Summary Of All Chap PDF

lOMoARcPSD|26894422 Summary of all chap Introduction Psychology and its Methods AI (Vrije Universiteit Amsterdam) Scansiona per aprire su Studeersnel Studocu non è sponsorizzato o supportato da nessuna università o ateneo....

lOMoARcPSD|26894422 Summary of all chap Introduction Psychology and its Methods AI (Vrije Universiteit Amsterdam) Scansiona per aprire su Studeersnel Studocu non è sponsorizzato o supportato da nessuna università o ateneo. Scaricato da Tommaso Ceccato ([email protected])  lOMoARcPSD|26894422 Psychology Lecture 1 Notes By Somansh – former Prince of Nigeria Overview Ø Genetic basis of life Ø Evolution by natural selection Ø Genes and behaviour linkage Genetic Basis of life Does violent person have violent genes o Varied in past o 70s and 80s belief – Behaviour (incluiding violence) was influenced by environment. Because ideology influenced their scientific thinking. As if they wanted to believe that capitalism and strict parents created violent kids. § Dutch dude/prof called Bowhouser wanted to find biological basis of crime, like – does testosterone increase criminal behaviour. Fellow scholars and media trolled him and he quit science. o In 90s, the heritability studies became common. Studies found that genes were the basis of violence and other behaviour. Thus, refuted that environment was main cause of violence and other behaviour. Scholars like Rich, Udit ? wrote a book on it. o Today we know that both genes and environment affect behaviour. Genes and biology o Human cells have 23 pairs of chromosomes (46 in total). Chromosomes are mostly a coil of DNA strings/threads/wires. o DNA is a large string of alphabets [ built of bases A,T,G, and C ]. Combo of alphabets is called genes (words). Genes are read by a little chemical dudes (tRNA ,mRNA) in the cell and they tell ribosomes (located just outside nucleus of cell) to make proteins based on these words. These proteins help in making and working of muscles, eyes, skin, immune cells, neurones, blood, brain etc. Basically DNA builds and runs the body. o ‘A’ always pairs with ‘T’. G always pairs with C. These base pairs are held by Phosphate and sugar chemical structure. o Not all parts of DNA leads to creating proteins (non-coding DNA). We still don’t know what it does, completely. o Basically, genes give the blueprint of every part of our body, and how they will behave, mostly. But food, exercise, social life, random events also affect our body and behaviour. o This is where heritability comes in. § It answers the question: how much do genes affect a trait (violence, eye colour, height, depression, IQ ), and how much does environment affect a trait. o Gene expression - not all genes are expressed at all times. Every cell in body has same genes but the genes that are ON in a cell determine it’s function. Scaricato da Tommaso Ceccato ([email protected])  lOMoARcPSD|26894422 Neural cells, liver cells, skin cells have same genes but very different due to their gene expression. § Methylation – Methyl molecules come from environment/behaviour/random events. These Methyl molecules are attached to a gene, and turn it off. Thus restricting its expression. It stops whatever gene it touches. § Thus, cells are affected by environment. Thus, environment affects genes, genetic expression and consequently affects behaviour. § Spielman ? 1967 study showed that cells from embryo become teeth, when planted on mouth area, and become skin when planted outside the embryo. Cleary, the location (environment) of genes affect their expression. o So, not every protein encoded in the genes is created all the time. Hence, a person with genes for good muscles may not have a fit body coz she didn’t exercise. In other words, the genes for good muscles were not expressed. Genotype – Set of genes of a specific organism o Phenotype – features/traits/behaviour of a specific organism. It is an outcome of genes and environment’s interaction. o Monozygotic twins (2 persons born out of one sperm fusing with one egg) have 100% genes in common. But they differ in many features – behaviour, hobbies, skin health, fitness etc. Clearly, environment, not genes, led to these differences. o Alleles - Each baby gets 23 chromosomes from mother and 23 chromosomes from father. Except sex chromosomes X and Y, the genes on every chromosome from mother’s side is similar to genes on chromosome from father’s side. For example, mother and father’s chromosome number 11 will have similar pair of genes at same position. These similar genes are called alleles. Think of alleles as genes that are located at the same position in chromosome, and do similar task. But vary slightly. § Note: NOT EXACTLY SURE ABOUT THIS ONE. VERIFY LATER. There may be multiple alleles of a gene in a population, such as alleles of eye colour genes: blue, green, black, brown. But a person gets only two genes out of the total genes available. One from mother and another from father. § If the two genes (alleles) at same position are identical, the person is homozygous for that gene pair. If they’re somewhat different, the person is called heterozygous for that gene pair. o In the alleles (genes), one gene may be dominant and other may be recessive. In that case, dominant gene will express, and recessive won’t. To illustrate, assume a gene ‘B’ leads to blue eyes (when expressed), and gene ‘G’ leads to grey eyes when expressed. If G is dominant and B is recessive , the person will have grey eyes. Recessive genes are expressed when both alleles are recessive. § Sometimes both genes are recessive or dominant. Then, a weird mixed expression of genes happens. o Not every gene leads to one trait. Many genes may influence one trait (height/Schizophrenia) – called Polygenic inheritance. Scaricato da Tommaso Ceccato ([email protected])  lOMoARcPSD|26894422 o Or one gene may influence multiple traits. How does an organism end up with a genome ? o Due to natural selection – explained by Darwin. o Genes that are expressed and lead to advantageous traits (good hunting skills, sense of smell, vision) allowed an individual to survive long enough and reproduce. Thus passing the genes. With time, genes that help in life survive and thrive. Though, some not so useful genes also slip through, which may turn out to be useful after many generations, or turn out to be lethal. o 3 conditions for natural selection § The population of organisms must have variation in genes. § Individuals with genes suited for the environment survive and reproduce more than others. § Traits are thus passed from parents to offspring. o Example – a moth of brown colour used to blend with the tree colour, so birds couldn’t eat it. But in cities, the brown colour didn’t blend well with dark polluted walls. So, moths of darker shades survived more in polluted cities. After pollution restrictions, brown moth was back. o Evidences of evolution § Fossil evidence – dinosaur, bird, human, fish fossils over millions of years. § Similar genomes of various organisms. Chromosome 2 of humans is a fusion of two chromosomes of anthropoid apes that existed thousands of years ago. § Pseudogenes – inactive genes in DNA. Maybe functioned in the past but now just sits there. Humans have 2000 such genes. We carry genes required to make Vitamin C from glucose. But one part is inactivated. Eating Vitamin C rich foods must’ve inactivated the gene. So, another proof of evolution. § Distribution of species across Continents. Japan – Earlier connected to a continent. Diverse species. Hawaii – Oceanic island, never connected to a Continent. Lacks diverse animals like freshwater fish, reptiles. Only long distance travelling species could colonise the island – like birds. But how does it explain evolution ? o Evolution doesn’t improve the species, nor does it create the best genome. It only creates species adapted to the environment. A fish has genes suited to water life but on land they are useless. § Evolution doesn’t create rigid behaviour patterns. It may change when needed. Nature nurture debate o Scholars used to argue if nature(natural build/biology/genes) or nurture(environment, outside events, parenting, random events) shaped the organism o Today we know it is both, so the debate is irrelevant now. Nature and nurture interact and shape the organism Scaricato da Tommaso Ceccato ([email protected])  lOMoARcPSD|26894422 Who we are and how we behave is determined by – how our genes behave in a certain environment. MAO study o Persons with low MAO activity combined with parental mistreatment were more like to commit crime and show aggressive behaviour. o Low MAO didn’t automatically lead to higher aggression. Mistreatment alone did increase aggression, but when combined with low MAO activity, aggression shot up. Thus confirming: nature and nurture influence behaviour. Scaricato da Tommaso Ceccato ([email protected])  lOMoARcPSD|26894422 Psychology Topic – 2 By Somansh – successfully auditioned for Coldplay twice The Brain and the nervous system. v Overview o Nervous system structure o Communication among neurones o Communication of brain and body o The Brain v Genes and environment interact to build a trait of organism o It also shapes our nervous system o Nervous system has § Central nervous system – Brain & Spinal cord (C.N.S) § Peripheral nervous system – Other nerves in body o Brain is critical for behaviour § Weighs 1.5 kg approx o Nervous system – including brain – is made up of 2 basic cells § Glia – supportive functions § Neurones – Receive and send information via electric pulses. § Allow us to think, talk, walk v More on neurones o Dendrites receive signal from other neurones connected