Set 4: Sensation Flashcards
To represent the world, we must detect physical energy (a stimulus) from the environment and convert it into neural signals. This is a process called
sensation
We we select, organize, and interpret our sensations, the process is called
perception
A message is sent from your senses to your brain.
Bottom-Up Processing
Your brain telling your senses what was just experienced
Top-Down Processing
are sensory nerve endings that respond to stimuli.
Sensory Receptors
A study of the relationships between physical characteristics of stimuli and our psychological experience with them.
Psychophysics
Minimum stimulation needed to detect a particular stimulus at least 50% of the time.
Whether you can detect a the ticking of a clock in a quiet room
Absolute Threshold
When stimuli are below one’s absolute threshold for conscious awareness.
Rome Cheese Ellen
Subliminal Threshold
Minimum difference between two stimuli required for detection 50% of the time, also called just noticeable difference.
Car radio being turned up
Difference Threshold
Two stimuli must differ by a constant minimum percentage (rather than a constant amount), to be perceived as different.
a person is much more likely to react to a quiet commercial that suddenly doubles in volume than a commercial that only slightly increases in volume
Weber’s Law
A person’s absolute threshold can change depending on the situation they are in.
Signal Detection Theory
Diminished sensitivity as a consequence of constant stimulation. Colonge
Sensory Adaptation
Transduction
In sensation, the transformation of stimulus energy into neural impulses.
Phototransduction
Conversion of light energy into neural impulses that the brain can understand.
How the brain understands images
Wavelength
Short wavelength = high frequency
(bluish colors and high pitched sounds)
is the distance from the peak of one wave to the peak of the next.
Hue (color)
Long wavelength = low pitched sounds
(reddish colors and low pitched sounds)
is the dimension of color determined by the wavelength of the light.
Intensity
Amount of energy in a wave determined by the amplitude. It is related to perceived brightness.
Cornea
Transparent tissue where light enters the eye.
Iris
Muscle that expands and contracts to change the size of the opening (pupil) for light.
Lens
Focuses the light rays on the retina.
Retina
Contains sensory receptors that process visual information and sends it to the brain.
Accommodation
The process by which the eyes lens changes shape to help focus near or far objects on the retina. (Not to be confused with schemes)
Nearsighted
A condition in which nearby objects are seen more clearly than distant objects.
Farsighted
A condition in which faraway objects are seen more clearly than near objects.
Optic nerve:
Carries neural impulses from the eye to the brain. This creates a blind spot.
Fovea
Central point in the retina around which the eye’s cones cluster.
Blind Spot
Point where the optic nerve leaves the eye because there are no receptor cells located there.
Photoreceptors
-Rods/Cones are photoreceptors that transduce light to color and brightness.
-You have more rods than cones.
-Cones in the center of the retina, rods in the periphery.
-Cones see in color, Rods don’t
Rods see in the dark, Cones don’t