PSY110 Area 1: Foundations of Psychology, Scientific Method, Biological Bases, and Sensation & Perception

What is Psychology

Defining Psychology

• Psychology is the scientific study of behavior and mental processes.

• As a science, psychology uses the scientific method to describe, predict, and explain behavior.

• Behavior: Observable actions of people and animals.

• Mental processes: Internal thoughts, feelings, and motives that cannot be directly observed.

The Psychological Frame of Mind

• Psychologists test assumptions and examine evidence using four core attitudes:

  • Critical thinking: Reflecting deeply, asking questions, and evaluating evidence.

  • Skepticism: Challenging facts and questioning what is assumed to be true.

  • Objectivity: Using empirical methods to evaluate events as they are.

  • Curiosity: Asking questions and seeking to understand phenomena.

• Pseudoscience: Claims presented as scientific but lacking empirical support.

• Psychologists research ways to stop the spread of misinformation and promote critical thinking.

Psychology as the Science of All Human Behavior

• Psychology covers all aspects of human behavior, not just clinical or abnormal psychology.

• Positive Psychology: Focuses on positive aspects such as hope, optimism, happiness, and gratitude.

Historical Perspectives

• Early philosophers (Socrates, Plato, Aristotle) debated the mind-body relationship.

• Structuralism (Wundt): Focused on basic elements of mental processes using introspection.

• Functionalism (James): Focused on the functions and purposes of the mind in adaptation.

• Natural selection (Darwin): Traits aiding survival are passed to future generations.

• Contributions from women and people of color, e.g., Mary Whiton Calkins, Charles Henry Turner, Inez Beverly Prosser.

Contemporary Approaches to Psychology

• Biological approach: Emphasizes the brain and nervous system (neuroscience).

• Behavioral approach: Focuses on observable behaviors and environmental determinants (Watson, Skinner).

• Psychodynamic approach: Emphasizes unconscious thought and early family experiences (Freud).

• Humanistic approach: Focuses on positive qualities and free will.

• Cognitive approach: Studies mental processes such as attention, perception, memory, and problem-solving.

• Evolutionary approach: Uses adaptation and survival to explain behavior.

• Sociocultural approach: Examines how social and cultural environments influence behavior.

What Psychologists Do

• Careers: Research, teaching, business, therapy (practitioners).

• Clinical psychologist: Doctoral degree in psychology; psychiatrist: Medical degree, can prescribe medication.

• Specializations include: physiological psychology, sensation and perception, learning, cognitive psychology, developmental psychology, motivation and emotion, psychology of women and genders, personality, social psychology, industrial/organizational psychology, clinical and counseling psychology, health psychology, community psychology, school and educational psychology, environmental psychology, forensic psychology, sport psychology, cross-cultural psychology.

Psychology, Health, and Wellness

• The mind impacts the body (e.g., healthy behaviors improve well-being).

• The body impacts the mind (e.g., sleep and nutrition affect cognition).

• Debate: Nature (genetics) vs. nurture (environment).

Psychology's Scientific Method

The Scientific Method

• Science is defined by its method, not its subject matter.

• Five steps:

  1. Observe a phenomenon (often based on a theory).

  2. Formulate hypotheses and predictions (testable statements derived from theory).

  3. Test through empirical research (collect and analyze data).

  4. Draw conclusions (interpret data, publish findings).

  5. Evaluate theory (replication, meta-analysis, ongoing revision).

• Replication: Repeating studies to confirm findings (direct and conceptual replication).

• Meta-analysis: Statistical summary of multiple studies to assess the strength of an effect.

Types of Psychological Research

• Descriptive research: Observes and records behavior (observation, surveys/interviews, case studies).

• Correlational research: Examines relationships between variables (correlation coefficient $r$ ranges from $-1.00$ to $+1.00$).

• Experimental research: Manipulates variables to determine causation (independent and dependent variables, random assignment).

Descriptive Research

• Observation: Systematic, planned, and objective.

• Surveys/Interviews: Self-reported attitudes or beliefs; may be affected by socially desirable responding.

• Case studies: In-depth look at individuals or small groups; not generalizable.

