Learning Chapter 7 PDF

Learning Chapter 7 1  Overview Learning associations: Classical Conditioning Operant Conditioning Observational Learning 2  Defining Learning A Behaviourists Definition: Learning is a relatively permanent (long l...

Learning Chapter 7 1  Overview Learning associations: Classical Conditioning Operant Conditioning Observational Learning 2  Defining Learning A Behaviourists Definition: Learning is a relatively permanent (long lasting) change in an organism’s behaviour due to experience. As we will see later, more modern approaches to learning focus on more than just behaviour. 3  Associative Learning Brains naturally associate events that co-occur. This is called associative learning or learning by association. Much of the early psychological investigations of learning focused on this type of learning. 4  Classical Conditioning Classical conditioning, learning to associate one stimulus with another, was discovered by the Russian physiologist Ivan Pavlov. His work provided a basis for behaviourism. Ivan Pavlov (1849-1936) 5  Before Conditioning Before conditioning, food (Unconditioned Stimulus, US) produces salivation (Unconditioned Response, UR). Unconditioned stimulus (US): Unconditioned yummy dog food response (UR): dog salivates Unconditioned stimulus (US): a stimulus that unconditionally (automatically) triggers a response. The response is usually instinctual. Unconditioned response (UR): the unlearned, naturally occurring response to the unconditioned stimulus (US) 6  Before Conditioning A neutral stimulus (NS) (e.g., a tone) does not produce a salivation response. Neutral stimulus (NS) No response 7  During Conditioning The bell/tone (NS) is repeatedly presented with the food (US). Neutral Unconditioned stimulus (NS) Unconditioned response (UR): stimulus (US) dog salivates 8  After Conditioning The dog begins to salivate upon hearing the tone. The tone isn't neutral any more, it causes a response. The tone is now a Conditioned Stimulus (CS) and the salivation is the Conditioned Response (CR). Conditioned Conditioned response: stimulus dog salivates (formerly neutral) Conditioned stimulus (CS): an originally irrelevant stimulus that, after association with an unconditioned stimulus (US), triggers a conditioned response. Conditioned response (CR): the learned response to a previously neutral conditioned stimulus (CS). Usually the same behaviour as the UR. 9  Classical Conditioning The NS and the CS are the same stimulus. The difference is whether or not the stimulus triggers the conditioned response. The UR and the CR are the same response, triggered by different events. The difference is whether learning was necessary for the response to happen. 10  Acquisition Acquisition is the initial learning stage in classical conditioning in which an association between a neutral stimulus and an unconditioned stimulus takes place. In most cases, for conditioning to occur, the neutral stimulus needs to come before the unconditioned stimulus. The optimal time in between the two stimuli is about half a second. Learning is useful when it helps predict future relevant events. 11 Acquisition 12  Acquisition and Extinction Extinction refers to the diminishing of a conditioned response. If the US (food) stops appearing with the CS (bell), the CR decreases. The CS no longer predicts the US. 13  Spontaneous Recovery When extinction is followed by a rest period, presenting the tone alone might lead to a spontaneous recovery (a return of the conditioned response). If the CS (tone) is again presented repeatedly without the US, the CR becomes extinct again. 14  Stimulus Generalization Tendency to respond to stimuli similar to the CS is called generalization. Pavlov conditioned the dog’s salivation (CR) by using miniature vibrators (CS) on the thigh. When he subsequently stimulated other parts of the dog’s body, salivation dropped but still occurred. 15  Stimulus Discrimination Discrimination is the learned ability to distinguish between a conditioned stimulus and other stimuli that do not signal an unconditioned stimulus. 16  Watson: Applying Classical Conditioning to People Little Albert Study (1920): 9-month-old Little Albert was not afraid of rats John B. Watson and Rosalie Rayner then clanged a steel bar every time a rat was presented to Albert Albert acquired a fear of rats, and generalized this fear to other soft and furry things Watson prided himself in his ability to shape people’s emotions. He later went into advertising. 17 Applications of Classical Conditioning Classical Conditioning has been applied to many contexts. For example, drug rehabilitation: Substance abuse involves conditioned associations between drugs and various stimuli (people, places, etc.) To avoid cravings users should avoid people and places associated with previous drug use 18  Limits to the Behaviourist Approach Although the behaviourist approach provided many insights into learning, over time it became clear that it was inadequate. Behaviourist failed to fully appreciate two important factors that affect learning: 1) Biological predispositions an constraints 2) Cognitive Processes  Biological Predispositions Behaviourists believed that laws of learning were similar (almost identical) for all animals. Therefore, a pigeon and a person do not differ in their learning. However, later research demonstrated that learning is constrained by an organism’s abilities acquired through natural selection. People and animals are not Tabula Rasa (blank slates). Our ability to learn new behaviours is constrained by our innate nature.  Biological Predisposition in Classical Conditioning: Taste Aversion Taste Aversion conditioning demonstrates that the duration between the CS and the US may sometimes be long (hours). A biologically relevant CS (taste) led to John Garcia conditioning but other non-relevant stimuli (sight or sound) did not. Only a single pairing of the CS and US are required for this type of conditioning.  Cognitive Processes Early behaviourists believed that learned behaviours of all organisms (including humans) could be described by simple mechanisms that described links between stimuli and behaviours. Reference to internal mental states was not required. However, late in the behaviourists era it was suggested that animals learn the predictability of a stimulus, meaning they learn expectancy about the occurrence of a stimulus.  Expectancy and Classical Conditioning In the Rescorla-Wagner model of classical conditioning, a CS sets up an expectation that the US will soon appear. The expectation leads to many behaviours associated with the US. Respondent vs. Operant Behaviour Respondent behaviour: behaviour that occurs as an automatic response to a stimulus In classical conditioning, the behaviour elicited by the CS and US is respondent Operant behaviour: any behaviour that operates on (affects) the environment May or may not be in response to an external event 24  Operant Conditioning Operant conditioning forms an association between behaviours and their consequences (events that are a result of the behaviour). The results of behaviour determine the likelihood of that behaviour being repeated in the future. The consequence of the behaviour may be reinforcing (rewarding), punishing or neutral. 25  Thorndike’s Law of Effect Edward Thorndike studied problem solving by placing cats in a puzzle box; they were rewarded with food when they solved the puzzle. The cats appeared to learn by trial and error. Thorndike proposed the law of effect: behaviours followed by favourable consequences become more likely, and behaviours followed by unfavourable consequences become less likely. 26  B.F. Skinner B. F. Skinner pioneered more controlled methods to explore Edward Thorndike’s principles. 27  Reinforcement Reinforcement refers to any feedback from the environment This meerkat has just that makes a behaviour more completed a task out in the cold likely to recur. Positive reinforcement: adding something desirable (e.g., warmth) Negative reinforcement: ending something unpleasant (e.g., turn For the meerkat, this warm light is off an annoying sound) desirable. 28  Context and Learning The consequence of a behaviour can depend on the context it is performed in Reinforcement and punishment become associated with salient aspects of the environment in which they occur (discriminant stimuli) The learned response will only be emitted when the appropriate discriminant stimulus is present 29 Primary & Secondary Reinforcers Primary reinforcer: a stimulus that meets a basic need or otherwise is intrinsically desirable, such as food, sex, fun, attention, or power Secondary/conditioned reinforcer: a stimulus (e.g., money) which has become associated with a primary reinforcer (money buys food, builds power) 30  Shaping Behaviour When a creature is not likely to randomly perform exactly the behaviour you are trying to teach, you can reward any behaviour that comes close to the desired behaviour. Shaping is the operant conditioning procedure in which reinforcers guide behaviour towards the desired target behaviour through successive approximations. This technique is used extensively in animal training. 