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ch. 3 Learning, memory, and behavior

Terms in this set (71)

-nonassociative learning occurs when an organism is repeatedly exposed to one type of stimulus
-two important types of nonassociative learning are habituation and sensitization
-a habit is an action that is performed repeatedly until it becomes automatic, and habituation follows a very similar process
-essentially, a person learns to "tune out" the stimulus
--ex. if you live near a train track and trains pass by your house on a regular basis. When you first moved into the house it was annoying but after living there for a few months you became used to it and stopped covering your ears every time the trains pass

-dishabituation occurs when the previously habituated stimulus is removed
-more specifically, after a person has been habituated to a certain stimulus, and the stimulus is removed, this leads to dishabituation; the person is no longer accustomed to the stimulus
-if the stimulus is then presented again, the person will react as if it was aa new stimulus, and is likely to respond even more strongly to it than before
-in the train example above, dishabituation could occur when you go away on vacation for a few weeks to a quiet beach resort
-the train noise is no longer present, so you become dishabituated to that constant noise
-then, when you return to your home and the noisy train tracks, the first time you hear the train after you return, you notice it again
-the noise may cause you to cover your ears again or react even more strongly because you have become dishabituated to the sound of the trains passing

-sensitization is, in many ways, the opposite of habituation
-during sensitization, there is an increase in the responsiveness due to either a repeated application of a stimulus or a particularly aversive or noxious stimulus
-instead of being able to tune out or ignore the stimulus and avoid reacting at all (as in habituation), the stimulus actually produces a more exaggerated response
-ex. if you attend a rock concert and sit near the stage. The feedback noise from the amplifier may at first be merely irritating, but as the aversive noise continues, instead of getting used to it, it actually becomes much more painful and you have to cover your ears and eventually move
-sensitization may also cause you to respond more vigorously to other stimuli
-ex. suppose you leave the rock concert, and an ambulance passes
-the siren noise, which usually doesn't bother you, seems particularly loud and abrasive after being sensitized to the noise of the rock concert
-sensitization is usually temporary and may not result in any type of long-term behavior change
-desensitization occurs when a stimulus that previously provoked an exaggerated response (something that we were sensitized to), no longer evokes an exaggerated response
-going back to the example of leaving a rock concert and being more sensitized to noise: at first the sound of the siren is very abrasive, but by the next morning noises no longer bother you-you have become desensitized
-classical (or respondent) conditioning is a process in which 2 stimuli are paired in such a way that the response to one of the stimuli changes
-ivan pavlov, who first named and described the process of classical conditioning, did so by training his dog to salivate at the sound of a ringing bell
-dogs naturally salivate at the sight and smell of food; it is the biological response that prepares the dogs for food consumption
-the stimulus (food) naturally produces this response (salivating), however, dogs do not intrinsically react to the sound of a bell in any particular way
-pavlov's famous experiment paired the sound of a bell (an auditory stimulus) with the presentation of food to the dogs, and after a while, the dogs began to salivate to the sound of a bell even in the absence of food
-the process of pairing the two initially unrelated stimuli changed the dogs' response to the sound of the bell over time; they became conditioned to salivate when they heard it
-the dogs effectively learned that the sound of the bell was meant to announce food

-this example demonstrates a few key concepts about classical conditioning. This type of learning relies on specific stimuli and responses
--a neutral stimulus is a stimulus that initially does not elicit any intrinsic response. For Pavlov's dogs, this was the sound of the bell prior to the experiment
--an unconditioned stimulus (US) is a stimulus that elicits an unconditioned response (UR). Think of this response like a reflex. It is not a learned reaction, but a biological one: in this case, the presentation of food is the unconditioned stimulus and the salivation is the unconditioned response
--a conditioned stimulus (CS) is an originally neutral stimulus (bell) that is paired with an unconditioned stimulus (food) until it can produce the conditioned response (salivation) without the unconditioned stimulus (food)
--finally then, the conditioned response (CR) is the learned response to the conditioned stimulus. It is the same as the unconditioned response, but now it occurs without the unconditioned stimulus. For the dogs, salivating at the sound of the bell is the conditioned response

-acquisition, extinction, spontaneous recovery, generalization, and discrimination are the processes by which classically conditioned responses are developed and maintained

1. Acquisition: refers to the process of learning the conditioned response. This is the time during the experiment when the bell and food are always paired

2. Extinction: in classical conditioning, occurs when the conditioned and unconditioned stimuli are no longer paired, so the conditioned response eventually stops occurring. After the dogs have been conditioned to salivate at the sound of bell, if the sound is presented to the dogs over and over without being paired with the food, then after some period of time the dogs will eventually stop salivating at the sound of the bell

3. Spontaneous recovery: is an extinct conditioned response again when the conditioned stimulus is presented after some period of time. For example, if the behavior of salivating to the sound of the bell becomes extinct in a dog, and it is then presented to the dog again after some amount of lapsed time and the dog salivates, the conditioned response was spontaneously recovered

4. Generalization: refers to the process by which stimuli other than the original conditioned stimulus elicit the conditioned response. So, if the dogs salivate to the sound of a chime or a doorbell, even though those were not the same sounds as the conditioned stimulus, the behavior has been generalized

5. Discrimination: is the opposite of generalization, and occurs when the conditioned stimulus is differentiated from other stimuli; thus, the conditioned response only occurs for conditioned stimuli. If the dogs so not salivate at the sound of a buzzer or a horn, they have differentiated those stimuli from the sound of a bell

-organisms seem predisposed to learn associations that are adaptive in nature
--one powerful and very long lasting association in most animals (including humans) is taste aversion caused by nausea and/or vomiting
-an organism that eats a specific food and becomes ill a few hours later will generally develop strong aversion to that food
-many organisms develop the aversion specifically to the smell or taste of the food (occurs in most mammals), but it is also possible to develop an aversion to the sight of the food (occurs in birds)
-the function of this quickly learned response is to prevent an organism from consuming something that might be toxic or poisonous in the future
-the response happens to be one that does not need a long acquisition phase (it is typically acquired after one exposure) and has a very long extinction phase; in fact for most organisms, it never extinguishes
-the other category of associative learning is operant (or instrumental) conditioning
-whereas classical conditioning connects unconditioned and neutral stimuli to create conditioned responses, operant conditioning uses reinforcement (pleasurable consequences) and punishment (unpleasant consequences) to mold behavior
-however, just as with classical conditioning, timing is everything
-in classical conditioning, it was important for the neutral stimulus to be paired with the unconditioned stimulus (that is, for them to occur together or very close together in time), in order for the neutral stimulus to become conditioned
-in operant conditioning, it is just as important for the reinforcement or the punishment to occur around the same time as the behavior in order for learning to occur

