Biological Bases of Behavior

Unit 1: Biological Bases of Behavior Student Notes

Psychology Overview

  • Psychology: The scientific study of behavior and mental processes.

    • Behavior: Anything that can be observed.

    • Mental Processes: Internal experiences such as thoughts, feelings, sensations, and perceptions.

Psychological Perspectives (7)

1. Behavioral Approach

  • Focuses on observable behavior and understanding humans through behavior analysis.

  • Key Ideas:

    • Behavior results from learning and experiences.

    • Behaviorists argue behavior is a product of the environment (nurture).

  • Analyze the ABCs of Behavior:

    • Antecedent: Environmental conditions preceding a behavior.

    • Behavior: The observable action.

    • Consequences: Results that follow the behavior.

  • B.F. Skinner: Worked with lab rats and pigeons; demonstrated organisms repeat actions with positive consequences and avoid negative ones.

2. Psychoanalytic/Psychodynamic Approach

  • Sigmund Freud: Disagreed with behaviorists; focused on unconscious conflicts and motives to enhance self-knowledge.

  • Key Concepts:

    • Importance of unconscious: Source of desires, thoughts, and memories beneath conscious awareness.

    • Early life experiences significantly influence personality development.

  • Notables: Freud, Jung, Adler, Kohut.

3. Humanistic Approach

  • Emerged in the mid-20th century; key figures include Abraham Maslow and Carl Rogers.

  • Emphasizes innate human qualities like free will and potential for personal growth.

    • Views human nature as positive and growth-seeking.

  • Humanists advocate for self-problem solving through therapy, especially in non-distressed clients.

4. Biological Approach

  • Technological advances allow examination of biological processes linked to behavior.

  • Key Ideas:

    • Maturation: Biological growth that affects behavior, thought, and physical growth, relatively unaffected by experience (nature).

    • Biological Psychologists: Link mind to brain functions.

5. Evolutionary Approach

  • Based on Charles Darwin's Theory of Natural Selection; behavior patterns as adaptations aiding reproduction.

  • Key Concepts:

    • Natural selection favors traits beneficial for survival.

    • Personality and behaviors evolved for reproductive success.

  • Examples:

    • Instinctive dislike of snakes and spiders due to ancestral threats.

    • Birds migrating to warmer climates for survival.

    • Caution: Application can lead to discrimination (Eugenics).

6. Cognitive Approach

  • Cognition: Involves thinking, memory, and reasoning.

  • Key Ideas: Emphasizes information processing: receiving, storing, and analyzing data.

  • Notable: Piaget.

7. Sociocultural Approach

  • Recognizes the influence of different cultures on behavior and interpretation of social cues.

  • Emphasis on environmental factors shaping cultural differences.

Nature-Nurture Debate

  • Ongoing discussion on hereditary (nature) vs. environmental influences (nurture) on behavior.

  • Nature: Heredity, biological factors.

  • Nurture: Environment, upbringing, experiences.

Research Methods

  • Twin Studies: Assess the role of genes in behavior comparisons between identical twins (100% DNA) and fraternal twins (50% DNA).

  • Adoption Studies: Compare adopted children's behaviors with biological and adoptive parents.

  • Behavioral Geneticists: Study genetic and environmental roles in mental ability and personality development.

The Nervous System

Components of the Nervous System

  1. Central Nervous System (CNS): Composed of the brain and spinal cord.

  2. Peripheral Nervous System (PNS): Relays messages; includes:

    • Autonomic Nervous System: Involuntary processes (sympathetic and parasympathetic).

    • Somatic Nervous System: Voluntary control of movement.

Neurons

  • Basic Unit: Neurons perform three major functions:

    • Receive information.

    • Process information.

    • Transmit information.

  • Types of Neurons:

    1. Sensory Neurons (Afferent): Relay information to CNS.

    2. Motor Neurons (Efferent): Carry signals from CNS to initiate actions.

    3. Interneurons: Connect sensory and motor neurons in the CNS.

Neurogenesis and Synapses

  • Neurogenesis: Growth of new neurons throughout life.

  • Synapse: Junction for communication between transmitting and receiving neurons.

Neurotransmitters and Their Functions

  • Neurotransmitters communicate either excitatory (increase likelihood of an action potential) or inhibitory (decrease likelihood of an action potential).