31 Immediate & Delayed Reinforcers Immediate Reinforcer: A reinforcer that occurs instantly after a behaviour. A rat gets a food pellet for a bar press. Delayed Reinforcer: A reinforcer that is delayed in time from behaviour that produces it. For example, a paycheck that comes twice a month. Reinforcers become increasing less effective as the delay increases. 32  Delayed Reinforcers Humans have the ability to link a consequence to a behaviour even if they aren’t linked sequentially in time. However, we may be inclined to engage in behaviours that provide small immediate reinforcers (watching TV) rather than large delayed reinforcers (getting an A in a course) which require consistent work. 33  Reinforcement Schedules B.F. Skinner experimented with the effects of giving reinforcements in different patterns or “schedules” to determine what worked best to establish and maintain a target behaviour. Continuous reinforcement: Reinforces the desired response each time it occurs the subject acquires the desired behaviour quickly Partial/intermittent reinforcement: reinforces a response only part of the time the target behaviour takes longer to be acquired but, persists longer without reward 34 Partial Reinforcement: Ratio Schedules Ratio Schedules determine rewards based on the number of instances of the desired behaviour Fixed-ratio schedule: Reinforces a response only after a specified number of responses e.g., piecework pay. Variable-ratio schedule: Reinforces a response after an unpredictable number of responses. hard to extinguish because of the unpredictability. (e.g., behaviours like gambling, fishing.) 35 Partial Reinforcement: Interval Schedules Interval schedules reinforce behaviours based on the interval of time since the last reinforcement. Fixed-interval schedule: Reinforces a response only after a specified time has elapsed e.g., getting your paycheck every two weeks Variable-interval schedule: Reinforces a response at unpredictable time intervals produces slow, steady responses. 36 Effect of Schedules of Reinforcement Fixed ratio: Predictable rewards leads to Fixed interval: short bursts of fast learning, high rate of responding responding when anticipating reward Variable ratio: high, consistent responding, even if reinforcement stops Variable interval: slow, consistent (resists extinction) responding  Punishment Punishments have the opposite effects of reinforcement. These consequences make the target behaviour less likely to occur in the future Positive Punishment: ADD something unpleasant/aversive (e.g., spank a child) Negative Punishment: TAKE AWAY something pleasant/ desired (e.g., no TV time, no attention) Positive does not mean “good” or “desirable” and negative does not mean “bad” or “undesirable.”  When is punishment effective? Punishment works best in natural settings when we encounter punishing consequences from actions such as reaching into a fire; in that case, operant conditioning helps us to avoid dangers. Artificial punishments work best when consequences happen as they do in nature: Severity of punishments is not as helpful as making the punishments immediate and certain. Problems with Physical Punishment Punished behaviours may restart when the punishment is over; learning is not lasting a child may learn to discriminate among situations, and avoid those in which punishment might occur. The child might learn an attitude of fear or hatred, which can interfere with learning. This can generalize to a fear/hatred of all adults or many settings Physical punishment models aggression and control as a method of dealing with problems Problems with Physical Punishment Punishing focuses on what NOT to do, which does not guide people to a desired behaviour Even if undesirable behaviours do stop, another problem behaviour may emerge that serves the same purpose, especially if no replacement behaviours are taught and reinforced In order to teach desired behaviour, reinforce what’s right more often than punishing what’s wrong Applications of Operant Conditioning Operant Conditioning principles (reinforcement, shaping) are widely applied in education, sports, and business.  Applications of Operant Conditioning Parenting 1) Rewarding small improvements toward desired behaviours works better than expecting complete success, and also works better than punishing problem behaviours. 2) Giving in to temper tantrums stops them in the short run but increases them in the long run. Self-Improvement Reward yourself for steps you take toward your goals. As you establish good habits, then make your rewards more infrequent (intermittent).  Biological Predisposition in Operant Conditioning Biological constraints predispose organisms to learn associations that are naturally adaptive. The article “The misbehavior of organisms” (Breland and Breland, 1961) showed that animals drift towards their biologically predisposed Marian Breland Bailey instinctive behaviours.  Evolutionary Predisposition and Operant Conditioning After being rewarded with food for turning right, rats turn left on the next trial. Why was the reinforced behaviour not emitted? Rats are foraging animals. After clearing out the food in one location they search new locations. It takes many trials for them to consistently turn right.  Cognition & Operant Conditioning According to behaviourist laws of operant conditioning, animals learn by the consequences of their actions. If no reward or punishment occurs nothing is learned. However, it was discovered that if rats are allowed to explore a maze without any reward given (e.g., cheese) they develop mental representations of the layout of the maze (a cognitive map). This type of learning is known as latent learning: skills or knowledge gained from experience, but not apparent in behaviour until rewards are given.  Latent Learning When a reward for completing a maze is given, previously unrewarded rats that have wandered the maze demonstrate their knowledge by quickly completing the maze.  Cognitive Maps When rats were rewarded with food in maze A, they could easily emit the correct behaviour to obtain the food reward in maze B. This indicates they had built a cognitive map of the maze allowing them to determine a new route.  Learning by Observation Higher animals, especially humans, learn through observing and imitating others. Observational learning: watching other people's behaviour & learning from their experience.  Modelling Modelling: The behaviour of others serves as an example of how to respond to a situation. We may imitate this model regardless of reinforcement.  Modeling and Imitation Modeling and imitation begins early in life. This 14-month-old child imitates the adult on TV in pulling a toy apart. Children are prone to over-imitating: copying adult behaviours that have no function and no reward. Humans imitate both behaviours and emotions (“emotional contagion”).  Bandura’s Bobo Doll Experiment Bandura’s classic “Bobo doll” experiment illustrated the powerful effect of imitation.  Video: Bobo (2m:47s)  Antisocial Effects of Observational Learning Children who witness violence in their homes, but are not physically harmed themselves, may hate violence but still may become violent more often than the average child  Media Models of Violence Research shows that viewing media violence (TV, video games) leads to increased aggression and reduced prosocial behaviour (such as helping an injured person). This violence-viewing effect might be explained by imitation, and also by desensitization toward pain in others.  Prosocial Effects of Observational Learning Prosocial behaviour: actions which benefit others, contribute value to groups, and follow moral codes and social norms Children model prosocial behaviour at least as well as antisocial behaviour Demonstrating prosocial behaviour is more effective that creating rules, lecturing or punishing Especially when the positive effects of the behaviour is made clear  Defining Learning A Modern Definition: Learning is the acquisition of new knowledge, skills, or responses from experience that results in a relatively permanent change in the state of the learner. 57 Development Chapter 11 1  Overview Prenatal Development Infancy and Childhood: Brain Development Motor Development Cognitive Development Social Development Moral Development Puberty, sexuality and teenage social development Adulthood and aging 2  Conception Conception: A sperm and an egg unite to bring genetic material together and form one organism: the zygote (the fertilized cell). Fertilization typically happens 1 to 2 days after intercourse, but can happen as much as 5 days later. 