Psychology Overview PDF

# OneClass - Notes ## 1. Week 1 LEC What is psychology? - Scientific study of behavior, thought, and experience, and how they can be affected by physical, mental, social, and environmental factors ### Pop Psychology **Email psych test** - Implied hypothesis - The act of doing calculations mag...

# OneClass - Notes ## 1. Week 1 LEC What is psychology? - Scientific study of behavior, thought, and experience, and how they can be affected by physical, mental, social, and environmental factors ### Pop Psychology **Email psych test** - Implied hypothesis - The act of doing calculations magically includes thoughts of red hammers - Typicality hypothesis - Red is the most typical color, hammer is the most typical tool - Under any circumstances, most people asked the color/tool will say red/hammer - Don't think too much hypothesis - Given a chance to think about it, person might deliberately avoid saying the first color/tool that comes to mind - Encouraging speedy decisions on calculations prevents overthinking on color/tool decision - Norm hypothesis - Preceding color/tool question with norm information (98% of people say same time) causes people to ask: what would other say? ### Intuitive psychology - Intuitive/folk psychology - Psychology = common sense ## 1. Week 2 LEC ### Chronic Traumatic Encephalopathy (CTE) - Chronic: - Long term consequences - Traumatic: - Thought to be caused by trauma, such as mild traumatic brain injury (mTBI), aka concussion - Encephalopathy: - Fancy word for brain pathology ### Cellular level: Terminology - Axon (pg. 93-95) - Long, tail-like structure that leads from neuron body to synapses, which connects to the dendrites of downstream neurons ### System level: Terminology: - White matter (pg. 111-112) - In the cerebral cortex, bundles of axons connecting the bodies of some neurons with the dendrites of others ### TBI: cellular level: - Short-term: blow to head causes quick stretching of axons (deflated balloon analogy) ### CTE: cellular level: - Long-term: affected neurons slowly die and tau proteins are a byproduct ### Systems level: - Localization of function - Mapping structure (brain) to function (behavior) ### How have scientists mapped structure to function? - Brain damage - Functional neuroimaging #### Brain damage - Cause: region-specific damage to brain. - Accidental (e.g stroke) or deliberate (e.g neurosurgical lesioning) - Confirmed via: - Autopsy - Structural neuroimaging (pg. 123-124) - Effect: specific change to behavior - Inference: damaged region underlies affected behavior - Functional neuroimaging - Region-specific brain activity - While participant performs specific behavioural task - Inference: active region(s) underlies performed behavior ### CTE: Systems level - Brain damage inference - Cause: region-specific neuron death (e.g hippocampus) - Effect: specific change to behavior (e.g memory loss) - Problem: - CTE is only diagnosable via autopsy - Staining highlights tau protein - Regions of significant neuron death unknown until patient dies - CTE: Reverse inference - Effect: behavioural changes reported by patient and loved ones. Memory loss, impulsivity, emotion regulation - Inferred cause: sports à mTBI à CTE - Autopsy prediction: - Tau protein in brain regions known to be involved in memory (hippocampus), control (frontal cortex), emotion (limbic system) - Predictions often accurate - CTE: Good science? - Can examining the brains of deceased athletes prove the casual chain? - Sports à mTBI à CTE à behaviour - Problem: most autopsied players have experienced behavior - Solution: - CTE: control groups - Players: no mTBI history, no behavior. Players: mTBI history, no behavior (if they exist) - Non players. Non players: with similar behavioural symptoms - CTE: earlier diagnosis - Can we detect CTE before patient dies? - New research using positron emission tomography (PET) - PET (pg. 125): - Radioactive isotopes injected into bloodstream. Cluster in relevant brain regions, where they can be localized using a scanner. [F-18] FDDNP binds to tau proteins # **3.2 Neural Communication** - Neurons: - One of the major types of cells found in the nervous system, that are responsible for sending and receiving messages throughout the body - Primary purpose is to "fire", to receive input from one group of neurons and to then transmit that information to other neurons - Cell body (soma) - The part of a neuron that contains the nucleus that houses the cell's genetic material (figure 3.12) - Genes in the cell body synthesize proteins that form the chemicals and structures that allow the neuron to function - Dendrites: - Small branches radiating from the cell body that receive messages from other cells and transmit those messages toward the rest of the