Chapter 4 Flashcards
Sensation
Simple stimulation of a sense organ (not aware)
Perception
Organization, identification, and interpretation of a sensation in order to form a mental representation
Synesthesia
Perceptual experience of one sense that is evoked by another sense
Transduction
when many sense in the body convert physical signals from the environment into encoded neural signals sent to CNS; vision, hearing, touch, taste, smell
Psychophysics
Methods mesure strength of stimulus and observer’s sensitivity
Psychophysicists
measure minimum amount of a stumbles needed for detection
Absolute threshold
Minimum intensity needed to just barely detect a stimulus 50% of the time
Just Noticeable Difference (JND)
Minimum change in stimulus that can barely be detected
Weber’s Law
JND of a stimulus is a constant proportion despite variations in intensity
Signal Detection Theory
Response depends on person’s sensitivity to stimulus; individual perceptual sensitivity
Sensory adaptation
Sensitivity to prolonged stimulation leads to decline over time as organism adapts
Multitasking
perception is active and resources are limited; We use selective perception to focus in on chosen stimuli in environment; involves paying attention to more than one stimulus at a time
Visual Acuity
ability to see in fine detail
Visible light
between 400 and 700 nanometers; purple to red
Properties of light waves
- length=color
- intensity/amplitude=brightness
- purity=saturation/richness of the color
Retina
- back of the eye
- accomodation (process, eye maintains clear image)
- rods and cones
- layers of cells including bipolar and ganglion cells
Cornea
- light passes through pupil
- iris contracts pupil depending on light
Lens
- light waves pass through to the retina
- nearsighted, image projected too close
- farsighted, image projected too far
Rods
low level and low light; everywhere in retina but the forea pit
Cones
Color, shorter than rods; forea pit
Blind spot
location in visual field that produces no sensation in the retina bc area of the retina has no rods and cones
Color opponent system
Color afterimage
Color mixing
Additive- based on light; emitting white light
Subtractive- paints, absorbing every light wave (black)
Lateral Geniculate Nucleus (LGN) V1
part of occipital lobe that contains the primary visual cortex
Ventral stream
temporal lobe
Dorsal stream
parietal lobe
Area V1
Neurons that respond to specific orientations of images
Receptive fields
region of sensory surface that, when stimulated, causes a change in the firing rate of that neuron; on ad off center cells
Illusory conjunctions
occur when features such as color and have are combined incorrectly
Binding problem
How features are linked together so we see unified objects instead of free floating or miscombined features
Binding processes
Utilizes structures in the ventral and dorsal streams
Perceptual constancy
Even as aspects of sensory signals change, perception remains consistent
Gestalt perceptual grouping rules
Simplicity, closure, continuity, similarity, proximity, and common fate
Grouping
Involves separating a figure from its background
Image based object recognition theory
Objects are stored as templates (directly compared to a viewed shape in retinal image)
Parts based object recognition theory
Brain deconstructs viewed objects into a collection of parts; geons: geometric elements combined to make objects
Monocular depth cues
Info about depth when viewed with only one eye; relative and familiar size, linear perspective, texture gradient, interposition, and relative height
Binocular disparity
the difference in the retinal images of the 2 eyes that provides info about depth
Color and motion perception
- Rely partially on opponent processing, which is why we fall prey to illusions such as color aftereffects and the waterfall illusion
- to sense motion, the visual system must encode info about both space and time
Change blindness
when people fail to detect changes to the visual details of a scene
Inattention blindness
failure to perceive objects that are not the focus of attention
Audition
Hearing involves detection of sound waves, pure tones and simple sound waves
Outer ear
collects sound waves
Middle ear
transmits vibrations
inner ear
transduction unto neural impulses
Place code
cochlea encodes different frequencies at different locations along the basilar membrane; low frequencies fire at apex, high frequencies fire at base
Temporal code
cochlea registers low frequencies via the firing rate of action potentials entering the auditory nerve
Area A1
portion of the temporal lobe that contains the primary auditory cortex; 2 distinct streams, spacial and nonspacial
Spacial
stream in Area A1 “where” auditory features locate source of sound
Nonspacial
stream in area A1 “what” auditory features locate temporal aspects of a sound
Transduction involves…
cochlea, basilar membrane, hair cells
Cochlea
fluid filled tube; organ of auditory transduction
Basilar membrane
structure in inner ear that undulates when vibrations from ossicles reach cochlear fluid
Hair cells
specialized auditory receptor neurons embedded in basilar membrane
Conductive hearing loss
damage to eardrums or ossicles
Sensorineural hearing loss
damage to cochlea, hair cells, or auditory nerve
Hapticperception
somatosenses; active exploration of environment by touching and grasping objects with your hands
Touch receptors
- pressure
- texture
- pattern
- vibration
- thermoreceptors which respond to temperature
Touch…
Also has contralateral representation, cortical space allocation related to sensitivity, and “what”/”where” pathways
A delta fibers
quick, sharp pain
C fibers
long, dull pain
Referred pain
when sensory info from internal and external area converges on same nerve cells in the spiral cord
Gate Control Theory
Signals arriving from pain receptors in the body can be stopped or gated by interneurons in the spinal cord via feedback (PAG) from two directions
Vestibular system
3 fluid filled semicircular canals and adjacent organs located next to cochlea in inner ear; used with visual feedback to maintain balance
Olfactory Receptor Neurons (ORNs)
receptor cells that initiate the sense of smell
Olfactory Bulb
Rain structure located above the nasal cavity beneath the frontal lobes
Pheromones
Biochemical odorants emitted by other members of its species that can affect an animal’s behavior or physiology
Object centered approach to smell
info about the identity of odor object is quickly accessed from memory
Valence centered approach to smell
emotional response comes first and provides basis for determining identity of odor
Primary responsibility of taste
identify things that are bad for you
