Chapter 3: Sensation and Perception

Question 1

What is sensation?

Answer 1

sensation is detecting physical energy from the environment and converting it into neural signals

o Occurs when specialized receptors in the body are activated allowing various forms of outside stimuli to become neural signals in the brain

o Process by which information from outside world enters brain § Information enters through sensory receptors ( tongue, ear, etc.)
Convert different stimuli into neural activity Consciously or unconsciously

Question 2

What is Transduction?

Answer 2

Transduction is converting outside stimuli into neural activity.

Question 3

What is perception?

Answer 3

When we select, organize, and interpret our sensations, the process is called perception. Perception occurs when we give meaning to our sensations, interpreting them.

Question 4

What are the five senses of transduction?

Answer 4

Transduction

• Taste (gustation): food molecules chemical signals coming in
• Vision: light (photons)
• Hearing ( audition): sound waves
• Touch (somatosentaion): pressure and temperature
• Smell (olfaction): molecules in the air

Question 5

Who was Ernest Weber?

Answer 5

Ernest Weber (1795-1878)

o Just noticeable differences- smallest difference between two stimuli that is detectable 50% of the time; whatever the difference might be, it is always a constant
o Ex: lifting a 55lb weight and a 50lb weight and half the time you say there is a difference

Question 6

What is absolute threshold?

Answer 6

Absolute Threshold: Minimum stimulation needed to detect a particular stimulus 50% of the time.

Question 7

What is the difference threshold?

Answer 7

Difference Threshold: Minimum difference between two stimuli required for detection 50% of the time, also called just noticeable difference (JND).

Question 8

What is Weber law?

Answer 8

Weber’s law in humans, difference thresholds (experienced as a jnd) increase in proportion to the size of the stimulus

Two stimuli must differ by a constant minimum percentage to be perceived as different

k=ΔI/I

Question 9

What are Sublimal Threshold?

Answer 9

Subliminal stimuli are those just strong enough for our sensory receptors to pick them up, but not strong enough for us to be able to detect them

Question 10

What is habituation?

Answer 10

Habituation is tendency of the brain to stop tending to constant, unchanging information; air conditioning; at the neural level

Question 11

What is the priming effect?

Answer 11

Priming effect reveals that we can process some information from stimuli too weak to recognize, No powerful enduring effects but really subtle

Question 12

What are microsacchades?

Answer 12

Microsacchades constant movement of the eyes; tiny little vibrations that people do not notice consciously; prevents sensory adaption to visual stimuli

Question 13

What is sensory adaptation?

Answer 13

Sensory adaption is the tendency for the sensory receptors to be less responsive to stimulus unchanged; don’t send the signals to the brain

Question 14

What is transduction?

Answer 14

Transduction is the transformation of stimulus energy into neural impulses.

Question 15

What is photo transduction?

Answer 15

Photo transduction Conversion of light energy into neural impulses that brain can understand.

Question 16

Color is determined by wavelength. What is a wavelength?

Answer 16

Wavelength is determined by the length of the wave, distance between wave peeks

Question 17

The brightness of a color is determined by amplitude and intensity of a wavelenght. What is amplitude and intensity?

Answer 17

• Amplitude is determined by the height of the wave, how high or low the wave actually is
• Intensity is the amount of energy in a wave; determined by amplitude; related to perceived brightness

Question 18

What determines saturation?

Answer 18

Determined by whether or how much there is a mixture of wavelengths.

Question 19

What are the parts of the eye?

Answer 19

The parts of the eye are the cornea, iris, lens, and the retina.

Question 20

What is the cornea?

Answer 20

Cornea Transparent tissue where light enters the eye.

Question 21

What is the iris?

Answer 21

The Iris is the muscle that expands and contracts to change the size of the pupil for light.

Question 22

What are the lens?

Answer 22

The lens focuses the light rays on the retina ( through visual accommodation a process by which the eye’s lens changes the shape to help focus near or far objects on the retia)

Question 23

What is the retina?

Answer 23

Retina Light sensitive inner surface of the eye containing photoreceptor rods and cones plus layers of other neurons (bipolar and ganglion cells that process visual information)

Question 24

What are rods and cons?

