Biological Psychology Overview

Biological Underpinnings of Behavior

• Phrenology, an early, incorrect belief that skull shape determined personality, initially sparked brain mapping efforts. Scientific thinking is crucial in psychology.

Genetics and Behavior

• Chromosomes, in 23 pairs, carry genetic material (half from each parent).
• Genes, segments of DNA, control traits; humans have about 20,000. Genes can be active or inactive.
• The genome is the complete set of genetic instructions.
• Heritability quantifies the proportion of individual differences attributable to genes.
• Gene-environment interaction means environment influences gene expression (environment "plays the hand" that genes "deal").
• Epigenetics studies how the environment alters gene activity.

Evolutionary Psychology

• Natural selection explains behaviors like fear of heights or preference for high-calorie foods.
• Evolutionary psychology suggests men are attracted to signs of youth and fertility; women look for resources.
• Criticism exists regarding the interplay of biological and social learning explanations.

Nervous System Overview

• The Central Nervous System (CNS) comprises the brain and spinal cord.
• The Peripheral Nervous System (PNS) is outside the CNS; it is divided into Somatic (voluntary) and Autonomic (involuntary) branches.
  • The Autonomic system has two branches:
    • Sympathetic: "fight-or-flight" response.
    • Parasympathetic: "rest-and-digest" response.

Neurons and Neurotransmitters

• Neurons are the basic units of the nervous system (sensory, motor, interneurons).
• Key neurotransmitters include:
  • Acetylcholine: Muscle movement, memory (Alzheimer's link).
  • Dopamine: Reward, learning, emotion (Schizophrenia, Parkinson's link).
  • Serotonin: Mood, hunger, sleep (Depression link).
  • Endorphins: Natural painkillers released during exercise.

Endocrine System

• The endocrine system uses hormones with slower, long-lasting effects.
• Key glands include:
  • Hypothalamus: Regulates homeostasis.
  • Pituitary: Master gland controlling other glands.
  • Adrenal: Produces adrenaline for stress responses.
  • Pineal: Secretes melatonin (sleep hormone).

Sleep and Circadian Rhythms

• Sleep occurs in stages including NREM-1 (light sleep), NREM-2 (moderate sleep), NREM-3 (deep sleep), and REM (dreaming).
• Sleep cycles repeat approximately every 90 minutes, progressing from deep to REM sleep.
• Sleep is vital for memory consolidation, problem-solving, growth, and overall health.

Psychoactive Drugs

• Psychoactive drugs are categorized as depressants, stimulants, or hallucinogens. Tolerance, withdrawal, and addiction result from their use.

Sensation and Perception

• Sensation involves detecting stimuli (absolute and difference thresholds).
• Sensory systems include visual (retina processing light, rods and cones), auditory (hair cells), chemical (taste and smell), tactile (touch—pressure, temperature, pain), and vestibular (balance).

Brain Functionality

• The brainstem comprises the medulla (heart rate, breathing), pons (communication), and reticular formation (alertness).
• The cerebral cortex, divided into four lobes (frontal, parietal, occipital, temporal), includes association areas for higher-level processing.
• Brain plasticity refers to its ability to adapt and rewire.
• Split-brain studies demonstrated hemisphere specialization.

This quiz explores the biological underpinnings of behavior, including genetics, evolutionary psychology, and the role of epigenetics. It covers key concepts such as gene-environment interactions and the influence of natural selection on human behavior. Test your understanding of how biology shapes psychology!