5) Sensation & Perception Flashcards
Define sensation.
The process through which the senses pick up visual, auditory, and other sensory stimuli and transmit them to the brain
Define perception.
The process by which the brain actively organizes and interprets sensory information
What is the absolute threshold?
The minimum amount of sensory stimuli that can be detected 50% of the time
What is the difference threshold?
A measure of the smallest increase or decrease in a physical stimulus that is required to produce the just noticeable difference (JND) 50% of the time
What is the just noticeable difference?
The smallest change in sensation that a person can detect 50% of the time
What does Weber’s Law state?
The law stating that the just noticeable difference for all senses depends on a proportion or percentage of change in stimulus rather than on a fixed amount of change
What is transduction?
The process through which sensory receptors convert the sensory stimulation into neural impulses
What is sensory adaptation?
The process in which sensory receptors grow accustomed to a constant, unchanging level of stimuli over time
What is the lens?
The transparent disk-shaped structure behind the iris and the pupil that changes shape as it focuses on objects at varying distances
What is the retina?
The layer of tissue that is located on the inner surface of the eyeball and contains the sensory receptors for vision
Which structure of the eye has the image projected upside down and reversed from left to right?
Retina
What are the cones? Do they function in low light?
- The light-sensitive receptor cells in the retina that enable humans to see COLOUR and fine detail in adequate light
- Do not function in low-light
What are the rods? Do they function in low light?
- The light-sensitive receptor cells in the retina that allow the eye to see black-and-white
- Respond to low-light conditions
How do electrical visual impulses travel through nerves?
Optic chiasma –> Thalamus –> Primary visual cortex
What does the trichromatic theory state?
Suggests that three types of CONES in the retina each make a maximal chemical response to one of three colours
What does the opponent-process theory state?
Suggests that three kinds of cells respond by increasing or decreasing their rate of firing when different colours are present
What is frequency? What is the unit?
o Determined by the number of cycles completed by a sound wave in one second.
o The unit is Hertz (Hz)
What determines the pitch?
- Frequency
- How high or low the sound is
What is amplitude? What is the unit?
o The measure of the loudness of the sound
o The unit is Decibels (dB)
What components are apart of the outer ear?
- Pinna
- Auditory canal (ear drum)
What components are apart of the middle ear?
Ossicles, which connect the ear drums to the oval window and amplify sound waves
What is the order of the ossicles?
Hammer, anvil, stirrup
What components are apart of the inner ear?
Cochlea, vestibular sacs, and the semicircular canals
How do electrical impulses perform auditory transduction?
Electrical impulses occurs when the hair cells in the cochlea move
Where are the olfactory receptors?
Olfactory epithelium in the nostril
Where do olfactory sensations travel?
Olfactory epithelium –> Olfactory bulb (above nasal cavity)
What are the five taste sensations?
Sweet, sour, salty, bitter, umami
What relays gustation messages to the brain?
Taste buds located on the tongue and on the roof of the mouth
What are the four skin sensations?
- Touch
- Pain
- Pressure
- Hot/cold
How do skin receptors relay information to the brain? Which structures does it travel to?
The somato-sensory cortex at the front of the parietal lobes
Who is behind the Gate-Control Theory of Pain?
Melzack
What is the Gate-Control Theory of Pain?
- You feel pain when messages are carried by small nerve fibers
- Large nerve fibers carry other sensory messages, and can create traffic at the “gate” to stop pain from getting through
What naturally blocks pain?
Endorphins
Define attention.
The process of sorting through sensations and selecting some of them for further processing
Define in-attentional blindness.
The phenomenon in which we shift our focus from one object to another and, in the process, fail to notice changes in objects to which we are not directly paying attention
What is also known as data-driven processing?
Bottom-Up Processing
What is Bottom-Up Processing?
Information processing in which individual components or bits of data are combined until a complete perception is formed
What is also known as concept-driven processing?
Top-Down Processing
What is Top-Down Processing?
Information processing in which previous experience and conceptual knowledge are applied to recognize the whole of a perception and thus easily identify the simpler elements of the whole
What is a perceptual set?
An expectation of what will be perceived, which can affect what is perceived
What is Gestalt?
A German word that roughly refers to the whole form, pattern, or configuration that a person perceives
What are the five laws of Gestalt?
- Figure-Ground
- Similarity
- Proximity
- Continuity
- Closure
What is Figure-Ground?
As we view the world, some object (the figure) often seems to stand out from the background (the ground)
What is similarity?
Objects that have similar characteristics are perceived as a unit
What is proximity?
Objects that are close together in space or time are usually perceived as belonging together
What is continuity?
We tend to perceive figures or objects as belonging together as if they appear to form a continuous pattern, such as a line or wave
What is closure?
We perceive figures with gaps in them to be complete
What is perceptual constancy?
The phenomenon that allows us to perceive objects as maintaining stable properties, such as size, shape, and brightness, despite differences in distance, viewing angle, and lighting
What is depth perception?
The ability to perceive the visual world in three dimensions and to judge distances accurately
What are binocular depth cues?
Depth cues that depend on both eyes working together
What are monocular depth cues?
Depth cues that can be perceived by one eye alone
What are the 7 monocular depth cues?
- Interposition
- Linear perspective
- Relative size
- Texture gradient
- Atmospheric perspective
- Shadow or shading
- Motion parallex
What is interposition?
When one object partly blocks your view of another, you perceive the partially blocked object as being farther away
What is linear perspective?
Parallel lines that are known to be the same distance apart appear to grow closer together, or converge, as they recede into the distance
What is relative size?
Larger objects are perceived as being closer to the viewer and smaller objects as being farther away
What is texture gradient?
Objects close to you appear to have sharply defined features, and similar objects that are farther away appear progressively less well defined or fuzzier in texture
What is atmospheric perspective?
Objects in the distance have a bluish tint and appear more blurred than objects close at hand
What is motion parallex?
♣ When you ride in a moving vehicle and look out the side window, the objects you see outside appear to be moving in the opposite direction and at different speeds
♣ Those closest to you appear to be moving faster than those in the distance
What is shadow or shading?
When light falls on objects, they cast shadows, which add to the perception of depth
What is an illusion?
A false perception or a misperception of an actual stimulus in the environment
What is the blind spot in the eye due to?
No rods or cones where the optic nerve exits the eye
What colour is produced by short, frequent waves?
Bluish color
What colour is produced by long, frequent waves?
Red colour
What colour is produced by high waves?
Bright colours
What colour is produced by low, flat waves?
Dull colours
What is deafness the result of?
Damage to hair cells in the inner ear
Where do the auditory signals relay to in the brain?
Auditory cortex in the temporal lobe
What is the gorilla in the room an example of?
In-attention blindness
What are the two cues for perceiving motion?
1) Object passes through our visual field
2) Eyes and head move (tracking formation)
