Psychology 101 Notes - Part I
This note is taken from Prof. Judith McLaughlin's PSYCH 101 lecture at the University of Washington, Winter 2017.
History of Psychology and Psychological Perspectives
Major issues in psychology
Nature vs Nurture
- Are behavioral difference due to biology or environment?
- Consensus: All behavior depends on both.
- Genetics -> Potential
- Environment -> Outcome
Mind vs Brain
- How are the mind and the brain related?
- Does the brain produce the mind?
- Does the mind control the brain?
- Rene Descartes: Interactionism, Seperate, but they interact. Physical change <-> Mental change.
- Franz Gall: all mental faculties reside in the brain; these faculties are revealed thru contours of the skull. Founder of phrenology (reading personality from the bumps of skull).
- Current view:
- The mind is not just the brain.
- The mind is not independent from the brain.
Stability vs Change
- How stable are our behaviors and traits?
- Goal: Identify the factors that influence change?
- Age effects
- Situational effects
History and Perspectives
Structuralism (Wilhelm Wundt)
- Goals / Emphasis
- Discover the laws and principles that explain conscious experience.
- Identify simplest essential unites of the mind.
- Introspection: report experience w/o interpretation. Problem: too subjective.
Functionalism (William James)
- Goals / Emphasis
- Discover how the mind functions to help us adapt to our environment.
- To study phenomena in real life situation.
Behavioral Perspective (Watson / Skinner)
- Goals / Emphasis
- Study observable responses and their relation to observable stimuli.
- Focus on env factors that cause behavior (i.e., rewards, punishments, etc.)
- Stimulus -> ? -> Response
Gestalt Perspective (Wertheimer)
- Goals / Emphasis
- Must analyze the whole of behavior, not just its elements.
- Emphasize the role that organizational processes play in perception, thinking and learning.
- The relationships among the elements as a whole play an important role in determining our experience.
Psychodynamic (psychoanalytic) Perspective (Freud)
- Goals / Emphasis
- Unconscious mental processes and conflict influence behavior.
- Childhood experiences determine adult personality and behavior.
Humanistic Perspective (Rogers / Maslow)
- Goals / Emphasis
- Subjective human experience.
- Individuals have free will and must take responsibility for their choices.
- Understand each person as a whole and hlep each person reach his/her fullest potential.
- Goals / Emphasis
- Examine internal mental processes and how they influence behavior.
- Study how people perceive, learn, remember, speak, think and solve problems.
- Goals / Emphasis
- Every behavior, emotion and thought is caused by a physical event in the brain or nervous system.
- Understand the functioning of the brain and nervous system and how they affect behavior.
Steps in the scientific process
- Identify a question of interest.
- Gather information and form a hypothesis (statement that attempts to describe or explain a behavior).
- Test the hypothesis by conducting research.
- Analyze data, draw tentative conclusions and report findings.
- Build a body of knowledge
- Generate new hypotheses
- Build on existing theories
- Develop new theories
Observe behavior in its natural setting w/o attempting to influence or control it. (Hidden cameras, two-sided mirrors, etc.)
- Study behavior in normal setting
- Behavior is natural and spontaneous
- The only way to study some phenomena
- Time consuming
- Can't control the situation
- Can't determine causation
- Observer effect: People behave differently when they know they're being watched
- Observer bias: Researchers' expectations can cause them to see what they expect to see
The use of questionnaires and interviews to gather information about people's experiences and attitudes.
- Can gather a lot of information in a short amount of time
- Useful for collecting data that can't be directly observed
Representative sample: a group of participants that accurately represents the larger population that the researcher wishes to describe.
- Biased sample
- Can't determine causation
- People may not be truthful in their answers
Determines the degree of relationship between two factors and how well each factor predicts the other.
Correlation coefficient: the sign indicates the direction, the number indicates the strength.
Types of Correlations
- Positive correlation: variables vary in the same direction.
- Negative correlation: variables vary in the opposite direction.
- Zero correlation.
- Directionality problem: if a causal relationship between the two variables does exist, it could go in either direction.
- Third variable problem: a third factor could underlie the relationship of the two factors of interest.
Researchers deliberately manipulate certain factors and measure their effects. Experiments are designed to test hypotheses.
Variables in an experiment
A variable is any condition that can be manipulated, controlled, or measured.
Types: independent (manipulated) and dependent (measured). The DV (effect) depends on the IV (cause).
