Unit 3 - Sensation and Perception

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Summary

• Study of how people sense and perceive the world
• Includes visual, auditory perception, and the integration of senses

Sensation

• Definition: Biological sensory inputs
• Three Steps:
  1. Reception: Information gathering through receptors
  2. Transduction: Converting stimulus to neural impulses
  3. Transmission: Sensory neurons convey data to the brain

Perception

• Definition: Personal interpretation of sensory inputs
• Processing Types:
  • Bottom-up Processing: Interpretation of raw data sensed for the first time
  • Top-down Processing: Interpretation influenced by prior knowledge and biases
• Thresholds:
  • Absolute Threshold: Minimum stimulus detectable
  • Subliminal Stimuli: Below threshold, not explicitly perceived
  • Difference Threshold (Weber's Law): Minimum difference noticed between stimuli

Signal Detection Theory

• Factors influencing stimulus detection
• Example: Psychological factors like recognizing one’s name

Sensory Adaptation

• Examples: Adapting to a smell in a new place or ignoring a ticking clock over time
• Concept: Reactivation of senses when stimulus changes

Perceptual Sets

• Expectations influence perception
• Priming affects sensory perception
• Example: Daytime vs. nighttime interpretation of sounds

Selective Attention

• Focusing on one thing at a time
• Cocktail Party Effect: Directing attention selectively (e.g., hearing one's name in a crowd)

Selective Inattention

• Missing out on things while focusing on another
• Change Blindness: Failure to notice changes in the environment

Vision

• Color and Brightness: Perceived through varying wavelengths and amplitudes
• Lens Accommodation: Focuses on near and far objects
• Retina Function: Receives information via rods (dark, blurry vision) and cones (color, detail)
• Transduction Pathway: Rods/cones → Bipolar cells → Ganglion cells → Optic nerve → Occipital lobe

Parallel Processing

• Brain’s ability to process multiple aspects simultaneously

Color Vision Theories

• Young-Helmholtz (Trichromatic Theory): Red, green, blue cone reception
• Opponent Process Theory: Processing of opposite colors (e.g., red vs. green)

Motion Perception

• Phi Phenomenon: Perception of motion through a series of images (e.g., stop motion films)

Figure-Ground Perception

• Differentiating between foreground and background

Grouping Principles (Gestalt)

• Types: Proximity, similarity, continuity, and closure

Depth Perception

• Binocular Cues: Convergence and retinal disparity
• Monocular Cues: Interposition, linear perspective, relative size, shading, etc.

Constancies in Vision

• Perception remains stable despite changes in environment
• Types: Perceptual, brightness, shape, color, and size constancy

Hearing

• Ear Structure: Outer, middle (bones: hammer, anvil, stirrup), and inner ear (cochlea)
• Sound Characteristics: Frequency affects pitch, amplitude affects volume
• Hearing Theories: Place and Frequency theories, Volley Principle

Deafness

• Types: Conduction (bone damage) and nerve deafness

Touch

• Senses: Pressure, pain, temperature, texture

Taste

• Taste Buds: Receptors that can regenerate; affected by top-down processes

Smell

• Olfactory Sensation: Direct signals to the brain

Synesthesia

• Cross-modal sensory phenomena
• Example: Associating colors with smells

Kinesthetic and Vestibular Senses

• Kinesthetic: Awareness of body movements
• Vestibular: Balance and spatial orientation related to gravity