  • Key Neurotransmitters:

    • Dopamine: Involved in movement, learning, attention, and emotion. Too much can lead to schizophrenia; too little results in Parkinson’s.

    • Serotonin: Regulates mood, hunger, sleep, and arousal. Too little is associated with depression.

    • Norepinephrine: Related to alertness; too little also results in depression.

    • GABA: Inhibitory neurotransmitter; too little can cause seizures and insomnia.

    • Endorphins: Induced euphoria during exercise.

    • Acetylcholine: Important for learning and memory; low levels related to Alzheimer's.

Hormones vs. Neurotransmitters

  • Hormones are chemical messengers influencing various functions akin to neurotransmitters but generally occur outside the nervous system.

  • Examples: Adrenaline, leptin, ghrelin, melatonin, oxytocin.

    • Adrenaline: Activates sympathetic NS (“fight or flight”).

    • Leptin: Inhibits appetite.

    • Ghrelin: Stimulates appetite.

    • Melatonin: Regulates sleep-wake cycle.

    • Oxytocin: Influences social bonding.

Psychoactive Drugs

  • Can be agonists (mimicking neurotransmitters) or antagonists (inhibiting neurotransmitter action).

  • Common treatments for depression include SSRIs (Selective Serotonin Reuptake Inhibitors) like Prozac, Paxil, Zoloft, enhancing the availability of serotonin.

Brain Structure and Functions

Brain Stem

  • Connects spinal cord to brain; governs basic life functions (breathing, heart regulation).

    • Medulla Oblongata: Controls heartbeat and breathing.

    • Reticular Activating System: Involved in learning and cognition.

Cerebellum

  • Coordinates movement and balance; critical for nonverbal learning.

Cerebral Cortex

  • Involved in higher cognitive functions: thinking, perception, language, and memory.

    • Divided into two hemispheres and includes lobes: frontal, parietal, occipital, temporal.

Limbic System

  • Regulates emotions, memory, motivation.

  • Components: thalamus, hypothalamus, hippocampus, amygdala.

Key Brain Regions

  1. Frontal Lobes: Decision-making, planning, and speech production (Broca's area).

  2. Parietal Lobes: Sensory processing and spatial awareness.

  3. Occipital Lobes: Visual processing.

  4. Temporal Lobes: Auditory processing and language comprehension (Wernicke's area).

Neuroplasticity

  • Ability of the brain to form/reorganize connections, particularly after injury or learning.

Research Methods in Psychology

Brain Imaging Technologies

  • CT Scan: Visualizes brain structure; doesn’t show function.

  • fMRI: Maps blood flow and brain activity; expensive, requires stillness.

  • PET Scan: Measures brain activity via glucose metabolism; exposes to radiation.

  • EEG: Electrode-based measurement of electrical activity; shows brain function.

Sleep and Consciousness

  • Regulated by the hypothalamus; circadian rhythms influence physical and mental cycles over 24 hours.

  • Sleep Stages:

    1. Stage 1: Light sleep and relaxation.

    2. Stage 2: Decreased responsiveness; sleep spindles occur.

    3. Stages 3-4: Deep sleep; restorative processes occur.

    4. REM Sleep: Dreaming state; essential for memory consolidation and neuroplasticity.

Sleep Disorders

  • Insomnia: Difficulty falling/staying asleep.

  • Sleep Apnea: Pauses in breathing during sleep.

  • REM Sleep Behavior Disorder: Acting out dreams.

Sensation and Perception

  • Sensation: Detection of stimuli; involves transduction (conversion to neural messages).

  • Absolute Threshold: Minimum stimulus intensity for detection.

  • Difference Threshold: Minimum difference detectable.

  • Sensory Adaptation: Reduced sensitivity with unchanging stimuli.

Vision

  • Light enters the eye: Cornea, Lens, Retina.

  • Rods: Detect movement and light; no color.

  • Cones: Responsible for color and detail.

  • Accommodation: Process of lens adjustment for focus.

Hearing

  • Sound waves: Move air molecules affecting pitch (frequency) and loudness (amplitude).

  • Cochlea: Where sound transduction occurs.

Other Senses

  • Olfaction: Smell processed in nasal cavity; not routed through the thalamus.

  • Gustation: Taste perception through chemicals in food.

Pain Perception

  • Gate-Control Theory: Explains how psychological factors influence pain.

  • Phantom Limb Sensation: Experiencing sensations in an amputated limb.