Operational Definition: Specify how variables are to be observed and measured. (Quantify)
Groups in an experiment
Experimental group: A group of participants who are exposed to different levels of the IV (treatment).
Control group: A group of participants, similar to the experimental group, who receives the zero value of the IV (not given the treatment).
Random assignment: Using chance procedures to make sure all participants have an equal chance of being assigned to a group.
Can only generalize results to the population being represented in the experiment.
Must replicate experiment using different populations to apply findings to different groups.
- Confounding variables
- Selection bias (Random assignment minimizes the effects of selection bias)
- Experimenter expectancy effect: unintended changes in participants behavior due to cues inadvertently given by the experimenter (mitigation: double-blind procedure, neither the experimenter nor participants know who is in what group)
- Placebo effect: when a participant's response to a treatment is due to/her expectations about the treatment rather than to treatment itself (mitigation: placebo: an inert substance or fake treatment used as a control in an experiment)
Brain and Behavior
Cells of the Nervous System
Basic building blocks of the nervous system.
Dendrites -> soma -> axon -> axon terminals.
Glia (Glial cells)
- Supply nutrients to neurons (astrocytes)
- Agents of the immune system (Microglia)
- Form myelin that aids neuronal transmission (Schwann cells and oligodendrocytes)
- Resting potential +(outside) / -(inside), voltage ~70mV
- Action potential -(outside) / +(inside), sodium channel opens, Na+ come in; after, potassium channel opens, K+ go out.
Synapse 突触: gap between neurons, or neurons and muscles, in which one neuron releases a chemical that either excites or inhibits the next neuron.
Presynaptic neuron (synaptic vesicles 突触小泡) -> synapse -> postsynaptic neuron.
Two types of synapses:
- Excitatory synapse: the binding of the neurotransmitter (NT) to the receptor cause positively charge ions to enter the cell. Increases the likelihood of an action potential.
- Inhibitory synapse: the binding of the NT to the receptor causes negatively charged ions to enter the cell and positively charged ions to exit. Decreases the likelihood of an action potential.
A single neuron may receive input from many synapses.
NT reabsorption and deactivation.
- Reuptake: reabsorption of NTs by presynaptic neuron.
- Deactivation: enzymes break down remaining NTs.
- Acetylcholine 乙酰胆碱: Found in the CNS and peripheral NS and is involved in: movement, learning and memory, Alzheimer's disease.
- Dopamine 多巴胺: Primary neurotransmitter involved in: reward circuits (food, sex, drugs), fine motor control (Parkinson's disease), cognition/emotion (Schizopherenia).
- Norepinephrine 去甲肾上腺素: Primary neurotransmitter involved in: "fight-or-flight" response.
- Serotonin 血清素: Neurotransmitter involved in: sleep and arousal, appetite regulation, pleasure and pain (too little -> depression).
- Endorphins 内啡肽: produced by pituitary gland and hypothalamus. Natural opiates that are released in response to pain and vigorous exercise.
How do drugs alter neurotransmitters? Neurotransmitters only bind to appropriate receptor.
Agonist: mimics/enhances the activity of a particular NT.
Antagonist: blocks the activity of a particular NT.
Divisions of the Nervous System
- Central Nervous System 中枢神经系统 -- brain and spinal cord.
- Spinal cord -- nerve fibers that transmit info from sense organs, muscles and glands to the brain, and from the brain to the rest of the body.
- Brain -- body's main processing system for info.
- Peripheral Nervous system 边缘神经系统 -- nerves and ganglia.
- Somatic Nervous System 躯体神经系统 -- carries input from sense organs to the brain (input); from brain/spinal cord to the skeletal muscles (output).
- Autonomic Nervous System 自主神经系统 -- controls body's vital/automatic activities and the functioning of the internal organs.
- Sympathetic Nervous System 交感神经系统 -- responds to emergencies by activating bodily resources, such as "fight-or-flight response".
- Parasympathetic Nervous System 副交感神经系统 -- Controls normal body operation; calms body down after an emergency.
Structures of the brain
- Hindbrain 后脑 -- contains the brainstem and cerebellum.
- Medulla 延髓 -- controls heart rate, breathing, blood pressure, coughing and swallowing.
- Pons 脑桥 -- important in muscle control, sleep regulation, attention, and other vital functions.
- Cerebellum 小脑 -- controls motor coordination maintains posture, and plays a role in basic learning and memory.
- Reticular formation 网状结构 -- controls arousal and attention and screens messages entering the brain.