cell - Axon hillock: - A neuron will receive input from several other neurons and these impulses from other cells will travel across the neuron to the base of the cell body known as the axon hillock - If it receives enough stimulation from other neurons, it will initiate a chemical reaction that will flow down the rest of the neuron - Axon: - Transports information in the form of electrochemical reactions from the cell body to the end of the neuron - When activity reaches end of axon, it arrives at axon terminals, bulb-like extensions filled with vesicles called "Neurotransmitters": - The chemicals that function as messengers allowing neurons to communicate with each other - Impulse travelling down the axon will stimulate the release of these neurotransmitters which allows neural communications to take place - Sensory neurons: - Receive information from the bodily senses and bring it toward the brain - Motor neurons: - Carry messages away from the brain and spinal cord and toward the muscle where they control their flexion and extension - Glial Cells: - Specialized cells of the nervous system that are involved in mounting immune responses in the brain, removing waste, and synchronizing the activity of the billions of neurons that constitute the nervous system - They outnumber neurons in the brain by a ratio of approx 10:1 - Myelin: - A fatty sheath that insulates axons from one another, resulting in increased speed and efficiency of neural communication - In an unmyelinated axon, the neural impulse decays quickly and needs to be regenerated along the axon, the myelin protects the impulse from this decay, thus reducing how often the impulse needs to be regenerated - Resting potential: - Relatively stable state during which the cell is not transmitting messages - Action potential: - A wave of electrical activity that originates at the base of the axon and rapidly travels down its length - Charge of that part of the axon changes from -70mV to +35mV (changes from neg. to pos.) - Refractory period: - Brief period in which a neuron cannot fire - Synapses: - The microscopically small spaces that separate individual nerve cells - All-or-None principle: - Individual nerve cells fire at the same strength every time an action potential occurs ### The Chemical Messengers: Neurotransmitters and Hormones - The presynaptic neuron releases neurotransmitters into the synapse; a fraction of these neurotransmitters will bind to receptors on the postsynaptic neuron - Binding can have 1 of 2 effects on the postsynaptic cell - Synaptic cleft: - The minute space between the axon terminal (terminal button) and the dendrite - Reuptake: - A process whereby neurotransmitter molecules that have been released into the synapse are reabsorbed into the axon terminals of the presynaptic neuron - Serves as sort of a natural recycling system for neurotransmitters - Types of Neurotransmitters | Neurotransmitter | Major Functions | |---|---| | Glutamate | Excites nervous system; memory and autonomic nervous system reactions. Most common excitatory neurotransmitter in the brains of vertebrates | | GABA (gamma-amino butyric acid) | Inhibits brain activity; lowers arousal, anxiety, and excitation; facilitates sleep. Primary inhibitory neurotransmitter of the nervous system, meaning that it prevents neurons from generating action potentials | | Acetylcholine | Movement; attention. One of the most widespread neurotransmitters within the body, found at the junctions between nerve cells and skeletal muscles; very important for voluntary movement | | Dopamine | Control of movement; reward-seeking behavior; cognition and attention. A monoamine neurotransmitter involved in such varied functions as mood, control of voluntary movement, and processing of rewarding experiences | | Norepinephrine | Memory; attention to new or important stimuli; regulation of sleep and mood. Monoamine synthesized from dopamine molecules that is involved in regulating stress responses, including increasing arousal, attention, and heart rate | | Serotonin | Regulation of sleep, appetite, mood. A monoamine involved in regulating mood, sleep, aggression, and appetite | - Drug effects - Agonists: - Drugs that enhance or mimic the effects of a neurotransmitter's action - Nicotine - an acetylcholine agonist, it stimulates the receptor sites - Direct agonist: - Physically binds to that neurotransmitter's receptors as the postsynaptic cells - Indirect agonist: - Facilitates the effects of a neurotransmitter, but does not physically bind to the same part of the receptor as the neurotransmitter - Antagonists: - Inhibit neurotransmitter activity by blocking receptors or preventing synthesis f a neurotransmitter - Ex: Botox - Direct antagonist: Botox directly binds with acetylcholine receptors