3  Prenatal Development Germinal stage: ~2-week period that begins at conception; brief lifetime of zygote Zygote: Fertilized egg that contains chromosomes from both a sperm and an egg the initial cell divides in 2, 4, 8, 16... After ~100 cells have been produced the individual cells begin to differentiate Eventually groups of cells will produce different structures 4  Prenatal Development Embryonic stage: Period that lasts from the 2nd to the 8th week Fetal stage: Period that lasts from the 9th week until birth At 5 months creation of neurons is mostly complete. Myelination starts but will not be complete until adulthood 6 month old fetuses might be able to survive outside the womb 5  Prenatal Development Teratogens are substances such as viruses and chemicals that can damage the developing embryo or fetus. 6  Prenatal Development Fetal Alcohol Spectrum Disorder (FASD) refers to cognitive, behavioural, and body/brain structure abnormalities caused by exposure to alcohol during pregnancy. Changes physical appearance Lowers intelligence Causes learning difficulties Distressingly common Especially in disadvantaged communities 7  Prenatal Development Tobacco Smoke Exposure: various chemicals found in tobacco smoke act as teratogens Lower birth weight (correlated with health difficulties) More likely to have perceptual, attentional and learning problems as children Increased risk of stillbirth and infant death Even secondhand and third-hand smoke is dangerous Exposure remains a danger during childhood 8  Prenatal Development The fetus's brain starts processing information long before birth After 6 months of development the fetus responds to sounds and even bright lights A fetus can learn to even before birth: Immediately after birth infants prefer the sound of their own mother's voice 9  Newborn Both physical and mental abilities are very limited The brain of a newborn infant is only 25% of the size of an adult brain Unlike many species, humans are born with limited instinctual knowledge and abilities 10  Newborn Reflexes are behaviours that are inborn and do not have to be learned. Reflexes to ensure that infants can feed: Rooting reflex: when something touches a newborn’s cheek, the infant turns toward that side with an open mouth. Sucking reflex: will suck on things put into their mouths Crying when hungry: extremely effective way to motivate caregiver to take actions 11  Maturation In developmental psychology, maturation refers to biologically-driven growth and development enabling orderly (predictably sequential) changes in behaviour (e.g., people sit, then crawl, then walk) Experience (nurture) can adjust the timing, but maturation (nature) sets the sequence. 12  Motor Development Development of motor abilities is dependent on maturation processes affecting both body (e.g., muscle strength) and brain (e.g., cerebellum, motor cortex). As long as the child is healthy and has sufficient opportunity to exercise, experience has little effect of this sequence and attempts at training are ineffective. 13  Jean Piaget (1896-1980) Jean Piaget is the most influential early researcher of childhood cognitive development. Piaget believed that children think in fundamentally different ways than adults. According to Piaget, cognitive development is made possible by biological development of the brain aided by learning achieved through interacting with the environment. 14  Learning About the World: Schemas A schema is a mental framework used to hold and organize information about a certain topic or category. They provide a mental framework for understanding the world. Piaget believed schema formation and adjustment plays an important role in childhood learning about the world. “Cow!” “Cow!” This child has formed a schema called “COW” which he uses to think about animals of a certain shape and size. 15 Schemas: Assimilation & Accommodation After learning about dogs and forming a “Dog” Schema she can assimilate (apply an existing schema to new information) a new experience into her schema by categorizing the cat as a “Dog” she can accommodate (update and add schemas) her animal schemas by separating cats and dogs into separate schemas. 16  Piaget's Theory of Cognitive Development Piaget's theory describes cognitive development as progression through a series of age dependent stages. During each stage the child gains new mental abilities and thinking is qualitatively different at each stage. The timing of these stages is approximately the same for most healthy individuals. 17 Piaget’s Stages of Cognitive Development 18  Sensorimotor Stage In the sensorimotor stage (birth to age 2), babies explore the world by looking, hearing, touching, mouthing, and grasping. Piaget believed that a child at this stages has very limited knowledge of how the world works. They mainly sense and react. However, this knowledge grows rapidly. 19  Sensorimotor: Understanding of the World According to Piaget, children younger than 6 months of age do not understand object permanence: knowing that objects exist even when they are out of sight. However, recent research shows that even very young children show evidence of understanding characteristics of the world such as object permanence. 20  Preoperational Stage In Piaget's preoperational stage (2 to 6 or 7 years) children could form more sophisticated internal representations (schemas, words, etc.) but were unable to perform mental operations (transformations) on these representations. 21  Conservation Evidence for difficulty in performing mental operations comes from an inability of preoperational children to correctly perform an conservation task. Conservation refers to the ability to understand that a quantity is conserved (does not change) even when it is arranged in a different shape. The characteristics do not change despite changes in appearance. 22  Egocentrism Piaget concluded that preschool children are egocentric: They cannot understand that other people may perceive they world differently. For example, when asked to show her picture to mommy, a 2-year-old holds the picture facing her own eyes, believing that her mother can see it through her eyes. 23  Theory of Mind By ages 4-5 children start develop the ability to understand an other person’s mental state when they begin forming a theory of mind. Theory of mind refers to the ability to understand that others have their own mental representations of the world (thoughts and perspective). The false belief problem on the right probes such ability in children. 24  Autism Spectrum Disorders Autism Spectrum Disorders has been associated with difficulties in developing a theory of mind. Individuals with this disorder have difficulty in mentally mirroring the thoughts and actions of others; this difficulty has been called “mind blindness.” Children with disorders on the autism spectrum have difficulties in three general areas: establishing mutual social interaction using language and play symbolically displaying flexibility with routines, interests, and behaviour 25  Concrete Operational Stage In the concrete operational stage (ages 6 to 11) children demonstrate an ability to perform mental operations for concrete concepts (not abstract). For example, they can: grasp conservation & other concrete transformations understand simple mathematical transformations and the reversibility of operations Reversing 3 + 7 = 10 to figure out that 10 - 7 = 3 26  Formal Operational Stage During the formal operational stage (11+ years) children gain the ability to think abstractly. Like adults, they are able to use symbols and create mental simulations of the world. They are able to begin to understand abstract ideas (political, religious, etc.) and learn symbolic math (algebra). 27  Reflecting on Piaget’s Theory Although Jean Piaget’s observations and stage theory are useful, today’s researchers believe: Development is a continuous process (not stages) Children show some mental abilities and operations at an earlier age than Piaget thought, e.g., Object permanence Mental operations Formal Reasoning Formal logic is a smaller part of cognition, even for adults, than Piaget believed. 28  Culture and Cognitive Development Lev Vygotsky focused on how children learn in the context of social communication. People actively teach children about the world. Vygotsky saw development as building on a scaffold of mentoring, language, and cognitive support from parents and others. Children learn thinking skills by internalizing language from others and developing inner speech: “Put the big blocks on the bottom, not the top…” 29  Culture and Cognitive Development The ability to learn from others depends on three fundamental skills: Joint attention: Ability to focus on what another person is focused on Imitation: notice & do what another person does Social referencing: Ability to use another person’s reactions as information about the world 30  Social Development Infants develop stranger anxiety at around 8 months of age. This is one early sign of a child's attachment to their caregiver. Attachment refers to an emotional bond between and infant and a care giver. In children, attachment can appear as a desire for physical closeness to a caregiver. 