Sensation and Perception Flashcards

Sensation and Perception

• Sensation: Activation of sensory receptors transmitting information to the central nervous system.
• Sensory Receptors: Located in eyes, ears, skin, and other areas, essential for processing stimuli.
• Stimulation Sources: Comes from energy forms like light and sound; involves automatic processes.

Perception

• Perception: Organizing and interpreting sensations to create mental representations of the environment.
• Absolute Threshold: The minimal stimulus strength needed for a person to detect a stimulus.
• Difference Threshold: The smallest noticeable difference in stimuli needed to perceive as distinct; known as just noticeable difference (JND).

Theories of Sensation

• Weber's Constant: A principle stating a 2% difference in light intensity is necessary for perception changes.
• Signal Detection Theory: Suggests perception involves physical, biological, and psychological interactions.

Visual Perception

• Light: Visible light that initiates visual sensations.
• Hue: The color perceived, determined by light wavelength.

Eye Anatomy

• Cornea: The eye's transparent outer layer.
• Iris: A muscular structure controlling light entry via pupil dilation.
• Pupil: The opening in the iris allowing light passage.
• Lens: Adjusts its thickness to focus light on the retina.
• Retina: Inner eye layer that contains photoreceptors (rods and cones).

Photoreceptors

• Rods: 125 million, sensitive to light intensity, enable black-and-white vision.
• Cones: 6.4 million, perceive color, crucial for daylight and color vision.

Visual Processing

• Visual Acuity: Sharpness of vision, highest in the retina.
• Adaptation: Dark adaptation increases sensitivity in low light.
• Complementary Colors: Colors that combine to produce white light (red-green, purple-yellow, blue-orange).

Color Theories

• Trichromatic Theory: Humans have three types of cones for red, green, and blue light.
• Opponent-Process Theory: Color perception involves opposing pairs (red-green, blue-yellow).

Perception Principles

• Gestalt Psychology: Emphasizes perception of wholes that exceed the sum of individual parts.
• Closure: The tendency to perceive incomplete figures as whole.
• Proximity and Similarity: Grouping of nearby or similar objects in perception.

Motion and Depth Cues

• Top-Down Processing: Organizing experiences based on past knowledge.
• Bottom-Up Processing: Building perceptions from individual components.
• Binocular Cues: Cues that require both eyes (convergence, retinal disparity).
• Monocular Cues: Visual depth cues perceptible with one eye (perspective, texture gradient, motion parallax).

Auditory Perception

• Cochlea: Inner ear structure housing auditory receptors.
• Basilar Membrane: Structure within the cochlea critical to hearing.
• Auditory Nerve: Transmits sound information from the organ of Corti to the brain.

Olfactory and Gustatory Perception

• Five Basic Tastes: Sour, salty, sweet, bitter, umami (rich taste).
• Smellen Chart: Tool for measuring visual acuity.

Illusions and Constancies

• Illusions: Misrepresentations in sensory experiences.
• Perceptual Constancy: Perception remains constant despite changes in stimuli (brightness, color, shape, size).

Additional Concepts

• Afterimages: Visual impressions lingering after stimuli removal, leading to perception of complementary colors.
• Stroboscopic Motion: Perceived motion from rapid presentation of stationary images.