to it. o Axon transmits the information received from dendrites to other neurones connected to axon terminals. The output pipe of neurone. § Axon is covered by fatty substance called Myelin Sheath. § Myelin sheath is fatty, so it doesn’t dissolve in watery surroundings of the brain. It is semi-permeable, so that some chemicals may enter or exit it. Ions (charged particles) can’t freely move in and out of Myelin sheath. Ions can travel via ion channels. § When the neuron is activated/fired/addressed there is a change in potential difference between inside and outside of the cell. Potential difference Scaricato da Tommaso Ceccato ([email protected])  lOMoARcPSD|26894422 means, amount of negatively and positively charged particles are different, inside and outside of neuron. § Voltage meters measure the potential difference by inserting one needle inside and another needle outside of axon. The number comes out to be -70 millivolts when the neuron is inactive. This state is called the resting potential of the neuron. -70mV means the neuron is negatively charged on the inside OR more positively charged particles (Na+ Sodium ions) outside the membrane than the positively charged particles on the inside (K+ Potassium ions). o This happens because K+ ions get in and out of neurons more easily than Na+ neurons. Sodium pumps and leakage channels are responsible for this. When the membrane is stimulated, the potential difference changes between inside and outside a cell. If the potential difference changes beyond a limit, we say that an action potential is generated. Action potential is a spike of positive charge inside the neuron. When the action potential exceeds -55mV, the neuron fires. o Suddenly, after the neuron fires, the inside potential goes back to -70mV (the resting potential) o The action potential happens at local level. This means that there’s no big potential difference in the full length of axon. The action potential travels along the axon like wave travels over water. This travel of action potential is called propagation. Myelin Sheath Membrane has ion channels where Na+ and K+ ions can travel in and out of neuron. Process: o When action potential arrives at that location, Na+ flows inwards into axon, from outside. o Shortly after the action potential leaves that particular point, K+ channels open and pump out K+ from the cell (axon) at that particular location on axon. o So, wherever action potential reaches the neuron, Na+ ions flood into the cell, and when it leaves, K+ ions are pumped out immediately. o Not every signal or stimulus to the neuron leads to an action potential. So, not every stimulus causes the neuron to fire. o Add neuron firing diagram – Communication among neurons. Scaricato da Tommaso Ceccato ([email protected])  lOMoARcPSD|26894422 o Steps § Sodium channels open § At 40mV Sodium channels close. § Repolarisation § Refractory period – No action potential possible for neuron in this period. Summary of neuron firing o Neuron gets a stimulus from other neuron o If stimulus is not strong enough to push potential above - 55mV, nothing happens o If level breached, Na+ ions on outside, flood in. In 1ms, K+ ions flood out the cell. o Within 2ms, K+ enter back and Na+ flood out. Restoring the cell back to -70mV. o Major types of Neurones § Sensory Neurones It’s a Specialised cell that has sensory receptors capable of translating a physical stimulus to an electric signal. Like changing pressure change to electric signal. Sensory neurones transmit the electric signal from sensory receptor to Central nervous system (CNS) via Interneurones § Motor or Efferent neurones send signal from central nervous system to muscles/other parts, thus executing the movement desired by brain. Scaricato da Tommaso Ceccato ([email protected])  lOMoARcPSD|26894422 § Interneurons make connections within the CNS, as well as connections to sensory and motor neurones. o Neuron firing features § Either neuron fires or doesn’t fire. Like 1 and 0 binary in Computers. Intensity of stimulus leads to 2 possibilities o Number of neurons may be larger or smaller o Rate of firing may be higher with higher intensity Neurons interact via chemicals travelling through synapses. o Synapse § The place where signal passes from one nerve cell to another. § Imagine signal travelling from neuron A to B § End of axon of neuron A is called pre-synaptic membrane. Then there’s synaptic gap. Dendritic surface of neuron B is called post-synaptic membrane. § Synapse working. Note: Pre-synaptic neuron is sending the signal and post- synaptic neuron receives it. The action potential arrives at presynaptic membrane, at the edge of terminal button of axon. The action potential causes the synaptic vessels ( located on presynaptic neuron ) to release chemicals. These chemicals are called neurotransmitters Neurotransmitters flow to the receptor sites of the post-synaptic membrane of the neuron. Note : Post-synaptic membrane is at the edge of the dendrite of receiving neuron. As neurotransmitters attach to the receptor site, the Na+ ion channels may open up and a rush/flood of Na+ ions enter the signal receiving neuron. The sudden rise in Na+ ions in the neuron is the stimulus for the neuron. If the stimulus has enough ions, it can push the action potential above -55mV in the receiving neuron. Thus will create an action potential in the neuron, and it will fire. The firing of this neuron will pass on signals to other neurons, which may or may not fire. This process keeps going on throughout our life. § Since neuron is connected to many other neurons, the sum of Na+ ions or stimulus from other neurons determines if the receiving neuron will fire. o Neurotransmitters. Made in USA ? No, made in the axon. Stored in vesicles at presynaptic membrane. § Chemical substances that transmit signals from one neuron to the other. § There are over 100 neurotransmitters – dopamine, serotonin etc § Neurotransmitters vary in shape (like keys), so they affect a receptor site, ONLY if they fit that shape. And only if it fits, the receptor will open Na+ channels to let the ion in, and only then the neuron will receive stimulus. § So, if a neuron doesn’t have receptors for serotonin, it won’t receive stimulus even if the pre-synaptic neuron sends the serotonin signal. This way, specific information is released to specific neurons. § After giving the signal via neurotransmitter, it has to be terminated. Otherwise the neurons will keep firing and the person will have a stroke and die. § Effect of neurotransmitter can be terminated in 3 ways Autoreceptors – Scaricato da Tommaso Ceccato ([email protected])  lOMoARcPSD|26894422 o Receptors on presynaptic neuron that monitor the amount of neurotransmitters released. When the released amount is large, these autoreceptors send signal to the presynaptic neuron to stop sending any more neurotransmitters. Synaptic reuptake o Since neurotransmitters can be used again, they are taken back in by the presynaptic neuron. Done by receptors at presynaptic membrane. Clean-up Enzymes o Clean-up enzymes capture and deactivate the neurotransmitters. § But, neurotransmitters don’t always lead to opening positive ion channels of a postsynaptic neuron. That is, sometimes the same neurotransmitter may lead to inhibition or activation of signals to different neurons, as they activate different receptors. Similarly different neurotransmitters may excite or inhibit a neuron. In such a case, neurotransmitters open channel for negatively charges ions like Chlorine ions Cl- This makes the potential difference negative, inside the postsynaptic neuron, and reduces it’s chance of firing. For eg. A neuron D is connected to neurons A, B and C. Here, A and B send neurotransmitters that can increase the potential difference of D, above -55mV. But C releases neurotransmitters that bring the potential difference of D to -60mV. Then D won’t fire § Add neurotransmitter list image. v Drugs. For Brain o Drugs work by inhibiting or enhancing the effect of specific neurotransmitters. o Agonists - ENHANCE ! § They work by Increasing the precursor i.e. forcing neurons to release more neurotransmitters. Done by amphetamine. Meth ? Counteract clean-up enzymes. Scaricato da Tommaso Ceccato ([email protected])  lOMoARcPSD|26894422 Blocking reuptake. Eg Cocaine and Prozac Mimic neurotransmitter’s action. Eg Nicotine - tobacco o Antagonists § Working Decrease precursor. Eg AMPT Enhance clean-up enzymes’ activity. Enhance reuptake Blocks receptors of post-synaptic neuron. Eg Propranolol o Parkinson’s patients are short on dopamine. So, they’re given L’dopa drug. How Brain talks to body. Ø Central Nervous System o Brain o Spinal Cord Ø Peripheral Nervous Sytem o Somatic Nervous System § Skin, muscles, ears etc send signal to brain § Brain sends signals to skin, muscle, ears etc o Autonomic Nervous system – Autonomous and we don’t need to think about it. Scaricato da Tommaso Ceccato ([email protected])  lOMoARcPSD|26894422 § Sending signals from Brain to glands and internal organs. Sympathetic Nervous System – prepares body for action o Dilate pupil to see clearly o Relax bronchi to take in air o Increase heartbeat – to prepare for new memes Parasympathetic Nervous System - prepares body for resting o Constricts pupils when things get boring. o Slows heart beat o Dilate blood vessels § Receiving signals from glands and internal organs Brain directs endocrine system – a system of glands Glands get the signal and release hormones like testosterone, oxytocin etc to parts of body. This creates certain events in the body. But this is long and slower process than neural communication But effects are longer