-one of the most famous people to conduct research in the area of operant conditioning was B.F. Skinner
-skinner worked with animals and designed an operant conditioning chamber (later called a "skinner box") that he used in a series of experiments to shape animal behavior
-for example, in one series of experiments, a hungry rat would be placed inside a Skinner box that contained a level
-if the rat pressed the lever, a food pellet would drop into the box
-often the rat would first touch the level by mistake, but after discovering that food would appear in response to pushing the lever, the rat would continue to do so until it was sated
-in another series of experiments, the Skinner box would be wired to deliver a painful electric shock until a lever was pushed
-in this example, the rat would run around trying to avoid the shock at first, until accidentally hitting the lever and causing the shock to stop
-on repeated trials, the rat would quickly push the lever to end the painful shock
1. Reinforcement: is anything that will increase the likelihood that a preceding behavior will be repeated; the behavior is supported by a reinforcement. There are two major types of reinforcement: positive and negative

-positive reinforcement: is some sort of desirable stimulus that occurs immediately following a behavior. In the above experiments, the food pellet was a positive reinforcer for the hungry rat because it causes the rat to repeat the desired behavior (push the lever)
-negative reinforcement: is some sort of undesirable stimulus that is removed immediately following the behavior
--in the above experiments, the electric shock is a negative reinforcer for the rat because it causes the rat to repeat the desired behavior (again, push the lever) to remove the undesirable stimulus (the painful shock)
-anything that increases a desired behavior is a reinforcer; both positive and negative reinforcements increase the desired behavior, but the process by which they do so is different
-positive reinforcement does it by adding a positive stimulus (something desirable) and negative reinforcement does it by removing a negative one (something undesirable)
-positive reinforcement adds and negative reinforcement subtracts
-while several brain structures are involved in operant conditioning, the amygdala is understood to be particularly important in negative conditioning, while the hippocampus is believed to be particularly important in positive conditioning
-another key distinction for reinforcement is between primary and secondary or unconditioned and conditioned reinforcers

1. Primary (or unconditioned) reinforcers are somehow innately satisfying or desirable. These are reinforcers that we do not need to learn or see as reinforcers because they are integral to our survival
-food is a primary positive reinforcer for all organisms because it is required for survival
-avoiding pain and danger are primary negative reinforcers for the same reason; avoidance is important for survival

2. Secondary (or conditioned) reinforcers are those that are learned to be reinforcers
-these are neutral stimuli that are paired with primary reinforcers to make them conditioned
-for example, suppose that every time a child reads a book, she receives a stamp
-after accruing ten stamps, she can exchange these for a small pizza
-the pizza, being food, is the primary reinforcer, and the stamps are secondary reinforcers
-the child learns to find the stamps desirable because they help her get something she wants-pizza
-secondary reinforcers can also be paired with other secondary reinforcers
-for example, suppose that after collecting ten stamps, instead of receiving a pizza, the child receives a coupon that is good for one small pizza
-in this example, both the stamps and the coupon are secondary reinforcers
-almost any stimulus can become a secondary reinforcer, but it must be paired with a primary reinforcer in order to produce learned behavior
-there are 4 important intermittent reinforcement schedules: fixed-ratio, variable-ratio, fixed-interval, and variable-interval
-ratio schedules are based on the number of instances of a desired behavior, and interval schedules are based on time

1. A fixed-ratio schedule: provides the reinforcement after a set number of instances of the behavior
-ex. if a rat receives a food pellet every 10 times it pushes the lever, after it has been conditioned, the rat will demonstrate a high rate of response (will push the lever rapidly, many times to get the food)

2. A variable-ratio schedule provides the reinforcement after an unpredictable number of occurrences
-a classic example of reinforcement provided on a variable-ratio schedule is gambling; the reinforcement may be unpredictable, but the behavior will be repeated with the hope of a reinforcement
-both fixed-ratio schedules and variable-ratio schedules produce high response rates; the chances that a behavior will produce the desired outcome (a treat or a jackpot or some other reinforcement) increases with the number of responses (times the behavior is performed)

3. A fixed-interval schedule provides the reinforcement after a set period of time that is constant
-the behavior will increase as the reinforcement interval comes to an end
-for example, if an employee is reinforced by attention from the boss, the employee might work hard all the time, thinking the boss will walk by any second and notice the hard work (and provide the positive reinforcement, attention)
-once the employee learns that the boss only walks by at the top of the hour every hour, the employee may become an ineffective worker throughout the day, but be more effective as the top of the hour approaches

4. A variable-interval schedule provides the reinforcement provides the reinforcement after an inconsistent amount of time
-this schedule produces a slow, steady behavior response rate, because the amount of time it will take to get the reinforcement is unknown
-in the employee-boss example, if the boss walks by at unpredictable times each day, the employee does not know when they might receive the desired reinforcement (attention)
-thus, the employee will work in a steady, efficient manner throughout the day, but not very quickly
-the employee knowns it doesn't matter how quickly he works at any given time, because the potential reinforcement is tied to an unpredictable time schedule
1. Continuous
-slow response rate
-fast extinction rate
-best way to teach new behavior, but has the fastest rate of extinction

2. Fixed-ratio
-reinforcer given after a set number of responses
-fast response rate
-medium extinction rate
-post-reinforcement pause may be an analogue to procrastination

3. Fixed-Interval
-reinforcer given after set amount of time
-medium response rate
-medium extinction rate
-long pause in responding following reinforcement ,followed by accelerating rate