Answer 24

Cones

• 6 million
• Center
• Low sensitivity to dim light
• Located in fovea
• Color and detail sensitive

Rods

• 120 million
• Responsible for peripheral vision
• Allow eyes to adapt to low levels of light; high sensitivity to dim lighting
• Not color or detail sensitive

Question 25

What are bipolar cells?

Answer 25

Bipolar cells receive information from photoreceptors and transmit them to the ganglion cells which form the optic nerve.

Question 26

What are optic nerve cells?

Answer 26

Optic nerve: carries neural impulses from the eye to the brain

Question 27

What is a blind spot?

Answer 27

Blind spot is the point where optic nerve leaves the eye, because there are no receptor cells located here, it creates a blind spot

Question 28

What is a Fovea?

Answer 28

Fovea is the central point in the retina, around which the eye’s cones cluster.

Question 29

Describe the process of visual processing?

Answer 29

At the optic chiasm, information crosses and left eye information is sent to right brain and vice versa. Optic nerves connect to the thalamus in the middle of the brain and the thalamus (switchboard of the brain directing sensory information with the exception of smell) to the visual cortex.

Question 30

What is trichromatic theory?

Answer 30

Trichromatic theory: theory of color vision that proposes three types of cones: red, blue, and green. Light of any color can be matched by the additive mixture of these three primary colors, Most known facts about color blindness are explained well through this theory. Trichromatic is good with explaining how cones work.

Question 31

What is opponet Process theory.

Answer 31

Opponent Process Theory: based on the idea that there are four primary colors: red, green, blue, yellow. If one member of the pair is stimulated, the other is inhibited. Explains why after image will be the compliment of the color originally stared at.

Question 32

What is size constancy?

Answer 32

Size constancy: the tendency to interpret an object as always being the same actual size regardless of its distance ( size on retina gets smaller).

Question 33

What is shape constancy?

Answer 33

Shape constancy: the tendency to interpret the shape of an object as being constant, even when its shape changes on the retina; a gestalt type principle

Question 34

What is the figure ground principle?

Answer 34

Figure Ground gestalt type principle; tendency to perceive objects as existing on a background

Question 35

What is perpetual set?

Answer 35

Perceptual set Perceptual expectancy: the tendency to perceive things a certain way because previous experiences or expectations influence those perceptions

Question 36

What is the difference between top dowm and bottom up processing?

Answer 36

Top down processing: use of pre existing knowledge to organize individual features into a unified whole. Bottom up processing: the analysis of the smaller features to build up to a complete perception.

Question 37

What is Muller Lyer illusion?

Answer 37

Muller- Lyer illusion is the illusion of line length that is distorted by inward turning or outward turning corners on the ends of the lines, causing lines of equal length to appear to be different

Question 38

What are sound waves?

Answer 38

Sound waves are vibration of the molecules of the air surrounding us

Question 39

What are acoustical transduction?

Answer 39

Acoustical Transduction conversion of sound waves into neural impulses in the hair cells of the inner ear.

Question 40

What is pitch?

Answer 40

Pitch is determined by the wavelength or frequency (low, medium, high). Wavelength: distance from peak to peak of waves, Frequency: (Hz) cycles of waves per second
•Long wavelengths= low frequency low pitch
•Short wavelength= high frequency high pitch

Question 41

What is volume?

Answer 41

Volume (loudness) is determined by amplitude, Amplitude is the amount of energy in a wave which relates to perceived loudness, Measured in decibels

• High amplitude= loud sound; low amplitude= quiet sound
• Sound threshold of about 80-90 where prolonged exposure can lead to hearing loss

Question 42

What is timbre?

Answer 42

Timbre is determined by the purity or the complexity of the tone of the sound (richness).

Question 43

What is place thoery?

Answer 43

Place Theory suggests that different sound waves stimulate the basilar membrane at different specific places resulting in perceived pitch. Good with high pitch higher than 1000Hz

Question 44

What is frequency theory?

Answer 44

Frequency Theory states that the rate of nerve impulses traveling up the auditory nerve. Matches the frequency of a tone, thus enabling us to sense a pitch. Imagine you have a sound traveling at 100 Hz so the action potential is traveling at 100Hz down nerve. Good with low pitched less than 1000hz

Question 45

What is volley priniciple?