lasting v Back to Brain o 19th century theory – Franz Gall – If a person uses a trait, that part of brain will create a bump in the skull. False theory § Bumps at back meant domestic and caring. o Methods to study brain § Clinical neuropsychology Compare injured part of brain to find which behaviour was changed. Patients who get damage to brain are studied P. Gage had an accident that put a rod in his head, damaging the brain. This impaired his social skills and temper but he was still alive. This means, injured part of brain was important for social behaviour. § Experiment Studying animals with invasive techniques on animals. Eg. Damaging part of brain of a rat and see the effect. o Hubel and Weisel (Nobel laurates) experiment 1982 § Studied cat’s visual cortex. § Registered activity of cortex by putting electrodes, and studied how neurons responded to the stimulus. § Specific neurons responded to specific orientation of images TMS – Transcranial Magnetic Stimulation. o Temporary dysfunction created in brain by magnetic impulses. o Done on humans Electrophysiology – EEG and ERP o EEG caps measure electrical activity at various locations on skull o ERP is Event Related Potential recording § Many recordings of same event – like showing dog’s image – are recorded and averaged over time. § Averaged ERP reduces the noise in measurements. Scaricato da Tommaso Ceccato ([email protected])  lOMoARcPSD|26894422 MRI scans – fMRI is functional MRI. fMRI measures blood flow and oxygen. Normal MRI reveals only structure, fMRI also reveals working. PET scan – Positron emission tomography. Shows activity in the brain after injecting radioactive glucose in subject. Indicates active areas. o Brain stem is bridge between spinal cord and the brain. Performs basic functions. § Brain stem is essential for survival – it controls breathing and heart rate. o Cerebellum coordinates motor activity – movement and balance o Cortex is outermost parts – 80% of brain o Frontal lobe – thinking, planning o Temporal lobe – hearing, memory. o Parietal lobe – touch, spatial relations and attention o Occipital lobe - vision o Sub- cortical regions – as they are below cortex. Belongs to limbic system e.g. motivation, memory, emotions, reward. o Brain is divided into left and right hemisphere – Connected by Corpus callosum – a bundle of fibres carrying info from one part to the other. Studied via split brain patient – patients whose Corpus callosum was cut, to avoid seizures. o Left and right brains are mostly symmetrical but many differences § Eg. Language is in let hemisphere of right handed people. o If Corpus callosum is cut, we can study which part of brain has which function, by designing experiments. § Eg. Split brain patients can’t read words in left field of view because right brain reads the left view while language processing is mostly in left brain. o Further divisions of Cortex o Primary visual cortex – visual info enters here o Primary Somatosensory cortex – info from skin o Primary motor cortex – moves parts of body o Primary auditory cortex – first audio info comes here. o Interesting division of body parts representation in brain. Scaricato da Tommaso Ceccato ([email protected])  lOMoARcPSD|26894422 Psychology Notes – Topic 3 By Somansh – close friend of Al Pacino. § Overview o What is Consciousness o Attention o Sleep o Drugs § Consciousness o It is a state or quality of awareness. Or, extent of being aware of an external object or something within oneself. Or One’s subjective experience of the world, resulting from brain activity. o In reality we aren’t fully aware or conscious of everything around us. § E.g. Bonneh et al 2000 (Nature journal) Paper on motion induced blindness. Disappearing yellow dots in green dot experiment. § Motion can suppress the consciousness of static stimuli. § But can it happen outside? Yes. At night a driver may lose sight of tail-lights of car in front, due to motion induced blindness of other cars coming from opposite side. o This shows us that brain and mind are inseparable. o Note: In earlier times, people believed that mind and body are like soul and a vessel. The body (including the brain) has finite capabilities but the power of mind is limitless. Mind can do or imagine anything: go back in time, imagine the future and so on. This was called, mind body dualism. Rene Descartes believed brain and mind to be different. § But now we know that mind or consciousness is just a phenomena of the brain. Since brain is just like any bodily organ, with certain limitations. This means the mind is also limited by the capacity of the brain. § Today we know that consciousness varies with brain activity. Neural activity produces consciousness § Everyone has their subjective experience of consciousness. We cannot know if two people experience the world differently. § Doubt : Can it be that: Even if some people have exactly same neural network/ brain, in different situations, different neurons will fire and they may have completely different consciousness? § Presently we can’t translate biological activity (neural activity) into conscious experience. Thus, we can’t study what a person experiences when certain neurons fire or when a certain brain activity is seen. § We can ask people what they experienced, but again that is subjective. For instance, two people might see a color differently and experience it in a different way. Scaricato da Tommaso Ceccato ([email protected])  lOMoARcPSD|26894422 o LOCATION - Ok, so if brain creates consciousness, where exactly is it located in the brain? § As per global workspace model, it resides everywhere in the brain. § Consciousness arises as a function of which brain circuits are active. § Parietal lobe activity creates consciousness of space. Occipital lobe creates consciousness of vision. § This means, if a brain area is missing, a person won’t be aware or conscious of that type of information. § In visual neglect patients, typically have legion in right Parietal lobe. This area processes spatial information. Since right brain processes left visual field information, these patients fail to process spatial info of their left visual field. That’s why they properly paint only right halves of what they see. These patients aren’t even aware that they are neglecting left visual field. o Other supporting evidences of global workspace model. § Study by Tong 1998 – Participants shown superimposed images of house and a face. Shown to patient via filter such that one eye saw house and other saw face. Interestingly, participants didn’t see both images, but ONLY either one of the images at a time. They may see house for 10 seconds and 5 seconds a face. Used MRI scanner to monitor brain activity. When they were aware of the face, brain activity was observed in Fusiform Face Area. A dedicated area to perceive faces. When they were aware of the house, brain activity was observed in Parahippocampal Place Area. A dedicated area to perceive places. This shows, same stimulus can lead to different consciousness depending on what the patient is aware of. o But ONLY activity doesn’t create consciousness. Other processes also happen in the unconscious part of brain. Sometimes that process may not even be known to our conscious part of brain. § Our conscious mind would struggle to explain what happened in the unconscious process. This is called after the fact explanation. For e.g. we don’t know how we retrieve info or memory from our brain. Yet our conscious mind would anyway explain the process. Scaricato da Tommaso Ceccato ([email protected])  lOMoARcPSD|26894422 § Experiment on split brain patient Gazzaniga 1978 study. They saw a house on left visual field and chicken foot on right visual field. While fixated on center of the field Patient picked chicken with the right hand and shovel with left hand. Note: right hemisphere controls left hand and vice versa. Then participant was asked about why they chose shovel and chicken. As left hemisphere has speech capability, and knew about seeing the chicken foot, it clearly explained why chicken was picked. But being a split brain, left brain didn’t know what right brain saw. So, it was an unconscious experience for the left brain. Consequently, left brain explained that shovel was picked to remove chicken shit. An after the fact explanation. Note: Left brain is called the interpreter of information and creates a story for us. § We can conclude that people don’t always know why they behave in such a way, and explain the unconscious action later on. 1977 paper by Wilson showed how we wrongly explain our mental processes. Here, all night gowns were of same fabric. Participants chose the rightmost gown. But explained that they chose the ones with best fabric feel. Also, insisted that position didn’t affect their choice. This shows we create an illusion of conscious behavior while in reality we acted on some unconscious thought. § Study by Libet showed that voluntary free will behaviour may be an outcome of unconscious decisions. And explained as a free will decision after the act itself. Experiment asked people to choose freely when to move their hand. While noting the dot’s position on the screen. Used EEG to check readiness potential of brain. This preceeds selection. Scaricato da Tommaso Ceccato ([email protected])  lOMoARcPSD|26894422 Outcome: The awareness of decision to move the hand occurred 204ms prior to the actual movement. BUT the readiness potential was already evident at 535ms before moving the hand. This shows that free will decision to move the hand wasn’t the CAUSE of moving the hand but just an explanation of unconscious decision to move the hand. Or does