What do mechanoreceptors sense?
only
pressure
; they do
not
sense pain, and would not be affected by pain if something painful happened
What does the Gestalt law of pragnanz state?
reality is reduced to its simplest form in our perceptions
What does "size constancy" refer to?
it relies on the knowledge that objects do not change size as they travel through space
What does the Gestalt law of proximity state?
we tend to group things by spatial relatedness
What do the "relative size monocular cues" tell us?
even if two objects are the same size, humans will only perceive them as such based on their size relative to nearby objects. Although we know that the two bikers are the same size, we perceive one as larger relative to the other based on how close it is
What in our bodies helps us with depth that requires
both
eyes?
aka: binocular cues
1. retinal disparity (the distance b/w our eyes)
2. convergence
convergence
rotating eyes toward each other to view an object close to the face
What in our bodies helps us w/ depth that only requires
one
eye?
aka: monocular cues
1. relative size
2. interposition
3. relative height
4. shading and contour
5. relative motion (motion parallax)
relative size
gives us an idea of the format of an object; we think things larger are closer to us, and things smaller as farther away
interposition
inference that when viewing overlapping objects, the one we perceive to be in front of other things is closer to us (like this blue circle being closer to us than the red circle)
relative height
objects perceived to be higher are thought to be farther away than objects perceived to be lower in height
shading and contour
using light and shadows to understand the form an object
What are the degrees of perceptual organization?
depth, form, and motion, constancy
motion parallax
the perception that things close to you are moving very quickly and things farther away are moving very slowly (this all being perceived while you are in motion)
What are the different types of constancies?
1. size
2. shape
3.
size constancy
understanding that two objects are the same size although one has bigger retinal image than the other
shape constancy
understanding that something that moves and has different shape with movement is still the same shape
color constancy
understanding that changes in lighting or other things are different, we are aware that the color remains the same
What is proprioception?
sense of balance and self; knowing where you are in space; form of sensory adaptation
Just noticeable difference
aka: JND; threshold at which one notices a change
Weber's Law
the ratio of the increment threshold (??I) to the background intensity (I) is constant
What is Weber's Law equation?
??I/I=K
Weber fraction
??I/I
I
intensity of stimulus
??I
just noticeable difference
What does weber's law predict?
a linear relationship b/w the background intensity and difference threshold
absolute threshold of sensation
minimum intensity of a stimulus needed to detect a particular stimulus 50% of the time.
absolute threshold vs. jnd
jnd=smallest
difference
that can be detected 50% of the time
absolute threshold=
minimum
sound detected
Is the absolute threshold of sensation a fixed number?
nope! can be influenced by many things
What things influence absolute threshold
psychological things!
psychological things affecting absolute threshold
1. expectations
2. experiences
3. motivation
4. alertness
subliminal stimuli
stimuli below our absolute threshold of sensation... (stimuli we cannot detect)
What are the different types of somatosensation?
1. thermoception
2. mechanoception
3. nociception
4. proprioception
thermoception
temperature
mechanoception
pressure
nociception
pain
proprioception
body's location in space
What are the different intensities of somatosensations?
encoded by how quickly the neurons fire; if less intense, less quick neuronal firing and vice versa
What are the different timings of somatosensation?
encoded three diff. ways... via:
1.nonadapting neurons
2. slow-adapting neurons
3. fast-adapting neurons
nonadapting neurons
neurons that consistently fire action potentials in equal amt of times per firing (firing rate doesn't change)
slow-adapting neurons
neurons that fire quickly at first and slow down over time... the space/time b/w each action potential increases
fast-adapting neurons
neurons fire quickly when stimulus starts, stop firing, and fire again when stimulus stops
...
...