Correlational Research

• Measures the strength and direction of relationships between variables.

• Positive correlation: Variables move in the same direction.

• Negative correlation: Variables move in opposite directions.

• Correlation ≠ causation; third-variable problem and directionality problem.

• Longitudinal designs: Measure variables over time; cannot prove causation.

Experimental Research

• Independent variable (IV): Manipulated by researcher.

• Dependent variable (DV): Measured outcome.

• Experimental group: Receives manipulation; control group: No manipulation.

• Random assignment: Participants randomly assigned to groups to control for bias.

• Quasi-experimental designs: No random assignment; weaker causal conclusions.

• Validity: Internal (IV causes DV) and external (generalizability to real world).

• Biases: Experimenter bias, demand characteristics, participant bias, placebo effect.

• Double-blind experiment: Both experimenter and participant unaware of group assignments.

Research Samples and Settings

• Population: Entire group of interest; sample: Subset studied.

• Random sample: Each member has equal chance of selection.

• Settings: Laboratory (controlled, but artificial) vs. naturalistic observation (real-world).

Analyzing and Interpreting Data

• Descriptive statistics: Summarize data (mean, median, mode, range, standard deviation).

• Inferential statistics: Determine if results support hypothesis; assess statistical significance (commonly $p < .05$).

Conducting Ethical Research

• APA guidelines: Informed consent, confidentiality, debriefing, and limited deception.

• Animal research: Humane treatment, proper housing, and care.

Critical Thinking in Research

• Avoid overgeneralizing from small samples.

• Distinguish group results from individual needs.

• Seek evidence from multiple studies.

• Do not infer causation from correlation.

• Consider the credibility of information sources.

Scientific Method and Health

• Expressive writing about trauma can improve health (Pennebaker's research).

• Guidelines: Write in a quiet place, focus on one topic, write daily, ignore grammar.

Biological Foundations of Behavior

The Nervous System

• The body's electrochemical communication network.

• Neuroscience: Study of the nervous system.

• Key characteristics: Complexity, integration, adaptability (plasticity), electrochemical transmission.

Pathways

• Afferent (sensory) nerves: Carry information to the brain/spinal cord.

• Efferent (motor) nerves: Carry information from brain/spinal cord to body.

Divisions

• Central nervous system (CNS): Brain and spinal cord.

• Peripheral nervous system (PNS): Connects CNS to rest of body; includes:

  • Somatic nervous system: Sensory and motor nerves (voluntary control).

  • Autonomic nervous system: Regulates internal organs; includes:

    • Sympathetic: Arouses body ("fight or flight").

    • Parasympathetic: Calms body ("rest and digest").

Neurons and Glial Cells

• Neurons: Nerve cells that process information; have cell body, dendrites, axon, myelin sheath.

• Glial cells: Support, nourish, and protect neurons; involved in memory and disease.

• Mirror neurons: Respond to both performing and observing actions; linked to empathy.

Neural Impulse

• Resting potential: $-60$ to $-75$ mV; neuron is inactive.

• Action potential: Electrical impulse travels down axon when threshold is reached (all-or-nothing principle).

Synapses and Neurotransmitters

• Synapse: Gap between neurons; neurotransmitters cross to transmit signals.

• Reuptake: Neurotransmitter reabsorbed by sending neuron after message delivery.

• Major neurotransmitters and functions:

  • Acetylcholine (ACh): Muscle action, learning, memory (deficiency in Alzheimer's).

  • GABA: Inhibitory; low levels linked to anxiety.

  • Glutamate: Excitatory; learning, memory, implicated in several disorders.

  • Norepinephrine: Alertness, stress response.

  • Dopamine: Voluntary movement, reward, attention (low in Parkinson's, high in schizophrenia).

  • Serotonin: Mood, sleep, attention (low in depression).

  • Endorphins: Pain relief, pleasure.

  • Oxytocin: Social bonding, love, stress response.

Neural Networks

• Interconnected pathways integrating sensory input and motor output.

• Connections strengthen with use (basis for learning).

Brain Structure and Function

Studying the Brain

• Lesioning: Studying effects of brain damage.