4. Variable-ratio
-reinforcer given after variable number of responses
-fast response rate
-slow extinction rate
-slowest rate of extinction (behavior persists longer despite lack of reinforcer)

5. variable interval
-reinforcer given after variable amount of time
-fast response rate
-slow extinction rate
-tends to produce a low to moderate steady rate of responding
-note: these same schedules can also be used for punishments

-reinforcements and reinforcement schedules explain how behaviors can be learned, but not every behavior is learned by simply providing a reinforcement
-for example, think about how a baby learns to walk. do babies spontaneously walk one day and then receive some sort of reinforcement from their parents for doing so? Of course not. Instead, parents shape the desired behaviors by reinforcing the smaller intermediate behaviors necessary to achieve the full desired behavior, walking
--thus, parents will reinforce their child's attempts to pull herself up, so she will try again
-once she's mastered pulling herself up and standing while holding onto something, they will reinforce the child's attempts to stand while not holding anything
--and so on until the child is able to walk on her own
--shaping is a way to learn more complex behaviors by breaking them down and reinforcing the "pieces of the puzzle" until the whole behavior is strung together
-like reinforcement, punishment is also an important element of operant conditioning, but the effect is the opposite: reinforcement increases behavior while punishment decreases it
-punishment is the process by which a behavior is followed by a consequence that decreases the likelihood that the behavior will be repeated
--like reinforcement, punishment can be both positive and negative
-positive reinforcement involves the application, or pairing, of an undesirable stimulus with the behavior
--for example, if cadets speak out of turn in military boot camp, the drill sergeant makes them do twenty push ups

-on the contrary, negative punishment involves the removal of a desirable stimulus after the behavior has occurred
--for ex. if a child breaks a window while throwing a baseball in the house, they lose TV privileges for a week

-positive reinforcement adds and negative reinforcement subtracts

-commonly, reinforcement and punishment are used in conjunction when shaping behaviors; however, it is uncommon for punishment to have as much of a lasting effect as reinforcement
-once the punishment has been removed, then it is no longer effective
--furthermore, punishment only instructs what not to do, whereas reinforcement instructs what to do
-reinforcement is therefore a better alternative to encourage behavior change and learning
-additionally, the process described for classical conditioning (acquisition, extinction, spontaneous recovery, generalization, and discrimination) ocur in operant conditioning, as well
-classical and operant conditioning fall under the behaviorist tradition of psychology, which is most strongly associated with skinner
-in behaviorism, all psychological phenomena are explained by describing the observable antecedents of behaviors and its consequences
-behaviorism is not concerned with the unobservable events occurring within the mind
-the perspective views the brain as a black box that does not need to be explored

-as a reaction to behaviorism, cognitive psychology emerged
-in cognitive psychology, researchers began to focus on the brain, cognitions (thoughts), and their effect on how people navigate the world
-cognitive psychologists do not see learning as simply due to stimulus pairing and reinforcement
-although its importance is acknowledged, cognitive psychologists do not believe that all learning can be explained this way
-for example, say a child learns that he can slide on his belly to reach a toy he wants under the bed
--and, he learns that a grabbing tool can be used to pick up his toys from the ground
--what will he do when his toy is under the bed out of reach?
--he may figure out that he can combine the two behaviors: sliding on his belly and using the grabbing tool to get the toy
--insight learning is the term used to describe when previously learned behaviors are suddenly combined in unique ways
--for the child, the two behaviors (sliding on the belly and using the grabbing tool) were perviously reinforced because he got the toy he wanted each time
--a new situation was presented (the toy is out of reach under the bed), and he was able to combine previously reinforced behavior in a novel way on his own to attain the desired outcome (retrieval of the toy)

-this also works the other way around: previously unseen behavior can manifest quickly when required
-the learning that is present here is latent learning
-in latent learning, something is learned but not expressed as an observable behavior until it is required
-for instance, if a child in middle school always receives a ride to school from his dad, he may latently learn the route to school, even if he never demonstrates that knowledge
-one day, when his dad is on a business trip, the child is able to navigate to school along the same route by bike

-finally, conditioning is not only behavioral learning
-for instance, in operant conditioning, certain behaviors are reinforced and the likelihood of that behavior being repeated increases as a result
-cognitively, the reinforcement establishes an expectation for a future reinforcer, so the process is not exclusively behavioral
-there is thinking involved in this kind of learning
-expectations may also present themselves in stimulus generalization
-if you were rewarded in one class for raising your hand before speaking, then you would expect that to be reinforced in another class, as well
-learning is a change in behavior as a result of experience
-while many extrinsic factors can influence learning, learning is also limited by biological constraints of organisms
--ex. chimpanzees can learn to communicate using basic sign language, but they cannot learn to speak, in part because they are constrained by a lack of specialized vocal cords that would enable them to do so
-it was long believed that learning could occur using any two stimuli or any response and any reinforcer
-but again, biology serves as an important constraint
-associative learning is most easily achieved using stimuli that are somehow relevant to survival
-furthermore, not all reinforcers are equally effective
-as previously discussed, a dramatic example of this is illustrated by food aversions
-if an organism consumes something that tastes strongly of vanilla and becomes nauseas a few hours later (even if the nausea was not caused by the vanilla food), that organism will develop a strong aversion to both the taste and smell of vanilla, even if the nausea occurred hours after consuming the food
-this aversion defies many of the principles of associative learning previously discussed because it occurs after one instance, it can occur after a significant time delay of hours, and it is often an aversion that can last for a very long time, sometimes indefinitely
-in studies, researchers tried to condition organisms to associate the feeling of nausea with other things, such as a sound or a light, but were unable to do so
-therefore, food aversions demonstrate another important facet of learning: learning occurs more quickly if it is biologically relevant

-the process of learning results in physical changes to the central nervous system
-different areas of the brain are involved with learning different types of things
-for example, the cerebellum is involved with learning how to complete motor tasks and the amygdala is involved with learning fear responses (brain lesion studies have helped scientists determine this)

