): eyeball too long, images focused in front of retina o Farsightedness (hyperopia): eyeball too short, images focused behind the retina - PHOTOTRASDUCTION IN THE RETINA  Photoreceptor cells form the innermost layer of the retina. 2 types of photoreceptor cells in the retina contain light-sensitive pigments that transduce light into neural impulses: o Cones: detect color, operate under normal daylight conditions, and allows to focus on fine detail  Each retina contain around 6 million cones, densely packed on fovea and sparsely distributed in the rest of the eye o Rods: become active under low-light conditions for night vision  More sensitive photoreceptors than cones  They don’t provide info about any colour and sense only shades of gray  Around 120 million of rods are distributed evenly in each retina except in fovea o Fovea: area of the retina where vision is the clearest and there are no rods at all  Absence of rods in it decrease the sharpness of vision in reduced light  Middle layer contains: o Bipolar cells: collect neural signals from the rods and cones and transmit them to the outermost layer of the retina o Retina ganglion cells (RGC): organize the signals and send them to the brain  Bundle of RGC axons (about 1.5 million per eye) form the optic nerve which leaves the eye through a hole in the retina  This hole in the retina creates a blind spot  Blind spot: location in the visual field that produces no sensation on the retina - RECEPTIVE FIELDS: region of the sensory surface that, when stimulated, causes a change in the firing rate of that neuron  Most receptive fields contain either a central excitatory zone surrounded by a doughnut shaped inhibitory zone, which is called an on-center cell, or a central inhibitory zone surrounded by an excitatory zone, which is called an off-center cell o Light that reaches on-center cell elicits a strong response o Light that reaches off-center cells elicit a weak or no response Perceiving Color - SEEING COLOR  Visible spectrum: rainbow of hues and accompanying wavelengths  Cones contain one of 3 pigments, red (long-wavelength), green (medium-wavelength), and blue (short-wavelength)  Additive color mixing: increasing light to create color  Subtractive color mixing: removing light from the mix to create darker colors o Black surfaces reflect no light - TRICHROMATIC COLOR REPRESENTATION IN THE CONES  There are 3 cone types: Short wavelength (blue) or S-Cones, Medium wavelength (green) or M-Cones, and Long wavelength (red) or L-Cones  Trichromatic color representation: pattern of responding across the three types of cones provides a unique code for each color  Color deficiency: genetic disorder in which 1, 2 or 3 of the cones are missing o It is often referred as color blindness, affects + men than women - COLOR-OPPONENT REPRESENTATION INTO THE BRAIN  Staring too long at one color fatigues the cones that respond to that color, producing a form of sensory adaptation that is called Color afterimage  Color opponent system: pairs of visual neurons work in opposition o Red-sensitive cells against green-sensitive cells o Blue-sensitive cells against yellow-sensitive cells The Visual Brain - Half of the axons in the optic nerve that leave each eye come from retinal ganglion cells that code info in the right visual field, whereas the other half code info in the left visual field. These bundle to the left or right hemisphere respectively - Optic nerve travel from each eye to the lateral geniculate nucleus (LGN) located in the thalamus - From there the visual signals travel to the occipital lobe to an area called area V1 o Area V1: part of the occipital lobe that contain the primary visual cortex o Here the info is systematically mapped into a representation of the visual scene o 30-50 brain areas in the occipital and temporal lobes specialized for vision - NEURAL SYSTEMS FOR PERCEIVING SHAPE  Area V1 is specialized in encoding edge orientation - PATHWAYS FOR WHAT, WHERE AND HOW  Two functionally distinct pathways, or visual streams, project from the occipital cortex to visual areas in other parts of the brain o Ventral stream: travels across the occipital lobe into the lower levels of the temporal lobes and include areas that represent an object’s shape and identity. {what pathway}  Damage to this pathway prevents recognition of familiar faces  Visual form agnosia: inability to recognize objects by sight o Dorsal stream: travels up from the occipital lobe to the parietal lobe (including some upper and middle levels of the temporal lobe), connecting with brain areas that identify the location and motion of an object. {where or how pathway}  Optic ataxia: difficulty using vision to guide reaching and grasping movements