EXAM 2: CHAPTER 4 Flashcards
Synesthesia
Two Greek words syn meaning together, and aesthesis meaning perception = joined perception. People with this condition experience stimulus that is perceived by one sense in most people in two or more sensory modalities
Why is it hard to measure those who experienced synesthesia
Because they assume their experiences are normal, but prevalence estimates 1 in 23 people
Grapheme-color synesthesia
Most common form of synesthesia. Person with this type sees color in response to specific letter or number
Sensation
Act of using our own sensory systems to detect environmental stimuli
Perception
The conscious recognition and identification of a sensory stimulus
Transduction
Process that involves converting stimulus energy into neural impulses to be interpreted by brain
5 senses and their physical stimuli:
- Olfactory (smell); odorants (airborne chemicals)
- Somatosensory (touch, heat, pain); pressure or damage to skin
- Gustatory (taste); chemicals (typically in food)
- Auditory (hearing) ; sound waves
- Visual (sight) ; light (photons)
Sensory receptor cells
Specialized cells that convert a specific form of environmental stimuli into neural impulses
Sensory transduction
Process of converting a specific form of environmental stimuli into neural impulses
Can sensory receptors be activated by weak stimuli?
Yes, but it must reach a certain level of intensity called threshold
Threshold
The point at which the magnitude or intensity of a stimulus initiates a neural impulse
Absolute threshold
Minimal stimulus necessary for detection by an individual
Difference threshold vs noticeable differences
The minimal difference between 2 stimuli necessary for detection of a difference between the two
Signal detection theory
Theory that the response to a signal in every situation depends on an individual’s ability to differentiate between signal and noise
Sensory adaptation
The process whereby repeated stimulation of a sensory cell leads to a reduced response (Eg. When some stimulus in our surroundings stays the same for a period of time, like pressure of clothing on skin, the sensory cells will respond to it less and less)
Olfactory adaptation
Occurs when a change in sensitivity to a particular odour reaches a point where the odour cannot be distinguished after a prolonged exposure
How does perception occur?
Through bottom-up processing
Bottom-up processing
Perception that proceeds by transducing environmental stimuli into neural impulses that move into successively more complex brain regions (Eg. When looking at your friends face, our eyes convert light energy into neural impulses)
Top-down processing
Perception processes led by cognitive processes such as memory or expectations (Eg. When looking at your friends face, our brain stores information about that face and helps you perceive)
Perceptual set
Top-down processing is more than our memories. The knowledge about how things typically appear/expectations will play a role. It is about the readiness to interpret a certain stimulus a certain way (Eg. Fuzzy photo of a UFO will look different depending on whether you believe in UFOs)
Ambiguous stimuli
Stimuli that could be interpreted in different ways (Eg. Photo of old women with big nose vs young)
Sensory systems
Part of nervous system consisting of sensory receptors that receive stimulus information and conduct information to parts of brain responsible for processing sensory information
Aritstotle claims
First to claim that there are five senses: Smell, taste, touch, sound and sight
Proprioceptive feedback
Our five senses + kinesthetic sense (body movement, posture, position). It is the unconscious awareness of the self and spatial orientation arising from stimulation within body
Kinesthetic
Monitors the position of the various parts of body. You know where your limbs are because you thought about putting them there
Vestibular
Responds to gravity, keeps you informed of your body’s location in space
Which sense is the major sense
Vision
The auditory system is designed for what
To convert sound waves, vibrations of the air into neural impulses
2 major qualities of sound waves to produce perception of different sounds
Frequency & amplitude
Frequency
Frequency of sound wave refers to the number of cycles the wave completes in a certain amount of time. It is measured in units called hertz (Hz). It is responsible for producing the pitch of a sound
Which range (in Hz) do we hear best
2,000-5,000 Hz
Amplitude
Amplitude of a sound wave refers to the strength of a given cycle. It is responsible for our detection of loudness and is measured in units called decibels (dB)
Steps of converting sound waves to neural impulses (10):
- Sound waves enter outer ear at its deepest part, reflect the ear drum (tympanic membrane)
- Vibrations of ear drum set in motion a series of three tiny bones (ossicles) called maleus, incus, and stapes.