-learning and memory are two processes that work together in shaping behavior, and it is impossible to discuss how learning is processed in the brain without discussing memory
-certain synaptic connections develop in the brain when a memory is formed
-short-term memory lasts for seconds to hours, and can potentially be converted into long-term memory through a process called consolidation
-newly acquired information (such as the knowledge that a reward follows a certain behavior) is temporarily stored in short-term memory and can be transferred into long-term memory under the right conditions
-when something is learned, the synapses between neurons are strengthened and the process of long-term potentiation occurs
-long-term potentiation occurs when, following brief periods of stimulation, an increase in the synaptic strength between two neurons leads to stronger electrochemical responses to a given stimuli
-when long term potentiation occurs, the neurons involved in the circuit develop an increased sensitivity (the sending neuron needs less prompting to fire its impulse and release its neurotransmitter, and/or the receiving neurons have more receptors for the neurotransmitter), which results in increased potential for neural firing after a connection has been stimulated
-this increased potential can last for hours or even weeks
-synaptic strength is thought to be the process by which memories are consolidated for long-term memory (so learning to occur)
-at a given synapse, long-term potentiation involves both presynaptic and postsynaptic neurons
-ex. dopamine is one of the neurotransmitters involved in pleasurable or rewarding actions
-in operant conditioning, reinforcement activates the limbic circuits that involve memory, learning, and emotions
-since reinforcement of a good behavior is pleasurable, the circuits are strengthened as dopamine floods the system making it more likely that the behavior will be repeated
-after a long-term potentiation has occurred, passing an electrical current through the brain doesn't disrupt the memory association between the neurons involved, although other memories will be wiped out
-ex. when a person receives a blow to the head resulting in a concussion, he or she loses memory for events shortly preceding the concussion
--this is due to the fact that long-term potentiation has not had a chance to occur (and leaves traces of memory connections), while old memories, which were already potentiated, remain

-long term memory storage involves more permanent changes to the brain, including structural and functional connections between neurons
-for example, long-term memory storage includes new synaptic connections between neurons, permanent changes in pre- and postsynaptic membranes, and a permanent increase or decrease in neurotransmitter synthesis
-furthermore, visual imaging studies suggest that there is greater branching of dendrites in regions of the brain thought to be involved with memory storage; drugs that appear protein synthesis appear to block long term-memory formation

-not all behaviors are learned of course
-the neural process described above occurs when animals or people learn new behaviors, or change their behaviors based on experience (environmental feedback)
-as our learned behaviors change, our synapses change, too
-on the other hand, some behaviors are innate
--these are things we know how to do instinctively (or our body does without us consciously thinking about it), bot because someone taught us to do them (for ex. breathing or pulling away from a hot stove)
--further, innate behaviors are always the same between members of the species, even for the ones performing them for the first time
-modeling is one of the most basic mechanisms behind observational learning
-in modeling, an observer sees the behavior being performed by another person
-later, with the model in mind, the observer imitates the behavior he or she observed
--ex. you likely participated in this behavior as a child
--when we were little and pretended to be a superhero
-as an adult, your appearance may be based on models in society; you dress, talk, and walk like your friends
-modeling is not limited to humans either; a lioness will take her cubs with her to hunt and her cubs watch her during the process and hunt based on what they observe
-typically, the likelihood of imitating a modeled behavior is based on how successful someone finds that behavior to be, or the type of reinforcement received for his behavior
-however, individuals may choose to imitate behaviors even if they do not observe the consequences of the model's behavior

-Albert Bandura (a pioneer in the field of observational learning) conducted a series of experiments using a Bobo doll (a large inflatable toy with a heavy base that will spring back up after being punched)
-bandura showed children videos of adults either behaving aggressively toward the bobo doll (punching, kicking, and shouting at the doll) or ignoring the doll all together
-even when children did not see the consequences of the adult's behavior, they tended to imitate the behavior they saw
-modeling, and social learning in general, is a very powerful influence on individual's behaviors
-persuasion is one method of attitude and behavior change
-when you change your beliefs about something there are a few factors that likely come into play
-for example, say you are listening to 2 speeches about the importance of increasing the ban on smoking in public spaces
-the first orator is attractive, but his argument is not well formulated
-the second orator's speech has better, more logical arguments, but he is not as attractive
-whose argument will persuade you more?
-the elaboration likelihood model explains when people will be influenced by the content of the speech (or the logic of the arguments), and when people will be influenced by other, more superficial characteristics like the appearance of the orator or the length of the speech

-since persuasion can be such a powerful means for influencing what people think and do, much research has gone into studying the various elements of a message that might have an impact on its persuasiveness
-the 3 key elements are message characteristics, source characteristics, and target characteristics
1. The message characteristics are the features of the message itself, such as the logic and number of key points in the argument. Message characteristics also include more superficial things, such as the length of the speech or article, and its grammatical complexity
2. The source characteristics of the person or venue delivering the message, such as expertise, knowledge, and trustworthiness, are also of importance
-people are much more likely to be persuaded by a major study described in the new england journal of medicine than the pages of the local supermarket tabloid
3. Finally, the target characteristics of the person receiving the message, such as self-esteem, intelligence, mood, and other such personal characteristics, have an important influence on whether a message will be perceived as persuasive
-for instance, some studies have suggested that those with higher intelligence, are less easily persuaded by one-sided messages