VISION II: Recognizing What We Perceive Attention: The “Glue” That Binds Individual Features into a Whole - Binding problem: how features are linked together so that we see unified objects in our visual world rather than free-floating or miscombined features - ILLUSORY CONJUNCTIONS: PERCEPTUAL MISTAKES  Illusory conjunctions: perceptual mistake where features from multiple objects are incorrectly combined  Feature interjection theory: focused attention is not required to detect the individual features that compromise a stimulus, such as color, shape, size and location of letters; but is required to bind those individual features together o Attention is the “glue” necessary to bind things together, and illusory conjunction occurs when it is difficult to pay full attention to the features that need to be glued Recognizing Objects by Sight - Perceptual constancy: as aspects of sensory signals change, perception remains constistent - PRINCIPLES OF PERCEPTUAL ORGANIZATION  Gestalt principles characterize many aspects of human perception  Gestalt perceptual grouping rules: govern how features and regions of things fit together o Simplicity: the simplest explanation is usually the best.  Idea behind Gestalt grouping rule of Pragnanz (good form), o Closure: We tend to fill in missing elements of a visual scene, allowing us to perceive edges that are separated by gaps as belonging to complete objects o Continuity: Edges or contours that have the same orientation have what Gestaltists called “good continuation,” and we tend to group them together perceptually o Similarity: Regions that are similar in color, lightness, shape, or texture are perceived as belonging to the same object o Proximity: Objects that are close together tend to be grouped together o Common fate: Elements of a visual image that move together are perceived as parts of a single moving object  Gestalt principles of perceptual grouping, such as simplicity, closure, and continuity, govern how the features and regions of things fit together. - SEPARATING FIGURE FROM GROUND  Grouping involves visually separating an object from its surroundings. In Gestalt terms, it means identifying a figure apart from the (back)ground in which it resides  Size, Movement, and edge assignment all help to separate a figure from the ground  Edgar Rubin, a Danish psychologist, capitalized on this ambiguity in developing a famous illusion called the Rubin vase, which is and has a reversible figure-ground relationship. - THEORIES OF OBJECT RECOGNITION  Image-based object recognition theories: an object seen before is stored in memory as a template. o Shape templates are stored along with name, category, and other associations to that object. o Memory compares its templates to the current retinal image and selects the template that most closely matches the current image. o Template: mental representation that can be directly compared to a viewed shape in the retinal image  Parts-based object recognition theories: propose instead that the brain deconstructs viewed objects into a collection of parts. o One important parts-based theory contends that objects are stored in memory as structural descriptions (mental inventories of object parts along with the spatial relations among those parts). o The parts inventories act as a sort of “alphabet” of geometric elements called geons that can be combined to make objects, just as letters are combined to form words o Parts-based object recognition does not require a template for every view of every object, and so avoids some of the pitfalls of image-based theories  Image-based and parts-based theories each explain some but not all features of object recognition Perceiving Depth and Size - MONOCULAR DEPTH CUES: aspects of a scene that yield info about depth when viewed with only one eye  This cue relies on relationship between distance and size. Brain uses the difference in relative size or retinal image to perceive distance  This works well in a monocular depth cue called familiar size  In addition to relative and familiar size, there are several more depth cues: o Linear perspective: parallel lines seem to converge as they recede into the distance o Texture gradient: arises when you view a more or less uniformly patterned surface because the size of the pattern elements, as well as the distance between them, grows smaller as the surface recedes from the observer o Interposition: occurs when one object partly blocks another, can infer that blocking object is closer than blocked object. Cannot provide info on how apart objects are o Relative height: depends on field of vision, objects that are closer to you are lower, while faraway objects are higher in visual field. - BINOCULAR DEPTH CUES: diff in retinal images of the two eyes that provides info about depth  Because our eyes are slightly separated, each registers a slightly different view of the world - Depth perception depends on monocular cues, such as familiar size and linear perspective, binocular cues, such as retinal disparity; and motion-based cues, such as motion parallax, which is based on the movement of the head over time. Perceiving Motion and Change - MOTION PERCEPTION  To sense motion, the visual system must encode info about both space and time.  