Ch.2 Sensation and Perception

Question 1

Sensation

Answer 1

Aligns with transduction: the conversion of physical, electromagnetic, auditory, and other info from our internal and external environment to electrical signals in the nervous system. Raw signal from receptors sent to the CNS

Question 2

Perception

Answer 2

The processing of receptor info to make sense of its significance. Includes external sensory experience and internal activities of the brain and spinal cord. Includes comprehension of stimuli.

Question 3

Sensory receptors

Answer 3

Neurons that respond to stimuli and trigger electrical signals.

Question 4

Ganglia

Answer 4

Collections of nerve cell bodies found outside the CNS

Question 5

Projection areas

Answer 5

Further analyze sensory input after electrochemical energy arrives

Question 6

Photoreceptors

Answer 6

Respond to electromagnetic waves in the visible spectrum

Question 7

Hair cells

Answer 7

respond to movement of fluid in the inner ear structures (hearing, rotational and linear acceleration)

Question 8

Nociceptors

Answer 8

Respond to painful or noxious stimuli (somatosensation)

Question 9

Thermoreceptors

Answer 9

Respond to changes in temperature (somatosensation)

Question 10

Osmoreceptors

Answer 10

Respond to the osmolarity of the blood (water homeostasis)

Question 11

Olfactory receptors

Answer 11

Respond to volatile compounds (smell)

Question 12

Taste receptors

Answer 12

respond to dissolved compounds (taste)

Question 13

Threshold

Answer 13

The minimum amount of a stimulus that renders a difference in perception

Question 14

Absolute threshold

Answer 14

minimum of stimulus energy that is needed to activate a sensory system. Threshold in sensation. How loud does something have to be for you to hear it?

Question 15

Subliminal perception (Threshold/theory of conscious perception)

Answer 15

Perception of a stimulus below a given threshold that arrives at the CNS, but does not reach the higher-order brain regions that control attention and consciousness.

Question 16

Difference threshold (Just-noticable difference)

Answer 16

Minimum difference in magnitude between two stimuli before one can perceive this difference.

Question 17

Webers law

Answer 17

There is a constant ratio between the change in stimulus magnitude needed to produce a just-noticable difference and the magnitude of the original stimulus. Meaning that for a higher magnitude stimuli, the actual difference must be larger to produce a jnd. True for almost all sense modalities.

Question 18

Signal detection theory

Answer 18

Perception of stimuli can be affected by nonsensory factors, such as experiences (memory), motives, and expectations. (eg. extroverted people tend to hear their names more easily than introverts)

Question 19

Response bias

Answer 19

Tendency of subjects to systematically respond to a stimuli in a particular way due to nonsensory factors

Question 20

Catch Trials

Answer 20

A signal detection experiment that studies response bias.
Trials:
-Catch trials: trials where stimulus is presented
-Noise trials: trails where stimulus is not presented
Outcomes:
-Hits: subject correctly perceives the signal
-Misses: subject fails to perceive a given signal
-False alarms: Subject perceives signal that was not give
-Correct negatives: subject correctly identifies that no signal was given

Question 21

Adaptation

Answer 21

Detection of a stimulus can change over time. (eg. pupils can dilate to let in more light, contract muscles in ear to reduce vibrations of ossicles). Also, get used to new stimuli (cold water no longer seems cold over time). Way the body focuses on the most relevant stimuli.

Question 22

Retina

Answer 22

contains photoreceptors that transduce light into electrical information that the brain can process

Question 23

Ciliary muscle

Answer 23

Muscle that pulls on the suspensory ligaments that change shape of the lens, leading to accommodation. Contraction of ciliary muscle is under PSNS control

Question 24

Duplicity theory of vision

Answer 24

States that the retina contains two kinds of photoreceptors: those specialized for light and dark detection, and those for color detection

Question 25

Cones

Answer 25

Used for color vision and to sense fine details. Most effective in bright light. Fovea of eye only contains cones

Question 26

Rods

Answer 26

Only allow sensation of light and dark because they contain rhodopsin. Low sensitivity to details and permit night vision

Question 27

Bipolar cells

Answer 27

Where rods and cones connect. Synapse with ganglion cells, which group to form the optic nerve.

