extra credit quiz: module 1 psych of learning study guide
Learning
Experience and Behavior or Input and Output
Learning: Processes involved
Hungry Animal à Tone à Food 1.Perception 2.Memory 3.Categorization
Innate Behaviors
•"Ethologists" study the adaptiveness and evolution of behavior •Ethos - Greek for "characteristic" •Innate behaviors are often found when studying animals in the wild •Range from simple to complex •Single cell organisms will move away from a heat source •Ducklings imprint on the first thing they see, attach other instinctive, drive-related behaviors to that organism
Aplysia Californica, the Sea Hare
•(A) This marine invertebrate, a shell-less mollusk, has a relatively simple nervous system that is useful for studying the neural bases of learning •(B) Schematic of how Aplysia are prepared for experiments If the siphon is touched lightly, both siphon and gill are protectively withdrawn (the gill-withdrawal reflex); with repeated light touches, the gill-withdrawal reflex habituates; in this photo, the gill is underneath the mantle
stroke/ constraint movement therapy
•A stroke occurs when blood flow to some region of the brain stops or when an artery bursts Lack of blood and swelling of brain tissue cause neurons in the affected region to die, effectively creating a brain lesion •Immediately after a stroke, a patient often experiences large losses in perceptual function (such as a numb arm) •Over time, they may stop trying to use the numb arm altogether, a phenomenon called learned non-use •Constraint-induced movement therapy: a motor-rehabilitation technique in which unaffected limbs are restrained to increase usage of dysfunctional limbs
Hebbian learning
•According to Hebb, learning-related changes in connections between neurons are an automatic result of the neurons' mutual activity and the brain's capacity for structural plasticity
Stimulus Specificity and Dishabituation
•An important feature of habituation is that habituation to one event does not cause habituation to every other stimulus in the same sensory modality •That is ... it is stimulus-specific •In some cases, presenting a novel stimulus can lead to recovery of responses after an individual has habituated to familiar stimuli •This renewal of responding after a new stimulus has been presented is called dishabituation
Habituation in Aplysia
•An initial, light touch on an Aplysia 's siphon activates the gill-withdrawal response, but if the touch is repeated, the gill-withdrawal reflex gradually becomes weaker, or habituates •In Aplysia, habituation can be explained as a form of synaptic depression, a reduction in synaptic transmission •An important feature of habituation in Aplysia is that it is homosynaptic, which means it involves only those synapses that were activated during the habituating event
Biochemical Control of Brain States
•Another method for manipulating neural activity is the use of pharmacology, that is the use of drugs, chemical substances that alter the biochemical functioning of the body •Drugs that affect the brain generally change neural activity by altering synaptic transmission •Neurochemical effects on the brain depend on a host of complex factors that are still being identified
Hebbian learning
•Any physical change in neurons, or in the systems that support them (such as glia and blood vessels), can affect neural connectivity—the connections between neurons through which brain systems interact •Learning that involves strengthening connections between neurons that work together is called Hebbian learning
Hippocampal Involvement in Spatial Learning and Familiarity
•As mammals experience repetitions of sensory events, neurons in their sensory cortices gradually become tuned to specific features of those events •Neurophysiological studies of rats navigating through mazes revealed that spatial learning actually depends much more on activity in the hippocampus than on cortical engrams
An Invertebrate Model System
•As simple as Aplysia are, however, they are still capable of adapting their behavior in response to experience •Aplysia show habituation, sensitization, and several other forms of learning, just as rats and humans do •In Aplysia, scientists can actually watch the nervous system in action as these learning processes occur
Hermann Ebbinghaus and Human Memory Experiments
•Bias •Subject bias: the influence a subject's prior knowledge or expectations can have (consciously or unconsciously) on the outcome of an experiment •Experimenter bias: the influence an experimenter's prior knowledge or expectations can have (consciously or unconsciously) on the outcome of an experiment
Brains
•Brains are among the most complex structures in nature •The brain is just one component of a collection of body organs called the nervous system, the organ system devoted to the distribution and processing of signals that affect biological functions throughout the body •Central nervous system (CNS): the part of the vertebrate nervous system consisting of the brain and spinal cord •Peripheral nervous system (PNS): the part of the nervous system that transmits signals from sensory receptors to the central nervous system and carries commands from the CNS to muscles •Afferent neurons - carry information 'into' the CNS - sensory •Efferent neurons - carry information 'out' of the CNS - motor •Neuron: a special type of cell that is one of the main components of the nervous system
