Test #3 Flashcards
Transduction
Changing sensory signals into nerve impulses
Absolute Threshold
Minimum stimulus needed to register a stimulus 50% of the time
Example Absolute thresholds for humans
Sight - Candle flame @ 30 mi. Sound - Mechanical watch tick at 20ft Taste - 1 tsp sugar in 2 gallons H2O Touch - bee wing falling from 1 cm Smell - 1 drop perfume in 3br apt.
Difference Threshold
Smallest change in stimulus that will be detected 50% of the time.
Weber’s Law
Size of diff threshold proportional to intensity of stimulus
Light waves and eye
The eye detects a portion of the EM spectrum known as the visible light spectrum. Shorter wavelength - blue, longer wavelength - red.
Order of light path in eye
Cornea - pupil - lens - retina w/ photoreceptors (rods - greyscale & peripheral, cones - detail & color) - Bipolar cells - ganglion cells - optic nerve - thalamus - visual cortex
Blind spot
The spot in the eye where the optic nerve exits. no photoreceptors, thus, no vision in that spot The other eye fills in that area.
Sound waves / frequency
frequency is number of times a wave completes a cycle in a given time. determines highness or lowness of pitch. usually in cycles / second (hz)
Parts of the ear
Outer ear (pinna, tympanic membrane), middle ear(hammer, anvil, stirrup), cochlea, basilar membrane, hairs -> nerve cells.
frequency theory
different hairs on basilar membrane react to different frequencies of sound. explains why humans can hear
Vestibular sense
sense of body position in regards to gravity.
The binding problem
no one knows how the brain takes all of the sensory data and build 1 perception from it.
Bottom - up processing
Stimulus driven perception (when you have no experience) focused on the details due to lack of knowledge about subject.
Top-down processing
experience based perception. Conceptually driven processing