Psych 1XX3 – Vision I & II Live Lecture
Sensation converts energy into nerve impulses.
Specialized receptors i.e. photoreceptors (rods and cones in the retina)
collect photon of light and encode that into vision.
Perception: interprets nerve impulses.
Unconscious perceptual mechanism at work
o Optical illusions
o The fact that all four in the top row interpret the same way and the
bottom is interpreted the same way is because the brain assumes
there is a single light source.
o The light source is the sun.
o The brain assumes that the light source comes from above (sun)
o Brain assumes that like objects are grouped together.
Sensation: stimuli to nerve impulse
o As photons of light enter your eye, they are focused in by the
retina and the image appears upside down
o Brain adapts to convert this to a right-side up image great adaptive
ability i.e. focus
o Visual acuity physically limited by photoreceptors. Visual acuity refers
to the ability to distinguish between 2 dots, are there two pixels or
o Visual acuity – eye doctor chart
o Hyperacuity – judging a relative distance
o Hyperacuity is not physically limited by photoreceptors.
o Retina to the primary visual pathway.
o Travels to the lateral geniculate nucleus.
o Back to v1 of the primary visual cortex.
o As you travel along the primary visual pathway the information is
Processing input in the primary visual cortex.