B. F. Skinner's Radical Behaviorism
•Burrhus Frederic Skinner (1904-1990) •Believed psychologists should limit themselves to the study of observable behaviors that can be learned through experience, and not try to speculate about what is going on in the mind of an animal while it learns
Comparing Humans to Other Animals
•By the early 1800s, this view of humans as being fundamentally different from animals was beginning to meet serious challenge •Erasmus Darwin (1731-1802) was an early and vocal proponent of the theory of evolution, which states that living species change over time, with new traits or characteristics emerging and being passed from one generation to the next
The Human Brain: Terms
•Cerebellum: A brain region lying below the cerebral cortex in the back of the head. It is responsible for the regulation and coordination of complex voluntary muscular movement, including classical conditioning of motor-reflex responses. •Brainstem: a group of structures that connects the rest of the brain to the spinal cord and plays key roles in regulating automatic functions such as breathing and body temperature.
The Human Brain: Terms
•Cerebral cortex: the brain tissue covering the top and sides of the brain in most vertebrates; involved in storage and processing of sensory inputs and motor outputs •Frontal lobe: the part of the cerebral cortex lying at the front of the human brain; enables a person to plan and perform actions
learning
•Changes in animals that learn are internal •Outwardly - no differences •Learning researchers create experimental situations where internal learning processes are externalized •Reflected in external behavior
Clark Hull and Mathematical Models of Learning
•Clark Hull (1884-1952) devoted his career to developing mathematical equations by which he hoped to describe the relationships among the factors that influence learning
The Synapse: Where Neurons Connect
•Communicating neurons are separated by a narrow gap of about 20 nanometers (1 nanometer is one-billionth of a meter), called a synapse, across which the neurons pass chemicals •Most synapses are formed between the axon of the presynaptic (or sending) neuron and a dendrite of the postsynaptic (or receiving) neuron, but synapses can also be formed between an axon and a cell body, between an axon and another axon, and even between dendrites
Charles Darwin and the Theory of Natural Selection
•Darwin's theory of natural selection, proposed a mechanism for how evolution occurs •Argued that species evolve when they possess a trait that meets three conditions •Inheritable •Variable •Relevant to survival
The Connectionist Models of David Rumelhart
•David Rumelhart (1942-2011) developed models of learning and thinking that he described as "connectionist network models" •These were mathematical models of networks of connections between simple processing units (nodes) that could be applied to a wide range of problems in understanding human learning and memory •In connectionist models, ideas and concepts in the external world are not represented as distinct and discrete symbols but rather as patterns of activity over populations of many nodes •Distributed representation: a representation in which information is coded as a pattern of activation distributed across many different nodes
elicited behaviors
•Definition: behaviors that are automatically drawn out by a certain stimulus •Involuntary •Occur with very little cognitive processing •Most likely innate •Dust à sneeze •Gunshot à startle reaction Response are stereotyped across a species
The Homunculus Corresponding to the Human Somatosensory Cortex
•Different regions of the somatosensory cortex respond most strongly to touches of specific body parts •These regions are organized such that body parts close together activate adjacent regions of the somatosensory cortex
Biochemical Control of Brain States
•Drugs can: •Increase or decrease the ability of the presynaptic neuron to produce or release neurotransmitter •Increase or decrease the ability of postsynaptic receptors to receive the chemical message •Alter the mechanisms for clearing neurotransmitter molecules out of the synapse
Dual Process Theory
•Dual process theory: the theory that habituation and sensitization are independent of each other but operate in parallel •In dual process theory, both sensitization and habituation processes occur in response to every stimulus presentation, and it is the summed combination of these two independent processes that determines the strength of responding
Cortical Changes in Adults After Exposure
