Perception Flashcards
Perception
information from gauges, indicators, and signs must be detected and interpreted correctly
Color Perception
determine by the wavelength of light reflected from or emitted by an object
Spectral colors
a color comprised of a single wavelength
Non-spectral colors
a color comprised of more than one wavelength
Additive mixing
combinations that increase the amount of light reflected (computer monitors)
Subtractive mixing
combinations that reduce the amount of light reflected (paint)
Hue
variations described by names such as red, purple, blue, orange, etc.
Saturation
apparent purity, vividness, or richness
Lightness
dark to light, physically measured in Luminosity, perceived as “brightness”
Color Circle
developed by Isaac Newton, describes the dimensions of hue and saturation
Trichromatic theory
human color vision, there are 3 types of photoreceptors, corresponding to blue, green, and red, that determine our color perception
Short Cone
wavelength (blue) receptors, photopigment: cyanolabe
Medium Cone
wavelength (green), photopigment: chlorolabe
Long Cone
wavelength (red), photopigment: erythrolabe
Color-Blind
color vision abnormality
Dichromatic vision
missing one photopigment, have 2 but missing 3rd
Protanopia
the long wavelength (red) cones do not contain the erythrolabe
Deutanopia
the medium wavelength (green) cones do not contain chlorolabe
Opponent Process Theory
color perception is controlled by the activity of two opponent systems: blue-yellow & red-green. Only one color can be signaled at a time
Visual Acuity: Snellen Eye Chart
represents the clearness and sharpness of vision
Contrast Sensitivity
represents the ability of the visual system to distinguish bright and dim components of a static image. A function of both contrast and the spatial frequency of what is being viewed
Perceptual Organization
we don’t perceive color patches and gray and white blobs, we perceive distinct objects. The world we perceive is constructed by cues such as similarities and differences of color. Perception is organized to help us make sense of the world
Gestalt
means “essence or shape of an entity’s complete form”
Proximity
elements close together are perceived as a group
Similarity
similar elements (in terms of color, form, or orientation) are perceived together
Continuity
points connected in straight or smoothly curving lines are perceived together
Closure
open curves are perceived as complete forms
Common fate
elements moving in the same direction at the same speed are perceived as together
Common region
an explicit boundary
Connectedness
explicit lines
Depth Perception
used to translate physiology and a 2D image on the retina into 3D spatial information
Proprioception (Oculomotor Depth Cues)
ability to feel what your muscles are doing and where your limbs are positioned
Accomodation
automatic adjustments of the lens that maintain a focused image on the retina
Vergence
degree to which the eyes are turned inward to maintain fixation on an object
Monocular Depth Cues (pictorial cues)
convey impressions of depth in a still image
Interposition
nearer objects will block the view of more distant objects if they are in the same line of vision
Size
the “bigness” of an object
familiar size cue
familiar with how big an object is supposed to be
relative size cue
not familiar with how big an object is supposed to be but there are multiples of different sizes than those
Perspective
angles such as when you know something is rectangular but it appears trapezoidal
Motion Parallax
apparent displacement or difference in position of an object viewed along two different lines of sight
Binocular Depth Cues
can only be perceived with 2 eyes
Binocular disparity
each eye receives a slightly different image of the world because of the eye’s location (3D movies)
Size and shape constancy
we tend to see objects as the same size despite how large the image on our retina
Object motion
external object is moving, with a single stimulus moving in a stationary background, we can detect movement as slow as 0.5mm per second
Induced motion
a stationary background causes movement to be attributed to the wrong part of a scene
Apparent motion
discrete jumps of retinal images can produce the appearance of smooth motion (TV)
Vision
(most important) Sense
Auditory
information can be used to convey important information like an ambulance siren (really important sense)
Skin senses or touch
provide feedback about things like temperature and if your hands are in the right place on the steering wheel
Scents
can be important if you have propane leaking from your gas grill
Taste
also plays a role in how we perceive the world, we are motivated to eat good tasting foods
Steven’s Law
Stevens developed a scale for measuring loudness in which the unit is called a sone
Perceived loudness
a function of intensity and the length of time it was presented (longer sounds = louder & vice versa, but when continuous = loudness diminishes)
Sound localization
the ability to locate sounds in space (closer ear hears louder sound)
Vestibular System
inside ear, allows us to feel the movements of our bodies, works with vision and proprioception to control movements (involuntary)
Somesthetic (Touch) System
(fingertips & mouth) detects facets of the environment that you can physically feel (sense of touch, pressure, vibration, temperature, pain, and proprioception)
Somatosensory Cortex
More sensitive areas have larger areas in the cortex
Absolute thresholds
for touch are the smallest amount of touch that is detected, these vary across the body (lowest absolute threshold is on the face)
Two-point thresholds
are obtained by asking participants if they can determine the distance between two stimuli on their skin, when they are perceived as one stimuli then they are below the two-point threshold (lowest two-point threshold is in the fingers)
Passive touch
the skin is stationary and an external pressure stimulus is applied to it (use to obtain absolute & two-point thresholds)
Active touch
the person contacts the stimulus by moving the skin (typing on keyboard w/o looking)
4 taste qualities (tastebuds)
sweet, salty, sour and bitter, and savory
Olfactory Epithelium
receptor cells in the nasal cavity