- Stapes, the last bone in chain hits the oval window (membrane separating ossicles and inner ear)
- Deflection of oval window causes wave to form in the fluid-filled structure in inner ear (cochlea)
- When fluid moves in cochlea, it deflects the basilar membrane (structure in cochlea where hair cells are located)
- Movement of basilar membrane bends hair cells that transduce the fluid sound wave into electrical activity
- Hair cells communicate with nerves in cochlea and send impulses to brain
- After sound waves are transduced, it travels as signals from nerves in the cochlea to brainstem, the thalamus, then auditory cortex (temporal lobe)
- Auditory information from one ear sent to auditory cortex areas on both sides of brain
- Auditory information moves to the auditory association areas in corte
Tympanic membrane
Ear drum
Ossicles
Tiny bones in the ear called the maleus, incus, and stapes
Oval window
Membrane separating the ossicles and the inner ear, deflection of which causes a wave to form in cochlea
Cochlea
Fluid-filled structure in inner ear with hair cells
Basilar membrane
Structure in cochlea where hair cells are located
Hair cells
Sensory receptors that convert sound waves into neural impulses
Tonotopic map
Representation in the auditory cortex of different sound frequencies
Two major theories about how the auditory system converts sound waves:
- Frequency theory: Different sound frequencies are converted into different rates of action potentials. High frequency sounds produce a more rapid firing than low frequency sounds
- Place theory: Differences in sound frequency activate different regions on the basilar membrane
Absolute pitch
The ability to recognize or produce any note on a musical scale (Eg. Mariah Carey)
Myths about absolute pitch
People who speak tonal languages (Vietnamese, Mandarin) are more likely to develop absolute pitch
Throat singing
Traditional form of singing for the Inuit that reinforces sense of connection with history, community, and tradition. Singing was believed that it had healing abilities
Cocktail party effect
Ability which enables brain to attend to, and pick up on relevant sounds (Eg. Hearing your name in a crowd)
3 cues of auditory system:
- General loudness
- Loudness in each ear
- Timing
Statistics of hearing loss in Canada
3 million people in Canada and 466 million people in the world suffering from hearing loss
2 major causes of deafness:
- Conduction deafness: Occurs when there is some sort of occlusion or break In the various processes by which sound is transmitted through the inner ear (Ear wax, infection, water)
- Nerve deafness: Results from damage or malformations of the auditory nerve in the brain
Tinnitus
Ringing in the ear; occurs in about 1 in every 200 people
Causes of tinnitus
Caused from abnormalities in the ear, to structural changes in brain
Retina
Specialized sheet of nerve cells in back of eye containing sensory receptors for vision
How many rods in human retina
100 million
How many cones in human retina
4.5 - 6 million per eye
Two major classes of visual receptors exist in the retina
- Rods responsive to levels of light and dark
- Cones responsive to colours
Optic nerve
Bundle of axons of ganglion cells that carries visual information from eye to brain
Blind spot
The location where the optic nerve leaves retina that is lacking rods and cones
Fovea
Centre of retina, containing only cones where vision is most clear
Myopia
Nearsightedness. A common vision condition in which near objects appear clear but objects far away look blurry
Hyperopia
Farsightedness. A common vision condition in which you can see far objects clearly but nearby objects look blurry
3 dimensions of experience of color:
- Hue: Experience of color based on wavelength of light that visual stimulus reflects
- Saturation: Refers to purity of color; how bright or vivid color is
- Brightness: Refers to how much light is reflected from the visual stimulus (white is considered brightest color and black is considered least bright)
Two theories of color vision:
- Young-Helmhotz trichromatic theory of color vision
- Opponent process theory
Young-Helmhotz trichromatic theory of color vision
States that there are 3 different receptors for color (Red, green and blue). All the colors we perceive are created by light waves stimulating combinations of these cones
Opponent process theory
States that colors pairs work to inhibit one another in the perception of color; suggests that looking at one color for a long period of time causes receptor cells to become fatigued (red-green, yellow-blue, black-white)
Define the term negative in relation to color
Used to acknowledge that the afterimage is the opposite color of the original image
Statistics of colour-blindness in gender
1 in 12 men and 1 in 200 women have some form of color blindness
Color vision deficiency
Inability to distinguish certain colors
Monochromatic
Unable to see any color at all
Most common form of color deficiency
red-green color blindness
Change blindness
When people fail to detect changes to the visual details of a scene
Inattentional blindness
Failure to perceive objects that are not the focus of attention
Pathways that process information about complex visual stimuli is divided into..