•During development, inputs from different sensory receptors determine how cortical neurons become tuned, as well as the proportion of available neurons that respond to a particular class of stimuli •Neuroimaging studies suggest that it is relatively easy to retune neurons within the sensory cortices of adults •Many neuroscientists now believe that all forms of perceptual learning in mammals depend on cortical plasticity
Deprived Environment Versus Enriched Environment
•Early studies of brain structure in rats found that simply providing young rats with more opportunities for learning, social interactions, and exercise (called environmental enrichment) could lead to visible changes in their neurons • •These changes in neurons have been shown to impact various forms of maladaptive learning •Rats raised in EE conditions, as opposed to isolated conditions, take less drugs and are less impacted by drug associated cues
Hermann Ebbinghaus and Human Memory Experiments
•Ebbinghaus was especially interested in forgetting—that is, in how memory deteriorates over time •Measured forgetting by examining how long it took to relearn a previously learned list •Ebbinghaus was able to plot a retention curve, which measures how much information is retained at each point in time following learning
The Neo-Behaviorism of Edward Tolman
•Edward Tolman (1886-1959) Argued that rats are like humans in that they are intrinsically motivated to learn the general layout of mazes by forming what he called a cognitive map, an internal psychological representation of the spatial layout of the external world •"Behavior reeks of purpose"
Electromagnetic Stimulation of Neurons
•Electrical stimulation can be used not only to generate movements but also to generate visual, auditory, and somatosensory sensations •Neural stimulation studies in patients and animal models have greatly increased our understanding of how neural activity is translated into behavior •Transcranial magnetic stimulation (TMS) changes activity in the cerebral cortex by generating strong magnetic pulses over the skull •Transcranial direct-current stimulation (tDCS) delivers low-level electrical current through electrodes placed on the scalp
How Researchers Change Brain Activity
•Electromagnetic stimulation of neurons •Researchers can use microelectrodes to stimulate neural activity by delivering tiny amounts of electrical current into the brain •Electrical stimulation of neurons was used as early as the 1800s to prove that neural activity in the motor cortex produces motor behavior •By painstakingly testing the effects of stimulating each point in M1, scientists can draw a map—called a homunculus (or "little man")—on the surface of M1, showing which parts of the body each subsection of M1 controls
W. K. Estes and Mathematical Psychology
•Estes built on Hull's mathematical modeling approach to develop new methods for interpreting a wide variety of learning behaviors •Most learning theorists of that era, including Hull, assumed that learning should be viewed as the development of associations between a stimulus and a response. •For example, suppose that a pigeon is trained to peck whenever it sees a yellow light in order to obtain a bit of food; Hull assumed that this training caused the formation of a direct link between the stimulus and the response, so that later presentations of the yellow light evoked the peck-for-food
Observing Brains in Action
•Event-related potential (ERP): electroencephalograms (EEGs) from a single individual are averaged over multiple repetitions of an event (such as a repeated stimulus presentation) •Compared with fMRI, EEG recording is a simple and inexpensive way to monitor changes in brain activity during learning and memory tasks
Recognizing and Responding to Repetition
•Everything is novel the first time it happens to you; even the most ordinary events become mundane only after repeated exposures •Through repetition, you may learn not to respond to a particular event, even if you originally responded with great excitement •Single-stimulus learning: •Habituation: a decrease in the strength or occurrence of a behavior after repeated exposure to the stimulus that produces that behavior •Sensitization is a phenomenon in which experiences with an arousing stimulus lead to stronger responses to a later stimulus
Biochemical Control of Brain States
•Few drugs have been developed specifically to affect learning and memory abilities •More commonly, a drug's positive or negative effects on memory are considered side effects. •However, drugs are often used in learning and memory research to shut down processing in neural circuits, disrupt structural plasticity mechanisms (especially in studies of LTP), and of course to test their effects on diseases that impair learning and memory abilities
Imaging Brain Structure
•Franz Joseph Gall (1758-1828) pioneered the idea that different areas of the cerebral cortex are specialized for different functions •He also proposed that differences in character or ability are reflected in differences in the size of the corresponding parts of the cerebral cortex •Gall assumed that these differences in cortical size would be evident from bumps in a person's skull •Developed a technique called phrenology, in which he used skull measurements to predict an individual's personality and abilities
