Sensation and Perception Lecture Notes

Introduction

• Sensation: Bringing information from the environment into the body and brain.
• Perception: Interpreting sensory information.
• Stimuli cause reactions and influence behavior.
• Conscious experiences: Thoughts, emotions, dreams, and the effects of meditation or drugs.

Vision

Light and the Eye

• Light is part of the electromagnetic spectrum.
• Visual process: Light enters through cornea → lens → optic nerve → brain.
• Cones and rods: Cones detect color, rods detect black and white.
• Optic nerve transmits visual information to the brain.
• Blind spot experiment (based on screen size and distance).

Color Perception

• Young-Helmholtz Theory: Three types of color cones (trichromatic theory).
• Color blindness: More common in males; evolutionary psychology explanations.

Visual Manipulations

• Ames Room: Manipulates perception of size.
• Misleading lines and shapes can test sensory limits.

Sound

Hearing Process

• Sound waves enter ear → cochlea (fluid and hairs) → neurons → brain.
• Perception of loudness and pitch.
• Cochlea fluid hardens over time, affecting balance and hearing.

Pain Perception

• Pain receptors and transmission through brain stem and spinal cord.
• Gate Theory: Endorphins can block pain signals.
• Phantom limb pain: Feeling pain in a non-existent limb.
• Types of pain receptors: Fast and slow.

Taste and Smell

Taste

• Taste receptors react to chemicals (e.g., salty, sweet).

Smell

• Related to airborne particles of the substances we eat.
• Smell affects taste.
• Pheromones: Influence attraction and mate selection.
• Signal Detection Theory: Sensory thresholds for detection.

Perception Theories

Feature Detection

• Patterns and surroundings influence perception.
• Gestalt theories: Overall patterns, top-down vs. bottom-up processing.

Depth Perception

• Monocular and binocular cues.
• Convergence: Eye muscle adjustments to perceive depth.
• Depth perception cues: Object size, linear perspective, etc.

Dream and Sleep Perception

• Dreams: Manifest (direct objects) vs. latent content (symbolic meaning).
• Nightmares and PTSD: Impact on mental health.
• Sleepwalking and talking: Cognitive presence in sleep.

Altered States of Consciousness

Daydreams and Meditation

• Consciousness drift and meditation (transcendental state, mindfulness).

Hypnosis

• State of suggestibility; can cause hallucinations and altered perception.
• Originated with Mesmer (mesmerism).

Drug-Induced States

• Hallucinogens, depressants, and their effects on consciousness.
• Substance abuse issues and demographic differences.

Conclusion

• Understanding sensation and perception helps in interpreting how we interact with the world around us.