lesson 5 Flashcards
Sensation
Simple stimulation of a sense organ
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
What takes place when many sensors in the body convert physical signals from the environment into encoded neural signals sent to the central nervous system
Psychophysicists
Often measure the minimum amount of a stimulus needed for detection
Psychophysics
Methods that measure the strength of a stimulus and the observer’s sensitivity to that stimulus
Absolute threshold
Minimal intensity needed to just barely detect a stimulus
Just noticeable difference (JND)
Minimal change in a stimulus that can just barely be detected
Weber’s Law
JND of a stimulus is a constant proportion despite variations in intensity
Signal detection theory
Response to a stimulus depends both on the person’s sensitivity to the stimulus in the presence of noise and on a person’s response criterion; takes into account individual perceptual sensitivity
Sensory adaptation
Sensitivity to prolonged stimulation tends to decline over time as an organism adapts to current conditions
Visual acuity
Ability to see fine details
Visible light
Portion of electro magnetic spectrum seen
length
determines color
Intensity / amplitude
determines brightness
Purity
Corresponds saturation or richness of colour
Accommodation
Process by which the eye maintains a clear image on the retina
Retina
Light‐sensitive tissue lining the back of the eyeball
Cones
Detect colour, operate under normal daylight conditions, and allow us to focus on fine details
Fovea
Area of the retina where vision is the clearest and there are no rods at all (only cones)
Rods
Become active under low‐light conditions for night vision
Retina
Layers of cells including the bipolar cells and the retinal ganglion cells (in addition to the rod and cone layers)
Blind spot
Location in the visual field that produces no sensation on the retina because the corresponding area of the retina contains neither rods nor cones and therefore has no mechanism to sense light
Receptive field
Region of the sensory surface that, when stimulated, causes a change in the firing rate of that neuron
Trichromatic colour representation
The pattern of responding across the three types of cones that provides a unique code for each colour
Colour‐opponent system
Pairs of visual neurons that work in
opposition
Ventral stream
(“what”) to temporal lobe
Dorsal stream
(“where”) to the parietal lobe
Visual‐form agnosia
The inability to recognize objects by sight
Binding problem
How features are linked together so that we see unified objects in our visual world rather than free‐floating or miscombined features
Illusory conjunction
Perceptual mistake where features from multiple objects are incorrectly combined
Feature integration theory
Idea that focused attention is not required to detect the individual features that comprise a stimulus, but is required to bind those individual features together
Binding process
Utilizes structures in the ventral and especially the dorsal stream (parietal lobe)
Synesthesia
May involve atypical feature binding
Perceptual constancy
Even as aspects of sensory signals change,
perception remains consistent.
Grouping
Involves separating a figure from its (back)ground: reversible figure/ground relationship
Template
Mental representation that can be directly compared to a viewed shape in the retinal image
Geons
Geometric elements combined to make objects
Monocular depth cues
Aspects of a scene that yield information about depth when viewed with only one eye
Binocular disparity (depth cues)
Difference in the retinal images of the two eyes that provides information about depth
frequency
corresponds to our perception of pitch
amplitude
corresponds to our perception of loudness
complexity
corresponds to our perception of timbre
Timbre
A listener’s experience of sound quality or resonance
The outer ear
collects sounds waves
the middle ear
transmits vibrations
the inner ear
transduction into neural impulses
Cochlea
Fluid‐filled tube that is the organ of auditory transduction
Basilar membrane
Structure in the inner ear that undulates when vibrations from the ossicles reach the cochlear fluid
Hair cells
Specialized auditory receptor neurons embedded in the basilar membrane
Place code
Cochlea encodes different frequencies at different locations along the basilar membrane
Temporal code
Cochlea registers low frequencies via the firing rate of action potentials entering the auditory nerve
Conductive hearing loss
Damage to eardrum or ossicles
Sensorineural hearing loss
Damage to the cochlea, hair cells, or auditory nerve
Haptic perception
Active exploration of the environment by
touching and grasping objects with our hands
A‐delta fibers
Quick, sharp pain
C fibers
Long, dull pain
Referred pain
Feeling of pain when sensory information from internal and external areas converges on the same nerve cells in the spinal 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 from two directions
Vestibular system
Three fluid‐ filled semicircular canals and adjacent organs located next to the cochlea in each 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 behaviour or physiology
Object‐centered approach
Information about identity of odour object is
quickly accessed from memory and then triggers an emotional response
Valence‐centered approach
Emotional response comes first and provides basis for determining the identity of the odour
Tastant molecules
dissolve in saliva and stimulate microvilli that form the tips of taste receptor cells. Each taste bud contacts the branch of a cranial nerve at its base.