John Watson's Behaviorism
•From his studies with rats, Watson came to believe that all behavior is learned and a product of our environments •Watson argued that the rats had learned an automatic set of motor habits for moving through a maze and that these motor habits were largely independent of any external sensory cues—but could be disrupted by changing the lengths of the various arms, and thus the points at which the rats should make turns
Observing Brains in Action
•Functional neuroimaging allows researchers to look at the activity, or function, of a living brain •For example: •When a brain structure becomes active, it requires more oxygen. Within 4 to 6 seconds, blood flow (with its cargo of oxygen) increases to that region •When a brain structure becomes less active, it requires less oxygen, and blood flow decreases •By tracking local changes in blood flow (or oxygen usage), researchers can infer which brain regions are more or less active
George Miller and Information Theory
•George Miller (1920-2012) adapted formal models of information theory to psychology to help us understand memory capacity •Miller's specific goal was to answer the question of whether information theory can help us understand how people make judgments about the magnitude of any stimulus •Miller discovered that people's capacity to make judgments concerning magnitude across a range was limited to about seven alternative values
Glia
•Glia: cells of various types that provide functional or structural support to neurons; some contribute to changes in connections between neurons •Astrocytes are glia that line the outer surface of blood vessels in the brain •Oligodendrocytes wrap the axons of nearby neurons in myelin, a fatty substance that insulates electrical signals transmitted by neurons
Hermann Ebbinghaus and Human Memory Experiments
•Hermann Ebbinghaus (1850-1909) conducted the first rigorous experimental studies of human memory •Proposed that the psychology of memory could also become a rigorous natural science, defined by precise mathematical laws
Factors Influencing the Rate and Duration of Habituation
•How rapidly a response habituates and how long the decrease in responding lasts depend on several factors, including how startling the stimulus is, the number of times it is experienced, and the length of time between repeated exposures •The effects of habituation may last for a few minutes or several hours and, under some circumstances, may last a day or more •Short-term habituation; long-term habituation •In spontaneous recovery, a stimulus-evoked response that has been weakened by habituation increases in strength or reappears after a period of no stimulus presentation
Clark Hull and Mathematical Models of Learning
•Hull's goal was to develop a comprehensive mathematical model of animal learning that would predict exactly what an animal will learn in any given situation •Hull conducted an intensive program of research on learning in animals and humans, seeking to test and refine his mathematical models •Although Hull's equations were influential in their era, their specifics are no longer considered relevant today
Cortical Maps of Sensations
•Humans and other mammals depend on the cerebral cortex to process information about stimuli and distinguish meaningful differences in their features •Sensory cortices are especially important •The range of sensory stimuli that cause a particular cortical neuron to fire is called the neuron's receptive field
Human Brain
•If you have trouble memorizing these four terms, remember: •Frontal is Front •Parietal is at the Peak •Temporal is behind the Temples •Occipital lobe is Out back
Sensitization in Aplysia
•In applying the dual process theory to Aplysia, the state system responsible for sensitization is not completely separate from the mechanism for habituation; instead, interneurons that are part of the circuit that generates the reflexive response increase synaptic transmission •Two independent processes are associated with habituation and sensitization effects—a decrease in glutamate in specific synapses and an increase in serotonin at many synapses, respectively
Hermann Ebbinghaus and Human Memory Experiments- retention curve
•In designing his experiments, Ebbinghaus started with a prediction, or hypothesis •To test this hypothesis, he began carefully manipulating an independent variable and measuring the effect on a dependent variable •The major limitation of Ebbinghaus's studies was that they were conducted with just one participant, Ebbinghaus himself
Recognizing Familiar Objects
•In order to use visual landmarks to navigate within a maze, rats must be able to recognize those landmarks •Neuropsychological studies of patients with lesions to the hippocampus and surrounding cortical regions found impaired recognition of familiar objects •Neurons in the hippocampus and surrounding cortical regions also contribute to object recognition, giving rise to a sense of familiarity
