Sensation and Perception Overview

Sensation and Perception

• Knowledge originates from perceptions.
• Sensation involves detecting, converting, and transmitting sensory information from sense organs to the brain.
• Senses include vision, hearing, smell, taste, touch, and internal body senses.
• Perception is the brain's interpretation of raw sensory input.
• Psychophysics studies the relationship between physical stimuli and sensations.
• Transduction converts physical energy into neural signals.

Sensation Thresholds

• Absolute Threshold: Minimum stimulation needed to detect a stimulus 50% of the time.
• Just Noticeable Difference (JND): Minimum difference between two stimuli detectable 50% of the time.
• Weber's Law: JND is a constant proportion of the original stimulus intensity, not a constant amount.

Signal Detection Theory

• Predicts how we detect signals in noise.
• Detection accuracy varies between individuals and even within individuals.

Somesthetic Senses

• Vestibular Sense: Balance and position in space.
• Kinesthetic Sense: Body position and movement.
• Touch (Somatosensory): pressure, warmth, cold, and pain.

Body Position and Movement

• Kinesthesis: Senses position and movement of body parts.
• Vestibular sense is the sense of balance, and head movement.

Vestibular System and Motion Sickness

• Motion sickness arises from a conflict between vestibular, visual, and body/motion sensations.

Vision and Audition

• Audition: Transduction of air pressure changes (sound waves) to neural impulses.
• Sound Waves: Oscillations of pressure in a medium.
  • Amplitude: Perceived as loudness.
  • Frequency: Perceived as pitch (hertz).
• Sound localization is based on slight differences in timing and intensity between ears.

Factors Influencing Perception

• Attention: Focusing awareness on specific stimuli.
  • Selective attention focuses on one stimulus.
  • Divided attention is split focus.
  • Cocktail party effect: Ability to focus on one conversation among others,.
• Organization: Pattern recognition
• Expectations: Previous experiences influence perception.
• Motivation: Needs/desires affect perception.
  • Inattentional blindness: The inability to perceive unexpected stimuli.

Perceptual Constancy

• Perceiving objects as unchanging even if retinal images change.
  • Color constancy: Perceiving colors despite variations in lighting.
  • Size constancy: Perceiving sizes despite distance changes.
  • Shape constancy: Perceiving shapes despite changes in viewing angle.

Depth Perception

• Estimating distance and seeing in three dimensions.
  • Monocular Depth Cues: Use of one eye information.
    • Accomodation: Lens adjust for focusing at different distances.
    • Pictorial depth cues: Use of monocular information including: linear perspective, relative size, relative height, interposition, texture gradient, and light and shadows
  • Binocular Depth Cues: Use of both eyes information.
    • Convergence: Eyes turn inward for near objects.
    • Retinal disparity: Difference between two eyes' images, creating a 3D effect.

The Visual Cliff

• Experiment by Eleanor Gibson to study depth perception in infants.

Explore the fascinating world of sensation and perception, where knowledge begins. This quiz covers essential concepts like sensory thresholds, psychophysics, and the intricacies of how our brain interprets sensory information. Understand the distinction between sensation and perception, as well as the factors that influence our ability to detect stimuli.