• EEG: Records electrical activity.

• CT, PET, MRI, fMRI: Imaging techniques for structure and function.

Major Brain Regions

• Hindbrain: Medulla (breathing, reflexes), pons (sleep, arousal), cerebellum (coordination), brain stem (survival functions).

• Midbrain: Substantia nigra (dopamine, movement), reticular formation (arousal, attention).

• Forebrain:

  • Limbic system: Amygdala (emotion), hippocampus (memory).

  • Thalamus: Sensory relay station.

  • Basal ganglia: Voluntary movement.

  • Hypothalamus: Regulates eating, drinking, emotion, stress, endocrine system.

Cerebral Cortex

• Divided into two hemispheres, each with four lobes:

  • Frontal lobe: Voluntary movement, intelligence, personality, planning (prefrontal cortex).

  • Parietal lobe: Spatial location, attention, motor control.

  • Temporal lobe: Hearing, language, memory.

  • Occipital lobe: Vision.

• Somatosensory cortex: Processes body sensations.

• Motor cortex: Controls voluntary movements.

• Association cortex: Integrates sensory and motor information; involved in higher functions.

Hemispheric Specialization

• Left hemisphere: Language, logic, analytical tasks.

• Right hemisphere: Spatial, visual, nonverbal, emotion.

• Corpus callosum: Connects hemispheres; split-brain research shows independent functioning.

• Broca's area: Speech production; Wernicke's area: Language comprehension.

The Endocrine System

• Glands secrete hormones into the bloodstream.

• Pituitary gland: Master gland, regulates growth and other glands.

• Adrenal glands: Mood, energy, stress response (epinephrine, norepinephrine).

• Pancreas: Insulin, metabolism.

• Ovaries/testes: Sexual development and reproduction.

• Endocrine system is slower than nervous system; uses circulatory system.

Brain Plasticity and Repair

• Plasticity: Brain's ability to change and adapt, especially in young children.

• Repair mechanisms: Collateral sprouting, substitution of function, neurogenesis (new neurons in hippocampus, olfactory bulb).

• Brain grafts and stem cells: Experimental treatments for brain injury and disease.

Genetics and Behavior

• Chromosomes: 46 per cell (23 pairs); contain DNA and genes.

• Dominant-recessive principle: Dominant gene overrides recessive.

• Polygenic inheritance: Multiple genes influence traits.

• Molecular genetics: Manipulating genes to study effects.

• Selective breeding: Used in animals, not ethical in humans.

• Genome-wide association: Links genetic variations to traits/diseases.

• Behavior genetics: Twin studies to assess heredity vs. environment.

• Genotype: Genetic makeup; phenotype: Observable characteristics.

Biological Foundations and Health

• Stress: Response to stressors; acute (short-term) vs. chronic (long-term).

• Chronic stress can harm the immune system; coping strategies are important.

Sensation and Perception

How We Sense and Perceive the World

• Sensation: Receiving stimulus energy and transforming it into neural impulses.

• Perception: Organizing and interpreting sensory information.

• Bottom-up processing: Sensory input sent to brain for interpretation.

• Top-down processing: Cognitive processes influence interpretation of sensory input.

• Purpose: Adaptation to stimuli for survival.

Sensory Receptors and the Brain

• Specialized cells detect stimuli and transmit information via afferent nerves.

• Types of energy detected:

  • Photoreception: Light (vision).

  • Mechanoreception: Pressure, vibration, movement (touch, hearing, balance).

  • Chemoreception: Chemical stimuli (smell, taste).

• Synaesthesia: One sense induces another (e.g., "seeing" music).

• Phantom limb pain: Sensation in a missing limb.

• Extrasensory perception (ESP): Controversial claim of perception without sensory input.

Thresholds

• Absolute threshold: Minimum stimulus energy detectable.

• Difference threshold (just noticeable difference): Smallest detectable difference between stimuli.

• Weber's law: Two stimuli must differ by a constant percentage to be perceived as different.

• Subliminal perception: Processing below conscious awareness.

Signal Detection Theory

• Decision making about stimuli under uncertainty; outcomes: Hit, Miss, False Alarm, Correct Rejection.

