Introduction to Psychology: Key Concepts, Methods, and Biological Foundations

Introduction to Psychology

Definition and Scope

Psychology is the scientific study of how people behave, think, and experience, and how these processes can be affected by physical, mental, social, and environmental factors.

• Scientific method: Systematic way of learning about the world through observation, experimentation, and theory development.

• Biopsychosocial model: Explains behavior as a product of biological, psychological, and sociocultural influences.

Scientific Literacy

• Gather knowledge

• Explain scientific concepts

• Critically think

• Apply knowledge

Empiricism and Determinism

• Empiricism: Knowledge is acquired through sensory experience.

• Determinism: Events are causally determined by preceding events according to natural laws.

Historical Perspectives

• Phrenology: Theory that personality traits are determined by the shape and size of the skull.

• Nature vs. Nurture: Debate on the influence of genetics (nature) versus environment (nurture) on behavior and mental processes.

Major Approaches in Psychology

• Behaviorism: Focuses on observable behavior and the ways it is learned.

• Cognitive psychology: Studies mental processes such as thinking, memory, and problem-solving.

• Humanistic psychology: Emphasizes personal growth and self-actualization.

• Biological psychology: Examines the biological underpinnings of behavior.

• Evolutionary psychology: Explains behavior in terms of adaptation and natural selection.

• Freud (Psychoanalysis): Focuses on unconscious mind, childhood experiences, and dream analysis.

• Functionalism: Early American psychology approach focusing on the purpose of behavior and mental processes.

Key Figures

• Wilhelm Wundt: Father of experimental psychology.

• William James: Founder of functionalism.

• Ivan Pavlov: Classical conditioning (dogs and salivation).

• B.F. Skinner: Operant conditioning (reinforcement and punishment).

• John Watson: Behaviorism, "Little Albert" experiment.

• Carl Rogers: Humanistic psychology, person-centered therapy.

Branches and Applications of Psychology

Major Branches

• Social psychology: How behavior is shaped by our environment.

• Personality psychology: Study of traits and individuality.

• Cognitive psychology: Focus on memory, thought, and perception.

• Neuroimaging: Techniques to study brain activity.

• Positive psychology: Promotes strengths and well-being.

Applied Psychology

• Basic research: Builds knowledge and explores theories.

• Applied research: Uses psychology to solve real-world problems.

Scientific Research in Psychology

Characteristics of Quality Scientific Research

• Objective

• Generalizable

• Free from bias

• Made public

• Replicable

Key Concepts

• Objectivity: Use of objective measurement.

• Subjectivity: Interpretation of events can become subjective.

• Generalizability: Applicability of results to broader populations.

• Informed consent: Participants must be informed about the study and consent to participate.

• Hypothesis: Testable idea or prediction.

• Variables: Concepts or events that are measured or manipulated.

• Reliability: Consistency and stability of a measurement.

• Validity: Degree to which a test measures what it claims to measure.

Sources of Bias

• Researcher bias: May treat participants differently.

• Subject/participant bias: Participants try to give what the experimenter wants.

• Placebo effect: Improvement due to expectation rather than treatment.

• Social desirability: Responding in a way that is viewed favorably by others.

Types of Research Design

• Quantitative: Involves numerical measurements.

• Qualitative: Involves flexible and creative interviews or observations.

Main Types of Studies

• Descriptive: Case studies, naturalistic observation.

• Correlational: Shows relationships between variables.

• Experimental: Manipulates variables to test for cause and effect.

• Quasi-experimental: Similar to experiments but lacks random assignment.

• Biological: Brain imaging, genetic studies.

Ethics in Research

• Follow research ethics code.

• Obtain informed consent.

Descriptive Statistics

• Frequency: Number of occurrences of a repeating event per unit of time.

• Normal distribution: Symmetrical distribution around a central mean value.

• Skewed distribution: Asymmetrical distribution with a long tail on one side.

• Central tendency: Mean, median, mode.

Biological Psychology

What is Biological Psychology?