31  Imprinting In some species, attachment forms through a process called imprinting. During a critical period shortly after birth the infant animal will become rigidly attached to the first moving object they see. Humans to not imprint. However, familiarity plays an important role in attachment. 32  Origins of Attachment Many lines of evidence suggest that attachment is based on physical affection and comfortable body contact, and not based on rewards such as food. Infant monkeys bond with a surrogate mother that is comfortable to hold and not to one that provides nourishment. 33  Attachment Differences: Separation The degree and style of parent-child attachment has been tested by the “strange situations” test. In this test, a child is observed as: 1) A mother and infant child are alone in an unfamiliar (“strange”) room; the child explores the room as the mother just sits 2) The mother leaves the room 3) After a few moments, the mother returns 34  Attachment Differences: Separation Secure attachment: most children (60 percent) often feel distress when mother leaves, and seek contact with her when she returns Insecure attachment (ambivalent style): clinging to mother, less likely to explore environment, and may get loudly upset with mother’s departure and is difficult to calm when she returns Insecure attachment (avoidant style): seeming indifferent to mother’s departure and return 35  Attachment: Nature or Nurture? Could these differences in attachment be due to the child's temperament (pattern of emotional reactivity)? Some infants have an “easy” temperament; they are happy, relaxed, and calm Some infants seem to be “difficult”; they are irritable, with unpredictable needs and behaviour, and intense reactions Temperament plays a role but parenting is also important. 36  Attachment: Nature or Nurture? The way the parents have interacted with the child previously affects how children react to separation. Attentive, responsive, sensitive, calm parenting is correlated with the secure attachment style. Training in sensitive responding for parents of temperamentally- difficult children led to doubled rates of secure attachment. Securely attached children do better than insecurely attached children. They have better: Academic achievement Cognitive functioning Psychological well-being Emotional adjustment 37 Separation Anxiety: Nature or Nurture? Children developed an Internal working model of relationships: beliefs about the self, the primary caregiver, and the relationship between them. A child with a secure attachment act as if they are certain that their care giver will respond when they feel insecure. A child with an insecure attachment act as if they are certain that their care giver will not respond when they feel insecure. 38 Effects of Environment on Attachment A long-term study by the National Institute for Child Health showed that attachment style is strongly influenced by maternal sensitivity and responsiveness, but not by the quality, amount, stability, or type of day care Attachment to parents will not be affected, if the parents spend sufficient time with their child and are attentive and caring 39  Attachment Later in Life Many psychologists believe that our early attachments have a strong influence on our adult relationships and our ability to build and maintain intimacy. Our attachment with our parents also influence our relationships with our children. Secure attachment at young ages is correlated with better relationship skills as an adult. The gender of the parents does not matter: Mom & Dad; Mom & Mom, Dad & Dad 40  Parenting Styles Style Response to Child’s Behavior Parents impose rules “because I said so” Authoritarian and expect obedience. Parents submit to kids’ desires, not Permissive enforcing limits or standards for child behavior. Parents enforce rules, limits, and Authoritative standards but also explain, discuss, listen, and express respect for child’s ideas and wishes. 41  Outcomes with Parenting Styles Authoritative parenting is more strongly correlated with: high self-esteem, high self-reliance & high social competence. low aggression. But are these caused by parenting style? or are parents responding to a child’s temperament or are both a function of culture ? Or genes? 42  Moral Reasoning Kohlberg sought to describe the development of moral reasoning by posing moral dilemmas to children and adolescents. For example, “Should a person steal medicine to save a loved one’s life?” 43 Kohlberg's 3 Levels of Moral Reasoning 1) Preconventional Morality (childhood): Morality of an action is primarily determined by its consequences for the actor (avoid punishment or gain reward). 2) Conventional Morality (adolescence): Morality of an action is primarily determined by the extent to which it conforms to social rules. 3) Postconventional Morality (some adults): Morality of an action is determined by a set of general principles that reflect core values decisions may differ based on context 44  Moral Intuition Jonathan Haidt believed moral decisions are often driven by moral intuition: quick, gut-feeling decisions. This intuition is not just based in moral reasoning but also in emotions such as: Disgust: We may turn away from choosing an action because it feels awful. Elevated feelings: We may get a rewarding delight from some moral behaviour such as donating to charity. 45  Moral Intuition Given a hypothetical choice to save five people from an oncoming trolley by killing one person, many people’s choice is determined not just by reasoning, but by disgust. Many people would flip a switch to make this choice, but not as many would push a person on the tracks to save five others. 46  Promoting Moral Action How can we promote moral action? Teach self-discipline: ability to resist impulses Teach people to delay gratification Promote empathy and compassion for others Provided experience serving others Teach people to evaluate social influences and refusal skills to resist immoral social pressure 47  Adolescence Adolescence is the transition period from childhood to adulthood. Period of development that begins with the onset of sexual maturity (about 11-14 years of age) and lasts until the beginning of adulthood (about 18-21 years of age) 48  Puberty Puberty is the time of sexual maturation (becoming physically able to reproduce). During puberty, increased sex hormones lead to: Primary Sex Characteristics: development of reproductive organs and external genitalia Secondary Sex Characteristics: non-reproductive sex linked traits 49  The Protraction of Adolescence The sequence of sexual maturation is predictable, but the time of onset varies. There exists considerable variation between genders, cultures, time periods/eras. Affected by: Improved diet and health Chemicals (especially those that mimic estrogen) Recently the age of puberty has decreased but the age of adulthood responsibility has increased. The exact social effects of this is not fully understood 50  Puberty Maturing early can have social advantages & costs. Tends to be more positive for boys & negative for girls. May create unrealistic expectations about the adolescent’s maturity. Timing of puberty for girls has greater emotional and behavioural influence than occurrence itself. For boys, the speed (slower=better) with which they pass through puberty may be a better predictor of negative outcomes than is the timing. 51  Brain Development Puberty is accompanied by increases in connectivity between cortical regions. In addition, the start of puberty is associated with the start of a series of substantial changes in frontal cortex. This includes synaptic pruning that makes the brain more efficient. The frontal lobes will continue to develop into the mid 20s. The emotional limbic system develops before the frontal judgment centres of the brain are sufficiently developed to guide and control those emotional impulses. This is thought to explain teenage impulsiveness observed in many cultures. 52 53  Adolescent Cognitive Development As the frontal cortex develops adolescents become capable of more abstract reasoning. They use this reasoning to: Think hypothetically about choices & their consequences plan how to pursue goals Think about the minds of others including “what do they think of me?” Think about how reality compares to ideals become critical about their parents, society & themselves 54  Peer Influences Adolescence marks a shift in emphasis from family relations to peer relations. Peer pressure forms but has less influence as we age. Adolescents form same-sex cliques that meet opposite-sex cliques in public places. Eventually, these people will form mixed-sex cliques, pair off into romantic relationships 55  Peer Influences After puberty peer influences become increasingly important in both negative & positive ways. Peers teach social skills and individuals learn to cooperate and to gain popularity. Although parents are often frustrated by peer influences they are necessary for proper social development. Adolescents make better decisions when no one is around Participants in one study played a video driving game with or without their peers in the room. The presence of peers greatly increased the number of risks taken and crashes experienced by adolescents but had little or no effect on adults. 