“what” and “where”
“what” pathway
Involves axons that travel from occipital cortex to temporal cortex. Allows people to have vision but cannot recognize objects visually
“where” pathway
Involves axons that travel from the occipital cortex to parietal cortex. Allows people to have normal vision but don’t have the ability to locate objects
Visual agnosia
Condition where patient has damage to the parts of the temporal cortex that house the “what” pathway
Hemi-neglect
Damage to the “where” pathway
Colors in relation to Gestalt principles
It relates because we don’t see images as a series of small patches of color or a series of simple features. We see them as a whole
Laws by which visual information is organized into coherent images - Gestalt Psychology (5)
- Figure ground: Perception used to identify whether something in visual field is the main object or background
- Proximity: Visual stimuli near to one another tend to be grouped together
- Continuity: Stimuli falling along same plane tend to be grouped together
- Closure: We tend to fill in small gaps in objects so that they are still perceived as whole objects
- Similarity: Stimuli resembling one another tend to be grouped together
To determine whether something is close or far away, we use cues called..
Binocular cues (both eyes) and monocular cues (one eye)
Retinal disparity
Slight difference in images processed by the retinas of each eye
Convergence
Inward movement of the eyes to view objects close to oneself
Monocular cues
Visual clues about depth and distance that can be perceived using information from only one eye like photographs, pictures
Examples of monocular cues:
- Interposition: When one object blocks part of another from our view
- Relative height: We see objects that are higher in our visual plane as farther away than those that are lower in visual plane
- Texture gradient: We see more details of textured surfaces, such as veins in leaves when object is closer to us
- Linear perspective: Parallel lines seem to get closer together as they recede
- Light and shadow: We use light as a cue to distance. Objects that are bright are perceived as closer
- Clarity perspective: We tend to see closer objects with more clarity than ones further away
- Familiar size: Once we have learned size of objects, such as people or buildings, we assume that they stay the same size
- Relative size: When we look at two objects we know are about the same size, if one seems smaller than the other, we see the smaller objects as farther away
- Motion parallax: Requires observer to be moving. Relative movement of objects that are stationary against background gives idea about relative distance
Perceptual constancies
Tendency to view objects as unchanging despite shifts in environmental stimuli we receive
Size constancy
We perceive objects as the same size, regardless of distance from which it is viewed
Shape constancy
We see an object as the same shape, no matter from what angle it is viewed
Color constancy
See different colors the same (Eg. Restaurant dimming lights and making color of the food look all the same)
Strabismus
Misalignment of eyes. Results in two different images being sent to the brain (one from each eye)
Strabismus can be treated by surgery
Amblyopia
Partial or complete loss of vision due to abnormal development of the brain’s visual cortex in infancy. Caused by strabismus most of the time
Two distinct pathways from the occipital cortex to visual areas:
- Ventral stream: What is it, name the object to temporal lobe
- Dorsal stream: Where is it, action reaching to the parietal lobe
Visual-form agnosia
Inability to recognize objects by sight
Braille
System of reading that involves touch
How many Canadians have an optical disease
Over 5.5 million Canadians have a disease like age related macular degeneration, glaucoma, diabetic retinopathy, cataracts and refractive error
Where is vestibular sense
Vestibular sense is located in semicircular canals of inner ear where the fluid the canals contain shifts as we move. Our vestibular system provides us with body movement