Sensitization to Stress in Anxiety and Depression
•In research laboratories, sensitization is relatively innocuous because the stimuli that lead to sensitization are purposefully controlled so as not to be too arousing •In severe cases, a single highly emotional event can lead to lifelong amplification of emotional responses to a wide range of stimuli, as occurs in posttraumatic stress disorder •Recent studies suggest that even in cases where highly arousing events are not traumatic, a person's susceptibility to certain mental illnesses can still increase
General Features of Habituation
•In the laboratory, researchers examine simpler examples of habituation that they can describe in terms of a single, easily controlled stimulus and a single, easily measurable response •Acoustic startle reflex: a defensive response (such as jumping or freezing) to a startling stimulus (such as a loud noise) •Orienting response: an organism's innate reaction to a novel stimulus
Identifying Places
•John O'Keefe coined the term place cells to refer to neurons with such spatially tuned firing patterns •Each of these neurons has a certain preferred location to which it responds with maximal activity (the place field) •Part of what leads a place cell to respond seems to be the animal's inner sense of its location in space •Place cell responses also depend heavily on visual inputs
John Watson's Behaviorism
•John Watson (1878-1958) is considered the founder of behaviorism •Behaviorism: a school of thought that says psychology should restrict itself to the study of observable behaviors (such as lever presses, salivation, and other measurable actions) and not seek to infer unobservable mental processes
Searching for Memories in the Cerebral Cortex
•Karl Lashley (1890-1958), was an American psychologist who was looking for the location of the engram—the supposed physical change in the brain that forms the basis of a memory (also referred to as a memory trace) •A group of rats were trained to navigate a maze, and then a different small area of the cortex was removed in each rat •No one cortical area seemed to be more important than any other
Searching for Memories in the Cerebral Cortex
•Lashley eventually endorsed the theory of equipotentiality, which states that memories are not stored in one area of the brain; rather, the brain operates as a whole to store memories •Lashley discovered that brain lesion experiments are useful, but limited in terms of what they can reveal •Showing that a particular brain region needs to be intact for learning and memory processes to work normally also does not mean that memories are stored in that region
synaptic plasticity
•Learning and memory researchers have focused almost exclusively on understanding the role of synaptic plasticity, the ability of synapses to change as a result of experience
Perceptual Learning
•Learning in which repeated experiences with a set of stimuli make those stimuli easier to distinguish is called perceptual learning •Perceptual learning that happens without explicit training is sometimes called statistical learning because the percepts that individuals learn the most about are those that are experienced most frequently and consistently
Brain Regions Known to Contribute to Memory
•Located near the center of the human brain, the basal ganglia, thalamus, hippocampus, and amygdala all contribute to learning and memory in different ways Key structures associated with the 'Limbic System
Long-Term Potentiation/depression
•Long-term potentiation (LTP): a process in which synaptic transmission becomes more effective as a result of recent activity; with long-term depression, LTP is widely believed to represent a form of synaptic plasticity that could be the neural mechanism for learning •Long-term depression (LTD): a process in which synaptic transmission becomes less effective as a result of recent activity; with long-term potentiation, LTD is widely believed to represent a form of synaptic plasticity that could be the neural mechanism for learning
Recording from Neurons
•Memory functions are affected not only by which neurons fire but also by how often they fire •Neurophysiology is the study of the activity and function of neurons •One technique scientists use to measure the firing patterns of individual neurons is single-cell recording •Single-cell recording: using an implanted electrode to detect electrical activity (spiking) in a single cell (such as a neuron)
Imaging Brain Structure
•Modern techniques for creating pictures of anatomical structures within the brain are described collectively as structural neuroimaging •Images produced using these methods can show details of brain tissue and also brain lesions, areas of damage caused by injury or illness •Magnetic resonance imaging (MRI): a method of structural neuroimaging based on recording changes in magnetic fields •Diffusion tensor imaging (DTI): a type of MRI that measures connections between brain regions