56 Is adolescence a cultural convention? About 60% of preindustrial societies don’t even have a word for adolescence (Schlegel & Barry, 1991). When a Krobo female menstruates for the first time, older women take her into seclusion for 2 weeks and teach her about sex, birth control, and marriage. a public ceremony is held to announce her status as an adult woman 57  Sex and Gender Sex refers to a set of biological attributes and is primarily associated with physical and physiological features including genetics, hormone function, and sexual anatomy. Sex is usually categorized as female or male but there is variation in the biological attributes that comprise sex and how those attributes are expressed. Gender refers to the socially constructed roles, behaviours, expressions and identities of girls, women, boys, men, and gender diverse people. It influences how people perceive themselves and each other. Although usually conceptualized as a binary (woman/ man) there is considerable diversity in how individuals and groups understand, experience, and express it. A Cisgendered person has a gender identity that matches their sex assigned at birth 58  Sexuality Adolescent interest in sex often precedes knowledge about it. Sex education is lacking in many areas Even teens provided with education often lack basic knowledge and/or ignore advice Teen pregnancy and sexually transmitted diseases are still common despite efforts to reduce them 59 60  Sexual Orientation ~2% of Canadians identify as homosexual or bisexual An awareness of sexual orientation usually occurs during or slightly before puberty (Males: ages 6-18; Females: ages 11-26) Men tend to me ridged in their sexual orientation than women Biology (genes, prenatal environment) plays a major role in determining orientation “Conversion” techniques do not work 61  Adulthood Adulthood: Stage of development that begins around 18 to 21 years and ends at death. Defining adulthood into stages is more difficult than defining the stages of childhood or adolescence. However, changes continue to occur. Physical Changes: physical decline sensory changes health Cognitive Changes: memory, processing seed Emotional and Social Development 62  Adult Physical Development In our mid-20’s, we reach a peak in the natural physical abilities which come with biological maturation: muscular strength cardiac output reaction time sensory sensitivity The gradual decline in later years is only partially due to age Lifestyle, diet, and exercise all play a role 63 Impact of Sensory and Motor Decline 64 Lifestyle Can Slow the Aging Process Good food and exercise can: build muscles and bones maintain telomeres – extends the lifespan of cells stimulate neurogenesis (in the hippocampus) and new neural connections improve cognition reduce the risk of dementia 65  Cognitive Decline After age 25, people show declines on some measures of cognitive performance but not others. Short-term memory declines more than long-term memory Memory for specific experiences (episodic memory) declines more than general knowledge (semantic memory). 66  Cognitive Decline Techniques for improving memory also work for elderly individuals. An elderly individual that uses a mnemonic can outperform a young person that doesn't. 67  Brain Adaptation to Aging Across a variety of tasks, older adult brains show bilateral activation and young adult brains show unilateral activation. Older brains seem to compensate for the declining abilities of one neural structure by calling on other neural structures for help. 68  Social Aspects of Aging Older adults experience much lower levels of stress, worry, and anger than younger adults do 69  Social Aspects of Aging Younger adults are oriented toward future-pertinent (useful) information while older adults focus on (positive) emotional satisfaction in the present, perhaps because of shortened futures. Older adults focus on and remember more positive experiences and emotions. 70 Consciousness Chapter 5 1  Overview Consciousness & Unconsciousness Difficulties in studying consciousness The properties of consciousness Changes in Consciousness: Sleep: Sleep cycle Dreaming Drugs: Addiction Drug type Hypnosis 2  Consciousness In the textbook, Consciousness is defined as: “A person’s subjective experience of the world and the mind.” Other descriptions and definitions include: Alertness: being awake vs. being unconscious Mental content: thoughts, & imaginings Self-awareness: the ability to think about self Free will: being able to make a “conscious” decision 3  Consciousness As we saw in the Chapter 1, consciousness was once psychology's main focus but it fell out of favour a number of reasons. One reason is because we are not even close to solving the “Hard Problem”: Nothing we know about the laws of physics explains how consciousness is produced. 4  Other Reasons... Problem of other minds: Fundamental difficulty we have in perceiving the consciousness of others You cannot observe another person's conscious experience and introspection is unreliable Consciousness is hard to study Can we even know that other people have consciousness? Could they be zombies? Phenomenology: How things seem to a conscious person Are people's conscious experience the same? Is your red the same as my blue? 5  Levels of Consciousness Minimal consciousness: Low-level kind of sensory awareness and responsiveness that occurs when the mind inputs sensations and may output behaviour Full consciousness: Consciousness in which you know and are able to report your mental state 6 Modern Cognitive Unconscious Mind Cognitive unconscious: Mental processes that give rise to a person’s thoughts, choices, emotions, and behaviour even though they are not experienced by the person Answers often come into consciousness without any awareness of the processes used to generate them Conscious efforts to analyze and solve problems often lead to better solutions than “gut” unconscious ones But not always 7  Brain and Consciousness Mind-body problem: how is the mind is related to the brain and body? Research has shown that there is a widespread pattern of brain activation (the default network) that is engaged when a person is conscious and: Is not engaged in any task or a well practised task that requires little effort Is associated with daydreaming 8  Circadian Rhythm Sleep is part of our natural 24 hour Circadian Rhythm. This daily cycle is controlled by one of our bodies “biological clocks” located in the suprachiasmatic nucleus. The suprachiasmatic nucleus is connected to the eye and is affected by the brightness of light. This nucleus affects alertness and sleep by causing the pineal gland to decrease melatonin production in the morning and increase production in the evening. 9  Investigating Sleep & Dreams We monitor brain and body activity during sleep Brain activity usually measured by EEG Measure muscle activity, body temperature, eye movements, etc. Expose the sleeping person to noise and words, and then examine the effects on the brain (waves) and mind (memory). We can wake people and see which mental state (e.g. dreaming) goes with which brain/body state. 10 The Sleep Cycle: Stages of Sleep Sleep Stages: there are distinct patterns of brain waves and muscle activity that are associated with different types of consciousness and sleep There are five distinct types of sleep The Sleep Cycle refers to the patterns of shifting through all the sleep stages over the course of the night We “cycle” through all the sleep stages in about 90 minutes on average. 11 Falling Asleep: From Alert to Alpha When an individuals close their eyes but remains awake, brain activity slows down from generating beta waves (12.5-30 Hz) to a large amplitude and slow, regular alpha waves (~10 Hz). 12  Falling Asleep: Entering Stage 1 As a person falls asleep: breathing slows down You may have hypnagogic hallucinations. Your brain waves change from alpha waves to those of NREM-1 (Non-REM Stage 1) Brain waves become slower and irregular (~4-7Hz) 13  Non-REM Sleep Stages As time passes the brain progresses into deeper stages of sleep. In the deep sleep state (stage 3/4) brain activity slows in delta waves (~3 Hz). 14  REM Sleep After reaching the deepest stage of sleep the brain suddenly becomes more active (beta waves: ~25 Hz) and the eyes start moving rapidly. This stage is known as REM (rapid eye movement). Most dreams take place during REM sleep. 