Answer 45

Volley principle is the theory of pitch that states that different frequencies cause the hair cells ( auditory neurons) to fire in a volley pattern, or take turns in firing. Good with moderate to high pitch between 40 Hz to about 4000 Hz.

Question 46

What are the parts of the ear?

Answer 46

The parts of the ear are the outer ear, inner ear, and middle ear.

Question 47

What is the outer ear?

Answer 47

The Outer ear consists of pinna that collects and funnels sounds. It includes the Eardrum which vibrates when sound hits it.

Question 48

What is the middle ear?

Answer 48

The Middle ear is the chamber between eardrum and cochlea containing three tiny bones (hammer, anvil, stirrup aka ossicular) chain that sends vibrations to the cochlea’s oval window.

Question 49

What is the inner ear?

Answer 49

The Inner Ear is the innermost part of the ear consists largely of the cochlea, a fluid filled, coiled shaped tunnel that contains receptors for hearing.

Question 50

How does sound travel through the ear?

Answer 50

As the oval window vibrates, it vibrates the fluid in the cochlea which transmits sound to the basilar membrane and Organ of Corti. This will cause the hair cells to move which will cause them to be excited and send off action potentials down their axons which form the auditory nerve and go to the brain. These messages can be ipsalateral or contralateral. Goes to auditory complex located in temporal cortex.

Question 51

What is conduction hearing impairment?

Answer 51

Conduction hearing impairment: sound vibrations cannot be passed from the eardrum to the cochlea. Caused by damage to the mechanical system that conducts sound waves to the cochlea. Ex: ear drum punctured or tiny bones broken

Question 52

What is nerve hearing impairment?

Answer 52

Nerve hearing Impairment problem lies in inner ear or in the auditory pathways and cortical areas of the brain, Caused by damage to cochlea’s hair cells or auditory nerve. Also called nerve deafness, Ex: disease, aging, over‐exposure to loud sounds

Question 53

What is hearing deficit?

Answer 53

Hearing deficit: older people tend to hear low frequencies well but suffer hearing loss for higher frequencies. This can be accommodated by increasing volume. Ex: playing the high frequency in the hallway to get the kids to class or the high frequency ringtone.

Question 54

What is the stimulus input of taste?

Answer 54

Chemicals are the stimulus input of taste, The gustatory receptors are clusters of cells responsible for the sense of taste. Mostly located on the tongue; not the bumps but located on the bumps which are called papillae.

Question 55

What is gusatry transduction?

Answer 55

Gustatory Transduction: conversion of food molecules into neural impulses

Question 56

What are the basic taste?

Answer 56

Five Basic Tastes:

• Sweet
• Sour
• Salty
• Bitter
• Umami: stimulated by glutamate found in MSG monosodium glutamate

Question 57

What is the Gustatory cortex?

Answer 57

Gustatory cortex insular lobe; parts of frontal, temporal, and parietal lobes folded over it

Question 58

Describe the process of smell?

Answer 58

• The olfactory cilia are the hair-like structure located in the upper portion of the nasal passages and are responsible for smell
• Chemicals bind to the olfactory cilia
• Olfactory transduction: conversion of chemical molecules in the air into neural impulses by the olfactory cilia
• Olfactory receptors send neural signals related to smell directly
• Olfactory bulb has projections to the limbic system but not the thalamus

Question 59

What are Olfactory cilia?

Answer 59

Olfactory Cilia are airflow through the mouth and up the trachea can get to cilia.

Question 60

What are the somesthetic senses?

Answer 60

Somesthetic Senses are body’s senses consisting of the skin sense, kinesthetic sense, and vestibular senses.

Question 61

What are the vestibular senses?

Answer 61

The Vestibular Sense is sense of movement, balance, and body position. Processed by vestibular organs in the inner ear, Otolith organs for sensing translations, Semicircular canals for sensing rotations.

Question 62

What are kinesthitic senses?

Answer 62

Sense of the location of body parts in relation to the ground and each other. Processed by proprioceptors in the skin, joints, muscles, and tendons