Week 7,Ch.4 Sensation and Perception Flashcards
Psychophysics
is the study of the external world and how we detect them and then how we translate then into consciousness into our brain
sensation
detecting happens at the level of the sensory organs
perception
translating organizes and interprets that raw sensations
Transduction
the way sensory organs communicate with the brain. Sense receptors convert physical signals from the environment into neural signals sent to the CNS
Absolute threshold
the smallest amount of stimuli needed to detect a stimulus at least half of the time
Sensory adaptation
we gradually become less sensitive to a constant unchanging stimulus
Acuity
how well we can distinguish two very similar stimuli. Just noticeable difference
Difference threshold
The ability to detect a change in stimuli what is the faintest change you can detect. Weber’s law
Snellen chart
20/20 vission. A way to assess visual acuity. (ability to see fine detail)
Signal detection theory
In the real world there is no 100% accuracy, life doesn’t have ideal and controlled conditions,depends on psychology or external factors
Decision criterion
perception of a stimulus depends on two independent factors the
strength of the sensory evidence for that stimulus and the amount of evidence necessary
Selective attention
Attention is a limited mental ressource, some we can control some we cannot attention is a controlled mental process but it can be taxing and its slower and its limited
Selective spotlight
on 1 thing at a time, multi tasking with task that require the same amount of attention do not exist Depends also on what is most self relevant or motivating
Inattentional blindness
missing something obvious that we are not paying attention to
Change blindness
if where not paying attention we may miss change like the basketball gorilla experiment
Placebo effect
when you expect something to happen your body will essentially will it into existence this can happen with pain because its a subjectif process
Context(effect)
yields different perception of the same stimulus
For example daylight and artificial light when it comes to the black and blue or white and gold dress
Transduction
physical stimuli registered by sensory receptors are converted into neural signals
-transmitted by the nervous system
-signals go to the thalamus and end up on the cerebral
what are human beings’ dominant sense
Vision
however humans only sese a small fraction of the electromagnetic spectrum
Visible light
a portion of the electromagnetic spectrum
Length
hue/colour of light. Distance between crests
Amplitude
Brightness. Height of the crests
Purity
saturation of colour. Depends on the number of wavelengths making up the
Colour
Cornea
clear smooth outer layer. Light wave hits the eye at the cornea
Pupil
a hole in the iris(coloured part) pupil focused by a lens
Iris
a muscle that controls the size of the pupil
Retina
a layer of light-sensitive tissue lining the back of the eyeball. projected onto the retinas light receptors and then transduced into the neural signals to be sent to the brain via optic nerves
myopia
nearsightedness
hyperopia
farsightedness
Rods
light and grays they work in darkens they also detect motion
Cones
make our vision sharp and detailed function in well lit detect colour
Fovea
region of the retina with the clearest vision. No rods here
Color deficiency
it means you lack one type of cone, Pairs of opposite colours are wired together Red-green blue-yellow black- white
Optic nerve
bundled RGC axons,No rods or cones so can’t sense light. Creates a blind spot
Binding neurons
receive coincident (simultaneous) input from other neurons involved in
representing different features of an object
Parallel processing
the brain’s capacity to perform many activities at the same time. Illusory conjunction: a perceptual mistake where the brain incorrectly combines features from multiple objects.
Feature-integration theory
focused attention is not required to detect the individual features that make up a stimulus, but it is required to bring the individual features together.
Visual agnosia and Prosopagnosia
a condition in which you cannot name the actual object its like a form of brain blindness and inability to recognize faces
during perception where does, the neural data come from
via the thalamus to
the primary visual cortex (Area V1) in the occipital lobe
activate feature detectors
specialized neurons,
respond selectively to specific aspects of stimuli
- edges, angles, size, location, motion, colour
Gestalt principles
we perceive a unified whole (vs. separate bits)
“The whole is other than the sum of its parts”
top-down processing:
top down processing
perceiving the world around us by drawing from what we already know in order to interpret new information
Figure & Ground rule
an object (figure) is
perceived as separate
from its (back)ground
Grouping rules
Proximity,Similarity
Closure rule
completing a familiar form when it appears to have gaps
are Depth & distance sensed or perceived?
perceived
Monocular depth cues
aspects of a scene that yield information about depth when viewed with only one eye.
Familiar size
we expect objects to be a certain size
Linear perspective
parallel lines seem to converge as they recede into the distance
Texture gradient
described how textures look more textured up close but monotonous
far away
Interposition
occurs when one object partly blocks another. The blocking object is closer
than the block object
Pictorial cues
Objects that are closer appear lower in the visual field
Motion perception
as an object moves across a stationary observer’s visual field, it stimulates
one location on the retina
Motion parallax
objects that are closer to us move faster across a visual field