15  REM Sleep During REM Sleep: Heart rate rises and breathing becomes rapid. “Sleep paralysis” occurs when the brainstem blocks the motor cortex’s messages and the muscles don’t move. Genitals are aroused (not caused by dream content) and stay this way after REM is over. REM is sometimes known as “paradoxical sleep”; the brain is active but the body is immobile. 16  The Sleep Cycle During sleep the brain cycles through the sleep stages. The longer you remain asleep the longer REM cycles become and less time is spent in deep sleep. With age, there are more awakenings and less deep sleep. 17  Why do we Sleep? We need to Sleep Deprivation: Fatigue and subsequent death. Impaired concentration. Memory impairment Emotional irritability. Depressed immune system. Greater vulnerability to depression. 18 19 Sleep Loss Increases Accident Risk Accident Frequency Sleep loss results in more accidents, probably caused by impaired attention and slower reaction time. 20  Sleep Hygiene: How to Sleep Well Turn the lights low and turn all screens off. Helps increase melatonin production Eat earlier, and drink less alcohol and caffeine. Get up at the same time every day. Exercise (late afternoon is best). Don’t check the clock; just let it happen. Get help for anxiety and depression. 21  Sleep Disorders Insomnia: persistent difficulty in falling or staying asleep. A common disorder with many causes: Depression, anxiety or stress Irregular sleep schedules Narcolepsy: sudden sleep attacks during waking activity. may collapse into REM sleep may occur at almost any time sleep may last from 30 seconds to 30 minutes 22  Sleep Disorders Sleep apnea (“with no breath”): repeated awakening after breathing stops; time in bed is not restorative sleep Sufferer is often unaware of the frequent but short lived awakenings Age and excess weight are risk factors Severe health hazard, seek medical attention 23  Sleep Disorders Night terrors: The sudden arousal from deep sleep with intense fear accompanied by physiological reactions (e.g., rapid heart rate, perspiration). Sleepwalking and Sleeptalking: A deep sleep disorder which is usually harmless and not recalled the next day. These behaviors, mostly affect children, and occur in deep sleep. They are not related to dreaming. 24  Dreams Discovering the link between dreams and REM sleep has allowed us to discover a great deal about what people dream about and the roles that dreams play in our life. Want to know what people dream about? Wake them during REM sleep and ask. 25  Video: What’s in a Dream? (13m:23s) 26  Dream Consciousness The experience of dreaming is similar to, but different from, waking consciousness. Dreaming can be distinguished from waking consciousness in several ways. Illogical thought and Uncritical acceptance: sudden and impossible changes are readily accepted during dreams Meaningful sensation: perceptual experiences during dreams are realistic. Vision and auditory sensations dominate. Intense emotion: the full range of emotion is experienced Difficulty remembering: dreams are rarely remembered unless we wake from the dream state 27  What We Dream About Negative Emotional Content: 8 out of 10 dreams have some negative emotional content. e.g., failure dreams are common Sexual Dreams: Contrary to what some people think, sexual dreams are sparse. Sexual dreams in men are 1 in 10; and in women 1 in 30. Recent Events: elements of events that occurred recently; especially new or unusual events. Sensory Experience: incorporate some salient ongoing stimuli (e.g., if the phone rings you may also dream it). 28  Dream Theories Freud's Wish Fulfillment: Sigmund Freud suggested that dreams provide a psychic safety valve to discharge unacceptable feelings. The dream’s manifest (apparent) content may also have symbolic meanings (latent content) that signify our unacceptable feelings. Lacks scientific support Easy to make up stories to explain someone's dreams 29  Dream Theories Across cultures, a majority of people agreed with Freudian theories that dreams contain something deep and relevant. 30  Dream Theories Activation-Synthesis Theory: REM sleep involves the stimulation of random activity in the cortex (sights, sounds, emotions, memories, etc.) by subcortical structures. Dreams are our cortex's attempts to provide structure and meaning to these random disjointed experiences. The bizarness of dreams may be the result of a deactivation of prefrontal cortex 31  Dream Theories Areas with increased activation during REM are in Red and deactivated areas are in Blue. 32  Why We Dream: We Need To All dream researchers believe we need REM sleep. When deprived of REM sleep and then allowed to sleep, we show increased REM sleep called REM Rebound. 33  Psychoactive Drugs Psychoactive Drug: are chemicals that, when introduced into the body alter conscious experience (perceptions, mood, etc.) and/or affect behaviour. These drugs act as neurotransmitter agonists or antagonists. Many psychoactive drugs are physically and/or psychologically harmful. 34  Tolerance Tolerance of a drug refers to the diminished psychoactive effects after repeated use. Tolerance feeds addiction because users take increasing amounts of a drug to get the desired effect. 35  Dependence Physical dependence: the body has been altered in ways that create cravings for the drug. Absence of a drug may lead to a feelings of physical pain or other negative physical symptoms (e.g., exhaustion, depression, hallucinations, convulsion) Psychological dependence: A person feels a strong desire to use the drug even in the absence of physical dependency. a person’s ability to cope with daily life decrease as a drug becomes “needed” to relax, socialize, or sleep. 36 Dependence 37  Withdrawal After tolerance and dependency has developed, drug users experience withdrawal if they stop using the drug. Withdrawal: negative physiological and psychological consequences to the absence of a drug to which there is a dependency Withdrawal worsens addiction because users want to resume taking the drug to end withdrawal symptoms. 38  Addiction When a drug user has developed a tolerance and dependency for a drug they are said to be addicted Addiction is a compulsive craving for a chemical substance, despite its adverse consequences (physical & psychological). “Meth” user from 1998 to 2002 39  Depressants Depressants are drugs that reduce neural activity in the central nervous system and slow body functions. They include: Alcohol Barbiturates & Benzodiazepines Opiates (Narcotics) 40  Alcohol Effects of Alcohol: Slow neural processing, reduced sympathetic nervous system activity, and slower thought and physical reaction Reduced memory formation caused by disrupted REM sleep and reduced synapse formation Alcohol myopia: alcohol hampers attention leading people to respond in simple ways to complex situations Impaired self-control: impaired judgment, self-monitoring, and inhibition; increased accidents and aggression (disinhibitor) 41  Alcohol Not all effects of alcohol arise solely from changes in neurological changes. Expectancy theory: alcohol effects can be produced by people’s expectations of how alcohol will influence them in particular situations Numerous studies using placebos have shown that people that think they have consumed alcohol will exhibit stereotypical “drunk” behaviours 42  Alcohol Although alcohol can be safely used very, very infrequently, alcohol is the most harmful drug in our society. This is due, in part, to the fact that is legal, inexpensive and readily available. 43  Opiates Opiates are chemicals such as morphine and heroin that are made from the opium poppy. reduce anxiety, and especially reduces pain. high doses produce euphoria. work at receptor sites for the body’s natural pain reducers (endorphins) highly addictive: extreme withdrawal symptoms 44  Opiates Rate of opioid overdoses has increased by over 400% since the year 2000, creating a public health emergency. Most opioids originally received from physician- written prescriptions. Current strategies for dealing with this epidemic include physician training, policy changes, and public education. 45  Stimulants Stimulants are drugs that excite neural activity and speed up body functions. Physical effects include: dilated pupils, increased breathing and heart rate, increased blood sugar, decreased appetite Examples of stimulants: Caffeine Nicotine Amphetamines, Methamphetamine Cocaine Ecstasy 46  Caffeine adds energy and increases alertness disrupts sleep for 3-4 hours can lead to withdrawal symptoms if used daily: headaches irritability fatigue difficulty concentrating depression 47  Nicotine Nicotine is the active ingredient in cigarettes Mild stimulant for some people Is highly addictive Very bad withdrawal symptoms: Insomnia, Anxiety, Irritability Is very, very harmful to health 48 Nicotine The main effect of nicotine use is ADDICTION. 