Chapter 4: Sensation & Perception Flashcards
What is bottom-up processing?
using small components and building up
What is top-down processing?
using the larger components and breaking down (guided by experience and expectations)
Perception
influenced by both the raw sensory data that’s coming in, the bottom-up processing, but also the top-down processing, which is where your goals, your schemas, your experiences shape that perception
Sensation
process through which senses detect visual, auditory, and other sensory stimuli and transmit them to the brain
What are the four attributes common to all senses?
transduction, sensory adaptation, receptive fields, and thresholds
What is transduction?
process through which sense receptors transform physical stimulation into neural impulses
What is sensory adaptation?
the process of becoming less sensitive to unchanging sensory stimulation over time
What are receptive fields?
region of space where stimuli affect the activity of a cell in a sensory system
What is two-point discrimination (2PD)?
the ability to discern that two nearby objects touching the skin are truly two distinct points
Which of the four attributes is responsible for the way the brain filters out large quantities of sensory information?
sensory adaptation
Absolute threshold
the lowest percentage you can detect a stimulus half the time
What does it mean when a stimulus is below threshold?
it is detected fewer than 50% of the time
What is psychophysics?
study of stimulus and the brain’s response
What is the difference threshold?
the smallest physical difference between two stimuli that can still be recognized as a difference. Also known as the Just Noticeable Difference (JND)
Weber’s fraction
smallest change in the magnitude of a stimulus that can be detected expressed as a proportion to the original stimulus. Calculated as delta I/I =k
Signal detection theory
determines that sensation is not just a yes/no
What are the four outcomes as determined by the signal detection theory?
hit, false alarm, miss, and correct rejection
What is a hit?
there was a signal and it was detected
What is a false alarm?
thought there was a signal, but there wasn’t
What is a miss?
there was a signal that wasn’t detected
What is a correct rejection?
decided there was no signal and are correct
What is the sclera?
the mostly white part of the eye that provides protection and structure to the eye
What is the cornea?
the membrane that goes around the outside of your eye, which protects the eye and bends incoming light waves
What is the iris?
the ring-shaped pigmented muscle tissue in the eye, which changes pupil size to regulate the amount of light that enters your eye
What is the function of the lens in the eye?
to focus light in your retina, and change shape depending on how far away an object is
When an object is closer to your face, your lens becomes _____
rounder