Sensing the Environment

Question 1

threshold

Answer 1

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

Question 2

absolute threshold

Answer 2

the minimum of stimulus energy that is needed to activate a sensory system (i.e.: trigger an action potential). present in sensation, but not perception.

Question 3

subliminal perception

Answer 3

perception of a stimulus below a given threshold (i.e.: a threshold of conscious perception)

Question 4

difference threshold

Answer 4

just-noticeable difference (JND). the minimum difference in magnitude between two stimuli before one can perceive the difference between them.

Question 5

Weber’s Law

Answer 5

there is a constant ratio between the change in stimulus magnitude needed to produce a JND and the magnitude of the original stimulus.

Question 6

signal detection theory

Answer 6

perception of the same stimuli can differ based on both internal and external contexts. example: the volume required to respond to your name in a crowded room vs. the volume required in a quiet room

Question 7

sensory adaptation

Answer 7

how our sensory system adapts to and focuses attention on the most relevant stimuli, usually changes in our environment.

Question 8

psychophysics

Answer 8

the study of the relationship between the physical nature of stimuli and the sensations and perceptions they evoke.

Question 9

distal stimuli

Answer 9

stimuli that originate outside the body

Question 10

proximal stimuli

Answer 10

stimuli that directly interact with and affect sensory receptors

Question 11

photoreceptors

Answer 11

respond to electromagnetic waves in the visible spectrum (sight)

Question 12

hair cells

Answer 12

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

Question 13

nociceptors

Answer 13

respond to painful or noxious stimuli (somatosensation)

Question 14

thermoreceptors

Answer 14

respond to changes in temperature (thermosensation)

Question 15

osmoreceptors

Answer 15

respond to the osmolarity of the blood (water homeostasis)

Question 16

olfactory receptors

Answer 16

respond to volatile compounds (smell)

Question 17

taste receptors

Answer 17

respond to dissolved compounds (taste)

Question 18

describe how sensory pathways work.

Answer 18

different types of sensory receptors (nerve endings or sensory cells) receive stimuli and transmit data to the CNS through sensory ganglia. once transduction occurs, the electrochemical energy is sent along neural pathways to various projection areas in the brain, which further analyze the sensory input.

Question 19

ganglia

Answer 19

collections of neuron cell bodies found outside the CNS

Question 20

cornea

Answer 20

clear, domelike window on the front of the eye. gathers and focuses incoming light.

Question 21

iris

Answer 21

colored part of the eye. composed of two muscles: dilator pupillae (opens pupil under sympathetic stimulation) and constrictor pupillae (constricts pupil under parasympathetic stimulation)

Question 22

ciliary body

Answer 22

produces aqueous humor

Question 23

canal of Schlemm

Answer 23

drains aqueous humor

Question 24

lens

Answer 24

helps to control refraction of incoming light

Question 25

retina

Answer 25

in the back of the eye, converts incoming photons of light to electrical signals

Question 26

sclera

Answer 26

thick structural layer that covers most of the exposed portion of the eye. "white" of the eye.

Question 27

parallel processing

Answer 27

ability to simultaneously analyze and combine information regarding color, shape, and motion, and then comparing information to stored memories to determine what is being viewed

Question 28

feature detection

Answer 28

neuroscience correlate of parallel processing.

Question 29

rods

Answer 29

used for sensation of light and dark, low sensitivity to detail, permit night vision

Question 30

cones

Answer 30

used for color vision and fine details, most effective in bright light

Question 31

bipolar cells

Answer 31

connect to rods and cones to highlight gradients between adjacent rods and cones. synapse with ganglion cells.

Question 32

optic disk

Answer 32

blind spot of the eye, place where optic nerve leaves the eye. no photoreceptors.

Question 33

retinal ganglion cells

Answer 33

form the optic nerve

Question 34

retinal ganglion cells

Answer 34

form the optic nerve

Question 35

pinna/auricle

Answer 35

outer part of the ear, made of cartilage

Question 36

tympanic membrane

Answer 36

eardrum. vibrates in phase with soundwaves coming into the ear.

Question 37

ossicles

Answer 37

three smallest bones in the body, all inside the ear: malleus, incus, and stapes

Question 38

cochlea

Answer 38

spiral-shaped organ of the ear.

Question 39

gestalt principles

Answer 39

ways for the brain to fill in information when a picture is incomplete

Question 40

law of proximity

Answer 40

gestalt principle. says that elements close to one another tend to be perceived as a unit.

Question 41

law of similarity

Answer 41

gestalt principle. says that objects that are similar tend to be grouped together.

Question 42

law of good continuation

Answer 42

gestalt principle. says that elements that appear to follow the same pathway tend to be grouped together.

Question 43

subjective contours

Answer 43

gestalt principle. perceiving contours (and therefore shapes) that are not actually present in the stimulus.

Question 44

law of closure

Answer 44

gestalt principle. says that when a space is enclosed by a contour it tends to be perceived as a complete figure (some figures may be perceived to be more complete than they actually are)

Question 45

law of pragnanz

Answer 45

perceptual organization will always be as regular, simple, and symmetric as possible

Question 46

bottom-up processing

Answer 46

recognition of objects by parallel processing and feature detection. data driven. slower, but less prone to mistakes.

Question 47

top-down processing

Answer 47

recognition of an object by memories and expectations, with little attention to detail. conceptually driven. faster, but more prone to mistakes.

Question 48

perceptual organization

Answer 48

our synthesis of stimuli to make sense of the world, including integration of depth, form, motion, and constancy.