Introductory Psychology Notes

What is Psychology?

  • Psychology = scientific study of behavior and mental processes.

  • Scientific = objective and verifiable.

  • Behavior = observable acts.

  • Mental processes = internal processes like thoughts, memory, emotions (much harder to measure!).

  • Unlike other social sciences, it focuses on individual behavior.

  • Rooted in the study of physiology (the study of the body) and philosophy (the study of knowledge).

Nature vs. Nurture

  • Nature: “Our genetics determine our behavior.”

    • Products of heredity, genetics, evolution.

    • You are born that way.

    • Innate characteristics: Examples include physical characteristics (e.g., blue eyes), certain behavioral traits, and some behavioral tendencies.

  • Nurture: “Our environment, upbringing, and life experiences determine our behavior.”

    • Environmental factors.

    • What you learn in your environment.

    • Examples: Parenting styles, cultural background, educational experiences.

  • Nature v. Nurture Debate

    • Central theme across psychological theories and research; interaction between inherited tendencies and environmental experiences.

Approaches to Psychology

  • Biological Approach: Focus on genetic, hormonal, and neurochemical explanations of behavior.

  • Psychoanalysis: Innate drives of sex and aggression (nature) and social upbringing during childhood (nurture).

  • Cognitive Psychology: Innate mental structures such as schemas, perception, and memory; continually changed by the environment.

  • Humanism: Maslow emphasized basic physical needs; society influences a person’s self-concept.

  • Behaviorism: All behavior is learned from the environment through conditioning.

Twin Studies

  • Monozygotic twins (identical): 100%100\% genetic match.

  • Dizygotic twins (fraternal): 50%50\% genetic match.

  • Use of twin studies to determine which characteristics are nature and which are nurture.

The Nervous System: Overview

  • The nervous system acts as the body's central control center and communication network, enabling us to move, think, feel, and react to our surroundings.

The Nervous System Divisions

  • Central Nervous System (CNS): Brain; Spinal Cord.

  • Peripheral Nervous System (PNS): Nerves.

  • Somatic Nervous System: Controls voluntary movements (e.g., walking, picking up a pencil).

  • Autonomic Nervous System: Controls involuntary actions (e.g., heartbeat, digestion).

  • Autonomic divisions: Sympathetic Division; Parasympathetic Division.

Functions of the Nervous System

  • Sensory Input: Gathers information from senses (sight, sound, touch, taste, smell) and sends it to the brain.

  • Integration: Brain processes information and makes decisions about what to do.

  • Motor Output: Brain sends signals to muscles and glands to respond (e.g., move hand away from something hot; release hormones).

Central Nervous System

  • Brain: The boss of the nervous system; controls thinking, feeling, and moving; processes information from our senses.

  • Spinal Cord: A highway that connects the brain to the rest of the body; transmits messages back and forth.

Peripheral Nervous System

  • Nerves: Wires that connect the brain and spinal cord to the rest of the body; carry messages to and from the brain and spinal cord; bundles of interconnected neurons.

  • Somatic Nervous System: Controls voluntary movements.

  • Autonomic Nervous System: Controls involuntary actions; two main parts.

Autonomic Nervous System

  • Sympathetic Nervous System: The flight, fight, or freeze response.

  • Parasympathetic Nervous System: Calms you down; rest and digest.

TYPES OF NEURONS

  • Sensory (afferent) Neurons: Take messages from sensory receptors (your five senses) to the brain and spinal cord.

  • Motor (efferent) Neurons: Transmit signals from the brain back to the muscles and organs.

  • Interneurons: Relay neurons (connectors) that allow for information to pass between neurons and between the spinal cord and brain.

REFLEXES

  • Reflex: A simple, automatic response to a sensory stimulus.

    • Example: Doctor taps your knee with a hammer; it jerks.

    • The movement is directed by the spinal cord rather than the brain and is much quicker.

  • Reflex arc: When a sensory organ directs the message to the spinal cord instead of the brain.

    • Example: You put your hand on a hot stove and jerk it away; you realize it was hot after.

THE BODY SYSTEMS: ENDOCRINE SYSTEM

WHAT IS IT?

  • The endocrine system is the system of glands in our body that circulates and regulates hormones.

  • Hormones have effects on behavior and mental processes like neurotransmitters do, but they are circulated through the bloodstream.

  • This makes them slower-acting but with longer-lasting effects.

ENDOCRINE SYSTEM

  • The pituitary gland is considered the “master gland” of the endocrine system.

  • It regulates stress, growth, and reproduction.

  • The pituitary gland sends signals to the other glands to release their hormones.

  • PITUITARY GLAND

HORMONES TO KNOW

  • Adrenaline

    • Secreted by the adrenal glands which are at the top of each kidney.

    • Adrenaline is a hybrid because it is secreted by the adrenal glands and also transmitted as a neurotransmitter called epinephrine.

    • Adrenaline increases heart rate, blood pressure, and blood sugar, providing us with a surge of energy, known as the fight-or-flight response.

    • Long-term excess of adrenaline can cause heart disease, high blood pressure and diabetes.

  • Ghrelin

    • Produced in the stomach; it tells the body you are hungry and need food.

    • “If your stomach is growling, it is ghrelin.”

  • Leptin

    • Produced in the small intestine; signals fullness or that you have reached satiety.

  • Testosterone

    • Produced by both women and men in the ovaries and testes, respectively.

    • It is the hormone most responsible for human sex drive.

    • Men have it in greater quantities.

    • Too much testosterone can lead to aggression.

  • Estrogen

    • Important for reproduction; women have greater quantities.

  • Oxytocin

    • Social bonding hormone; produced by the hypothalamus and released by the pituitary gland.

    • Produces positive feelings (like serotonin and endorphins).

    • Plays a role in labor and mother’s bonding with babies after birth.

    • Plays a role in bonding with friends and love interests.

    • Low levels can result in postpartum depression.

  • Melatonin

    • Produced in the pineal gland in response to darkness.

    • Regulates circadian rhythms (sleep-wake cycle).

    • Helps you sleep.

    • Synthetic forms of melatonin are used to treat insomnia.