-the two cognitive routes that persuasion follows under this model are the central route and the peripheral route
-under the central route, people are persuaded by the content of the argument
-they ruminate over the key features of the argument and allow those features to influence their decision to change their point of view
-the peripheral route functions when people focus on superficial or secondary characteristics of the speech or the orator
-under these circumstances, people are persuaded by the attractiveness of the orator, the length of the speech, whether the orator is considered an expert in his field, and other features
-the elaboration likelihood model then argues that people will choose the central route only when they are both motivated to listen to the logic of the argument (they are interested in the topic), and they are not distracted, this focusing their attention on the argument
-if those conditions are not met, individuals will choose the peripheral route, and, if persuaded at all, will be persuaded by more superficial factors
-messages processed via the central route are more likely to have longer-lasting persuasive outcomes than messages processed via the peripheral route
-the social cognitive theory perspective incorporates elements of cognition, learning, and social influence
-social cognitive theory is a theory of behavior change that emphasizes the interactions between people and their environment
-however, unlike behaviorism (where the environment controls us), cognition (how we process our environment) is also important in determining our behavior
-social cognitive theory focuses on how we interpret and respond to external events, and how our past experiences, memories, and expectations influence our behavior
-according to social cognitive theory, social factors, observational learning, and environmental factors can also influence a person's attitude change
-the opinions and attitudes of your friends, family members, and other peer groups often have a major influence on your beliefs
-reciprocal determinism is the interaction between a person's behaviors (conscious actions), personal factors (individual motivational forces or cognitions; personality differences that drive a person to act), and environment (situational factors)
-there are 3 different ways that individuals and environments interact
1. People choose their environments which in turn shape them. For example, the college you chose had some unique impact on you
2. Personality shapes how people interpret and respond to their environment. For example, people prone to depression are more likely to view their jobs as pointless
3. A person's personality influences the situation to which she then reacts. Experiments have demonstrated that how you treat someone else influences how they will treat you. For example, if you call customer service because you are furious at something, you are more likely to receive a defensive or aggressive response on the phone

-in these 3 ways, people both shape and are shaped by their environments
-genetics play an important role in the behavior of humans and other animals
-behavioral genetics attempts to determine the role of inheritance in behavioral traits; the interaction between heredity and experience determines an individual's personality and social behavior

-almost every cell in the body contains DNA, and this DNA contains genes, some 20,000 or so in humans
-genes encode the information for creating proteins, the building blocks of physical development
-humans share 99.9% of their DNA with other species, therefore, to help determine what makes us different (for ex. why one person suffers from schizophrenia and his brother does not), it is vital to understand the variations in both our genes and our environment
-the genotype is the genetic makeup of an organism, while the phenotype is the observable characteristics and traits
-behavioral genetics seek to understand how the genotype and environment affect the phenotype

-most phenotypes are influenced by several genes and by the environment; for example, tallness in humans is the result of the interaction between several genes, and is also the result of proper nutrition at key developmental stages
-in order to determine the influence of genes vs. the environment, behavioral genetics use two types of studies in humans: twin studies and adoption studies''

-twin studies compare traits in monozygotic (identical) and dizygotic (fraternal) twins
-monozygotic twins have essentially identical genotypes and an almost identical environment, starting from the womb
-dizygotic twins share roughly 50% of their DNA (they are genetically no more similar than ordinary siblings), and an arguably similar environment, starting in the womb
-the classic twin study attempts to assess the variance of a phenotype (behavior, psychological disorder) in a large group in order to estimate genetic effects (heritability) and environmental effects (both from shared environment or experiences and unshared/unique environment or experiences)
-if identical twins share the phenotype more than fraternal twins (which is the case for more traits), genes likely play an important role
--for example, if one MZ twin develops alzheimer's disease, the other MZ twin has a 60% chance of developing it as well
-alternatively, if one DZ twin develops the disease, the other only has a 30% chance of developing it
-by comparing hundreds of twin pairs, researchers can then understand more about the roles of genetic effects, shared environment, and unique environment in shaping behavior
-adoption studies present another unique way to study the effects of genetics and environment on phenotype
-adoption creates two groups: genetic relatives and environmental relatives
-adopted individuals can be compared with both groups to determine if they are more similar to their genetic relatives or their environmental relatives
-the advantage of adoption studies over twin studies is that they can help elucidate the impact of both heredity and environment on phenotype
-twin studies can only examine the impact of genetics because the environment is so similar for each twin
-hundreds of studies have shown that people who grow up together do not much resemble each other's personality
-adopted children have personalities more similar to their biological parents than to their adopted parents; traits such as agreeableness, extraversion, introversion, etc. tend to pass from parents to biological offspring
-however, adopted children are more similar to their adoptive families in terms of attitudes, values, manners, faith, and politics

-a few cases of identical twins separated at birth have shown that despite being raised in completely different environments with no contact with each other while growing up, they are remarkably similar in terms of tastes, physical abilities, personality, interests, attitudes, and fears

-using twin and adoption studies, behavioral geneticists can estimate heritability for many phenotypes
-heritability does not pertain to an individual, but rather to how two individuals differ
--ex. the estimated heritability of intelligence (the variability of intelligence scores attributable to genetic factors) is roughly 50%
--this does not mean that your genes are responsible for 50% of your intelligence, rather, it means that heredity is responsible for 50% of the variation in intelligence between you and someone else
-in fact, it means that genetic differences account for 50% of the variation in intelligence among all people
-in animals, the interaction between genotype and phenotype is easier to study because genes and environment can be more tightly controlled
-researchers can use transgenesis (the introduction of an extrogenous or outside gene) or knockout genes to alter genotypes while controlling for environment
-transgenic animal models are useful for helping researchers understand what happens when a certain gene is present
-for example, transgenic mice that have had human cancer genes introduced can help researchers study how and when cancer develops, and how cancer responds to various treatment in the mouse model (before trying the treatment on humans)
-knock-out animal models are useful for helping researchers understand what happens when a gene is absent
--ex. knock-out mice that are missing a specific gene known to protect against cancer can also help researchers understand how and why cancer develops, and how it responds to treatment

-one of the most important adaptive aspects of all life-from single-celled organisms to human begins-is the capacity for adaptation
-genes are environment work together; not only do genes code for proteins, but they also respond to the environment
-genes might be turned on in one environment and turned off in another
-for example, in response to an ongoing stressor, one gene may begin producing more of a neurotransmitter involved in overeating, which then leads to obesity
-the gene itself was not hard-wired to produce obesity, but an interaction between the gene and the environment resulted in obesity

-genes are environment interact
-consider the example of temperament (emotional excitability): infants who are considered "difficult" have a temperament that is more irritable and unpredictable, while infants who are considered "easy" have a more placid, quiet, and easygoing temperament
-while heredity might predispose infants toward these temperament differences, an easy baby will be treated different than a difficult baby, and studies have shown that temperament persists through childhood and beyond
-do difficult babies grow up to be aggressive, pugnacious teenagers because their temperament is genetically wired, or because their parents reacted to their irritability and unpredictability in infancy with frustration and unsupportive caregiving?
--it is difficult to say, but it is important to understand that both heredity and environment play an important role in many complex traits , such as personality (of which temperament is one aspect), intelligence, motivation, etc
-in the mid-twentieth century, psychologist Raymond Cattell proposed two types of intelligence: fluid intelligence (Gf), which is the ability to "think on your feet" and solve novel problems, and crystallized intelligence (Gc), which is the ability to recall and apply already-learned information (which is the majority of what you are expected to do in school-learn and memorize information, then apply it on test day)

