AP Psychology Unit 3: Sensation and Perception

Overview

• This lecture covers the fundamental differences and principles of sensation and perception in AP Psychology.
• Sensation: Raw data received from our five senses (sensory receptors).
• Perception: Interpreting the information received through our senses.

Gestalt Psychology

• Perceptual Organization: Whole is greater than the sum of its parts.
  • Principles:
    • Figure and Ground: Simplifying visual input into figures and background.
    • Continuation: Follow lines and curves naturally (e.g., exit signs).
    • Closure: Brain fills in missing information (e.g., incomplete images).
    • Similarity and Proximity: Group objects as a single unit if they are similar or close together.
    • Symmetry: Symmetrical objects are perceived as one.

Depth Perception

• Ability to perceive the relative distance of objects in one's visual field.
• Binocular Cues:
  • Convergence: Eyes move inward for close objects.
  • Retinal Disparity: Different views from each eye provide depth.
• Monocular Cues:
  • Relative Size, Interposition, Relative Height: Closer objects appear larger and unobstructed.
  • Shading, Contour, Texture Gradient: Clearer and more detailed objects appear closer.
  • Linear Perspective: Parallel lines converging implies depth.
  • Motion Parallax: Closer objects move faster than distant ones.

Sensory Processing

• Sensory Transduction: Activation of sensory neurons to create a sensation.
• Absolute Threshold: Minimum stimulation needed to detect a stimulus.
• Signal Detection Theory: Predicts perception of weak signals (e.g., signal present vs. misses).
• Sensory Adaptation vs. Habituation:
  • Adaptation: Decreased sensitivity to unchanging stimuli.
  • Habituation: Reduced response due to repeated exposure.
• Difference Threshold: Minimum change required to notice a difference between stimuli.
  • Weber's Law: Stimuli must differ by a constant percentage.

Perceptual Constancy

• Size, Color, Shape, Lightness Constancy: Objects perceived consistently despite changes.
• Schemas and Perceptual Sets: Cognitive frameworks based on experiences affecting perception.
  • Can lead to biases based on prior knowledge and emotional states.

Vision

• Anatomy of the Eye:
  • Sclera, Cornea, Lens, Retina, Optic Nerve: Key components in processing visual information.
  • Rods and Cones: Photoreceptors for dim light and color vision.
• Color Perception:
  • Trichromatic Theory: Color vision based on three receptor types.
  • Opponent Process Theory: Neurons excited/inhibited by color pairings (red-green, blue-yellow).
• Color Blindness:
  • Achromatism: Only see black, white, gray.
  • Dichromatism: Difficulty distinguishing certain colors.

Sound and Hearing

• Structure of the Ear:
  • Pinna, Auditory Canal, Eardrum, Cochlea: Pathway for sound waves transforming into neural signals.
• Sound Wave Properties:
  • Frequency and Amplitude: Influence pitch and loudness.
• Hearing Loss:
  • Sensorineural vs. Conductive: Damage to nerve vs. blockage in ear.

Chemical Senses

• Smell (Olfaction):
  • Olfactory Epithelium and Bulb: Pathway for detecting odors.
• Taste (Gustation):
  • Taste Buds and Papillae: Structures for detecting five basic tastes.

Somatosensory System

• Skin Structure:
  • Epidermis, Dermis, Hypodermis: Layers contributing to touch and pain perception.
• Phantom Limb Sensations: Pain felt in amputated limbs.
• Kinesthesis and Vestibular Sense: Awareness of body positioning and balance.

Final Notes

• The interaction of senses is crucial for experiencing the world.
• Recommended actions: Review the study guide and take practice quizzes.

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