lec 4 sensation and perception Flashcards
what is sensation?
receiving, translating, transmitting raw sensory info
external+ internal environments to
brain
-bottom-up processing
what is perception?
-selecting, organizing, interpreting sensory data
-Enables us to recognise meaningful objects
and events
-top-dow processing
what is Prosopagnosia?
-face blindness
-inability to recognize faces
sensation and perception in simple terms?
sensation: brain receives input from sensory organs
perception: brain makes sense of inputs
what are the 3 steps of sensation?
reception, transduction, transmission
what is the main idea of each step of sesation?
Reception- sensory receptors stimulated by energy
Transduction-stimulation–>neural impulses
Transmission-neural info to brain for processing
what are 2 other important conepts with respect to sensation?
Sensory Reduction and Coding
what is Sensory Reduction? what is coding?
Sensory Reduction:
Filter + analyze incoming sensations before sending neural impulses to brain
(ex dont feel clothes on body)
Coding
Neural impulses travel by different routes to different parts of the brain, allowing us to detect physical stimuli as distinct sensation
what is absolute threshold?
minimum level of stimulus intensity needed to detect a stimulus half the time
what are stimuli below the threshold considered?
subliminal
what is the strength and weakness of our ability to detect+interpret stimuli called?
threshold
what does our ability to detect weak stimuli depend on?
-psychological state
-(experiences, expectations, motivation, alertness)
what is priming? how do companies do this?
activation (often unconsciously) of certain associations, thus predisposing ones perception memory+respose of that thing
ad placements: once we see a product, we are primed to choose it next time we see it
what is the difference threshold? what is it also known as?
AKA: “just noticeable difference”
minimum difference (in colour, pitch,
weight, temperature, etc) for person
to be able to detect the difference half
the time
what is Weber’s law?
two stimuli to be perceived as
different, they must differ by a
constant PROPORTION and not a
constant amount
(e.g. 1/100th of the weight, not 2 ounces)
-Exact proportion varies depending on
the stimulus
what is the concept of sensory adaptation?
to detect novelty in surroundings, our senses tune out constant stimulus (ex ticking of clock)
does sensory adaptation apply to our vision? why or why not?
no, because our eyes are always moving, so stimulus always changing
what happens when we see light?
-eyes receive light energy, then transform it into neural message
-then brain processes into what we consciously see (colour, etc)
what are the main parts of the eye? what is their main function?
cornea- protects eye
pupil-small adjusting opening
iris (colored part)- dilates or restricts pupil in response to light intensity
lens- changes in curvature or thickness to focus on near or far objects
retina- transduction into neural impulses to send to optic nerve
optic nerve- sends neural impulses to brain
when looking at light, what does each part of the eye do?
-passes thru cornea, bends light to provide focus
-passes thru pupil controlled by iris
-passes thru lens, light is focused +inverted
-light lands on retina, then sent to optic nerve
if the image on our eye is inverted, how do we see everything right-side up?
-retina itself doesn’t see whole image
-rather, millions of receptor cells convert light energy into neural impulses
-neural impulses sent to brain, then reassembled into perceived upright image
What happens when light enters the retina
-light enters, triggering rods and cones
-photochemical reactions –> neural impulses
-neural impulses–>bipolar cells
-bipolar cells –> ganglion cells
-ganglion cells axons intertwine to form the optic nerve
where does optic nerve carry info to?
thalamus, stands ready to distribute info
what is the area missing from our retina’s in each eye called? why does this happen?
blind spot
no receptor cells where optic nerve leaves eye
how do we compensate for blindspots?
2 ways
- blind spot on eyes are in different spots, so they compensate for each other
-eyes constantly moving, so brain will fill in missing info with all the info our eyes take in
what do rods do? where are they located in retina?
-help is see black and white actions in peripheral view
-helps us see in dark
-located in periphery
why is our peripheral vision dull
several rods will share a bipolar cell, sending combined messages
what happens with rods in respect to dim light?
sensitive in dim light
b/c they share their energy output onto the single bipolar cell