Chapter 4 Flashcards
Sensation
Process of detecting external events with sense organs and turning these stimuli into neural events
Perception
Interpreting and organizing stimuli
Transduction
Conversion of physical energy to neural impulses
Doctrine of Specific Nerve Energies
Muller 1826. Different senses are separated in the brain.
Psychophysics
Fechner. How physical stimuli such as light and sound are interpreted by the brain.
Absolute Threshold
Minimum stimulation so as to detect presence of stimulus 50% of the time.
Difference Threshold
Smallest difference in stimulation that can be detected 50% of the time
Weber’s Law
Just noticeable change between two stimuli changes as proportion of stimuli
Signal Detection Theory
Whether a signal is perceived is based on both the sensory experience and judgement made by the subject
Sensory Process
providing of stimulus or no stimulus
Decision process
Subject reports whether they perceived a stimulus or not
JND
Minimum difference between two stimuli that can be detected 50% of the time
Weber’s Law noticeable light difference
8%
Noticeable weight difference
2%
Noticeable frequency difference
0.2%
Gestalt Psych
Whole greater than sum of parts
Figure-Ground
Grouping of figures and ground
Similarity
Items group according to visual similarities
Proximity
Items grouped due to proximity to each other
Continuity
Lines are perceived to continue
Closure
Tendency to close a figure
Phonetic Reversal
A word pronounced backwards sounds like another word
Top-down processing
Perceptions influenced by prior knowledge
Bottom-up processing
Using sensory info to construct a more complex perception
Divided Attention
Paying attention to more than one stimulus at a time
Selective Attention
Focusing on one event and excluding others
Inattentive Blindness
Failure to notice an event when focused on another event
Wavelength
Distance from peak to peak
Amplitude
Distance from x axis to crest
Hue
Dimension of color determined by wavelength
Intensity
Brightness. Determined by amplitude
Saturation
How many different wavelengths are mixed together
Sclera
Whites of eye
Cornea
Clear layer that covers front of eye and contributes to eye’s ability to focus light
Pupil
Regulates amount of light that enters eye
Iris
Muscle around eye that controls dilation and constriction of the pupil
Lens
Focuses light onto back of eye
Retina
Back of eye. Contains cones and rods
Accomodation
Change in shape of lens to focus light
Optic Nerve
Fibres connecting to brain
Cones
Receptors for bright light. Located on fovea
Rods
Receptors for dim light
Acuity
Sharpness of vision
Nearsighted
Can focus on nearby object
Farsighted
Can focus on far away objects
How many cones per ganglion cell?
One
How many rods per ganglion cell?
Ten
Dark adaption
Cones and rods become more sensitive to light under low levels of illumination
Trichromatic Theory
Young-Helmholtz Theory. Three types of cones corresponding to red, green, blue. All other colors combination of these three
Opponent Process Theory
Colors are in opposition to each other. Hering
Dichromat
Confuse two colors
Monochromat
Can only see one colour
Colour Blindness
Misfunction in cones
Nearsightedness (myopia) caused by
Elongation of the eye, image falls short of retina
Farsightedness (hyperopia) caused by
Image focused behind retina
Optic chiasm
Part of brain where optic nerves cross at the midline
Ipsilateral
Same side
Contralateral
Other side
Lateral Geniculate Nucleus
In thalamus. Processes information and sends it to visual cortex
Function of Ventral Stream
Object recognition
DF
Had damaged ventral stream. Could still put mail in mailbox, therefore had a working dorsal stream.
