Sensation and Perception (2) Flashcards
Sensation
conversion of physical, electromagnetic, auditory, and other info from the internal and external environment into electrical signals in the nervous system.
Perception
processing of sensory information to make sense of its significance.
Photoreceptors
responds to electromagnetic waves in the visible spectrum (vision)
Nociceptors
responds to painful or noxious stimuli (somatosensory)
Olfactory receptors
responds to volatile compounds (smell)
Taste receptors
respond to dissolved compound (taste)
Threshold
the minimum stimulus that causes a change in signal transduction
Absolute threshold
minimum of stimulus energy that is needed to activate a sensory system.
The threshold of conscious perception
minimum of stimulus energy that will create a signal large enough in size and long enough in duration to be brought in awareness.
difference threshold or just-noticeable difference (jnd)
the minimum difference in magnitude between two stimuli before one can perceive this difference.
jnd for sound frequency is more accurately quantified as 0.68%.
Weber’s Law
states that there is a constant ratio between the changes in stimulus magnitude needed to produce a jnd and the magnitude of the original stimulus.
Signal detection Theory
focuses on the changes in our perception of the same stimuli depending on both internal and external context.
Cornea (eye)
gathers and focuses incoming light
pupil
allows passage of light from anterior to posterior chamber
Iris
- Dilator pupillae
- Constrictor pupillae
Iris: controls the size of the pupil
Dilator pupillae –> opens the pupil under sympathetic
Constrictor pupillae –> constricts pupil under parasympathetic.
Cilary body
produces aqueous humor; accommodation of the lens
Lens
refracts the incoming light to focus it on the retina
Retina
detects images