Chapter 4 Sensation & Perception Flashcards
Sensation
Stimulation of sense organ
Perception
Organization, identification and interpretation of sensation
Transduction
Conversion of physical signals from the environment into encoded neural signals sent to the central nervous system
Psychophysics
Methods that measure the strength of a stimulus and the observer’s sensitivity to that stimulus
Absolute Threshold
Minimal intensity needed to just barely detect a stimulus in 50% of the trials
Just Noticeable Difference
Minimal change in a stimulus that can just barely be detected
Weber’s Law
JND of a stimulus is a constant proportion despite variations in intensity
Signal Detection Theory
The response to a stimulus depends on both a person’s sensitivity in the presence of noise and on a person’s decision criterion
Perceptual Sensitivity
How effectively the perceptual system represents sensory events
Sensory Adaptation
Sensitivity to prolonged stimulation tends to decline over time as an organism adapts to current conditions
Visual Acuity
Ability to see fine detail
Length of Light
Determines hue or colour
Amplitude of Light Wave
Determines brightness
Purity
Determines saturation
Retina
Light-sensitive tissue lining the back
Accommodation
Process by which the eye maintains a clear image on the retina
Cones
Detect colour, operate under normal daylight condiitons
Rods
Become active under low-light conditions for night vision
Fovea
An area of the retina where vision is the clearest and there are no rods at all
Blind Spot
Location in the visual field that produces no sensation on the retina
Colour Deficiency
One of the cone types is missing
Colour Opponent System
Pairs of visual neurons work in opposition
Lateral Geniculate Nucleus
Located in the thalamus which receives the inputs
Ventral Stream
What
Dorsal Stream
Where
Binding Problem
How features are linked together so that we see unified objects in our visual world
Illusory Conjunction
Perceptual mistake where features from multiple objects are incorrectly combined
Feature Integration Theory
Focused attention is not required to detect the individual features that comprise a stimulus, but is required to bind those individual features together
Perceptual Constancy
Even as aspects of sensory signals change, perception remains consistent
Principles of Perceptual Organization
Simplicity Closure Continuity Similarity Proximity Common Fate
Image-based Object Recognition
Object is stored in memory as a template
Parts-based Object Recognition
Object is stored in geons
Apparent Motion
Perception of movement as a result of alternating signals appearing in rapid succession in different locations
Change Blindness
When people fail to detect changes to the visual details of a scene
Inattentional Blindness
Failure to perceive objects that are not the focus of attention
Pitch
How high or low a sound is
Loudess
A sound’s intensity
Timber
Sound quality or resonance
Outer Ear
Auditory canal, eardrum
Middle Ear
Ossicles (hammer, anvil and stirrup)
Inner Ear
Cochlea, basilar membrane with tiny hair cells
Place Code
Different frequencies stimulate signals at specific places along the basilar membrane
Temporal Code
Registers low frequencies via the firing rate of action potentials
Haptic Perception
Active exploration of the environment by touching and grasping objects with our hands
A-delta Fibers
Transmit the initial sharp pain one might feel
C Fibers
Transmit longer-lasting, duller pain
Referred Pain
Sensory information from internal and external areas converges
Gate-Control Theory of Pain
Signals can be stopped by interneurons in the spinal cord
Vestibular System
Three fluid-filled semicircular canals and adjacent organs located next to the cochlea in each innder ear