it? § But sometimes unconscious behaviors make people struggle to explain that decision Attention o We don’t get aware of everything we see. We are conscious of ONLY the things we give attention to. o Attention is the process that enables you to focus selectively on some things and avoid focusing on others. So, we have limited awareness of our surroundings. § We focus on one conversation in the party but ignore the others § Cherry 1953 creates an experiment - shadowing task. Participants are given two different streams of audio in both ears. Then, asked them to repeat what they heard. People are able to shadow messages that they didn’t want to hear. Further research showed that info in unattended ear was processed but ignored. Change in frequency of unattended messages was immediately detected. So, physical changes in the signal was detected because they were monitored. But the signal contents were not monitored/decoded. Sometimes the unattended audio info breaks through our attention. For instance, when someone calls our name, we immediately detect it. § Unattended information may sometimes affect our behavior. This is called subliminal perception. E.g. A US political ad tried to alter people’s perception by putting a repulsive message (Rats) flashing in between opponent’s video clip. But this doesn’t seem to influence long term behaviour. o Phenomena of change blindness – how we selectively give attention to our environment. We ignore even major changes, while focusing on something. § Daniel’s experiment showed we can fail to detect change of our conversation partner (if it’s a stranger) and when gender or general clothing is similar. So, attend only a small proportion of our visual scope. § We only store specific visual features of a stranger we are talking to: gender, what they want, peculiar features. We may not always compare features even if we noticed them. § In driving, accidents can happen when we fail to register changes in speed or direction of car ahead of us. Scaricato da Tommaso Ceccato ([email protected])  lOMoARcPSD|26894422 § In creating learning programs for people/children, we should not overwhelm the person with info. As, we have only limited attention span. In training Ai the same applies ? § In website design, key changes and features should happen such that people can give attention to it. § Vision varies with context we are in. So, consciousness varies with context. o Affecting consciousness – Sleep § Many brain regions are active when we are asleep. § Brain never shuts down § Sleep and awakening are influenced by circadian rhythm. § Changes in light are registered by Suprachiasmatic nucleus of hypothalamus. This nucleus is just above the crossing of two optical nerve nerves. It signals to the pineal gland that it is time to go to sleep. § Pineal gland secretes melatonin. This tells brain and body to go to sleep. Light suppresses production of melatonin and dark suppresses it. § See sleep cycle EEG above. Alpha waves are same when a person is focused § K Complex signals are spike in brain activity during sleep. § Rapid Eye Movement – REM sleep has same beta wave pattern as alert wave forms. Dreaming happens but paralysis of motor functions during this stage. Scaricato da Tommaso Ceccato ([email protected])  lOMoARcPSD|26894422 But WHY do we sleep § Restorative theory Allows body to repair itself – Evidences: Exercise increases sleep activity; sleep improves immune system; sleep depravation reduces vigilant tasks and causes problems in cognition, mood and even death. But sleep deprivation may help in reducing depression § Circadian rhythm theory o Animals need only few hours to eat, reproduce and live. In night there is danger. So, sleep helps us survive. § Facilitation of learning theory o Helps neurons connect, thus helps in learning. o Participants that slept well, performed better in exams. o Participants who dreamt of a concept were better at that concept than others who didn’t dream. Also, students have more REM cycles during exams. o Dreams § Dreams are a product of an altered state of consciousness in which the images and fantasies are confused with reality. § Only after we wake up, we realize we were dreaming. § REM dreams are different from Non-REM dreams. NON-REM is NOT COOL dreams. REM dreams are AWESOME, BIZZARE and INTENSE. § REM dreams are illogical yet seem logical. Because brain regions of planning and thinking (prefrontal cortex) is deactivated while areas of visuals, reward, emotions (Amygdala) are active. Blue is inactive, red is active. Scaricato da Tommaso Ceccato ([email protected])  lOMoARcPSD|26894422 Drugs Used to alter state of minds. They may be used for recreation or treatment. Heroin and codiene is same. Ritalin is ADHD drug, sold on street as smart drug. Can treat a person when used correctly. When abused, can mess them up pretty good. Addiction – Compulsive drug use despite its negative effects. It creates dependency of the drug. A person can’t literally live without it sometimes. Withdrawal symptoms – anxiety, tension, craving, physical issues. Also, drug users develop tolerance to a drug. Types of Drugs o Stimulants – I’m the one who knocks stimulates § Increases sympathetic nervous system activity – Meth, Cocaine, Nicotine, Caffeine. Increases anxiety, insomnia, weight loss. § Cocaine inhibits reuptake of serotonin, dopamine, and neferine. § Meth is same as coke but stronger. It inhibits uptake while also enhances release of neurotransmitters. § This depletes dopamine levels and damages brain, body and health. Frontal lobe, temporal lobe, memory, emotion brain parts hurt. Finally, death. Scaricato da Tommaso Ceccato ([email protected])  lOMoARcPSD|26894422 o Depressants § Alcohol, anti-anxiety drugs § Reduces mental activity. § Alcohol is a GABA agonist Enhances the suppressant effects of GABA receptors. Alcohol attaches itself to receptors and alters its functions. This allows GABA molecules fit easily in this receptor. This reduces neuron activity. Alcohol withdrawal can cause: anxiety, seizure, stress. o Opiates. Narcotics § Slow down Central nervous system, create pleasure, slow down pain. Effects the parasympathetic nervous system. § Heroin, Morphine and Codeine. § They bind to natural opioid receptors in brain. § Opioid receptors are used by endorphins to inhibit the sensation of pain. Endorphins work by blocking the release of substance P. Opioids just enhance this pain blocking mechanism. o Hallucinogens § Produce alterations in cognition, mood and perception. § LSD, Psilocybin mushrooms, Mescaline. § Don’t clearly affect the autonomic nervous system. But distort perception. § Prolong use can create recurrent hallucinogen perception – recurrent trips. Scaricato da Tommaso Ceccato ([email protected])  lOMoARcPSD|26894422 § Withdrawal symptoms are not as clear. o Many drugs like Marijuana, MDMA don’t fit into these categories. Marijuana can show effects of stimulant, depressant and hallucinogen. MDMA affects serotonin more, by blocking the reuptake. MDMA increases oxytocin or cuddle hormone. § Severe withdrawal symptoms of MDMA – fatigues, depression, damage to hippocampus and prefrontal cortex. o In the long run drugs cause damage. Scaricato da Tommaso Ceccato ([email protected])  lOMoARcPSD|26894422 Psychology Notes – Topic 4 By Somansh – won the Nobel Meme Prize in 2013 Humphreys case study – We apply structure and classification on things. But John can’t structure his perception. What the eyes see is ok, but the head can’t focus on what he sees. Can’t put together faces. Can recognize objects but has difficulty putting information together. Can see the details but fails to connect those details to their concepts. Can’t give meaning to the patterns that he sees. Lecture begins Sensation and Perception: Vision Overview ¨ The senses ¨ Vision – beyond the retina ¨ Vision – the retina ¨ Visual perception ¨ Perception organization ¨ Perception of depth ¨ Perception of size ¨ Perceptual constancies The Senses Are our perceptions a true reflection of reality or do they only represent reality. Locke wrongly believed, our senses register reality truly, so they show our surroundings as they are. Eyes as camera. Empiricists believed a baby was a blank slate with nothing but ability to learn. Babies learn everything as they experience them. Nativists like Immanuel Kant thought that important aspects of cognition were available at birth. Certain hardwired presumptions about the world exist at birth. Perception can never be pure. SO, perception is based on these innate (by birth) assumptions. We are born with skills to interpret the world. Scaricato da Tommaso Ceccato ([email protected])  lOMoARcPSD|26894422 Proximal stimulus (stimulus on our eyes or pattern of energy on our sense, in this case our eyes) and Distal stimulus (outside stimulus) – Empiricists believed that with experience we learn that smaller proximal stimulus means that distance is larger. But Nativists believed that this ability to perceive distant objects was pre- built at birth. Sensation – the detection of external stimuli and the transmission of this information to the brain. Perception – the processing, organization, and interpretation of sensory signals. Distal stimulus -> Proximal stimulus -> Transduction -> Sensation -> Perception Types of senses: Vision, Hearing, Taste, Smell, Skin senses(pressure, temperature, pain), Vestibular sense(sense of balance in the ear), Kinesthesis (conceives info about our body’s orientation in space. Receptors are located in muscles, tendons and joints). Quantitative variation/ Intensity of stimulus perceived by our senses. Occurs by 2 means. o Rate of firing in neurons may