Ch 2 - Sensation & Perception Flashcards
Threshold of conscious perception
The signal reaches the CNS but does not reach higher-order brain regions that control attention and consciousness.
“Subliminal perception” is the perception if a stimulus below a given threshold
Difference threshold
Other name?
“Just-noticeable difference”
Minimal difference in two stimuli before one can perceive this difference
Weber’s Law
The ratio between the change in stimulus and it’s original value.
Related to the Difference Threshold (JND) but a percentage. Suggests that the higher the stimulus, the higher the difference needs to be to produce a JND
Signal detection theory
Changes in our perception of the same stimuli depending on internal (psych) and external (environmental) contexts
Ie: would you acknowledge someone yelling your name in a crowd?
What is the sclera
What blood vessels supply the eye (2)
The white of the eye
- Choroidal vessels (between the sclera and the retina)
- Retinal vessels
What is the retina
The innermost portion of the eye
Contains photoreceptors
What is the cornea
First thing that light passes through
Clear, dome-like
Gathers and focuses incoming light
What is the Anterior chamber?
What is the Posterior chamber?
Anterior:
The front of the eye, lies in front of the iris
Posterior:
Between the iris and the lens
What is the iris?
What muscles is it composed of? (2)
The colored part of the eye.
Continuous with the choroid
- Dilator pupillae (sympathetic) opens
- Constrictor pupillae (parasympathetic) closes
What is the ciliary body?
What is the ciliary muscle?
Also consistent with the choroid
Produces aqueous humor that moistens the front part of the eye before draining into the Canal of Schlemm
Muscle:
It’s contraction is under parasympathetic control
Contraction pulls on suspend pry ligaments and changes the shape of the lens (“accomodation”)
What is the lens?
Lies behind the iris.
Controls the refraction of incoming light
Vitreous humor
A gel that supports the retina
Absolute threshold
The minimal intensity at which a stimulus is transduced (converted into an action potential)
Sensation threshold