Biological psychology links biological variables (e.g., brain, hormones, genes) to psychological outcomes.

Behavioral Genomics and Genetics

• Principles of Hereditary Transmission: Chromosomes store genetic info; genes are DNA segments; alleles are different forms of genes (dominant or recessive).

• Behavioral genomics: How genetic variations influence traits, behavior, and mental health.

• Human genome project: Mapped DNA, found in the brain-related gene.

• Epigenetics: Environment can alter gene expression.

• Methylation: Biochemical process that silences gene expression.

• CRISPR gene editing: Allows precise changes to DNA for potential treatments.

Dominant vs. Recessive Genes

• Dominant: Trait is expressed if at least one dominant allele is present.

• Recessive: Trait is expressed only if both alleles are recessive.

Genotype and Phenotype

• Genotype: Genetic makeup.

• Phenotype: Observable traits (genes + environment).

Neurobiology of Behavior

• Central nervous system: Brain and spinal cord.

• Peripheral nervous system: Nerves outside CNS.

• Somatic nervous system: Voluntary muscle control.

• Autonomic nervous system: Involuntary functions (sympathetic and parasympathetic divisions).

Major Brain Structures and Functions

• Cerebellum: Balance and coordination.

• Thalamus: Sensory relay station.

• Basal ganglia: Movement and reward.

• Hypothalamus: Regulates hunger, thirst, body temperature.

• Midbrain: Relays information and processes sensory input.

• Spinal cord: Controls simple reflexes and communicates with the nervous system.

Neurons and Neurotransmitters

• Neuron: Specialized cell for receiving and transmitting information.

• Synapse: Junction where neurons communicate.

• Action potential: Sudden change when a neuron fires.

Major Neurotransmitters

• Dopamine: Movement, learning, reward, and executive functions.

• Serotonin: Mood, sleep, appetite, arousal.

• Acetylcholine: Muscle action, learning, memory.

• GABA: Main inhibitory neurotransmitter.

• Glutamate: Main excitatory neurotransmitter.

• Norepinephrine: Arousal and alertness.

• Endorphins: Pain relief and pleasure.

• Adrenaline (epinephrine): "Fight-or-flight" response.

Endocrine System

• Uses hormones to influence behavior and physiology.

Neuroplasticity

• Brain rewires itself after damage; brain changes and adapts.

Sensation and Perception

Key Concepts

• Sensation: Detecting external events with sense organs and turning stimuli into neural signals.

• Perception: Interpreting, organizing, and identifying sensory stimuli.

Thresholds

• Absolute threshold: Minimum stimulation needed to detect a stimulus.

• Difference threshold (just noticeable difference): Smallest detectable change in a stimulus.

Signal Detection Theory

• Detecting stimuli depends on both signal and background noise.

Transduction

• Conversion of physical energy into neural signals.

Sensory Adaptation

• Decreased sensitivity to constant unimportant stimuli.

Subliminal Information Processing

• Processing of sensory input below conscious awareness.

Gestalt Principles of Perceptual Organization

• Help explain how we perceive patterns and wholes.

Perceptual Constancies

• Shape constancy: Object shape seems stable despite angle.

• Size constancy: Object size seems stable despite distance.

• Color constancy: Object color seems stable under different illumination.

Bottom-Up and Top-Down Processing

• Bottom-up: Perception from raw sensory input.

• Top-down: Perception guided by prior experience and context.

Visual System

• Structure of the eye

• Myopia and hyperopia

• Pathway of sensory information from the eye to the occipital lobe

Auditory System

• Frequency

• Amplitude

• Timbre

• Outer ear, middle ear, inner ear

Somatosensory System

• Sense of touch

• Pain sensation (acute vs. chronic pain)

• Role of brain in pain

Olfactory and Gustatory Perception

• Senses of smell and taste

• Receptors for smell and taste

• Process of sensing and perceiving smell and taste

Example: The process of seeing a cup of coffee involves sensation (light entering the eye), transduction (conversion to neural signals), and perception (recognizing the object as coffee).