increase with increased instensity o Total number of neurons firing – intense stimulus causes more neurons to fire. Qualitative variations – or sensory quality – like colors, texture of surface, sound differences. Two mechanisms: o Different sensory info signaled by different neurons. Sound triggers auditory cortex and colors trigger visual cortex. o Certain sensory qualities activate same set of neurons differently. Color yellow results in an activity pattern in a set of neurons, while color red activates the same set of neurons, but activity pattern of those neurons is different. Adaptation – sensation is biased towards new events and changes. It is the tendency to respond less to a stimulus that has been present and unchanging for some time. o After some time, neurons stop firing to a unchanging/static stimulus. But not all stimuli disappear because we keep making eye movements, that keeps changing the stimuli. o Looking at clouds is just like looking at static stimuli. Vision Scaricato da Tommaso Ceccato ([email protected])  lOMoARcPSD|26894422 The stimulus for vision is light. Light varies in brightness (intensity), color (quality/wavelengths). o What we perceive as colors is 400 to 700 nm wavelength of electromagnetic radiation. So, we only ever see a partial part of the world. We never get to see UV rays and radio waves. Retina – the light comes into the eye and creates proximal stimulus at the retina. Retina consists of light sensitive receptors called rods and cones. o Rods and cones are behind a thin layer of cells on the retina. Light reaches rods and cones. o Rods and cones contain pigments that absorb the light, here the signal is converted into electrical signal – this process is called transduction. o The electric signal is sent from rods and cones to Bipolar cells, to Ganglion cells to the optic nerve. This nerve reaches the brain. o The Amacrine and horizontal cells modulate and regulate the electric signal from receptors to Ganglion cells. o Rods are large and cylindrical. Cones are small and conical. Scaricato da Tommaso Ceccato ([email protected])  lOMoARcPSD|26894422 § Rods have rhodopsin pigment (opsin + retinal) § Cones have conopsin (photopsin + retinal) § When light is absorbed by these pigments, they change shape, this change of shape creates electric signal o More on rods and cones § Rods are relied on during night because they are more sensitive to light. Cease to fire during day as the light intensity is high. They have no color vision § Cones are relied on during day. More sensitive to color. Less light sensitive Has color vision. How we see color ? o Trichromatic Theory – by Young-Helmholz § Conopsin have 3 different pigments or molecules with different amino acids. § Three pigments are able to transduce Red Blue Green color wavelengths. § Young-Helmholz postulated the trichromatic theory – since we can’t have a receptor for every color, we have limited (three) receptors for RGB colors. A mix of signals from these 3 pigments creates different stimulus for hundreds of color we see. § Color vision arises due to pattern of activity across all 3 cones. Scaricato da Tommaso Ceccato ([email protected])  lOMoARcPSD|26894422 So, cones vary with respect to their sensitivity to light of different § wavelengths. Blue cone can absorb more blue light than green and red cones. However, we see blue because blue cones fire more strongly than other two. § Note: It is never the case that only one cone is activated by a certain wavelength. All three are active BUT at different intensity. § So, combined activity of these cones creates perception of color. § Color blind people lack pigments in either of these cones. o Opponent-process theory on color vision by Hering 1892 §Some aspects of color vision can’t be explained by trichromatic theory §Certain colors seem to be complimentary. Some color combinations are just not possible like Bluish yellow or reddish green. § He proposed that there are 3 opposing processes Black(-) - white (+) Red (+) - Green(-) Blue (-)- Yellow(+) § When we fixate on a color, and after a while, look away. We will see the complement of that color in after images § He argued, prolonged exposure to a process, the opposite of that process will begin. So, after viewing Red for a while, the Red+ process will be exhausted. In the after image, the Green (-) process will begin. So, we will see green - as its after image. o Today we know both theories are correct. Scaricato da Tommaso Ceccato ([email protected])  lOMoARcPSD|26894422 Back to cones and retina o Distribution of cones and retina in the figure above. o Fovea has cones ONLY. It is the point of fixation. § There is high resolution at this point. Why ? Because the cones (primarily responsible for high resolution perception) are concentrated in fovea region, while less cones at periphery. § So, things must be bigger in our peripheral vision to be seen clearly. o Peripheral retina has more Rods there than Cones. o Blind spot has no cones and no rods. o We don’t feel the blind spot because § Info is filled by other eye § Info filled by the brain § We don’t feel any absence of info because there is no receptor there to tell us something is missing Beyond the Retina From retina, info goes to Lateral geniculate nucleus in Thalamus, then towards visual cortex. Then it splits to main pathways: parietal and temporal Scaricato da Tommaso Ceccato ([email protected])  lOMoARcPSD|26894422 Info of left visual field ends up in right visual cortex and vice versa. Note the optic chiasm is located neat thalamus. What pathway - Ventral pathway to the temporal lobe. WHAT part. When pathway – Dorsal pathway to the parietal lobe. WHERE/HOW part. o How we know ? One study in 1982 by Ungerleider and Mishkin ? o He trained monkeys to identify object shape. Failed this task when temporal lobe was removed. But did well in Landmark identification test o Also trained them to identify landmarks/ spatial relations. Failed it when parietal lobe was removed. But did well in object recognition. o Goodale 1995 study - DF patient couldn’t copy the apple and book but could draw them both from memory. Had no problem with WHERE and HOW part of tasks. But had trouble identifying the WHAT or object recognition. Within both these pathways there is strong modularity. Which means there are different functions within these different areas. E.g. PPA and FPA areas. Also there are different cross linkages with different areas. All the areas communicate with each other but we don’t know how. Visual Perception How the information we receive is modulated, organized and interpreted. Beyond sensing the stimulus. We combine our previous knowlege and extract information from visual signals. Therefore, visual perception is not just bottom up process (from senses to our mind/consciousness) but also top down process (from previous knowledge to mind). Knowledge affects what we “see” through our senses. Scaricato da Tommaso Ceccato ([email protected])  lOMoARcPSD|26894422 o Priming is a way to influence our knowledge about a picture/ stimulus. A stimulus will be perceived differently, based on primer that was seen or stimulated before it. o Context implicitly shape our expectations, thus affect our perception. Same stimulus of a theft can be perceived as joke when in a movie, or serious when in a documentary. o Orientation of stimulus/picture can affect the perception. Face perception depends on correct orientation of the mouth and the eyes. o Perceptual organization of stimulus – we organize what we see in form of background and foreground. Showing an image of vase/face image experiment. When faces were in foreground(figure), person took more time to recognize vase in the background. When vase was in foreground(figure), it took the person longer to recognize faces in the background. So, we give more processing power to figures rather than the backgrounds. o Vecera et al 2002 study showed - Lower areas are more frequently perceived as figure than upper areas. While we see the upper part as the background. Which is mostly true in reality. o Similarly, Peterson et al 2008 noted, we perceive convex figures and concave as background. o Perceptual organization on basis of organization principles – aka Gestalt principles. Formulated in early 20th century. Perception is not just sum of senses but creating a bigger picture. § Proximity – the closer two figures are, the more likely we are to group them as part of one single object.. black dots image § Similarity – we group figures based on similarity. Black grey circles image § Continuity – we perceive/group together the edges and lines that have same orientation. Lamp image Scaricato da Tommaso Ceccato ([email protected])  lOMoARcPSD|26894422 § Closure – we perceive objects as closed and connected even if some part of its information is missing. Triangle image. o Perception of depth – How we make 3D perception from a 2D image we receive. Different cues used based on context/situation. § Binocular depth cues – that arise due to us having 2 eyes Binocular disparity – the slight difference in images that fall on to the retina of each eye. Brain cells are also dedicated to understand this binocular disparity. Used upto 10 m. Convergence - information our brain receives from eye muscles. When we look at something closer, muscles move inward and brain perceives the depth of that object. § Monocular cues Occlusion – we know that nearby objects obstruct/occlude far away objects – thus we deduce that occluded object is farther. Linear perspective. Seemingly parallel lines like railway tracks seem to converge. Texture gradients. Texture of different coloured objects like a field