Chapter 3 - Sensation & Perception Flashcards
Transduction
The process of converting outside stimuli into neural activity
Just noticeable difference (jnd or the difference threshold)
The smallest difference between two stimuli that is detectable 50 percent of the time
Absolute threshold
The lowest level of stimulation that a person can consciously detect 50 percent of the time the stimulation is present
Subliminal stimuli
Stimuli that are just strong enough to activate the sensory receptors but not strong enough for people to be consciously aware of them
Signal detection theory
Is used to compare our judgments, or the decisions we make, under uncertain conditions
Habituation
Tendency of the brain to stop attending to constant unchanging, information
Sensory adaption
Process by which constant unchanging information from the sensory receptors is effectively ignored
Sensation
Occurs when special receptors in the sense organs are activated, allowing various forms of outside stimuli to become neural signals in the brain
Brightness
Amplitude of the wave - how high or how low the wave actually is
The higher the wave, the brighter the light
Color
Determined by the length of the wave
Short wavelengths are found at the blue end (portion of light visible to the human eye)
Saturation
The purity is the color
Refraction
Light bends as it passes through substances of different densities
Visual accommodation
Process where the lens changes it’s shape from thick to thin, enabling it to focus on objects that are close or far away.
Blind spot
Area in the retina where the axons of the three layers of retinal cells exit the eye to form the optic nerve; insensitive to light.
Dark adaptation
Occurs as the eye recovers its ability to see when going from a brightly lit state to a dark state
Light adaption
The recovery of the eye’s sensitivity to visual stimuli after exposure to darkness
Trichromatic (“three colors”) theory
Proposes three types of cones: red, blue, and green.
One for each of the three primary colors of light
Afterimages
Images that occur when a visual sensation persists for a brief time even after the original stimulus is removed
Opponent-process theory
Proposes visual neurons are stimulated by light of one color and inhibited by light of another color
Cochlea
Snail-shaped structure of the inner ear that is filled with fluid
Auditory nerve
Bundle of axons from the hair cells in the inner ear
Place Theory
Theory of pitch that states that different pitches are experienced by the stimulation of hair cells in different locations on the organ of Corti
Frequency theory
Theory of pitch that states that pitch is related to the speed of vibrations in the basilar membrane
Volley Principle
States that frequencies from above 400 Hz to 4,000 Hz cause the hair cells (auditory neurons) to fire in a volley pattern, or take turns in firing.
Top-down processing
The use of existing knowledge to organize individual features into a unified whole
Bottom up processing
Analysis of smaller features and building up to complete perception
