Barron's: Chapter 4 - Sensation and Perception Flashcards
Transduction
- signals that are transformed into neural impulses
Sensory adaption
- decreasing responsiveness to stimuli due to constant stimulation
Sensory habituation (also called perceptual adaptation)
- our perception of sensations is partially due to how focused we are on them
Cocktail-party phenomenon
- if you are talking with a friend and someone across the room says your name, your attention will probably involuntarily switch across the room
Sensation
- the activation of our senses (eyes, ears, and so on)
Perception
- the process of understanding these sensations
Energy senses
- vision, hearing, and touch
- gather energy in the form of light, sound waves, and pressure
Chemical senses
- taste and smell
Vision
- dominant sense in human beings
- people use vision more than any other sense to gather information about their environment
Cornea
- protecting covering of eye
Pupil
- the muscles that control the pupil (iris) open it (dilate) to let more light in and also make it smaller to let less light in
Lens
- curved and flexible in order to focus the light
Retina
- image we see projected on retina
- like a screen on the back of your eye
Feature detectors
- are individual neurons—or groups of neurons—in the brain which code for perceptually significant stimuli.
Optic nerve
- sends impulses to a specific region in the thalamus called the later geniculate nucleus (LGN)
Occipital lobe
- visual cortex in it
- some researchers say that sensation ends and perception begins
Visible light
- the wavelengths that are visible to most human eyes
Rods and cones
- cones: activated by color
- rods: responds to black and white
Fovea
- contains the highest concentration of cones
Blind spot
- the sport where the optic nerve leaves the retina
Trichromatic theory
- hypothesizes that we have three types of cones in the retina: cones that detect the different colors blue, red, and green
Color blindness
- two types: dichromatic and monochromatic
Afterimages
- an impression of a vivid sensation (especially a visual image) retained after the stimulus has ceased
Opponent-process theory
- states that the sensory receptors arranged int he retina come in pairs
Hearing
- the ability to perceive sound by detecting vibrations, changes in the pressure of the surrounding medium through time, through an organ such as the ear
Sound waves
- created by vibrations, which travel through the air, and are then collected by our ears
Amplitude
- the height of the wave and determines the loudness of the sound
Frequency
- the length of the waves and determines pitch, measured in megahertz
Cochlea
- a structure shaped like a snail’s shell filled with fluid
Pitch theories
- theories which describe how we hear different pitches
Place theory
- holds that the hair cells in the cochlea respond to different frequencies of sound based on where they are located in the cochlea
Frequency theory
- lower tones are sensed by the rate at which the cells fire
Conduction deafness
- occurs when something goes wrong with the system of conducting the sound to the chochlea
Nerve deafness
- occurs when the hair cells in the cochlea are damaged, usually by a loud noise
Touch
- when our skin is indented, pierced, or experiences a change in temperature, sense of touch is activated by this energy
Gate-control theory
- helps explain who we experience pain the way we do
Taste (or gustation)
- chemicals form the food we eat are absorbed by taste buds on our tongue
Smell (or olfaction)
- depends on chemicals emitted by substances
Vestibular sense
- help with body position and balance
Kinesthetic sense
- help with body position and balance
Absolute threshold
- the smallest amount of stimulus we can detect
Subliminal messages
- stimuli below our absolute threshold
Difference threshold
- the smallest amount of change needed in a stimulus before we detect a change
Weber’s law
- states that the change needed is proportional to the original intensity of the stimilus
Signal detection theory
- investigates the effects of the distractions and interference we experience while perceiving the world
Top-down processing
- we perceive by filling in gaps in what we sense
Perceptual set
- a predisposition to perceiving something in a certain way
Bottom-up processing
- the opposite of top-down processing, instead of using our experience to perceive an object, we use only the features of the object itself to build a complete perception
Gestalt rules
- describes principles that govern how we perceive groups of objects
Proximity
- objects that are close together are more likely to be perceived as belonging in the same group
Similarity
- objects that are similar in appearance are more likely to be perceived as belonging in the same group
Continuity
- objects that form a continuous form are more likely to be perceived as belonging in the same group
Closure
- similar to top-down processing. objects that make up a recognizable image are more likely to be perceived as belonging in the same group even if the image contains gaps that the mind needs to fill in
Constancy
- our ability to maintain a constant perception of an object despite changes
Size constancy
- objects closer to our eyes will produce bigger images on our retinas, but we take distance into account in our estimations of size. we keep a constant size in mind for an object and know that it does not grow or shrink in size as it moves closer or farther away
Shape constancy
- objects viewed from different angles will produce different shapes on our retinas, but we know the shape of an object remains constant. for example, the top of a coffee mug viewed form a certain angle will produce an elliptical image on our retinas, but we know the top is circular due to shape constancy. again, this depends on our familiar with the usual shape of the object
Brightness constancy
- we perceive objects as being a constant color even as the light reflecting off the object changes. for example, we will perceive a brick wall as brick red even as the daylight fades and the actual color reflected from the wall turns gray
Depth cues
- without depth perception we would perceive the world as a two-dimensional flat surface unable to differentiate between what is near and what is far
David Hubel
- discovered that groups of neurons in the visual cortex has feature detectores for vertical lines, curves, motion, and many other features of images
Torsten Wiesel
- discovered that groups of neurons in the visual cortex has feature detectores for vertical lines, curves, motion, and many other features of images
Ernst Weber
- made Weber’s law which is about thresholds
Gustav Fechner
- he was the founder of psychophysics
Eleanor Gibson
- she focused on reading development and perceptual learning in infants and toddlers
ganglion cells
- the axons of the cells make up the optic nerve
optic chiasm
- the spot were our optic nerves cross each other