of flowers becomes denser with viewing distance. Brain can estimate that denser texture must be father away. Shadow. Since in real life light comes from above, we perceive objects with shadow on top as depressed surface and objects with light on above as emergent surfaces. Motion parallax – objects moving at constant speed appear to move faster when they are closer, while father away objects move slower. As we see during a train ride. Scaricato da Tommaso Ceccato ([email protected])  lOMoARcPSD|26894422 o Perception of size § Depth perception is used in estimating size, because size perception depends on perceived distance of an object. § Same length of line seems bigger if it seems father away and seems smaller in it seems closer to us. Because they create equal size of image on the retina, so depth cues are necessary to determine size. Similarly lack of depth view can fool us about size. E.g. Ames Room. o Perceptual Constancies – Size constancy - we correctively perceive different properties of distal stimuli despite continuously changing proximal stimuli. o People walking towards us keep increasing in size of image on the retina but we don’t perceive them as getting bigger because our we combine it with depth perception of that person to adjust our perception. o This proves that we keep figuring out what we see. Change constancy – we constantly perceive the same thing, despite changes in our viewing angles or object’s orientation in space. We keep interpreting the perception based on the context. Lightness constancy – despite changes in illumination, we perceive the objects as same. We adjust our perception based on our knowledge that objects in light appear brighter than they are and darker than they are in the dark, and objects don’t change their own brightness. Color constancy – we perceive colors as not changing despite the proximal stimulus might change. We simply adjust our perception based on surroundings. Scaricato da Tommaso Ceccato ([email protected])  lOMoARcPSD|26894422 Psychology Notes – Topic 5 By Somansh – that’s what she said Overview – focus on acquired behavior this time. § Non-associative learning o Associative learning: classical conditioning o Associative learning: operant/instrumental conditioning § Observational learning – changing behavior after exposure to another person doing something. Learning § Learning implies a change in behavior resulting from experience. Learning theories began in 20th century. Freud’s different approach to human behavior ignited many theories. o Earlier theories arose from the view that all behaviors are either reflexes or are the consequence of learning history or experience. This view is called behaviorism. § It was dominant in 20th century and influenced every area in psychology. Focus was too much on environment, stimulus and reaction. Didn’t focus on the mind that much. Mind was treated as black box, so its input, output was studied, not the mind itself. § Used animals rather than humans in experiments. John Watson was the founder of this thought – the school of behaviorism. Watson once claimed § “Give me a dozen healthy infants, well-formed, and my own specified world to bring them up in and I’ll guarantee to take any one at random and train him to become any type of specialist I might select—doctor, lawyer, artist, merchant- chief and, yes, even beggar-man and thief, regardless of his talents, penchants, tendencies, abilities, vocations, and race of his ancestors. (1930)” § But today we know they were wrong in many areas. However, science was enriched by their studies. Scaricato da Tommaso Ceccato ([email protected])  lOMoARcPSD|26894422 Non-associative learning – responding after repeated exposure to a single stimulus. § Habituation – a decrease in behavioral response to a stimulus. A simple way of learning. Depends on memory, otherwise we won’t know if something is repeating. It is different from sensory adaptation where a recurring stimulus is ignored by our perception. In habituation we are aware of the stimulus. Usually occurs for stimulus that is neither rewarding nor harmful. For example, getting used to sound of planes. o It allows us to focus on what’s new and ignore the familiar. o Dishabituation – it’s an increase in response to a change in something familiar, that was habituated previously. Might notice an airline sound if it sounds weird. § Sensitization – an increase in behavioral response after exposure to a stimulus. Usually happens for painful stimulus. May become sensitive to pain in stomach after a stomach disease. Associative learning: Classical conditioning § A form of learning in which a neutral stimulus comes to elicit a response when it is associated with a stimulus that already produces that response. § Pavlov was the grandfather of classical conditioning. Won Nobel prize in 1904 for his work on digestive processes. Dogs get reflexive saliva in the mouth when they have food in mouth. But later found that sight of food bowl and sound of footsteps of caregivers led to saliva in their mouth. o He studied these learning processes more deeply. o See dog diagram above o Unconditional response [UR] is the natural response, without having to learn it. Unconditional stimulus [US] triggers the unconditional response [UR]. o Conditional stimulus [CS] doesn’t trigger the UR intially. o After conditioning, the CS leads to a response similar to Unconditional response – called Conditional Response [CR]. CR happens when the Scaricato da Tommaso Ceccato ([email protected])  lOMoARcPSD|26894422 organism has learned of an association between Conditional Stimulus and Unconditional Stimulus like the Bell [CS] and the Food [CS]. § Classical conditioning not just in dogs o Observed in many animals – cockroaches, dolphins, humans. o Can happen in specific situations. Humans can learn to associate certain smells, events and sounds with certain emotions. § Having repeated experiences of painful injections after hearing ‘This is not going to hurt’, a person will learn to associate this phrase with pain and fear. § Here the phrase, ‘This is not going to hurt’, becomes a CS that creates fear § Features of Classical conditioning o Second order conditioning – when a CS is paired with a new stimulus S, that stimulus S produces CR. Scaricato da Tommaso Ceccato ([email protected])  lOMoARcPSD|26894422 § If being bitten by a dog is combined with the view of a dog, the fear [UR] will be associated with view of the dog [CS]. Later, just the view of a dog [CS] create a fear [CR]. § If a neighbor’s dog is barking whenever it is seen, the person will associate barking with viewing the dog. Consequently, only by hearing a bark, the person will feel fear [CR]. o Extinction – where the association between the CS and CR can be eliminated by repeatedly presenting the CS in isolation. o Spontaneous recovery – recovery of response after extinction and a resting interval. In dog’s case, it will generate saliva after hearing the bell, but in very less quantity. o Stimulus generalization – the CR can also be elicited by stimuli that are similar to the CS. For e.g. saliva production may be conditioned to 1000Hz sound but playing similar frequency sounds like 800 or 1100 Hz can also generate saliva but in lesser quantity. o Discrimination – it is possible to teach animals to discriminate between different but similar stimuli. If 1000 Hz frequency tone always result in food, and 800 Hz never gives food. There will be a strong response only in a narrow range around 1000 Hz or CS frequency. This reduces the stimulus generalization effect by narrowing down the range of CS. Video clip on Watson – a child conditioned to a loud hammer sound [US] that creates anxiety [UR] whenever Watson touched a white rat [CS]. He started to fear [CR] after seeing rats [CS] and similar stimuli like rabbits and dogs even Scaricato da Tommaso Ceccato ([email protected])  lOMoARcPSD|26894422 when there was no hammer sound. Even repulsed by fur coat and furry objects. Today such studies are unethical. Early behavioralists believed that humans and animals can learn any association between any US and CS. o But there are biological constraints to such learning. It was shown by a study in 1966 by Garcia. o Rats were given sweet water to drink but whenever they drink, light and sound were turned on. There was either a shock to some rats or illness given [US] given to other rats shortly after. o Associations made by rats § Rats that got shocked – drank sweet water but didn’t drink as soon as lights and sound were turned on. So, pain was associated with light and sound, not the smell of sweet water. § Rats that got illness – avoided the sweet water based on its smell but drank it when lights and sound were turned on. Doubts in this part. This means that rats associated illness with sense of smell and taste rather than light. o This means that taste and smell goes with feeling and sickness while sight and sound go with pain. o Later it was shown that monkeys can be easily conditioned to fear snakes but very difficult to condition them to fear flowers or baby monkeys. Criticisms and features of Classical conditioning o There needs to be a contiguity in presenting Conditional Stimulus. Which means, CS must be presented before the US. If CS is after or simultaneous with US, no learning can occur. So, CS serves as some kind of warning for US. Scaricato da Tommaso Ceccato ([email protected])  lOMoARcPSD|26894422 o Contingency – the CS should be informative with respect to the chance that US is offered. So, CS must be a predictor of US happening. As shown in the experiment below: o Contiguity and contingency features created support