Unit 3 - Sensation and Perception

Overview

• Understanding how we sense and perceive the world is crucial in psychology.
• Focuses on visual and auditory perception and the collaboration of senses.

Sensation

• Definition: Biological sensory inputs.
• Three Steps:
  1. Reception: Gathering information through receptors.
  2. Transduction: Converting stimulus to neural impulses.
  3. Transmission: Passing impulses from sensory neurons to the brain.

Perception

• Definition: Personal interpretation of sensory inputs.
• Types of Processing:
  • Bottom-up Processing: Analysis of raw data sensed for the first time.
  • Top-down Processing: Influenced by personal experiences and biases.
• Thresholds:
  • Absolute Threshold: Minimum stimulus needed to be detectable.
  • Subliminal Stimuli: Below threshold, not directly perceived.
  • Difference Threshold (Weber's Law): Minimum difference needed to notice a change in stimuli.

Signal Detection Theory

• Addresses the detection of stimuli based on psychological factors.
• Example: Waking up upon hearing one's name.

Sensory Adaptation

• Adaptation to constant stimuli over time.
• Examples: Ignoring background smells or sounds after initial exposure.

Perceptual Sets

• Expectations influence perception.
• Priming affects perception based on preceding stimuli.

Selective Attention

• Focusing on one item at a time.
• Cocktail Party Effect: Ability to focus auditory attention on a single stimulus.

Selective Inattention

• Missing information while focusing elsewhere.
• Change Blindness: Failure to notice changes in the environment.

Vision

• Color: Seen in varying wavelengths.
• Brightness: Seen in varying wave heights/amplitudes.
• Lens Accommodation: Adjusting focus between near and far objects.
• Retina Function:
  • Rods: Detect dark, blurry images.
  • Cones: Detect color, detailed images.
• Transduction Pathway: Rods/Cones → Bipolar Cells → Ganglion Cells → Optic Nerve → Supercells in Occipital Lobe.
• Parallel Processing: Simultaneous processing of multiple aspects of a stimulus.

Color Vision

• Young-Helmholtz Theory (Trichromatic): Red, green, blue cones contribute to color vision.
• Color Blindness: Result of malfunctioning cones.
• Opponent Processing Theory: Neural processing of opposing colors.

Perception Phenomena

• Phi Phenomenon: Perception of movement in static images.
• Figure-Ground Perception: Differentiating an object from its background.
• Gestalt Principles of Grouping: Proximity, similarity, continuity, closure.

Depth Perception

• Binocular Cues:
  • Convergence: Eyes move together to focus on an object.
  • Retinal Disparity: Slight differences in images perceived by each eye.
• Monocular Cues: Interposition, blocking, linear perspective, relative size, shading, relative motion, vertical perception, relative height.

Visual Constancies

• Perceptual Constancy: Perception remains consistent despite changes.
• Brightness, Shape, Color, and Size Constancy: Perceive objects as constant in varying conditions.

Auditory System

• Outer Ear: Visible part.
• Middle Ear: Contains bones (hammer, anvil, stirrup) that amplify sound.
• Inner Ear: Contains cochlea with hair cells responsible for transducing sound.
• Auditory Localization: Determining sound source based on volume and timing.

Characteristics of Sound Waves

• Wavelength Frequency: Affects pitch.
• Amplitude: Affects volume.
• Complexity: Affects the perception of sound purity.

Hearing Theories

• Place Theory: High pitches detected based on the basilar membrane location.
• Frequency Theory: Rate of signal transmission corresponds to frequency.
• Volley Principle: Handling super high frequencies via neuron groups.

Types of Deafness

• Conduction Deafness: Bone damage; treatable with implants.
• Nerve Deafness: Damage to auditory nerves.

Other Senses

• Touch: Detects pressure, pain, temperature, and texture.
• Taste: Receptors are taste buds, influenced by top-down processing.
• Smell: Direct olfactory signals to the brain.

Synesthesia

• Interconnection of senses (e.g., associating colors with smells).

Kinesthetic and Vestibular Senses

• Kinesthetic Sense: Awareness of body movement without visual aid.
• Vestibular Sense: Balance and spatial orientation relative to gravity; involves inner ear fluid dynamics.