AP Psychology Unit 3: Sensation and Perception

Introduction

• Sensation: Raw data received from the five senses via sensory receptors.
• Perception: Interpretation of sensory information.
• Gestalt Psychology: Focuses on perceptual organization; "the whole is greater than the sum of its parts".

Gestalt Principles

• Figure and Ground: Differentiating main objects (figure) from background (ground).
• Continuation: Object continuation across visual field.
• Closure: Filling in missing information in familiar shapes.
• Similarity: Grouping objects based on similarity.
• Proximity: Grouping objects based on closeness.
• Symmetry: Perceiving symmetrical objects as a whole.

Depth Perception

• Binocular Cues:
  • Convergence: Eyes move inward for close objects.
  • Retinal Disparity: Each eye sees slightly different images.
• Monocular Cues:
  • Relative Size: Larger objects perceived as closer.
  • Interposition: Overlapping objects appear closer.
  • Relative Height: Higher objects appear farther.
  • Shading and Contour: Light/shadow define object's form.
  • Texture Gradient: Detailed textures appear closer.
  • Linear Perspective: Parallel lines converge in distance.
  • Motion Parallax: Nearby objects move faster than distant ones.

Sensory Transduction and Thresholds

• Sensory Transduction: Converting sensory stimuli to neural impulses.
• Absolute Threshold: Minimum stimulus required for detection.
• Signal Detection Theory: Predicts stimulus detection near threshold.
• Sensory Adaptation vs. Habituation:
  • Sensory Adaptation: Diminished response to unchanging stimulus.
  • Habituation: Reduced response to repeated stimulus.
• Difference Threshold: Minimum difference between stimuli for detection (Weber-Fechner Law).

Perceptual Constancy

• Size Constancy: Objects perceived as same size despite distance variations.
• Color Constancy: Color perceived consistent despite light changes.
• Shape Constancy: Shape perceived consistent despite movement.
• Lightness Constancy: Perception of color shading remains constant.

Schemas and Perceptual Sets

• Schemas: Cognitive frameworks based on experiences.
• Perceptual Sets: Expectations that influence perception.

Vision

• Structure of the Eye:
  • Sclera: Protective outer layer.
  • Cornea: Transparent front part, bends light.
  • Aqueous Humor: Maintains pressure and nourishment.
  • Iris: Controls light entry, determines eye color.
  • Pupil: Light entry point.
  • Lens: Changes focus.
  • Vitreous Humor: Supports eye shape.
  • Retina: Contains photoreceptors for light conversion.
  • Optic Nerve: Transmits impulses to the brain.
  • Rods: Dim light vision.
  • Cones: Color and detail.
• Astigmatism vs. Cataracts:
  • Astigmatism: Irregular cornea shape.
  • Cataracts: Cloudy lens.

Color Vision Theories

• Trichromatic Theory: Color perception via red, green, blue receptors.
• Opponent Process Theory: Color perception via opposing pairs (red-green, blue-yellow, black-white).

Auditory System

• Structure of the Ear:
  • Pinna: Directs sound into ear.
  • Auditory Canal: Funnels sound to eardrum.
  • Ossicles: Amplify sound (Malleus, Incus, Stapes).
  • Oval Window: Transmits sound to cochlea.
  • Cochlea: Fluid-filled for sound transduction.
  • Semicircular Canals: Balance and orientation.
• Hearing Loss:
  • Sensorineural: Damage to cilia or auditory nerve.
  • Conductive: Blockage in ear canal.

Chemical Senses: Taste and Smell

• Olfactory System:
  • Olfactory Epithelium: Contains smell receptors.
  • Olfactory Bulb: Processes smell signals.
• Taste (Gustation):
  • Papillae: Taste buds with five basic tastes (sweet, salty, sour, bitter, savory).

Skin and Body Senses

• Epidermis: Protective outer barrier.
• Dermis: Contains nerve endings for touch and pain.
• Nociceptors: Detect pain stimuli.
• Phantom Limb Sensation: Pain in amputated limbs.
• Kinesthesis and Proprioception: Sensing position and movement of body parts.
• Vestibular Sense: Balance and spatial orientation.

Conclusion

• Completing study materials and practice quizzes to reinforce learning.
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