for cognitive view of learning. That is, the animal is not learning to associate CS with UR but merely using CS to prepare for the arrival of US. Scaricato da Tommaso Ceccato ([email protected])  lOMoARcPSD|26894422 o CR and UR are rarely the same. Saliva when there’s food is much more than CR. Rats that get associate light with shock have different UR and CR. In case of shock [US], heart rate accelerates [UR] but when there is light [CS] heart rate decelerates [CR].This means CR may have been a preparation for upcoming UR. Drugs CR and UR Drug users take drugs in a regular place or use same objects to do drugs. So, the develop a CR which is opposite of drug effect [UR] to reduce the upcoming effects of drug. This creates tolerance in drug user, so the drug user takes more for getting the same effect. When there’s no drug, there is craving. This craving may be more when person is in contact with objects associates with drugs or inside room where the person takes drugs. So, CR is present but UR may not be there. Moreover, when the person is not in the regular drug use environment, there may not be any CR before drug use. So, the person is not prepared to dampen drug effects in this new environment. This can lead to drug overdose. Associative learning: Operant learning Operant or instrumental conditioning is a form of learning in which the consequence of an action (response) determines the likelihood that it will be performed again. Learned is the relationship between response and the consequence (reinforcer or punishment). o Here the response is voluntarily generated by the organism o Law of Effect (Thorndike 1898) § Behavior is governed by its consequences. Scaricato da Tommaso Ceccato ([email protected])  lOMoARcPSD|26894422 § Performance i.e. the tendency to give a response, is strengthened if it is followed by a reward and weakened if it is not. o Thorndike put a hungry cat in a box. Cat had to push a lever to get out and eat foot. After many trials, cat took less time on successive trials. But it was not a sudden decline. Only gradually did the cat learn. Which means, cat didn’t gain any insight into the mechanism of trap door. As per law of effect, animals and humans have different tendencies to perform in certain ways. By selectively rewarding a certain tendency, that tendency will become more common because it was rewarded. BF Skinner (1904 - 1990) - law of effect was the inspiration for his later work. Founder of instrumental learning theories. o Made a sharp distinction between classical and operant conditioning. Because operant conditioning is due to voluntary decisions of animals o Used Skinner boxes or operant chambers. Animals were given certain stimuli and were given the opportunity to respond voluntarily. How did Skinner affect their behavior? By using the techniques: o Shaping – Successive approximations by applying direct reinforcement. For example reward a pigeon for a particular movement, and keep rewarding it for more subtle forms of that movement. This will shape the pigeon to do a complex trick. Used on circus animals and college students. Scaricato da Tommaso Ceccato ([email protected])  lOMoARcPSD|26894422 o Reinforcers – increase probability of increasing a particular behavior. § Primary (food and US) or Secondary (CS like ‘Well done’) § Positive (add something) and negative (remove something) reinforcers. Positive reinforcer need not always be good. Negative reinforcer may also be good, like removing a painful stimulus. § Punishment Positive punishment – adding pain or shock to the organism Negative punishment – removal of pleasant stimulus. Punishment is less effective than reinforcement. § Continuous reinforcement – after every desired act. § Partial reinforcement Fixed ratio – reward after every 4 responses. Variable ratio – Reinforcer after an average of 4 responses but not always after same number of responses. Fixed interval – food pellet after every 4 minutes Variable interval – food after on average 4 minutes. Most successful reinforcers are in Variable ratio of reinforcers Scaricato da Tommaso Ceccato ([email protected])  lOMoARcPSD|26894422 o Partial reinforcement extinction effect – Partial reinforcement leads to less reinforcement as shown above. So, partial reinforcement stays. § Useful for parenting – when a baby cries, parents may sometimes attend the baby and sometimes not. Unknowingly, they put the baby on partial reinforcement schedule. This makes crying stay longer. Continuous reinforcement [attending the baby every time] will make crying extinct sooner More on operant conditioning But operant conditioning is not independent of cognition of the animal. An organism CANNOT just learn any association. What a pigeon can learn depends on its biological design. Learning can also happen in absence of responses. o Tolman (1948) claimed that learning is not just a change in behavior but also an acquisition of new knowledge. So, there’s an element of cognition involved in learning. o He did a study that showed – rats that were driven through a maze solved it quicker than those who were not driven through it. Which means, rats made a cognitive map of the maze. This explains their better performance. Operant conditioning only works when reinforcer has contiguity with behavior. Otherwise wrong behavior can be shaped. Contingency with the behavior is also required. Reinforcer must follow the desired behavior, otherwise it won’t work most of the time. o The organism should have some sort of agency or control over the action. o Study of learned helplessness shows – when organism feels lack of control, they start to give up and start to block the stimulus. Some dogs were taught to avoid shocks by jumping to other box while others were just given shocks and couldn’t control it. In a later stage, in a different setup, dogs that had learned to avoid shocks were able to learn the desired action to stop shock. While dogs that didn’t learn earlier just gave up. o Humans may also learn helplessness – in depression humans may give up on trying. People in situations where they couldn’t do anything, may develop a feeling of helplessness. Scaricato da Tommaso Ceccato ([email protected])  lOMoARcPSD|26894422 Observational learning or Social learning The acquisition or modification of a behavior after exposure to another individual performing that behavior. o Modelling: § Bandura did observational studies. Showed that social behaviors like aggression can be learned by observation and imitation. § Bobo doll experiments – children saw two videos: adults playing with bobo doll; and adults attacking bobo doll. § Children who saw adults attack the doll, were more likely to attack the doll than children of the other group. o Vicarious learning – you learn the consequences of an action by watching others get reward or punishment for that action. § Does violence in movies and games affect social behavior? § Columbine shooting led to debate that video game ‘Doom’ caused aggression. § Studies in lab setting show that watching aggressive clips invoke aggressive behavior. But there is only a correlation. It is not clear yet, if violence in media causes violence in real life. Neurological basis of observational learning: o Rizzolatti showed that monkeys possess mirror neurons which are active not only when performing a specific action but also when another person is doing that action. o So, mirror neurons may be the basis of observational learning. However, firing of these neurons does not always lead to imitation of the action being watched. o Mirror neurons may help an animal to understand behavior of others and feel empathy. o Humans also have mirror neurons that get active when exposed to other’s behavior. Scaricato da Tommaso Ceccato ([email protected])  lOMoARcPSD|26894422 Psychology Notes Topic- 6 By Somansh –knows Madonna and Madonna knows him Memory Video ted talk by Loftus. False memory. Hundreds of people convicted due to false memory of witness and victim. Our memories are constructed and reconstructed. We and other people can change our memory. In normal as well as stressful situations, memory can be altered. Misinformation can easily alter memory and today misinformation is everywhere. In the 90s the psychotherapy sessions of dream interpretations, imagination and hypnosis were creating false memories in the patients. Bizarre memories of satan, torture and abuse were drilled into the patient during these sessions. Memory implantation influences future thought and behavior. So, a really dangerous tool which can be abused. If a person describes a memory with confidence, detail and emotion doesn’t mean that the memory was real. Memory like liberty is a fragile thing. Overview The study of memory How memory operates o Encoding o Storage o Retrieval Variety of memory When memory fails Memory Perception is the organization of current stimuli BUT memory is the organization of stimuli from the past (ideas and events). It is the nervous system’s capacity to retain and retrieve skills and knowledge. We have multiple memory systems, and each memory system has its own ‘rules’. Memory operates over time in 3 different phases o Encoding: Processing of information so it can be stored, and how will it be stored o Storage: retention of encoded representations over time. Consolidation is the neural process by which memory is stored in brain o Retrieval: recalling or recognizing stored memory when it is needed. § Recall § Recognition Not remembering may be due to error in any of these stages. Not paying attention to a person’s name will cause the name to not be encoded, and not even be stored in memory. Having something in memory but still being unable to recall is retrieval error. Scaricato da Tommaso Ceccato ([email protected])  lOMoARcPSD|26894422 Encoding According to Atkinson, there are 3 types of memory that varies in capacity and duration. 