PSYC1200/ Chapter 5: Sensation and Perception

sensation

detection by sensory organs of the physical energy emitted or reflected by physical objects

sense receptors

sensation begins at our ___ ___

perception

the process by which the brain organizes and interprets sensory information

doctoring of specific nerve energies

the principle that different sensory input methods exist because sensory signals follow different pathways to get to the brain

anatomical code

the idea that certain sensory organs are connected to different areas of the brain

synesthesia

a condition in which a sensation in one sense organ consistently evokes a sensation in another

functional code

gives us information about which, how many, and the rate of neurons firing

• accounts for the subtle differences in visual and auditory stimuli we perceive

  • the reason we can differentiate between red and pink, and the sound of a tuba vs. the sound of a flute

absolute threshold

the minimum amount of a stimulus required for it to be reliably detected 50% of the time it is presented

difference threshold

also called the ‘just noticeable difference’

• the smallest difference between two stimuli that a person can detect

  • expressed as a weber fraction

signal detection theory

a psychophysical theory that divides the detection of a sensory signal into a sensory process and a decision process

• results are divided into hit, false alarm, miss, and correct

hit

signal was present and correctly detected by the subject

false alarm

signal was not present but was still detected by the subject

miss

signal was present but was not detected by the subject

correct

signal was not present, and it was not detected by the subject

sensory decline

the resulting decline in our sense’s functioning when the stimulus is repetitive or unchanging

• this is the reason for nose blindness

• this is also the reason why we do not constantly feel our clothes on our body

  • the neurons get tired of repeatedly firing, so they stop

selective attention

the process of focusing in selected aspects of the environment while blocking out others

• allows us to block out unnecessary information and maintain an attention span

inattentional blindness

the failure to consciously perceive something you are receiving sensory stimulus from because you are not paying attention to it

• stimulus makes it to the brain but the brain does not perceive it because the brain chooses to ignore it

  • this is a downside to selective attention

hus

the dimension of visual experience specified by color names

• related to the wavelength of light

saturation

the dimension of our visual experience related to the complexity of a wavelength

• how wide or narrow a wavelength is

brightness

the dimension of visual experience that relates the amount and intensity of light an object emits to the amplitude of the light’s wavelength

sclera

white outer later of the eye

cornea

clear layer that covers the front over the eye

• bends incoming light towards the lens

iris

muscle in the eye that regulates the amount of light let into the eye

• gives the eye its color

lens

clear structure that focuses light back onto the eye

retina

neural tissue at the back of the eye that contains receptors for vision

• contains rods and cones

rods

visual photoreceptors that are more sensitive to dim light

• provide peripheral vision

cones

visual photoreceptors involved in color vision

fovea

center of the retina covered in closely gathered cones

bipolar cells

the synapse of rods and cones that connects to ganglion cells

ganglion cell

transmits signals from the bipolar neuron to the brain

optic disk

area on the retina lacking rods and cones; causes a blind spot in our vision

feature-detector cell

cells that detect specific aspects of the visual world such as faces, the environment, and our body parts

trichromatic theory

color perception theory that states color vision is determined by 3 different cone types that are sensitive to short, medium, and long wavelengths

dichromatic

colorblind individuals have only 2 types of cones

• this is called ___ cone distribution

opponent-process theory

color perception theory that states we perceive colors in terms of opposite ends of the spectrum

gestalt psychologists

the first psychologists to study how people organize the visual world into meaningful units and patterns

dorsal stream

visual pathway that focuses on the where and how question

• responsible for our ability to move and interact with the world

  • responsible for depth perception

binocular depth cues

distance cues that are based on differing perspectives of both eyes

retinal disparity

the difference in perspective provided by each eye

monocular cues

distance cues used for objects farther than 50 feet; dependent on one eye

ventral stream

visual pathway that asks what questions

• responsible for telling us what we are looking at

fusiform face area

part of ventral stream

• responsible for facial recognition

pareidolia

seeing patterns in irregular objects

• cloud watching for example

prospognosia

the inability to recognize faces

perceptual constancies

the ventral stream is responsible for ___ ___

• the accurate perception of objects as stable and unchanged despite changes to the sensory patterns they produce

  • size, shape, location, and brightness constancy

loudness

describes the intensity of the soundwave

pitch

describes the frequency of the pressure wave

timbre

related to the complexity of the soundwave

• flute note has a low ___

cochlea

snail-shaped, fluid filled organ in the inner ear

• houses receptors for hearing

basilar membrane

stretches across the interior of the cochlea

• the movement of this controls the movement of hair cells which determines which neurons fire at the sound

hair cells

receptors for hearing located inside the cochlea

high

inner ear place theory does not explain how we can hear sound of ___ frequency

volley principles

a part of the frequency theory that explains how we can hear sounds of higher frequencies

• multiple neurons work together to distribute the soundwaves of higher frequency sounds

olfactory epithelium

thin layer of cells that are lined by smell sensory receptors

cilia

smell sensory receptors

nociception

sense of pain signaled by specialized nociceptors

gate control theory

pain theory that states that our ability to feel pain depends on where pain impulses get past a neurological “gate” in the spinal cord in order to reach the brain

p

phantom pain

when a person fells pain from a limb that isn’t present because it was amputated, or an organ that has been removed

kinesthesis

sense that tells is where are body parts are, and when they move

equilibrium

tells us the orientation of the body as a whole