49 The real reason dinosaurs became extinct 50  Why do people smoke? People usually start smoking because it is socially rewarding. Invited by peers and influenced by culture and media. Social pressure is also what causes people to quit. 51  Other Stimulants Other powerful stimulants: e.g., Cocaine, Methamphetamine, Ecstasy/MDMA Produce: euphoria and energy. Followed by: irritability, insomnia, seizures, depression Are typically highly addictive and users develop a tolerance Have short and long term health consequences Including death 52  Hallucinogens Hallucinogens are psychedelic (mind-manifesting) drugs that distort perceptions and evoke sensory images in the absence of sensory input. Effects can be dramatic and unpredictable. Types include LSD (or acid), mescaline, psilocybin, PCP, and ketamine. 53  LSD LSD (lysergic acid diethylamide) is powerful hallucinogenic drug that is also known as acid. Interferes with serotonin transmission Causes hallucinations--images and other “sensations” that didn’t come in through the senses Experiences range from euphoric to panic Users sometimes harm themselves Can have emotional consequences that last years 54  THC THC is the major active ingredient in marijuana that triggers a variety of effects, including mild hallucinations. amplifies sensations disinhibits impulses may cause euphoric mood (or sometimes panic) impaired motor coordination, perceptual ability, and reaction time affects judgment and short-term memory lack of ability to sense satiety may have some medicinal uses, research ongoing 55  THC With repeated long-term use of THC: THC accumulates in the body, increasing the effects of next use Over time, the brain shrinks in areas processing memory and emotion Smoke inhalation damage 56  Influences on Drug Use Biological factors: dependence in relatives, thrill- seeking in childhood, genes related to alcohol sensitivity and dependence, and easily disrupted dopamine reward system Psychological factors: seeking gratification, depression, problems forming identity, problems assessing risks and costs Social influences: media glorification, observing peers, community and cultural influences 57  Marijuana Use The use of marijuana in teenagers is directly related to the “perceived risk” involved with the drug. 58  Drug Prevention and Treatment Education about the long-term costs Efforts to boost people’s self-esteem and purpose Attempts to modify peer associations and teaching refusal skills 59  Hypnosis Hypnosis: a social interaction in which one person (the hypnotist) suggests to another (the subject) that changes in their subjective experiences will occur (perceptions, feelings, thoughts, or behaviours). This state has been called heightened suggestibility It has been proposed that hypnosis leads to an altered state of consciousness: experience that departs from the normal subjective experience of the world and the mind 60  Hypnosis Hypnotic induction: the process by which a hypnotist leads someone into the state of heightened suggestibility. 61  Hypnosis People vary in their susceptibility to hypnosis. About 20% of people are highly hypnotizable: These people seem to be more easily absorbed in imaginative activities. They are able to focus and to lose themselves in fantasy. 62  Hypnosis Hypnotic suggestion can have many effects: Alter perception: “The headache is fading away.” Alter behaviour: “Your arm might rise by itself.” Alter emotions: “You are feeling more relaxed.” Alter or create memories: “You got lost in a mall as a child.” 63 Hypnotic analgesia: reduction of pain due to hypnotic induction and suggestion 64  Hypnosis and Cognition Instructing hypnotized people to ignore the words can eliminate the Stroop effect fMRI reveals no conflict between the word and the ink colour However, hypnosis doesn't seem to be necessary for highly suggestible people 65  Hypnosis Hypnotic suggestion cannot: work when people refuse to cooperate bestow ‘superhuman’ abilities or strength accurately boost recall of forgotten events (it is more likely to implant false recall) 66 Sensation & Perception Chapter 4 1  Overview The interpretive nature of perception perceptions differs from reality Psychophysics: From stimulus energy to basic perceptions Attention: Selecting information The major senses: Including ones you probably don't even know that you have 2  Sensation & Perception Sensation: The process of encoding stimulus energy registered in our sense organs into neural impulses. Perception: Organization, identification, and interpretation of sensory signals in order to form mental representations of events in the world The conscious experience of objects and scenes (relationships between objects) 3  Sensory Systems To represent the world, we must detect physical energy (a stimulus) from the environment and convert it into neural signals. Transduction is the transformation of physical stimuli (sights, sounds, smells) into neural impulses. Transducers are located in our sensory organs. Eyes, ears, skin... 4  Perception To construct a perception the brain uses both the sensory information (bottom-up processing) and information already stored in the brain (top-down processing). Loch Ness monster or a tree Flying saucers or clouds? branch? 5 What’s on the bottle? Not Exactly G Rated? Don't worry, children see dolphins. Why? Children have less knowledge and do not rely on top-down processing as much as adults. 6  Psychophysics Psychophysics investigates the relationship between physical events and conscious experience. For every physical energy we can detect there is a corresponding conscious experience. Physical World Psychological World Light Intensity Brightness Sound Intensity Loudness Sugar Concentration Sweetness 7  A simple Question: New scientific disciplines usually start by asking simple question. Psychophysics started with: What is the weakest stimuli (light, sound,etc.) that we can consciously detect? The quietest sound? The dimmest light? 8  Thresholds Absolute Threshold: Minimal intensity needed to just barely detect a stimulus. Conventionally set to equal to the stimulation needed to detect the stimulus 50% of the time. 9  Difference Threshold Difference threshold (or JND: just noticeable difference) refers to the minimum difference between stimuli (in colour, pitch, weight, etc.) that can just barely be detected. 10  Difference Threshold Weber's Law: two stimuli must differ by a minimum proportion (rather than a constant amount), to be perceived as different. Stimulus % difference Light 8% Weight 2% Tone 3% 11  Sensory Adaptation To detect novelty in our surroundings, our senses tune out a constant stimulus. Put a bandage on your arm and after awhile you don’t sense it. Sensory adaptation: Sensitivity to prolonged stimulation tends to decline over time as an organism adapts to current conditions 12  Selective Attention Our conscious awareness processes only a small part of all that we experience. Our sensory systems provide far more information than consciousness can handle. Selective attention filters information and only passes on a small subset of information to consciousness. 13 Video:Colour Changing Card Trick (2m:39s) 14  Inattentional Blindness When our attention is focused on an object or task we will often not notice even very salient events. Inattentional blindness: Failure to perceive objects that are not the focus of attention. More than half of observers fail to see a person in a gorilla suit when counting the number of times a ball was passed. 15  Change Blindness Even when our attention is focused on an object we often fail to notice many of it's characteristics. Change blindness: When people fail to detect changes to the visual details of a scene to which they are attending. Two-thirds of individuals giving directions failed to notice a change in the individual asking for directions. 16 Vision Visible light is a small segment of the electromagnetic spectrum. Our visual system encodes to basic physical characteristics of light: 1) Wavelength 2) Intensity 17  Intensity Intensity: Amount of energy in a wave determined by the amplitude. It is related to perceived brightness. 18  Wavelength Wavelength is the distance from the peak of one wave to the peak of the next. Hue (colour) is related to the wavelength of the light. 19  Wavelength Violet Indigo Blue Green Yellow Orange Red 400 nm 700 nm Short wavelengths Long wavelengths Colours are related to different wavelengths of light. But the relationship isn't one-to-one. Colour vision is more complicated than that. 20  The Eye Cornea: Transparent tissue where light enters the eye. Acts as a lens to focus light into the eye. Iris: Muscle that expands and contracts to change the size of the opening (pupil) for light. Lens: Focuses the light rays on the retina. Retina: Contains sensory receptors (transducers) that process visual information and sends it to the brain. 21 The Eye 22  The Lens Accommodation: The process by which the eye’s lens changes shape to focus near or far objects on the retina. If accommodation occurs improperly, myopia (nearsightedness) or hyperopia (farsightedness) may occur. 