• Influenced by individual and contextual factors (fatigue, expectations).

Attention and Perceptual Set

• Attention: Focusing awareness on specific stimuli.

• Selective attention: Focusing on one aspect, ignoring others (e.g., cocktail party effect).

• Stroop effect: Difficulty naming ink color of a word when it differs from the word's meaning.

• Emotion-induced blindness: Missing stimuli presented after emotional events.

• Inattentional blindness: Missing unexpected events when attention is elsewhere.

• Perceptual set: Predisposition to perceive in a particular way.

Sensory Adaptation

• Change in responsiveness of sensory system based on average stimulation (e.g., adapting to cold water).

The Visual System

The Eye

• Light: Electromagnetic energy; wavelength (color), amplitude (brightness), purity (saturation).

• Eye structures:

  • Sclera: White outer part, protection.

  • Iris: Colored part, controls pupil size.

  • Pupil: Opening for light entry.

  • Cornea: Focuses light.

  • Lens: Flexible, focuses light on retina.

  • Retina: Light-sensitive, contains rods (low light, no color) and cones (color, bright light).

  • Fovea: Center of retina, only cones, sharp vision.

  • Optic nerve: Carries visual info to brain.

  • Blind spot: No rods or cones where optic nerve exits.

Visual Processing in the Brain

• Optic nerve transmits info to brain; left visual field to right brain and vice versa.

• Optic chiasm: Crossover point for visual info.

• Visual cortex (occipital lobe): Processes vision.

• Feature detectors: Neurons responding to specific features.

• Parallel processing: Simultaneous processing of multiple features.

• Binding: Integration of features into unified perception.

Color Vision

• Trichromatic theory: Three types of cones (red, green, blue).

• Color blindness: Deficiency in one or more cone types.

• Opponent-process theory: Cells respond to pairs (red-green, blue-yellow).

• Afterimages: Sensations that persist after stimulus removal.

Perceiving Shape, Depth, Motion, and Constancy

• Figure-ground relationship: Distinguishing object from background.

• Gestalt principles: Closure, proximity, similarity.

• Depth perception: Binocular cues (disparity, convergence), monocular cues (size, overlap, shading).

• Motion perception: Detecting movement; apparent motion (stationary objects appear moving).

• Perceptual constancy: Recognizing objects as unchanging (size, shape, color) despite sensory changes.

The Auditory System

Nature of Sound

• Sound waves: Vibrations in air; frequency (pitch), amplitude (loudness), timbre (quality).

Ear Structure

• Outer ear: Pinna, auditory canal.

• Middle ear: Eardrum, hammer, anvil, stirrup.

• Inner ear: Oval window, cochlea, basilar membrane, hair cells (cilia).

• Cochlear implants: Devices to restore hearing.

Theories of Hearing

• Place theory: Different frequencies stimulate different places on basilar membrane.

• Frequency theory: Frequency of nerve firing matches sound frequency.

• Volley principle: Clusters of nerve cells fire in rapid succession.

Auditory Processing and Localization

• Sound info travels from hair cells to auditory nerve to brain stem to cortex.

• Localization: Timing and intensity differences between ears help locate sound source.

Other Senses

Skin Senses

• Touch: Mechanical energy detected by skin receptors.

• Temperature: Thermoreceptors respond to changes.

• Pain: Warns of damage; fast and slow pathways; influenced by endorphins, culture, gender.

Chemical Senses

• Taste: Papillae contain taste buds (sweet, sour, bitter, salty, umami, fat); influenced by culture.

• Smell: Olfactory epithelium contains receptor cells; info sent to temporal lobe and limbic system.

Kinesthetic and Vestibular Senses

• Kinesthetic: Movement, posture, orientation (muscles, joints).

• Vestibular: Balance, head movement (semicircular canals in inner ear).

• Proprioceptive feedback: Position of limbs and body parts.

Sensation, Perception, and Health

• Eye health: Avoid high-fat foods, don't smoke, eat foods rich in vitamins and minerals, use proper lighting, wear sunglasses.

• Hearing health: Avoid loud noise, be cautious with technology (e.g., earbuds).