Modules 17-18 Flashcards
what is sensation
The process by which our sensory receptors and nervous system receive and represent stimulus energies from our environment
what is perception
The process of organizing and interpreting sensory information, enabling us to recognize meaningful objects and events
what is bottom-up processing
Sensory analysis that begins at the entry level, with information flowing from the sensory receptors to the brain
what is top-down processing
Information processing guided by high-level mental processes, as when we construct perceptions by filtering information through our experience and expectations
what is the signal detection theory
- Predicts how and when we will detect a faint stimulus (signal) amid background stimulation (noise)
- Individual thresholds vary depending on the strength of the signal and on our experience, expectations, motivation, and alertness
what is the absolute threshold
-The minimum stimulus energy needed to detect a particular stimulus 50 percent of the time
-Tested by defining the point where half the time a stimulus is detected and half the time it is not
what is the subliminal threshold
Input below the absolute threshold for conscious awareness
what is a subliminal stimuli
Subliminal stimuli are those that are too weak to detect 50 percent of the time; they are below the absolute threshold
what is a subliminal sensation
Subliminal sensation exists, but such sensations are too fleeting to enable exploitation with subliminal messages
what is a subliminal persuasion
Subliminal persuasion may produce a fleeting and subtle but not powerful or enduring effect on behavior (Greenwald, 1992).
what is the difference threshold
Minimum difference that a person can detect between any two stimuli half the time
what is sensory adaptation
diminished sensitivity as a consequence of constant stimulation
what is a perceptual set
Mental tendencies and assumptions that affect (top-down) what we hear, taste, feel, and see.
what determines our perceptual set
-Schemas organize and interpret unfamiliar information through experience.
-Preexisting schemas influence top-down processing of ambiguous sensation interpretation, including gender stereotypes
what are context effects
A given stimulus may trigger different perceptions because of the immediate context
how do emotions influence our perception
- Walking destinations look farther away when we are fatigued.
- Slopes look steeper when we are wearing a heavy backpack (or after listening to sad, heavy classical music).
- Water bottles look closer when we are thirst
what is a wavelength
Distance from the peak of one light wave or sound wave to the peak of the next. Electromagnetic wavelengths vary from the short blips of cosmic rays to the long pulses of radio transmission
what is the intensity
Amount of energy in a light wave or sound wave, which influences what we perceive as brightness or loudness. Intensity is determined by the wave’s amplitude (height
what is the hue
Dimension of color that is determined by the wavelength of light; what we know as the color names blue, green, and so forth.
what does the perceived light hue depend on
its wavelength
what does lights brightness depend on
its intensity
brighter colours =
greater amplitudes
high frequency =
bluish colors
what is the cornea
Portion of the eye through which light passes (to the pupil and lens) and is bent to help provide focus
what is the pupil
A small adjustable opening through which the light then passes
what is the iris
A colored muscle surrounding the pupil that controls its size
what is the lens
Focuses incoming light rays onto an image on the retina on the eyeball’s sensitive inner surface
what is the retina
Contains two types of receptors: rods and cones
Has layers of neurons that begin the processing of visual information
what is accommodation
The process by which the eye’s lens changes shape to focus near or far objects on the retina
Cones:
number, location in retina, sensitivity in dim light, color sensitivity, detail sensitivity
- 6 million
- center
- low
- high
- high
Rods:
number, location in retina, sensitivity in dim light, color sensitivity, detail sensitivity
- 120 million
- Periphery
- High
- Low
- Low
retinal processing: optic nerve
Carries neural impulses from the eye to the brain
retinal processing: blind spot
The point at which the optic nerve leaves the eye, where no receptor cells are located
retinal processing: fovea
The central focal point in the retina, around which the eye’s cones cluster
how is colour processed
- Young-Helmholtz trichromatic theory: The retina’s red, green, and blue cones respond in varying degrees to different color stimuli.
- Hering’s opponent-process theory: Cones’ responses are then processed by opponent-process cells.
what are feature detectors
Specialized nerve cells in the brain that respond to specific features of the stimulus, such as shape, angle, or movement
These cells receive information from the ganglion cells in the retina.
They pass the information to other cortical areas, where teams of cells (supercell clusters) respond to more complex patterns.
what does Gestalt mean
: An organized whole
what is figure-ground in form perception
The organization of the visual field into objects (the figures) that stand out from their surroundings (the ground
what is grouping in form perception
The perceptual tendency to organize stimuli into coherent groups
what are examples of grouping
proximity, continuity and closure
what is depth perception
The ability to see objects in three dimensions, although the images that strike the retina are two-dimensional
Allows us to judge distance
Is present, at least in part, at birth in humans and other animals
what are binocular cues
Two eyes help with perception of depth
what are monocular cues
Depth cue, such as interposition or linear perspective, available to either eye alone
what is perceptual constancy
Objects are perceived as unchanging (having consistent color, brightness, shape, and size), even as illumination and retinal images change.
