What is sensation?
Detection of physical stimuli and the transmission of that information to the brain
Includes light or sound waves, molecules of food or odor, or temperature and pressure changes.
What is perception?
The brain processing, organization and interpretation of sensory information
Results in our conscious experience and construction of useful/meaningful information.
What are the two types of processing in perception?
- Bottom-up processing
- Top-down processing
Bottom-up is based on physical features, while top-down is based on knowledge and expectations.
Define transduction.
Process by which sensory stimuli are converted into neuron signals
Involves specialized cells called sensory receptors.
What is the absolute threshold?
Minimum intensity of stimulation that must occur before you experience a sensation
Example: The quietest whisper you could hear half the time.
What is the difference threshold?
Smallest difference between two stimuli that you can notice
Also known as noticeable difference.
What does Weber’s law state?
Just noticeable difference is based on a proportion of the original stimulus
Not on a fixed amount of difference.
What is Signal Detection Theory (SDT)?
Detecting a stimulus is a subjective decision with two components: sensitivity and criteria
Distinguishes sensitivity from response bias.
Define sensory adaptation.
Decrease in sensitivity to a constant level of stimulation
Example: The smell of a litter box becoming unnoticeable over time.
What is synesthesia?
When color evokes smells, sights evoke sounds, and numbers come in colors
A phenomenon experienced by some individuals.
What are the two types of receptor cells in the retina?
- Rods
- Cones
Rods are for night vision; cones are for color and detail.
What is the function of the cornea?
Focuses incoming light
Light passes through the cornea before entering the lens.
What is accommodation in vision?
Muscles change the shape of the lens to focus on objects
Flattens for distant objects and thickens for closer objects.
What is the optic nerve?
Bundle of axons that transmits visual information from the retina to the brain
Exits the eye at the back of the retina, creating a blind spot.
What are the ‘What’ and ‘Where’ pathways in visual processing?
- Ventral stream: recognition of objects
- Dorsal stream: spatial perception
Ventral projects to the temporal lobe; dorsal to the parietal lobe.
What is the Trichromatic Theory?
Color vision results from activity in three types of cones
S (short wavelengths), M (medium wavelengths), L (long wavelengths).
What is the Opponent-Process Theory?
Describes the second stage in visual processing involving ganglion cells
Explains how colors are perceived in opposing pairs.
What are the Gestalt Principles of Perceptual Organization?
- Proximity
- Similarity
- Good continuation
- Closure
- Common fate
Principles that help organize sensory information into wholes.
Define object constancy.
Correctly perceiving an object as unchanging in shape, size, color, and lightness
Includes size, shape, color, and lightness constancy.
What is prosopagnosia?
Deficit in the ability to recognize faces
Individuals can judge if something is a face but cannot tell one face from another.
What is the expertise hypothesis regarding faces?
Faces are special because they are objects with certain properties we interact with extensively
Suggests that face recognition is a learned skill.
What are binocular depth cues?
Depth cues available from both eyes together
Help perceive the three-dimensional world.
What are monocular depth cues?
Depth cues available from each eye alone
Provide organizational information for depth perception.
What are the two types of depth cues?
- Binocular depth cues
- Monocular depth cues
Binocular depth cues require both eyes, while monocular cues can be perceived with one eye.