- Midbrain 中脑 -- contains areas involved in some sensory reflexes; helps regulate brain arousal and pain.
- Forebrain 前脑 -- contains the most advanced structures.
- Thalamus 丘脑 -- receives info from all senses (EXCEPT for smell) and relays it to other parts of the brain.
- Hypothalamus 下丘脑 -- controls release of some hormones, influences drive states, helps regulate emotion, body temperature, and sensations of pleasure.
- Amygdala 杏仁核 -- involved in emotion: aggression, rage and fear.
- Hippocampus 海马体 -- plays a role in memory formation. Damage causes inabilityto form NEW memory.
- Cerebral cortex 大脑皮质 -- perception and higher mental processes
Responsible for higher brain functions
- sensation and perception
- voluntary muscle control
- complex thought
- memory and language
- frontal lobe
- parietal lobe
- occipital lobe
- temporal lobe
- Functional specialization: different areas of the cortex serve different functions.
- Topographic organization: for sensory/motor areas, adjacent neurons receive input from adjacent portions of sensory/muscle tissue.
- Contralateral connections: each hemisphere is responsible for sensory/motor control of the opposite side of the body. "Corpus Callosum": bundle of axons that connects the two hemispheres.
- Hemispheric laterization: the two hemispheres have slightly different functions.
- Right hemisphere: primarily processes visual spatial information, is involved in holistic processing, and in recognizing and expressing emotion.
- Left hemisphere: processes language, sequential logical thinking, concerned with details.
Lobes of the cerebral cortex
- Frontal lobe 额叶: involved in working memory, movement, speech and language production, judgment and planning, and personality.
- Motor cortex: at the back of the frontal lobe; controls fine motor movements; each part of the motor cortex controls a different part of the body.
- Broca's area: involved in language production; damage leads to Broca's aphasia (slow, effortful speech that is meaningful, but ungrammatical)
- Parietal lobe 顶叶: specializes in processing information from the body's senses (touch, pain, temperature, awareness of body in space, etc.); involved in attention
- Sensory cortex: at the front of the parietal lobe; contains neurons that are sentitive to touch in different parts of the body.
- Damage might cause unilateral neglect: the neglect of the opposite side of the body and the opposite side of the world. A problem with attention.
- Occipital lobe 枕叶: specializes in processing visual information; different areas of the occipital lobe contribute to different aspects of vision.
- Damage might cause motion blindness: inability to see motion.
- Temporal lobe 颞叶: involved processing auditory information, language comprehension, and complex aspects of vision.
- Primary auditory cortex: at the top of the temporal lobe.
- Wernicke's area: behind the primary auditory cortex; responsible for the semantic aspects of language; damage results in Wernicke's aphasia (inability to comprehend language).
- Visual Agnosia: set of disorders where patients can't interpret visual information correctly. Prosopagnosia: inability to recognize faces.
Sensation and Perception
- Sensation: the process by which the senses detect sensory stimuli and transmit them to the brain.
- Perception: the process by which sensory information is actively organized and interpreted by the brain.
How do sensory systems work?
- Transduction 转导
- The conversion of one energy form to another. Sensory stimulus -> neural impulse.
- Receptor cells: specialized cells that respond to a specific physical stimulus, and are responsible for transduction.
- Sensory Adaptation 感觉适应
- The diminished sensitivity to prolonged stimulation.
- Adaptation of one stimulus can affect the perception of another.
- Allows us to shift our attention to what is important.
- Sensory Deprivation 感官剥夺
- The absence of normal external simulation for extended periods of time.
Visual Pathway: light -> photoreceptors (rods/cones) -> bipolar cells 双极细胞 -> ganglion cells 神经节细胞 -> optic nerve (blind spot) -> thalamus 丘脑 -> visual cortex 视觉皮质 (occipital lobe 枕叶)
Differences between rods and cones:
- Shape (cylindrical vs short, fat, tapered at one end)
- Prevalence (90-95% vs 5-10%)
- Location (toward periphery vs toward the center)
- Fovea: Area near center of retina that contains only cones and is responsible for most detailed vision
- Perception of detail (weak vs strong)
- Sensitivity to color (no vs yes)
- Response to dim light (strong vs weak)
- Dark adaptation: eye's increasing ability to see in dim light. Due to pupil dilation and recombination of rhodopsin in the rods.