FFA
Fusiform face area
Perceptual Constancies
Tendency to perceive things as similar despite change in perspectives
Binocular Cues
Based on differing perspectives of both eyes
Convergence
eyes move inward to focus on nearby object
Retinal Disparity
Difference of position of object as seen by each eye. Gives info about depth
Monocular Clues
Clues about depth perceived by only one eye
Paraprognosia
Cant recognize faces
Size constancy
Ability to perceive consistent size despite variations in size of retinal images
Shape consistency
Ability to perceive consistent shape despite differing position of shape
Light consistency
Ability to perceive consistent light despite changing illumination
Frequency
Cycles per time (Hz) relates to pitch
Amplitude of sound
How loud it is
Pitch
Highness or lowness of sound
Loudness
Amplitude of sound
Timbre
Complexity of sound wave
Pinna
External ear. Directs sound into ear and determines location of sound
Auditory canal
Leads to eardrum
Tympanic membrane
Eardrum
Ossicles
Transmit vibrations to cochlea. Malleus, incus, stapes
Conversion of sound waves to perception of sound
Sound waves, fluid waves, mechanical vibrations, electrical impulses to modal geniculate nucleus in thalamus to auditory cortex
Sound localization
Identifying where a sound comes from
Place Theory
Perception of sound based on location of the ear which sound stimulates. Problem: not enough hair cells, cochlea isn’t long enough. Therefore, struggles at explaining low frequencies
Frequency Theory
Related to pitch at which basiliar membrane vibrates. Problem: can’t explain high frequencies, as nerves can’t fire that fast.
Primary auditorial Cortex
Involved in perception of hearing
Interaural Time Difference
One ear experiences sound sooner and more intensely
Interaural Level Difference
One ear casts a sound shadow
Nerve HEaring Loss
Damage in cochlea’s receptors or auditory nerve
Conduction Hearing Loss
Damage to mechanical system that conducts sound waves to cochlea
Plasticity in 3 months
Can detect changes in pitch
Changes in 4-6 months
Can detect when sounds stop and start
Changes in 8 months
Can localize sound
Changes in 10-12 months
Audial specialization towards language
Functions of vestibular system
Balance, maintain upright head position, adjust eye movement for head movement
Semicircular Canals
Three fluid-filled canals that respond to acceleration of the head
Vestibular Sacs
Provides info about head’s orientation. Consists of utricle (little pouch) and saccule (little sac)
Haptics
Touch sensation and perception
Kinesthesis
System for sensing position and movement of body parts
Nociception
Sensation of pain. Can be top-down (experiences change how we experience pain) and bottom-up (things from outside world transmitted to brain)
RA Receptors
Rapidly adapting receptors (can be I or II)
SA Receptors
Slowly adapting receptors. Respond to ongoing sensation. Can be I or II
Myelinated alpha fibres
Rapid transmission of pain
Unmyelinated C fibres
Slow transmission of pain
Two point threshold
Minimum distance between points to be perceived as two different points. Bimodal distribution. Larger thresholds in the legs and arms, as opposed to the finger tips, lips, etc.
Gate Control Theory
Explains pain as interaction between transmitting and inhibiting fibres
“Gate” closed by?
Large A beta or gamma-fibres
“Gate” opened by?
Small C and A sigma fibres
Phantom Limb Pain
Sensations of pain in nonexistent limbs
Mirrox Boxes
Reduces phantom pain by tricking the brain into thinking that individual has two hands
Gustation
Taste
Umami
Taste sense related to savory foods/protein
Papillae
Taste buds
Secondary Gustatory Cortex
Associates pleasure with food
Gustatory Complex
In frontal lobe
Olfaction
Smell
Retronasal Olfaction
Smell enters from the back (eating food)
Olfactory Epithelium
In nose, lined with cilia
Olfactory Bulb
Processing of smell
Multimodal Integration
Ability to integrate different modalities into a single perception
McGurk Effect
Vision leads to altered hearing
Double Flash Effect
Hearing leads to altered vision
Syntesthesia
When you see a particular stimulus, you have a cross-modal response to it
Autonomic Sensory Meridian Response
Certain audial and visual stimulation incurs tingling sensations in spine and scalp
Distal Stimulus
Object in real world
Proximal Stimulus
Image on retina
Ambiguity
Open to multiple perceptions