Motion perception, like color perception, operates in part on opponent processes and is subject to sensory adaptation.  A motion aftereffect called the waterfall illusion is analogous to color aftereffects.  We experience a sense of motion through the differences in the strengths of output from motion-sensitive neurons. These processes can give rise to illusions such as apparent motion.  Apparent motion: perception of movement as a result of alternating signals appearing in rapid succession in different locations - CHANGE BLINDNESS AND INATTENTIONAL BLINDNESS  Change blindness: occurs when people fail to detect changes to the visual details of a scene o change blindness occurs even when major details of a scene are changed—changes that we incorrectly believe that we could not miss  Inattentional blindness: failure to perceive objects that are not the focus of attention AUDITION: More Than Meets the Ear Sensing Sound - pure tone: a simple sound wave that first increa air pressure and then creates a relative vacuum - As there are 3 dimensions of light waves, there are 3 physical dimensions of a sound wave o Frequency: or wavelength, correspond to our perception of pitch  Pitch: how high or how low a sound is  From the 3, frequency provides most of the info we need to identify sounds  Sound-wave freq. is as important for audition as spatial perception is for vision o Amplitude: corresponds to our perception of loudness  Loudness: sound’s intensity o Complexity: corresponds to our perception of timbre  Timbre: listener’s experience of sound quality or resonance o Amplitude and complexity contribute texture to our auditory perceptions, but it is frequency that carries their meaning The Human Ear - Light is a form of electromagnetic radiation whereas sound is a physical change in air pressure over time. Different forms of energy require different forms of transduction - Ear divided into 3 parts: o Outer ear: collect sounds and funnels them toward the middle ear  Consists of the visible part on the outside of the head (pinna), the auditory canal, the eardrum, an airtight flap of skin that vibrates in response to snd wave o Middle ear: transmits the vibrations to the inner ear, embedded in the skull  Tiny, air filled chamber behind the eardrum, contains 3 smallest bones in the body called ossicles.  Ossicles composed of the hammer, anvil and stirrup  Ossicles fit together into a lever that mechanically transmits and intensifies vibrations from the eardrums to the inner ears o Inner ear: transduces vibrations into neural impulses  Contains spiral shaped cochlea  Cochlea: fluid filled tube that is the organ for auditory transduction  Divided along its length by the basilar membrane  Basilar membrane: structure in the inner ear that undulates when vibrations from the ossicles reach the cochlear fluid  Its wavelike movement stimulates thousands of tiny hair cells  Hair cells: specialized auditory receptor neurons embedded in the basilar membrane. o The hair cells release neurotransmitter molecules, initiating a neural signal in the auditory nerve that travels to the brain Perceiving Pitch - Area A1: portion of the temporal lobe that contains the primary auditory cortex o The auditory areas in the left hemisphere analyze sounds related to language and those in the right hemisphere specialize in rhythmic sounds and music. - There is evidence that the auditory cortex is composed of 2 distinct streams: o Spatial: (“where”) – auditory features, which allow locating the source of a sound in space. Handled by areas toward the back (caudal) part of the auditory cortex o Non spatial: (“what”) – features, such as temporal aspects of the acoustic signal, are handled by areas in the lower (ventral) part of the auditory cortex - Ears have evolved 2 mechanisms to encode sound wave frequency, one for high & one for low: o Place code: used mainly for high frequencies, active when the cochlea encodes different frequencies at different locations along the basilar membrane o Temporal code: registers low frequencies via the firing rate of action potentials entering the auditory nerve - Action pot
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