-in the 1980s, Howard Gardner put forth a theory on multiple intelligences, which breaks intelligence down into 8 different modalities: logical, linguistic, spatial, musical, (bodily) kinesthetic, naturalist, intrapersonal and interpersonal intelligences (BILLS MINE) E for existential
-this theory is a nice counter to the idea that intelligence is a single general ability that can be conveniently measured and quantified with an IQ test
-while Gardner was not the first to consider the importance of social intelligence (Edward Thorndike first proposed the idea of social intelligence in the 1920s, defined as the ability oto manage and understand people), the theory of multiple intelligences did renew interest in the concept of social intelligence
-this renewed interest led to the idea of emotional intelligence in the 1990s
-emotional intelligence involves being well attuned to one's own emotions, being able to accurately intuit the emotions of others, and using this information as a guide for thinking and acting
-studies suggest that both emotional intelligence and social intelligence are correlated with good leadership skills, good interpersonal skills, positive outcomes in classroom situations, and better functioning in the world
-newborns have some automatic behaviors, called reflexes, which are useful for survival
-these reflexes are considered primitive because they originate in the central nervous system and are exhibited by all normal infants
1. Moro (startle) reflex-in response to a loud sound or sudden movement, an infant will startle; the baby throws back its head and extends its arms and legs, cries, then pulls the arms and legs back in. This reflex is present at birth and lasts for about 6 months
2. Rooting reflex- in response to touching or stroking one of the baby's cheeks, the baby will turn its head in the direction of the stroke and open its mouth to "root" for a nipple
3. Sucking reflex- linked with the rooting reflex, in response to anything touching the roof of the baby's mouth, it will begin to suck
4. Babinski reflex-in response to the sole of the foot being stroked, the baby's big toe moves upward or toward the top surface of the foot and the other toes fan out
5. Tonic neck reflex- in response to its head being turned to one side, the baby will stretch out its arm on the same side and the opposite arm bends up at the elbow. This reflex lasts about 6 to 7 months
6. Palmar grasp reflex-in response to stroking the baby's palm, the baby's hand will grasp. This reflex lasts a few months
7. Walking/stepping reflex- in response to the soles of a baby's feet touching a flat surface, they will attempt to "walk" by placing one foot in front of the other. This reflex disappears at around 6 weeks and reappears at around 8-12 months when a baby learns to walk

-it is difficult to determine what babies think, but research indicates that infants do have certain preferences
--ex. humans are born with a preference for sights and sounds that facilitate social responsiveness
-for example, newborns turn their heads toward human voices
-when shown the two images, newborns prefer (
gaze longer at) the first, because it is more similar to a human face
-other experiments determine that babies can distinguish their mother's voice and smell
-humans undergo a fairly predictable course of motor development, beginning with these rudimentary reflexes and progressing through the learning of specialized movements to assist with daily living and recreational activities

1. Reflexive movements are primitive, involuntary movements that serve to "prime" the neuromuscular system and form the basis for the more sophisticated movement to come. For example, the palmar grasp reflex primes the nervous system for the more controlled grasping learned at later stages. Reflexes, and learning to inhibit reflexes, occurs during the first year of a child's life and overlaps with the stage in which rudimentary movements are learned

2. Rudimentary movements serve as the first voluntary movement performed by a child. They occur in very predictable stages from birth to age 2, and include rolling, sitting, crawling, standing, and walking. These form the foundation on which the fundamental movements are built and is primarily dictated by genetics (more or less, preprogrammed)

3. The fundamental movement stage occurs from age 2 to age 7; during this time the child is learning to manipulate their body through actions such as running, jumping, throwing, and catching. This stage is highly influenced by environment, much more so than the rudimentary movement stage that precedes it. Children are typically in school at this stage, and physical activity and games are necessary for proper motor development. Movements initially start out uncoordinated and poorly controlled, but as the child advances in age, movements become more refined, coordinated, and efficient

4. During the stage of specialized movement, children learn to combine the fundamental movements and apply them to specific tasks. This stage can be subdivided into two shorter stages: a transitional stage and an application stage. This stage is from 7-14 years of age.
-the transitional substage is where the combination of movements occur; for example, grasping, throwing, and jumping are combined to shoot a basket in basketball.
-the application substage is defined more by conscious decisions to apply these skills to specific types of activity; for example, one child might choose to play basketball, whereas another might use the same set of skills and abilities to play baseball. Additionally, the application of strategy to movement is now possible, with the child say, choosing to delay shooting to the basketball until she has a clear shot at the basket

-ultimately, children progress to a lifelong application stage, typically beginning in adolescence and progressing through adulthood. During this time movements are continually refined and applied to normal daily activities as well as recreational and competitive activities
-during prenatal development, the brain actually produces more neurons than needed
-at birth, humans have the highest number of neurons at any point in their life, and these are pruned throughout the ensuing lifetime
-however, the immature brain does not have many neural networks, or codified routes for information processing (the types that are generated in response to learning and experience throughout a lifetime)
-during infancy and early childhood development, these neurons form neural networks, and networks are reinforced by learning and behavior
-from ages 3 to 6, the most rapid growth occurs in the frontal lobes, corresponding to an increase in rational planning and attention
-the association areas, linked with thinking, memory, and language, are the last cortical areas to develop


-maturation is the sequence of biological growth processes in human development
-maturation, while largely genetic, is still influenced by the environment
-for example, while humans are programmed to learn how to speak, first using one-word utterances, then developing progressively more complex speech, severe deprivation can significantly delay this process, while an incredibly nurturing environment might speed it up
-the developing brain allows for motor development; as the nervous system and muscles mature, more and more complex physical skills develop
-the sequence of motor development is almost entirely universal
-babies learn to roll over, then sit, then crawl, then stand, then walk
-the development of the cerebellum is a necessary precursor to walking, and most humans learn to walk around age one