Human-Machine Interfaces: Regaining Sensory Modalities Through Perceptual Learning
•Most current sensory prostheses are designed to replace lost abilities, but in principle, it should also be possible to use such devices to enhance existing capabilities or to create new sensory abilities •It seems likely that the human brain could accommodate a wide range of technologically provided inputs through perceptual learning
natural selection
•Moths that camouflaged survived longer and produced more offspring (higher fitness) •Natural selection works across many, many, many generations •Organisms need a way to adapt to a changing environment in the short-term •If behaviors are dependent on genes, they can also evolve through natural selection •Not possible to study evolution of a behavior (no fossils!) •Must look at innate behaviors and closely-related animals. Conduct experiments, and derive hypotheses about behaviors
An Invertebrate Model System
•Much work on the neural substrates of habituation has been conducted on a group of marine invertebrates called Aplysia (the sea hare) •When danger threatens, the Aplysia tends to retract its gills under the safety of the mantle—a reaction known as the gill-withdrawal reflex •Only 20,000 neurons, many of them very large, making it advantageous for studying the learning process
natural selection
•NS works b/c animals with adaptive traits are more likely to reproduce and be represented in future generations
Neurons and Glia
•Neurons come in a wide array of shapes and sizes •Pyramidal cells •Stellate cells •Interneurons •In many instances, structure dictates function
The Synapse: Where Neurons Connect
•Neurons contain neurotransmitters, chemical substances that can cross a synapse to affect the activity of a postsynaptic neuron •Several different chemicals act as neurotransmitters •Glutamate, gamma-aminobutyric acid (GABA), acetylcholine, dopamine, norepinephrine, epinephrine, and serotonin are primary examples •Receptors are molecules embedded in the surface of the postsynaptic neuron that are specialized to bind with and respond to particular kinds of neurotransmitters
Cortical Plasticity During Development
•Neurophysiological studies of neurons within the visual cortices of kittens show that their neurons become more selective over time and that maps in their visual cortex become more organized •Neuroimaging studies show that the areas of visual cortex that normally respond to visual stimuli in sighted people will, in blind people, respond to sounds and tactile stimulation •Developmental experiences can have a huge effect on how neurons within sensory cortices respond to stimuli, influencing both the perception of sensory events and the development of responses to perceived events
neuropsychology
•Neuropsychology is the branch of psychology that deals with the relationship between brain function and behavior, usually by examining the functioning of patients who have specific types of brain damage
Structural Plasticity in Nervous Systems
•Neuroscience—the study of the brain, and the rest of the nervous system, and how they function. •Overwhelmingly, believe that the brain is the seat of learning and memory •Historically, most early studies of learning and memory focused on observable behavior rather than on the brain and how it functions
Finding and Manipulating Memories
•Neuroscientists disagree on the riddle of how brains store memories •Most neuroscientists do agree that memories are stored in certain brain regions, and most assume that within those brain regions, memories are stored by physical properties of neurons •There are differing opinions about where or how specific kinds of memories might be stored •Two dominant research themes are that many memories are stored in the cerebral cortex and, more specifically, that they are stored in connections between cortical neurons
Novel Objects Results
•Novel object recognition task: a task in which an organism's detection of and response to unfamiliar objects during exploratory behavior are used to measure its memories of past experiences with those objects
Identifying Places
•One factor affecting the creation of place fields is experience When rats repeatedly explore an environment, their place cells gradually become more sensitive to locations within that environment •Place cells are not the only neurons tuned to spatial features •Head direction cells •Grid cells
Searching for Memories in the Cerebral Cortex
•One of the earliest approaches researchers attempted was to examine people whose brains were missing pieces to see how such losses could affect performance • •'Lesion' studies are still extremely common both in preclinical and clinical models
Imprinting
•One unique case of learning that has proven particularly informative is imprinting, in which a newborn animal forms a lifelong attachment to whatever movements it views early on •Involves elements of classical conditioning, perceptual learning, recognition memory, and operant conditioning •Memory produced by imprinting is one of the first memories some young animals form and is specific enough to enable youngsters to spot their mother in a lineup