Sensation: Color vision and audition
Trichromatic theory 三色说: Color perception depends on 3 receptors, each senstive to different wavelengths:
- Sensitive to short wavelengths (blue)
- Sensitive to medium wavelengths (green)
- Sensitive to long wavelengths (red)
Opponent process theory 对立过程说: Posits 6 primary colors that are complementary to one another. The color pairs are linked in the brain by 3 "opponent systems" (types of cells).
- Red/Green cells, red increases & green decreases, vice versa.
- Yellow/Blue cells, yellow increases & blue decreases, vice versa.
- White/Black cells, white increases & black decreases, vice versa.
Color blindness: Color deficiency (affects men more than women)
- Trichromats: People who can perceive all 3 primary colors and distinguish any hue (normal color vision)
- Dichromats: People who can distinguish 2 of the 3 primary colors.
- Monochromats: Total color blindness. Can't distinguish any color.
Auditory pathway: sound wave -> eardrum 鼓膜 -> ossicles 听小骨 -> cochlea 耳蜗 (basilar membrane 基膜, cilia/hair cells) -> auditory nerve -> thalamus 丘脑 -> auditory cortex (temporal lobe).
- Place theory: pitch perception depends on the area of the basilar membrane that vibrates the most.
- Frequency theory: for low frequency tones, the basilar membrane vibrates at the same frequency as the original sound and sends that information to the brain.
- Interaural time difference: if a sound is to either side of center, sound waves reach one ear slightly before they reach the other ear.
- Inte-raural intensity difference: if a sound is to either side of the center, the sound will be perceived as louder for the ear nearest the sound origins.
Illusions: McGurk Effect
- Demonstrates the interaction between hearing and vision in speech perception.
- Illustrates that our perceptions of sensory input are not always accurate.
Perception: Interpreting sensory information
- Perceptual Adaptation: in vision, this refers to our ability to adjust to an artificially displaced or inverted visual field.
- Perceptual Set: When our experiences, assumptions and expectations greatly influence what we perceive.
- Perceptual Habits: Learned patterns of attention and organization; knowing what to expect and where to look.
Perceptual Constancies: Perceptual constancies allow us to perceive objects as having stable properties.
- Size constancy: When the perceived size of an object stays the same even when there's a change in distance between object and viewer.
- Shape constancy: An object's perceived shape remains the same even though the object changes its orientation toward the viewer.
- Color constancy: An object's perceived color remains the same even when lighting conditions change.
- Figure Ground Organization: The organization of visual info into object (figure) that stand out from the surrounding background.
- Gestalt Principles of Organization
- Proximity: Tendency to perceive objects that are close together as belonging together.
- Similarity: Tendency to perceive objects that resemble each other as forming a group.
- Continuity: Tendency to perceive smooth continuous lines instead of discontinuous fragments.
- Closure: Tendency to "fill in" elements that are missing from the outline of a figure.
- Contiguity: Tendency to perceive objects that are near in time and space as belonging together.
- Common Region: Objects that are found within a common region are grouped together.
- Common Fate: Tendency to perceive elements that move together as belonging together and forming a group.
Depth Perception and Visual Illusions
- Binocular Depth Cues
- Convergence: Eyes turn inward when they focus on nearby objects. The closer the object, the greater the convergence.
- Retina Disparity: Slight difference between viewpoints of the two eyes. The closer the object, the greater the retinal disparity.
- Monocular Depth Cues
- Accommodation: The bending of the lens to focus on nearby objects.
- Pictorial Depth Cues:
- Linear Perspective: Parallel lines appear to converge at a distance.
- Relative Size: If two similar sized objects appear together, the one with the larger retinal image will be perceived as closer than the one with the smaller retinal image.
- Relative Height: We perceive objects that are near the horizon as being farther from the viewer.
- Light and Shadow: You can distinguish bulges from indentations by the shadows they cast.
- Interposition (overlap): When one object partly blocks your viewer of another, the one that is blocked is perceived as being farther away.
- Texture Gradient: Near objects appear to have sharply defined textures, whereas similar objects look smoother in the distance.
- Aerial Perspective: Distant objects often look hazy in the distance.
- Relative Motion (Motion Parallax): As we pass a scene objects closest to us seem to move in the opposite direction and faster than those farther away.
- This illusion may be culturally specific.
- Provides evidence that our exp and learning have a profound influence on perception.
- The retinal images of the two lines are the same size, but the distance cue tells you that the one on the top is larger.
- Linear perspective queue.
/ ----- \ / \ / ----- \ Ponzo Illusion.
In general , illusions result from the over-application of perceptual constancies in the face of conflicting distance cues.