-the average age of earliest conscious memory is roughly 3.5 years
-before this age, we are unable to remember much, if anything; this is referred to as infantile amnesia
-even though humans are unable to recall memories from this period, babies and young children are still capable of learning and memory
-in one experiment, a researcher tied a string to an infant's foot and attached the other end of the string to a mobile
-when the baby kicked its foot, the mobile moved
--they demonstrated learning-they associated kicking with mobile movement-because they kicked more when attached to the mobile, both on the day of the experiment and the day after
-interestingly, if the babies were attached to a different mobile, they did not kick more, however when attached to the same mobile a month later, they remembered the association and began kicking again
-humans are social organisms
-from approximately 8-12 months of age, young children display stranger anxiety (crying and clinging to caregiver)
--around this time, infants have developed schemas for familiar faces, and when new faces do not fit an already developed schema, the infant becomes distressed
-infant-parent attachment bonds are an important survival impulse
-stranger anxiety seems to peek around 13 months for children and then gradually declines
-for many years it was assumed that infants attached to their parents because they provided nourishment, but an accidental experiment actually countered this assumption

-in the 1950s, two psychologists (Harry Harlow and Margaret Harlow) bred monkeys for experiments
-to control for environment and to reduce the incidence of disease, infant monkeys were separated from their mothers at birth (maternal deprivation) and provided with a baby blanket
-when the blankets were removed for laundering, the baby monkeys became very distressed because they formed an intense attachment to the object
-this physical attachment seemed to contradict the idea that attachment was formed based on nourishment, so the Harlows designed a series of experiments to further investigate
-in one experiment, the Harlows fashioned two artificial mothers-one nourishing (a wire frame with a wooden head and a bottle) and the other cloth (wire frame with a wooden head and a cloth blanket wrapped around it)
-they found that the baby monkeys preferred the cloth mother, clinging to her and spending the majority of their time with her, and visiting the other monkey only to feed
-Harlow concluded that "contact comfort" was an essential element of infant/mother bonding, as well as to psychological development
-keep in mind, however, that even though these baby monkeys were provided with a surrogate wire mother, this mother was still largely inadequate
--therefore, when the monkeys from these experiments matured, they demonstrated social deficits when reintroduced to other monkeys
-harlow's monkeys demonstrated aggressive behavior as adults, were unable to socially integrate with other monkeys, and did not mate
-if female monkeys were artificially inseminated, they would neglect, abuse, or even kill their offspring
-Mary Ainsworth conducted a series of experiments called the "strange situation experiments," where mothers would leave their infants in an unfamiliar environment (usually a lab playroom) to see how the infants would react
--these studies suggested that attachment styles vary among infants
-securely attached infants in the presence of their mother (or primary caregiver) will play and explore; when the mother leaves the room, the infant is distressed, and when the mother returns, the infant will seek contact with her and is easily consoled
-insecurely attached infants in the presence of their mother are less likely to explore their surroundings and may even cling to their mother; when the mother leaves they will either cry loudly and remain upset or will demonstrate indifference to her departure and return
--observations indicate that securely attached infants have sensitive and responsive mothers who are quick to attend to their child's needs in a consistent fashion
-insecurely attached infants have mothers who are insensitive and unresponsive, attending to their child's needs inconsistently or sometimes even ignoring their children

-in the harlow's monkeys experiments described above, the cloth mother would be considered rather insensitive and unresponsive; when these monkeys were put in situations without their artificial mothers they became terrified

-psychologists believe that early interactions with parents and caregivers lay the foundations for future adult relationships
-securely attached infants grow up to demonstrate better social skills, a greater capacity for effective intimate relationships, and are better able to promote secure attachments in their children
-alternatively, children who are neglected or abused are more likely to neglect or abuse their own children
-note: more likely does not imply a destiny; most abused children do not grow up to abuse their own children
-humans display a large degree of resiliency, and most insecurely attached or abused children grow into normal adults
-despite the fact that infancy is crucial for development, development continues throughout our lifetime
-adolescence is the traditional stage between childhood and adulthood; this period roughly begins at puberty and ends with achievement of independent adult status
-therefore, adolescence generally encompasses the teenage years
-adolescence involves many important physical, psychological, and social changes
-the onset of puberty (typically around age 10 or 11 in girls, and age 11 or 12 in boys) involves surging estrogens and androgens (sex hormones) that cause a cascade of physical changes
-in girls, increased estrogen causes the development of secondary sex characteristics (increased body and pubic hair, increased fat distribution, breast development) as well as the initiation of the menstrual cycle
-in boys, increased testosterone (the primary androgen) also causes the development of secondary sex characteristics (increased body and pubic hair, increased muscle mass, voice deepening, enlargement of the penis and testes), and the onset of ejaculation

-while the sequence of events in puberty is fairly predictable, the onset of these events is less so, which can be distressing
--ex. early puberty for a girl means that she will begin developing breasts and menstruating before her peers, which can be psychologically upsetting

-during adolescence, the brain undergoes three major changes: cell proliferation (in certain areas, particularly the prefrontal lobes and limbic system), synaptic pruning (of unused or unnecessary connections and myelination (which strengthens connections between various regions)
-the prefrontal cortex-responsible for abstract thought, planning, anticipating consequences, and personality-continues to develop during this period
--the frontal lobes are not completely developed until age 26
-the limbic system-involved in emotion-develops more rapidly than the prefrontal cortex during adolescence, which may explain behavior that appears to be emotionally rather rationally driven
-though it may seem contradictory, adolescents are actually improving their self-control, judgment, and long-term planning abilities during this time
-implicit or procedural memory refers to conditioned associations and knowledge of how to do something, while explicit or declarative memory involves being able to "declare" or voice what is known
-for example, one could read a book on how to develop a great shot in basketball from cover to cover and be able to explain in great detail the necessary steps
--however, this book knowledge would not likely translate into being able to execute the shot on the court without practice
-explaining the concept involves explicit or declarative memory, while not having practiced it indicates a lack of implicit or procedural memory