Opponent Process Theory
•Opponent process theory is similar to dual process theory in assuming that an experienced event leads to two independent processes—such as two emotional processes: one that is pleasurable and one that is less pleasant •The overall emotion a person experiences in response to an event is the combined result of these two independent processes •Repeated experiences have different effects on the initial reaction versus the rebound reaction, causing the initial response to habituate faster than the rebound
The Human Brain: Terms
•Parietal lobe: the part of the cerebral cortex lying at the top of the human brain; important for processing somatosensory (touch) inputs •Temporal lobe: the part of the cerebral cortex lying at the sides of the human brain; important for language and auditory processing and for learning new facts and forming new memories of events •Occipital lobe: the part of the cerebral cortex lying at the rear of the human brain; important for visual processing
Perceptual Learning
•Perceptual learning is similar to priming in that it leads to more effective processing on subsequent encounters with the stimuli •Perceptual learning can happen even if the learner is not aware that her sensitivities to perceptual differences are increasing •Current theories suggest that the seemingly different phenomena of habituation, sensitization, and perceptual learning depend on similar (or identical) learning mechanisms
Priming
•Priming can occur even in the absence of any feelings of familiarity or recognition that a stimulus was previously experienced •Priming effects may persist much longer than recognition of past encounters
Priming
•Priming: a phenomenon in which prior exposure to a stimulus can improve the ability to recognize that stimulus later •Priming in humans is often studied using a word-stem completion task •Word-stem completion task: a task in which participants are asked to fill in the blanks in a list of word stems (eg, MOT__) to produce the first word that comes to mind; in a priming experiment, participants are more likely to produce a particular word (eg, MOTEL) if they have been exposed to that word previously
How Remembering Changes Brain Activity
•Researchers discovered that when remembering past events, savants with HSAM showed increased activity in several different brain regions, especially the prefrontal cortex, the hippocampus, and a region of cortex at the junction of the frontal and parietal lobes •HSAM: highly superior autobiographical memory •Studies show that the act of remembering experienced events engages a broad network of brain regions
Sensitization to Stress in Anxiety and Depression
•Robert Post (1992) found that after an initial stressful event triggered a disorder such as depression, increasingly minor stressful events could trigger additional bouts of depression later on •Proposed that this tendency occurred because some individuals become sensitized to stress and its associated physiological states •More recent studies indicate that depressed individuals show stronger responses to minor stressors than do healthy individuals
General Features of Sensitization
•Sensitization is a phenomenon in which experiences with an arousing stimulus lead to stronger responses to a later stimulus •One way that researchers can study sensitization experimentally in humans is by measuring electrodermal activity (EDA) •EDA is a measure of changes in the skin's electrical conductivity that are caused by fluctuations in the activity of the peripheral nervous system
Sensitization to Stress in Anxiety and Depression
•Sensitization to stress not only can contribute to depression but also is thought to be a factor in anxiety disorders •Repeated exposures to high stress levels during development, for example, can increase chances for depression later in life and also puts children at risk of developing anxiety disorders •Pathological anxiety can be viewed as an exaggerated response to potentially scary stimuli, resulting when sensitization to stress associated with fear-inducing situations amplifies a person's emotional responses to lower-level stimulation
sensory protheses/ cochlear implant
•Sensory prostheses are electromechanical devices that interface with neural circuits that normally process sensory information •Cochlear implant: a sensory prosthesis that directly stimulates auditory nerves to produce hearing sensations in deaf individuals
B. F. Skinner's Radical Behaviorism
•Skinner advocated an extreme form of behaviorism, often called radical behaviorism, in which he asserted that consciousness and free will are illusions •Skinner argued that humans, like all other animals, function by blindly producing learned responses to environmental stimuli
The Synapse: Where Neurons Connect