1. Sensory register or memory – has iconic (visual) and echoic memory (audio) § Contains all the raw input derived from senses. § Stays for about ~500 ms § Can be sent to short term memory if it is selected 2. Short term – remembers whatever we are working on. § Small capacity and can be easily replaced § Rehearsal helps to keep a short term memory alive 3. Long term memory § If a memory stays in short term memory for a long time, it may get transferred to long term memory § It has huge capacity and duration Short term memory – STM o Has limited capacity as shown by memory span studies. § In Memory span task, people get to view a sequence of items, and have to recall the sequence accurately. We usually remember around 7 (+/- 2) number/items sequences o Short term memory disappears as it decays and replaced. o But its capacity can be expanded by re-encoding the sequence § Eg UKEUCIAPHDFBIUSSR -> UK EU CIA PHD FBI USSR § Why? Because total number of chunks did not exceed 7. Figures show: Evidence for existence of STM and LTM Scaricato da Tommaso Ceccato ([email protected])  lOMoARcPSD|26894422 Long term memory – LTM o Unlimited capacity and relatively permanent. o Repeating short term memory can shift the memory to long term memory. o In free-recall task, people get a series of unrelated elements. They recall most elements from start of the list [LTM] and end of the list [STM]. § Initial items were rehearsed and put to LTM because people cared to rehearse items in the start but give up around after 7 items – the middle items. § Ending items were in STM so recall was easier. § In faster presentation of items, items couldn’t be rehearsed and thus items didn’t go to LTM. § Putting delay or giving participants a task after presenting last items on the list led to dip in recalling them. This proves that items in the last were indeed put in STM The idea that rehearsal caused a memory to be shifted from STM to LTM was challenged by later studies. Studies by Craik and Watkins (1973) and Nickerson and Adams (1979) o Craik and Watkins (1973) – gave participants a list of words, and they had to keep repeating the most recent word that started with letter ‘g’ while other words were presented. § Surprisingly, participants did not remember ‘g’ letter words any better than other words that were presented. This means, rehearsal by itself was not the key mechanism to shift a memory from STM to LTM. o Nickerson and Adams (1979) § Asked participants if penny had Lincoln facing left or right. People were only guessing the side. This means, people saw the penny every day for years, but still didn’t remember. Again, it is proven that mere repetition is not the key mechanism to shift a memory from STM to LTM. Today we know, memory is an active process requiring attention. Memory is the product of intellectual engagement and thinking. o So, STM is called Working Memory – a form of active processing system that keeps information available for current use. Can only do a limited number of processing o Working memory has the information being actively currently used. If the information in working memory [WM] is activated more and more, it goes to LTM. So, it is not the amount of time an information spends in STM/ WM but the encoding process of information Which encoding process promotes later recall o Depth of processing § Shallow or surface processing – does word have an uppercase or lowercase. Remembered less. § Deep processing or processing with meaning – does a word fit in a sentence. Remembered more Scaricato da Tommaso Ceccato ([email protected])  lOMoARcPSD|26894422 o Understanding – attach more meaning to it. This creates connections in brain and create more memory paths to that information. So, we remember much more complex information/story/concept if we understand it well. § A schema helps us understand and subsequently remember information contents. So, good encoding provides effective means to retrieve information later Storage o Retention of encoded representations over time. o It is in form of memory traces, done with memory consolidation o Memory consolidation is the neural process by which encoded information becomes stored in the memory. Transient and fragile potential memory contents are transformed into a more permanent state. o Process of memory consolidation takes some time. When a person gets a blow to the head, they don’t remember the recent events because they did not have the time to process it. May be that’s why videos played on high speed are not remembered well enough? § Memory consolidation restructures the neural setup and protein production is required for a memory trace to form. This is inhibited by the enzyme HDAC. When HDAC is active, proteins required for memory will not be formed and thus no memory created. The HDAC is the natural brake for memory creation. HDAC can be created by drugs. May be useful in treating dementia. Scaricato da Tommaso Ceccato ([email protected])  lOMoARcPSD|26894422 § Memory also requires neural adjustment called – Long term potentiation. LTP is, strengthening of a synaptic connection, making the postsynaptic neurons more easily activated by presynaptic neurons. Based on the work of Eric Kandel et al. Kandel and colleagues measured neural firing in a sea slug. If a presynaptic neuron is activated continuously, the post synaptic neuron’s firing increases with time. As if the neural link was strengthened. Or, cells that fire together, wire together. Maybe it is due to increased number of neurotransmitters at their synaptic connection points. § Memory is also consolidated if it is reconsolidation i.e. memory is recalled, used and reconsolidated again. When we recall, erase, reconstruct, activate memory, the memory gets reconsolidated. Used to treat PTSD o But where is memory stored o Everywhere in the brain. Lesley trained rats to run a maze, and removed various parts of rat’s brain. It was seen that the amount of brain removed affected their performance much more as compared to the area from which the brain was removed. So, memory is everywhere. But, central part of brain is of key importance in making new memories. Retrieval recalling or recognizing stored memory when it is needed. How do we retrieve – by using good retrieval cues, cues that help us enter a memory trace. Cues can work by: o Recreating the context in which the original learning occurred aka Context Reinstatement. § E.g. Divers learned 2 lists of words on land and underwater. They recalled the underwater list better when they were underwater, and land list when on land. § Mainly about recreating the mental state when learning occurred. Even imagining the learning context is good enough to enter the memory trace easily. Scaricato da Tommaso Ceccato ([email protected])  lOMoARcPSD|26894422 o Richer and deeper encoding results in better recall. § This means that creating more paths connected to the memory trace will ease the retrieval. Recreating or creating a related context helps create good encoding and cues. Varieties of memory o Long term memory also has various types o Explicit – conscious memory that can be recalled based on questions. § Episodic – specific individual events in one’s own life. Episodic and semantic memory have different brain structures. § Semantic – for memory in general. Moment or place we learned it is not important like, what’s capital of France? It is not dependent on when or how we learned it. Different contents are stored in different areas of the brain. Food knowledge is stored in different areas than facial knowledge. o Implicit – unconscious memory that cannot be voluntarily recalled. Requires indirect testing. No conscious attention needed. § Classical § Procedural Scaricato da Tommaso Ceccato ([email protected])  lOMoARcPSD|26894422 Memory failure o Forms of failure: o Inability to remember: o Amnesia is the deficit in long term memory, resulting from disease, brain injury, or psychological trauma – in which the individual loses the ability to retrieve vast quantities of information. § Retrograde amnesia – lose past memory of events, people and so on. Mostly due to injury on head. § Anterograde amnesia – lose the ability to make new memories. Due to alcohol abuse, bad surgery. In a failed surgery, patient lost the ability to form explicit memory but retained the ability to form implicit memory. o Absent mindedness – inattentive or shallow encoding of events. In everyday life we are attentive/aware of only small portions of our thoughts and actions. Every information is not encoded. § Some parents forget to drop the children at day-care and they die in the car o Memory reconstructions or distortions of memory – may be due to bias, suggestions or misattribution. Very common in patients as well as normal people. o Memory decay – forgetting over time. Memory is better for recent events as compared to older ones. o If there is longer period of retention, the memory will decay as seen in Forgetting curve by Ebbinghaus 1885. o This is because of § metabolic processes that cause decay in memory traces. In Goldfishes, metabolism increases in warm water, thus they have larger memory decay in hot water. § Due to interference from other information – That’s why there is less forgetting after sleep as compared to wakefulness state because no interference happened in sleep. Types of interference o Proactive and retroactive interference – Scaricato da Tommaso Ceccato ([email protected])  lOMoARcPSD|26894422