and thus prevents acetylcholine from doing so - Indirect antagonist: If a chemical reduces the influence of a neurotransmitter without physically blocking the receptor # **3.3 Divisions of the Nervous System** - Central Nervous System (CNS) - Consists of the brain and the spinal cord - Your personality, preferences, memories, and conscious awareness are all packed into your brain - Spinal cord: - Runs from your back down to the base of your spine - Receives information from the brain and stimulates nerves that extend out into the body - provides movements - Peripheral Nervous System (PNS) - A division of the nervous system that transmits signals between the brain and the rest of the body and is divided into 2 subcomponents, the somatic system and the autonomic system - Somatic nervous system: - Consists of nerves that control skeletal muscles, which are responsible for voluntary and reflective movement; it also consists of nerves that receive sensory input from the body - Division of PNS that is active when you wiggle your fingers or feel the edge of a book - Autonomic nervous system: - The portion of the peripheral nervous system responsible for regulating the activity of organs and glands - Includes 2 subcomponents: - 1 that increases our ability to make rapid responses and 1 that helps us return back to normal levels of emotional arousal - Sympathetic nervous system: - Responsible for the fight-or-flight response of an increased heart rate, dilated pupils, and decreased salivary flow - responses that prepare the body for an action. - Parasympathetic nervous system: - Helps maintain homeostatic balance in the presence of change; following sympathetic arousal, it works to return the body to a baseline, nonemergency state. # **The Brain and Its Structures** | Region and Structures | Functions | |---|---| | Hindbrain | Controls basic, life-sustaining processes | | Brain stem (medulla & pons) | Breathing, heart rate, sleep, and wakefulness | | Cerebellum | Balance. Coordination and timing of movements; attention and emotion | | Midbrain | Lobe-like structure at the base of the brain that is involved in the monitoring of movement, maintaining balance, attention, and emotional responses. Resides above the hindbrain, primarily functions as a relay station between sensory and motor areas. Orienting visual attention. Orienting auditory attention | | Forebrain | Most visibly obvious region of the brain, consists of all the neural structures that are located above the midbrain, including all of the folds and grooves on the outer surface of the brain; the multiple interconnected structures in the forebrain are critical to such complex processes as emotion, memory, thinking, and reasoning | | Basal ganglia | Movement, reward processing. Group of 3 structures that are involved in facilitating planned movements, skill learning, and integrating sensory and movement information with the brains reward system | | Amygdala | Emotion. Facilitates memory formation for emotional events, mediates fear responses, and appears to play a role in recognizing and interpreting emotional stimuli, including facial expressions | | Hippocampus | Memory. Critical for learning and memory, particularly the formation of new memories | | Hypothalamus | Temperature regulation, motivation (hunger, thirst, sex) | | Thalamus | Sensory relay station. Set of nuclei involved in relaying sensory information to different regions of the brain | | Cerebral Cortex | The convoluted, wrinkled outer layer of the brain that is involved in multiple functions, such as thought, language, and personality | | Frontal lobe | Thought, planning, language, movement. Important in numerous higher cognitive functions, such as planning, regulating impulses and emotion, language production, and voluntary movement | | Parietal lobe | Sensory, processing, bodily awareness. Involved in our experiences of touch as well our bodily awareness | | Occipital lobe | Visual processing. Located at the rear of the brain and are where visual information is processed | | Temporal lobe | Hearing, object recognition, language, emotion. Located at the sides of the brain near the ears and are involved in hearing, language, and some higher-level aspects of vision such as object and face recognition | - Neuroplasticity: - The capacity of the brain to change and rewire itself based on individual experiences # 3.4 Insights From Brain Damage - Lesioning and Brain Stimulation - Lesioning: - A technique in which researchers intentionally damage an area in the brain (a lesion is abnormal or damaged brain tissue) - Allows researchers to isolate single brain structures - Transcranial magnetic stimulation (TMS) - A procedure in which an electromagnetic pulse is delivered to a targeted region of the