Chapter 4 Sensation & Perception Flashcards
Illusion
The way we perceive a stimulus doesn’t match its physical reality
Sensation
Detection of physical energy by sense organs, which send info to brain
Perception
Brains interpretation of raw sensory inputs
Naive realism
What we perceive is true/real, the world is precisely as we see it
Filling in
Reconstructing parts of what we perceive
Transduction
Process of converting an external energy/substance into electrical activity within neurons
Sense receptor
Specialized cell responsible for converting external stimuli into neural activity for a specific sensory system
Sensory adaptation
Activation is greatest when a stimulus is first detected
Psychophysics
Study of how we perceive sensory stimuli based on their physical characteristics
Absolute threshold
Lowest level of a stimulus needed for nervous system to detect change 50% of time
Just noticeable difference (JND)
Smallest change in intensity of a stimulus that we can detect
Weber’s Law
There is a constant proportional relationship between the JND/original stimulus intensity
Signal detection theory
Theory regarding how stimuli are detected under different conditions
Signal to noise ratio
How hard it becomes to detect signal when background noise present
Response biases
Tendencies to make one type of guess over others
Synesthesia
People experience cross-modal sensations
Parallel processing
Ability to attend many sense modalities simultaneously
Bottom-up processing
Processing in which a whole is constructed from parts
Top-down processing
Conceptually driven processing influenced by beliefs/expectations
Perceptual set
Set formed when expectations influence perceptions
Perceptual constancy
Process by which we perceive stimuli consistently across varied conditions
Selective attention
Process of selecting one sensory channel and ignoring/minimizing others
Inattentional blindness
Failure to detect stimuli that are in plain sight when our attention is focused elsewhere
Subliminal perception
Perception below the threshold of conscious awareness
Pupil
Circular hole where light enters eye
Cornea
Part of eye containing transparent cells that focus light on retina
Lens
Part of eye that changes curvature to keep images in focus
Accommodation
changing shape of lens to focus on objects near/far
Retina
Membrane at the back of eye responsible for converting light into neural activity
Forea
Central portion of retina
Acuity
Sharpness of vision
Rods
Receptor cells in the retina allowing us to see in low levels of light
Dark adaptation
Time in dark before rods regain max. light sensitivity
Cones
Receptor cells in the retina allowing us to see in colour
Optic nerve
Nerve that travels from the retina to brain
Blind spot
Region of retina containing no rods/cones, completely devoid of sense receptors
Feature detector cell
Cell that detects lines/edges
Trichromatic theory
Idea that colour vision is based on our sensitivity to three primary colours (red, green, blue)
Colour blindness
Inability to see some/all colours
Opponent process theory
Theory that we perceive colours in terms of three pairs of opposite colours (red/green, blue/yellow, black/white)
Depth perception
Ability to judge distance/3D relations
Monocular depth cues
Stimuli that enable us to judge depth using only one eye
Binocular depth cues
Stimuli that enable us to judge depth using both eyes
Gestalt Principles
- Proximity
- Similarity
- Continuity
- Closure
- Symmetry
- Figure-ground
Gestalt: Proximity
Objects physically close to each other perceived as unified wholes
Gestalt: Similarity
See similar objects comprising a whole
Gestalt: Continuity
Perceive objects as wholes even if other objects block part of them
Gestalt: Closure
Partial visual info present, brains fill in what’s missing
Gestalt: Symmetry
Perceive objects that are symmetrically arranged as wholes more often than those that aren’t
Gestalt: Figure-ground
Make instantaneous decision to focus attention on what we believe to be the central figure, ignore what’s in the background
Monocular cues (List)
Relative size, texture gradient, interposition, linear perspective, height in plane, light and shadow
Mono cues: Relative size
All things being equal, more distance objects look smaller than closer objects
Mono cues: Texture gradient
Texture of objects become less apparent as objects become further away
Mono cues: Interposition
One object that is closer blocks our view of an object behind it (know which object is closer vs farther)
Mono cues: Linear perspective
Outlines of rooms/buildings converge as distance increases (vanishing point)
Mono cues: Light and shadow
Objects cast shadows that give us a sense of their 3D form
Binocular cues (list)
Binocular disparity, binocular convergence
Binocular disparity
Left/right eyes transmit different info for near objects but see distant objects similarly
Binocular convergence
Look at nearby objects, focus on them reflexively by using our eye muscles to turn eyes inward
Audition
Sense of hearing
Timbre
Complexity/quality of sound that makes musical instruments, human voices, other sounds
Cochlea
Bony, spiral-shaped sense organ used for hearing
Pitch
Frequency of sound wave
Loudness
Amplitude/height of sound wave
Organ of corti
Tissue containing hair cells necessary for hearing
Basilar membrane
Membrane supporting organ of corti/hair cells in cochlea
Place theory
Specific place along the basilar membrane matches a tone w/ a specific path
Frequency theory
Rate at which neurons fire action potentials faithfully reproduces pitch
Olfaction
Sense of smell
Gustation
Sense of taste
Taste buds
Sense receptor in the tongue that responds to sweet, salty, bitter, umami, fat
Pheromones
Odourless chemicals that serve as social signal to members of one’s species
Somatosensory
Our sense of touch, temperature, pain
Gate control model
Idea that pain is blocked/gated from consciousness by neural mechanisms in spinal cord
Phantom pain
Pain/discomfort felt in an amputated limb
Proprioception
Our sense of body position
Vestibular sense
Our sense of equilibrium/balance
Semicircular canals
Three fluid-filled canals in the inner ear responsible for our sense of balance
