Chapter 2 - Sensation and Perception Flashcards
1
Q
Types of Receptors (7)
A
- Photoreceptors: respond to electromagnetic waves in the visible spectrum
- Hair cells: respnd to movement of fluid in the inner ear structures (hearing)
- Nociceptors: respond to painful or harmful stimuli (somatosensation)
- Thermoreceptors: respond to changes in temperature (thermosensation)
- Osmoreceptors: respond to the osmolarity of the blood (water homeostasis)
- Olfactory Receptors: respond to volatile compounds (smell)
- Taste Receptors: respond to dissolved compounds (taste)
2
Q
Threshold
A
- The minimum amount of a stimulus that renders a difference in perception
3
Q
Absolute Threshold
A
- The minimum of stimulus energy that is needed to activate a sensory system. It is therefore a threshold in sensation, not in perception.
- In other words, the minimum intensity at which a stimulus will be transduced (converted into action potentials)
4
Q
Difference Threshold
A
- Refers to the minimum difference in magnitude between two stimuli before one can perceive this difference
- Also called just-noticeable difference (jnd)
5
Q
Weber’s Law
A
- There is a constant ration between the change in stimulus magnitude needed to produce a jnd and the magnitude of the original stimulus
6
Q
Signal Detection Theory
A
- Focuses on the changes in our perception of the same stimuli depending on both internal (psychological) and external (environmental) context.
7
Q
Response Bias
A
- Refers to the tendency of subjects to systematically respond to a stimulus in a particular way due to nonsensory factors.
8
Q
Signal Detection Experiment
A
- Catch Trials = trials in which the signal is presented
- Noise Trials = the signal is not presented
- After each trial, the subject is asked to indicate whether or not a signal was given
- Hits = subject correctly perceives the signal
- Misses = subject fails to perceive signal
- False Alarms = subject seems to perceive a signal when none was given
- Correct Negatives = subject correctly identifies that no signal was given
9
Q
Adaptation
A
- Refers to a decrease in response to a stimulus over time
10
Q
Cones
A
- Used for color vision and to sense fine details
- Most effective in bright light
- Fovea contains only cones. Therefore, visual acuity is best at the fovea.
11
Q
Rods
A
- More functional in reduced illumination
- Only allow sensation of light and dark because they all contain a single pigment called rhodopsin
- Low sensitivity to details and are not involved in color vision, but permit night vision
- More rods and cones in the human eye
- Concentration of rods increases further away from the fovea
12
Q
Parallel Processing
A
- The ability to simultaneously analyze and combine information regarding color, shape, and motion of an object and to integrate this information to create a cohesive image of the world
- Also calls on memory systems to compare a visual stimulus to past experiences to help determine the object’s identity.
13
Q
Parvocellular Cells
A
- Detects shape
- Allow us to see very fine detail (high spatial resolution)
- Only work with stationary or slow-moving objects because they have very low temporal resolution
14
Q
Magnocellular Cells
A
- Detects motion
- Very high temporal resolution
- Low spatial resolution
- So… provides a blurry but moving image of an object
15
Q
Visual pathway from where light enters the cornea to the visual projection areas in the brain?
A
cornea ==> pupil ==> lens ==> vitreous ==> retina ==> optic nerve ==> optic chiasm ==> optic tract ==> lateral geniculate nucleus (LGN) of thalamus ==> visual cortex (occipital lobe)
16
Q
Place Theory
A
- States that the location of a hair cell on the basilar membrane determines the perception of pitch when that hair cell is vibrated
- High-pitched sounds cause vibrations at the base of the cochlea, whereas low-pitched sounds cause vibrations at the apex of the cochlea
17
Q
5 Basic Tastes
A
- Sweet
- Sour
- Salty
- Bitter
- Umami (savory)
18
Q
4 Main Modalities of Somatosensation
A
- Pressure
- Vibration
- Pain
- Temperature
19
Q
Two-Point Threshold
A
- Refers to the minimum distance necessary between two points of stimulation on the skin such that the points will be felt as two distinct stimuli.
- The size of the two-point threshold depends on the density of nerves in the particular area of skin being tested.
20
Q
Gate Theory of Pain
A
- Proposes that there is a special “gating” mechanism that can turn pain signals on or off, affecting whether or not we perceive pain
- In this theory, the spinal cord is able to preferentially forward the signals from other touch modalities to the brain, thus reducing the sensation of pain.
- Ex: Rubbing an injury seems to reduce the pain of the injury.
21
Q
Bottom-Up Processing
A
- Data-driven
- Refers to object recognition by parallel processing and feature detection
- Essentially, the brain takes the individual sensory stimuli and combines them together to create a cohesive image before determining what the object is.
22
Q
Top-Down Processing
A
- Conceptually driven
- Driven by memories and expectations that allow the brain to recognize the whole object and then recognize the components based on these expectations.
- Allows us to quickly recognize objects without needing to analyze their specific parts
23
Q
Gestalt Principles (6)
A
- Proximity: Components close to one another tend to be perceived as a unit.
- Similarity: Components that are similar (color, shape, size) tend to be grouped together.
- Good Continuation: Components that appear to follow in the same pathway tend to be grouped together.
- Subjective Contours: Edges or shapes that are not actually present can be implied by the surrounding object.
- Closure: When a space is enclosed by a group of lines, it is perceived as a complete or closed line.
- Pragnanz: Perceptual organization will always be as regular, simple, and symmetric as possible.