brain - This pulse interacts with the flow of ions around the neurons of the affected area - Result is a temporary disruption of brain activity, similar to the permanent disruption caused by a brain lesion ## Structural and Functional Neuroimaging - Structural Neuroimaging - Structural neuroimaging: - A type of brain scanning that produces images of the different structures of the brain. - Used to measure the size of different brain areas and to determine whether any brain injury has occurred. - Computerized tomography (CT scan): - A structural neuroimaging technique in which x-rays are sent through the brain by a tube that rotates around the head - X-rays pass through dense tissue at a different speed than they will pass through less dense tissue, like fluid in the ventricles - Magnetic resonance imaging (MRI): - A structural imaging technique in which clear images of the brain are created based on how different neural regions absorb and release energy while in a magnetic field - Diffusion tensor imaging (DTI): - A form of structural neuroimaging allowing researchers or medical personnel to measure white-matter pathways in the brain - Functional neuroimaging: - Type of brain scanning that provides information about which areas of the brain are active when a person performs a particular behavior - Electroencephalogram (EEG): - Measures patterns of brain activity with the use of multiple electrodes attached to the scalp - Magnetoencephalography (MEG): - A neuroimaging technique that measures the tiny magnetic fields created by the electrical activity of nerve cells in the brain -Type of scan in which a low level of a radioactive isotope i injected into the blood, and its movement to regions of the brain engaged in a particular task is measured # 4.1 Sensing The World Around Us - Sensation - The process of detecting external events by sense organs and turning those stimuli into neural signals - At the sensory level the sound of someone's voice is just nose and the sight of a person is just a combination of color and motion - perception then occurs - Perception - Involves attending to, organizing, and interpreting stimuli that we sense - Includes recognizing the sounds as a human voice and understanding that certain colors, shapes, and motion together make up the image of a human being walking towards you - Raw sensations detected by sensory organs are turned into information that the brian can process through transduction - Transduction - When specialized receptors transform the physical energy of the outside world into neural impulses - Neural impulses travel into brain and influence the activity of different brain structures, which ultimately gives rise to our internal representation of the world - Sensory receptors are different for different senses | Sense | Stimuli | Type of Receptor | |---|---|---| | Vision | Light waves | Light-sensitive structures at the back of the eye | | Hearing | Sound waves | Hair cells that respond to pressure | | Touch | Pressure, stretching, or piercing of the skin surface | Changes in the ear. Different types of nerve ending that respond to pressure, temperature changes, and pain | | Taste | Chemicals on the tongue and in the mouth | Cells lining the taste buds of the tongue | | Smell | Chemicals contacting mucus-lined membranes of the nose | Nerve endings that respond selectively to different compounds | - All of our senses use the same mechanism for transmitting information in the brain; the action potential - The brain is continually bombarded by waves of neural impulses representing the world in all its complexity - Can still separate different sensory signals from 1 another so we can experience distinct sensations - sight, sound, touch, smell, and taste - We see - visual information gets sent to occipital lobes - We hear - auditory information gets sent to our temporal lobes - Different senses are separated in the brain - Proposed in 1826 by Johannes Muller - The doctrine of specific nerve energies - Researchers at McMaster University have demonstrated that infants have a number of overlapping sensations - Spoken language elicits activity in areas of the brain related to hearing, but also in brain areas related to vision - Doesn't go away until 3 years old - The orienting response describes how we quickly shift our attention to stimuli that signal a change in our sensory world - Sensory adaptation: - Reduction of activity in sensory receptors with repeated exposure to a stimulus - Benefits: allows us to adjust to our surroundings and shift our focus to other events that may be important # Stimulus Thresholds - William Gustav Fechner (1801-1887) - Psychophysics: the field of study that explores how physical energy such as light and sound and their intensity relate to psychological