•Some neurotransmitters—glutamate, for example—are excitatory, activating receptors that tend to increase the likelihood of the postsynaptic neuron firing •Other neurotransmitters— such as GABA—are inhibitory, activating receptors that tend to decrease the likelihood of the postsynaptic neuron firing •Neuromodulator: a neurotransmitter that acts to modulate activity in a large number of neurons rather than in a single synapse •Acetylcholine often functions as a neuromodulator, and one of its effects is to temporarily alter the number of receptors that must be active before a postsynaptic neuron can fire
Incoming Stimuli: Sensory Pathways into the Brain
•Specific regions of the cerebral cortex are specialized for processing light (primary visual cortex), sound (primary auditory cortex), and sensation (primary somatosensory cortex) •Other regions are specialized for generating coordinated movements ( primary motor cortex)
Sensitization in Aplysia
•The key to sensitization in Aplysia is that it is heterosynaptic, meaning it involves changes across several synapses, including synapses that were not activated by the sensitizing event •Because of this feature, a tail shock increases responses to any future stimulus
Observing Brains in Action
•The most commonly used functional neuroimaging technology is functional magnetic resonance imaging (fMRI) •Uses the same MRI technologies employed for structural imaging, but with fMRI the focus is on differences in oxygen levels in the blood •Electroencephalography (EEG): a method for measuring electrical activity in the brain by means of electrodes placed on the scalp; the resulting image is an electroencephalogram
Outgoing Responses: Motor Control
•The primary motor cortex (M1) is specialized for processing the outputs that control movements •M1 gets much of its input from the frontal lobes, which are responsible for making high-level plans based on the present situation, past experience, and future goals
Neurons and Glia
•The prototypical neuron has three main components •Dendrites, which are input areas that receive signals from other neurons •The cell body, or soma, which integrates signals from the dendrites •One or more axons, which transmit signals to other neurons •For the most part, neural activity flows in one direction: from dendrites to axons
cortical plasticity
•The spatial organization (body map) of the somatosensory cortex reveals that neurons with adjacent receptive fields are often found clustered close together •The receptive fields of neurons in sensory cortices change over time •The capacity for cortical receptive fields and cortical spatial organization to change as a result of experience is called cortical plasticity
cochlear implant : speech
•The virtual speech sounds generated by cochlear implants are quite different from normal speech, so people using the implants must learn to discriminate between the new sounds before they can begin to understand what they hear •It is likely that changes in speech-processing abilities after installation of a cochlear implant are the result of cortical plasticity, but this has yet to be experimentally demonstrated in humans
Hermann Ebbinghaus and Human Memory Experiments
•To avoid issues with bias, modern studies of memory employ a blind design, which means the participant does not know the hypothesis being tested or the variables being manipulated •Experimenter bias can be avoided by employing a double-blind design, in which neither the participant nor the experimenter knows which participant is getting which treatment or intervention •Participants will either get the treatment or the placebo
The Neo-Behaviorism of Edward Tolman
•Tolman showed the value of cognitive maps for understanding how rats can apply what they have learned in novel situations; rats, he showed, are able to find food in mazes by using alternative routes if their preferred route is blocked •Tolman argued that during their free exploration, the rats were learning a cognitive map that they could exploit later (latent learning) •Latent learning: learning that is unconnected to a positive or negative consequence and that remains undetected (latent) until explicitly demonstrated at a later stage
spatial learning
•When animals explore, they learn more than just what objects look, smell, and sound like; they also learn how to get from one place to another and what to expect when visiting particular places •Spatial learning: the acquisition of information about one's surroundings
How Experience Changes Brain Structure
•William James (1890) proposed that the links created during learning and memory formation are not just conceptual connections but actual, physical properties of brains •According to James, the ability to learn and remember shows that brain structure can be changed by experience •He believed that it is this plasticity of brain tissue that makes learning possible
W. K. Estes and Mathematical Psychology
•William K. Estes (1919-2011) and his colleagues established a new subdiscipline of psychology, mathematical psychology •Used mathematical equations to describe the laws of learning and memory and demonstrated how quantitative approaches can be applied to observable behaviors in order to understand, and formally model, mental functions