Question 28

Visual pathways (what happens)

Answer 28

physical and anatomical connections between the eyes and brain. Signals cross over at the optic chiasm. All visual fields that correspond to left side go to right side of brain and vice versa. Transfers through the lateral geniculate nucleus of the thalamus, then to the visual cortex in the occipital lobe. Inputs also in the superior colliculus, which controls responses to visual stimuli and eye movements

Question 29

Parallel processing

Answer 29

Ability to analyze and combine info regarding color, shape, and motion. (eg. can recognize car moving easily due to shape and color)

Question 30

Pathway of sound

Answer 30

Sound moves through the auricle to the external auditory canal, which directs sound to the eardrum (tympanic membrane). The eardrum vibrates and moves the ossicles (malleus, incus, stapes). Then vibrations move through the cochlea, which moves hear receptors on the organ of corti. Ascends through vestibulocochlear nerve to medial geniculate nucleus of thalamus. Then projects to auditory cortex in temporal lobe. Inferior colliculus can also be involved in the startle reflex.

Question 31

Cochlea arrangement

Answer 31

Composed of 3 parts (scalae). Middle has organ of corti, which has many hair cells. On top of this is the immobile tectorial membrane. Other scalae have perilymph that transmits vibrational signals across.

Question 32

Vestibule

Answer 32

Part of bony labyrinth that has utricle and saccule. Used as balancing apparatus to determine orientation in 3D space.

Question 33

Semicircular canals

Answer 33

Sensitive to rotational acceleration in ear

Question 34

Taste

Answer 34

Detected by chemoreceptors. Ascend to taste center in thalamus

Question 35

Two-point threshold

Answer 35

Minimum distance necessary between two points of stimulation on the skin such that the points will be felt as two distinct stimuli. Depends on the density of nerves in a specific area.

Question 36

Gate theory of pain

Answer 36

Proposes that there is a special gating mechanism that can turn pain signals on or off, affecting whether or not we perceive pain. Spinal cord preferentially forwards signals.

Question 37

Proprioception

Answer 37

The ability to tell where ones body is in space

Question 38

Bottom-up processing

Answer 38

Object recognition by parallel processing and feature detection. The brain takes individual sensory stimuli and combines them to create a cohesive image before determining what the object is. (used when seeing something new)

Question 39

Top-down processing

Answer 39

Driven by memories and expectations that allow the brain to recognize the whole object, then recognize the components based on these expectations. Allows us to recognize objects without needing to analyze specific parts.

Question 40

Perceptual organization

Answer 40

The ability to use bottom-up and top-down processes in tandem with all the other sensory clues about an object, to create a complete picture or idea. We fill in the gaps using Gestalt principles.

Question 41

Gestalt principles

Answer 41

There are ways for the brain to infer missing parts of a picture when a picture is incomplete

Question 42

Law of proximity

Answer 42

Gestalt principle that says that elements close to one another tend to be perceived as a unit (eg. seeing a group of dots as a triangle, rather than separate dots)

Question 43

Law of similarity

Answer 43

Gestalt principle. Objects that are similar tend to be grouped together. (eg. Small dots are separate from fat hollow dots)

Question 44

Law of good continuation

Answer 44

Gestalt principle. Elements that appear to follow in the same pathway tend to be grouped together. There is a tendency to perceive continuous patterns in stimuli rather than abrupt changes.

Question 45

Subjective contours

Answer 45

Gestalt principle. Perceiving contours, and therefore shapes that are not actually present in the stimulus

Question 46

Law of closure

Answer 46

Gestalt principle. When a space is enclosed by a contour it tends to be perceived as a complete figure.