23  Retina Retina: The light- sensitive inner surface of the eye, containing receptor rods and cones in addition to layers of other neurons (bipolar, ganglion cells) that process visual information. 24 Photoreceptors: Rods and Cones 25  Fovea Fovea: Central point in the retina around which the eye’s cones cluster. The fovea provides the highest visual acuity (ability to see fine details). 26  Bipolar & Ganglion Cells Bipolar cells receive messages from receptors and transmit them to ganglion cells, whose axons converge to form the optic nerve. 27  Optic Nerve and Blind Spot Optic nerve: Carries neural impulses from the eye to the brain. Blind Spot: Point where the optic nerve leaves the eye there are no receptor cells located there. 28  Colour Vision Trichromatic theory: the eye contains three types of cone receptors that are sensitive to red, blue and green colours. The pattern of responding (number of action potentials) across the three types of cones provides unique codes for each colour. 29 RGB Colour Mixing 30  Two Visual Pathways What pathway: identification of objects perception and conscious awareness Where pathway (How): identifying an object’s location controlling & coordinating motor interactions with objects 31  What Pathway Damage Visual Form Agnosia: inability to recognize objects by sight Patient D.F. could not to orient her hand to match the angle of the slot in the testing apparatus. However, was able to insert a card into the slot at various angles. 32  Perceptual Constancy Perceptual Constancy: our ability to see objects as appearing the same even under different lighting conditions, at different distances 33  Lightness Constancy The squares A and B are exactly the same shade of grey but our perception is that A is a dark grey in a bright light and that B is a light grey in shadow. 34  Colour Constancy Colour constancy provides the ability to see a consistent colour in changing illumination. However, this system can be fooled: 35  Size Constancy Size constancy: we have an ability to use distance-related context cues to help us see objects as the same size even if the image on the retina becomes smaller. 36 Gestalt Rules of Perceptual Organization Gestalt Psychologist proposed that the perceptual system constructed perceptions by apply simple grouping rules. 37  Grouping & Reality Although grouping principles usually help us construct reality, they may occasionally lead us astray. 38  Depth Perception Depth perception is the ability to judge how far away an object is. Depth perceptions can be calculated by using two types of information: Binocular Cues and Monocular Cues. 39  Binocular Cues Binocular Disparity: our two eyes view the world from different angles. The difference in the retinal images of the two eyes provides information about depth. 40  Monocular Cues Interposition: When one object appears to block the view of another, we perceive the blocking object as being closer than the object being blocked. 41  Monocular Cues Relative Size: If two objects are similar in size, we perceive the one that casts a smaller retinal image to be farther away. When we know the approximate size of an object we can compare the apparent size with the familiar size to judge distance. 42  Monocular Cues Linear Perspective: Parallel lines, such as railroad tracks, appear to converge in the distance. The more the lines converge, the greater their perceived distance. 43  Monocular Cues Relative Height: We perceive objects that are closer to the horizon in our field of vision to be farther away than those that are lower. 44  Monocular Cues Relative motion: Objects closer to a fixation point move faster and in opposing direction to those objects that are farther away from a fixation point, moving slower and in the same direction. 45  Monocular Cues Light and Shadow and provide a great deal of evidence about the shape of objects; which parts are closer and which parts are farther away. 46 47 48  Hearing Sound Waves: Sound waves are changes in air pressure over time causing compressing and expanding of the air molecules 49  Sound Waves Intensity: Amount of energy in a wave, determines the amplitude, relates to the perceived loudness. 50  Sound Waves Pitch is related to the frequency of a sound. Frequency is the inverse of the wavelength of sound. Low frequency waves: low pitch High frequency waves: high pitch 51  Sound Waves Sounds are rarely composed of a single frequency (pure tone) of constant amplitude. Complexity refers to the mix of frequencies and changes in amplitude that make up a sound. This is related to the sound’s timbre. 52  The Ear Outer Ear: Collects and sends sounds to the eardrum. Middle Ear: Chamber between eardrum and cochlea containing three tiny bones (hammer, anvil, stirrup) that amplify the vibrations of the eardrum on the cochlea’s oval window. Inner Ear: Innermost part of the ear, containing the cochlea, semicircular canals, and vestibular sacs. 53 The Ear 54  Cochlea Cochlea: Coiled, bony, fluid-filled tube in the inner ear, it contains basilar membrane. The auditory receptors, know as hair cells, are attached to the basilar membrane. c e lls hair a hle Coc 55  Perceiving Loudness Large amplitude sound waves are perceived as louder than low amplitude waves. The greater the amplitude of the sound wave the larger the amplitude of the vibrations of the basilar membrane. This causes a greater number of hair cells to send signals to the brain. 56  Hearing Loss Exposure to loud sounds can cause damage to the inner ear, especially the hair cells (sensorineural hearing loss) Structures of the middle and inner ear can also be damaged by disease or physical trauma (conduction hearing loss) 57  Perceiving Pitch Place Code: Different frequencies stimulate hair cells in different places along the length of the basilar membrane. The brain determines pitch on the basis of which neurons are activated. Best at encoding high frequencies. Temporal Code: Sound frequencies stimulate hair cells to fire at a rate proportional to the sound frequency. Best at encoding low frequencies. 58  Perceiving Location Intensity differences: The head acts as a “shadow” or partial sound barrier. Time differences: Time differences as small as 1/100,000 of a second can cause us to localize sound. 59  Somatosenses The body senses are referred to as the somatosenses. Touch: pressure, texture, vibration Thermoreceptors: warmth, cold Nocioreceptors (pain) 60  Pain Circuit Nociceptors are sensory receptors whose signals are interpreted by the brain as pain. Nociceptors send signals along thin nerve fibres to interneurons in the spinal cord that may pass the signals to the brain. 61  Gate-Control Theory Gate-Control Theory: neurons in the spinal cord act as “gates” that can block or transmit pain signals to the brain. The “gate” is opened by the activity of pain signals travelling up the small nerve fibres and is closed by non-pain activity in larger fibres or by information coming from the brain. 62 Body Position, Movement and Balance The vestibular sense monitors the head (and body’s) position to maintain balance Relies on the semicircular canals and vestibular sacs of the inner ear Kinesthesis (“movement feeling”) refers to sensing the movement and position of individual body parts relative to each other. sensors in the joints and muscles send signals that coordinate with signals from the skin, eyes, and ears 63  Video: Losing proprioception (3m:56s) 64  Smell Humans have a poor sense of smell for an animal. Even so, humans have 350 different types olfactory receptor neurons (ORNs) allowing us to detect about 10,000 different odours. 65  Smells, Memories and Emotions Sensations of smell do not pass through the “sensory switchboard” (thalamus). The output of the ORNs is sent to the olfactory bulb. The olfactory bulb sends output to the temporal lobe and the limbic system, influencing memory and emotion. Smells are effective in triggering emotional responses and are powerful memory cues, especially for very old (childhood) and emotional memories. 66  Taste The tongue is covered with thousands of bumps (papillae) which contain taste buds (which house taste receptor cells). There are receptors for five different types of tastes, each of which may have had survival functions. Some aspects of taste perception are genetic, while others are learned. There are individual differences in taste perception and Sweet: tolerance of food textures and spicy foods. energy Umami: Bitter: source (savoriness) potential proteins to grow poisons and repair tissue Sour: potentially toxic acid Salty: sodium essential to physiological processes 67  Video: Supertasters (9m:3s) 68  Sensory Interaction Sensory interaction occurs when different senses influence each other. The flavour of a food is actually a sensory interaction between its taste, smell and, pain receptors (hot spice) and texture. Sensory interactions are a normal part of sensory function. 69