experience - Was intersted in perceptual experience and general principles of perception - Popular approach: measure the minimum amount of a stimulus needed for detection, and the degree to which a stimulus must change in strength for the change to be perceptible - Absolute threshold: - The minimum amount of energy or quantity of a simulus required for it to be reliably detected at least 50% of the time it is presented. - EX: someone asked you to put on headphones and listen for spoken words; however, they manipulated the volume at which the words were presented so that some could be heard and some could not. Your absolute threshold would be the volume at which you could detect the words 50% of the time. But yours might differ from the person beside you. - Difference threshold: - The smallest difference between stimuli that can be reliably detected at least 50% of the time - EX: when you add salt to your food, you are attempting to cross a difference threshold that your taste receptors can register # Signal detection - Signal detection theory: - States that whether a stimulus is perceived depends on both sensory experience and judgment made by the subject - Theory requires us to examine 2 processes: - Sensory process: - In a typical signal detection experiment conducted in the lab, the experimenter either presents a faint stimulus or not stimulus at all - Decision process: - Then asked to report whether or not a stimulus was actually presented # Perceiving The World Around Us - Gestalt Principles of Perception - 1910 - Max Wertheimer - Gestalt psychology: - An approach to perception that emphasizes that "the whole is greater than the sum of its parts" - The individual parts of an image may have little meaning on their own, but when combined together, the whole takes on significant perceived form - Gestalt principles: - Figure-ground principle: - Objects or "figures" in our environment tend to stand out against a background - Proximity and Similarity principle - Influence perception - Tend to treat 2+ objects in close proximity to each other as a group - Similarity can be experiences by viewing groups of people in uniform - Tend to group together individuals wearing the same uniforms based on the visuals - Continuity/ "good continuation": - The perceptual rule that lines and other objects tend to be continuous, rather than abruptly changing direction # Attention and Perception - Divided attention - Paying attention to more than one stimulus or task at the same time - Selective attention - Focusing on 1 particular event or task - Doing something without distractions - Intentional blindness: - A failure to notice clearly visible events or objects because attention is directed elsewhere # 4.2 The Human Eye - Senses an array of information, translates that information into neural impulses, and transfers it to the brain for complex, perceptual processing ### How the Eye Gathers Light - Primary function of the eye is to gather light and change it into an action potential - For perspectives of human perception, "light" refers to radiation that occupies a relatively narrow band of the electromagnetic spectrum - Light travels in waves in terms of 2 different properties: - Length - Amplitude: height of a wave - Wavelength - Distance between peaks of a wave - Differences in wavelengths correspond to different colors on the electromagnetic spectrum ### Structure of the Eye - Sclera: - The white, outer surface of the eye - Cornea: - The clear layer that covers the front portion of the eye and also contributes to the eye's ability to focus - Light enters the eye through the cornea and passes through an opening called the pupil - Curved, transparent dome that protects the eye and helps bend incoming light - Pupil: - Regulates the amount of light that enters by changing its size; it dilates (expands) to allow more light to enter and constricts (shrinks) to allow less light into the eye - Changes in pupil's size is from the iris - Opening in the center of the iris that lets in light - Iris: - A round muscle that adjusts the size of the pupil; it also gives the eyes their characteristic color - Lens: - Behind the pupil - A clear structure that focuses light onto the back of the eye - Accommodation: - Can change its shape to ensure that the light entering the eye is refracted in such a way that it's focused when it reaches the back of the eye. - Transduction: - When light reaches the back of the eye - It will stimulate a layer of specialized receptors that convert light into a message that the brain can then interpret - Retina: - Lines the inner surface of the eye and consists of specialized receptors that absorb light and send signals related to the properties of light to the brain - Innermost layer of the eye, where