-semantic and episodic memory are two subdivisions of explicit memory
--semantic memory is memory for factual information, such as the capital of England
--episodic memory is autobiographical memory for personal importance, such as the situation surrounding a first kiss
-typically, semantic memory deteriorates before episodic memory does

-the distinction between explicit and implicit memory is supported by neurological evidence
-brain structures involved in memory include the hippocampus, cerebellum, and amygdala
-the hippocampus is necessary for the encoding of new explicit memories
-the cerebellum is involved in learning skills and conditioned associations (implicit memory)
-the amygdala is involved in associating emotion with memories, particularly negative memories; for example, a fear response to a dentist's drill involves fear conditioning
-the roles of the hippocampus, cerebellum, and amygdala are shown by studies on patients who have the capacity for either implicit or explicit memory (but not both)
-for example, amnesic patients with hippocampal damage may not have declarative memory for a skill they recently learned and yet may be able to demonstrate the skill, indicating that implicit memory exists
-interestingly, the implicit memories that infants make are retained indefinitely, but the explicit memories that infants make are largely not retained beyond age four-a phenomenon known as infantile amnesia
-it is only later, after the hippocampus has fully developed, that explicit memories are retained long term
-if our long-term memories contained isolated pockets of information without any organization, they might be difficult to access
-a person might have numerous memories for directions, peoples' faces, the definitions of tens of thousands of words, and other such content; with that much information, it could be nearly impossible to find anything
-just as hierarchies are a useful tool for processing information during the encoding process, it is believed that information is stored in long-term memory as an organized network
-in this network exist individual ideas called nodes, which can be thought of as cities on a map
-connecting these nodes are associations, which are like roads connecting cities
-not all roads are created equal; some are superhighways and some are dirt roads
-for example, for a person living in a city, there may be a stronger association between the nodes bird and pigeon than between bird and penguin
-the strength of an association in the network is related to how frequently and how deeply the connection is made
-processing material in different ways leads to the establishment of multiple connections
-in this model, searching through memory is the process of starting at one node and traveling the connected roads until one arrives at the idea one is looking for
-retrieval improves if there are more and stronger connections to an idea
-because all memories are neural connections, the road analogy provides a useful aid in understanding access to memories; strong neural connections are like better roads

-like any neural connection, a node does not become activated until it receives input signals from its neighbors that are strong enough to reach a response threshold
-the effect of input signals is cumulative: the response threshold is reached by the summation of input signals from multiple nodes
-stronger memories involve more neural connections int he form of more numerous dendrites, the stimulation of which can summate more quickly and powerfully to threshold
-once the response threshold is reached, the node "fires" and sends a stimulus to all of its neighbors, contributing to their activation
-in this way, the activation of a few nodes can lead to a pattern of activation within the network that spreads onward
--known as spreading activation
-it suggests that when trying to retrieve information, we start the search from one node
-then, we do not "choose" where to go next, but rather that activated node spreads its activation to other nodes around it to an extend related to the strength of association between that node and each other
-this pattern continues, with well-established links carrying activation more efficiently than more obscure ones
-the network approach helps explain why hints ,ay be useful
-they serve to activate nodes that are closely connected to the node being sought after, which may therefore contribute to that node's activation
-it also explains the relevance of contextual cues
-if you are reading this book while jumping on a trampoline, you are more likely to later recall this information if you are once again on the trampoline
--this is because you have developed some associations between the learned information and the cues in the environment when learning the information
-older adults vary in their memory abilities
-decline in memory is influenced by how active the person is :increased activity (both physical and mental) is a protective factor against neuronal atrophy
-memory loss may parallel the age-related loss of neurons
-as we age, memory decline tends to follow some common trends, with certain types of memory being affected earlier
-older adults have accumulated many experiences and so have a rich network of nodes and associations
-information that is meaningful and and connects well to that existing web of information, and information that is skill-based, show less decline with age
-however, there is greater decline for information that is less meaningful and less richly connected

-due to having a more extensive memory network, retrieval can also become trickier with time
-older adults show minimal decline in recognition, but greater decline in free recall
-one type of recall is prospective memory, remembering to do things in the future
-prospective memory is stronger when there are cues in the environment
--ex. an older adult may be asked to remember to take a particular medication 3 times a day
--unless there is a reminder cue such as a readily visible pillbox or an alarm, it may be difficult to remember that there is a task that needs to be completed
-thus, the person fails to remember to remember
-difficulty with prospective memory without cues also makes it difficult to complete time based tasks, since one must remember to look at a clock or keep track of a schedule
-our memories are far from being snapshots of actual experience
-we already know that when memories are encoded, they pass through a "lens"; the mood and selective attention of the observer influence how they are encoded
-memory is once again altered when passing through the lens of retrieval
-when we remember something, we do not pull from a mental photo album, but rather, we draw a picture, constructing the recalled memory from information that is stored
-this process is not foolproof

-sometimes the information that we retrieve is based more on a scheme than on reality
-a schema is a mental blueprint containing common aspects of some parts of the world
-for example, if asked to describe what your 4th grade classroom looked like, you might "remember" a chalkboard, chalk, desks, posters and books
--in this way, when we construct a memory, we tend to fill in the blanks by adding details that may have not been present at the time
-we may also unknowingly alter details
--for example, in eye witness testimony, leading questions often cause witnesses to misestimate or misremember
-when participants in an experiment were asked how fast cars were going when they smashed into each other, instead of just hit each other, they indicated higher speeds
-after people are exposed to subtle misinformation, they are usually susceptible to the misinformation effect, a tendency to misremember

-individuals may also misremember when asked to repeatedly imagine nonexistent actions and events
-simply repeatedly imagining that one did something can create false memories for an event
-false memories are inaccurate recollections of an event and may be the result of the implanting of ideas
-for example, if one repeatedly imagined being lost in a shopping mall, this imagined occurrence would begin to feel familiar and would take on the flavor of a real memory

-when recalling information, people are also susceptible to forgetting one particular fact-the information's source
--this is an error in source monitoring
--mad at someone for something that happened in a dream