incoming light is converted into nerve impulses - Has a number of different layers, each performing a slightly different function - Photoreceptors - At the back of the retina are specialized receptors - Where lights transformed into a neural signal that the brain can understand - Information from them at the back is transmitted to the ganglion cells closer to the front of the eye - This alters the rate at which they fire. - Then sent out of the eye through a dense bundle of fibers that connect to the brain called optic nerve - Optic nerve: - Nerve presents a challenge to the brain. - Travels through the back f the eye, and creates an area on the retina with no photoreceptors, called the optic disc. - Result is a blind spot; a space in the retina that lacks photoreceptors. ### The Retina; From Light to Nerve Impulse - 2 general photoreceptors: - Rods: - Photoreceptors that occupy peripheral regions of the retina - They are highly sensitive under low light levels - Particular responsive to black and grey - Cones: - Photoreceptors that are sensitive to the different wavelengths of light that we perceive as color - Tend to be clustered around the fovea - Fovea: - Central region around retina - Part of retina where light rays are most sharply focused - Dark adaption - The process by which the rods and cones become increasingly sensitive to light under low levels of illumination ### The Retina and the Perception of Colors - Trichromatic theory <Young-Helmholtz theory> - Maintains that color vision is determined by 3 different cone types that are sensitive to short, medium, and long wavelengths of light. Blue, green, and red - Opponent-process theory: - States that we perceive color in terms of opposing pairs: red to green, yellow to blue, and white to black ### Common Visual Disorders - Many have color blindness - Affect ability to distinguish between red and green mainly - Changes of shape of eye can prevent a focused image from reaching the photoreceptors in the retina - Nearsightedness, or Myopia: - Occurs when eyeball is slightly elongated - Causes the image that the cornea and lens focus on to fall short of the retina - Farsightedness or Hyperopia: - Imaged is focused behind the retina ### Visual Perception and the Brain - Information from the optic nerve travels to numerous area of the brain - Optic chiasm - First major stop. Point at which the optic nerve cross at the midline of the brain. - For each optic nerve - Half of the nerve fibers travel to the same side of the brain (ipsilateral) - Other half travel to the opposite side (contralateral) - Outside half of retina (closest to your temples) sends its optic nerve projections ipsilateral. - Inside held of retina (close to you nose) sends its optic nerve projections contralaterally - Fibers from optic nerve first connect with the thalamus, the brains "sensory relay station" - Lateral geniculate nucleus (LGN) - Specialized for processing visual information - Fibers from this nucleus send messages to the visual cortex, located in the occipital lobe where the complex process of visual perception begin - Ventral system - Extend from the visual cortex to the lower part of the temporal lobe - Dorsal stream - Extends from the visual cortex to the parietal lobe ### The Ventral Stream - Ventral stream of vision extends from the visual cortex in the occipital lobe to the anterior (front) portions of the temporal lobe - Division of our visual system performs a critical function; Object recognition - Groups of neurons in the temporal lobe gather shape and color information from different regions of the secondary visual cortex and combine it into a neural representation of an object - Perceptual constancy - The ability to perceive objects as having constant shape, size, and color despite changes in perspective ### The Dorsal Stream - Dorsal stream of vision extends from the visual cortex in our occipital lobe upwards to the parietal lobe - Function is less intuitive than that of the ventral system - Leslie Ungerleider and Mortimer Mishkin (1982) - Suggested that the ventral and dorsal stream of vision could be referred to as the "what" and "where" pathways - Ventral stream identifies the object - Dorsal stream locates it in space and allows you to interact with it # Depth Perception - Binocular depth cues; - Distance cues that are based on the differing perspectives of both eyes - Convergence: - 1 type - occurs when the eye muscles contract so that both eyes focus on a single object - usually occurs for objects that are relatively close to you - Retinal disparity <binocular disparity> - The difference in relative position of an object as seen by both eyes, which provides information to the brain about depth - Monocular cues: - Depth cues that we can perceive with only 1 eye