Psych GRE: Sensation and Perception

Absolute threshold

the amount of stimulus energy needed for a person to say that they perceive it

Difference threshold

the amount of stimulus energy that needs to be added to or subtracted from a stimulus for a person to say that they notice a difference

JND

one JND (just noticeable difference) needs to be added or subtracted from a stimulus for a person to say that they notice the difference

Weber's law

what's important in producing a JND is not the absolute difference between the two stimuli, but the ratio of them

Response bias

measures how risky the subject is in sensory decision making; based upon nonsensory factors

Sensitivity

measures how well the subject can sense the stimulus

ROC curve

used to graphically summarize a subject's responses in a signal detection experiment

Inattentional blindness

failure to notice something that is completely visible because of a lack of attention

Attention

a process in which consciousness is focused on particular stimuli

Selective attention

ability to focus on one stimulus while excluding other stimuli that are present

Divided attention

ability to respond to more than one stimulus

Perceptual organization

the process by which the elements of visual and other sensory information are structured into a coherent whole

according to traditional Gestalt psychology, the parts of a group are organized to form whole figures that constitute more than the parts separately

Simple cells respond to information about..

orientation

Complex cells respond to information about..

movement

Hypercomplex cells respond to information about..

shape

What is the difference between sensation and perception?

Sensation: what happens when our sensory modalities (vision, hearing, taste, etc.) are activated

Perception: how we understand these senses

What are the three stages of sensation?

1. reception

2. transduction

3. transmission through neural pathways to the brain

Stimuli from the outside world are converted into neural impulses to be processed by our brains through what process?

transduction

What two processes stop you from feeling your shirt press against the hairs on your arms all day?

1. sensory adaptation: when the hairs on our arms are constantly being pressed, we simply stop responding to the feeling of pressure

2. sensory habituation: the pressure on our hairs stops being novel, so there is no reason for us to continue paying attention to it

If you are zoning out in class and your teacher suddenly uses a swear word, you will snap back to attention. What is the phenomenon called that is responsible for this?

The cocktail party phenomenon/effect involuntarily focuses out attention on something salient, like hearing our name in a roomful of people, or hearing a teacher curse

What are the "energy senses" and why are they called that?

vision, audition (hearing), touch

These senses convert stimuli into energy, like light, sound waves, and pressure

What are the "chemical senses" and why are they called that?

taste (gustation), smell (olfaction)

These senses take stimuli and convert them into chemical signals to be processed

What is a human's dominant sense?

vision

What are the factors in seeing a bright light or a blue sky vs a black jacket?

Light intensity will affect how bright an object appears, and color or hue is affected by the light wavelength in the visual color spectrum and object reflects.

Objects that appear black actually absorb all colors, while objects that are white reflect all light wavelengths. The blue sky absorbs all colors but blue, which it reflects.

Illumination

An objective measure of the amount of light falling on a surface

Brightness

the subjective impression of the intensity of a stimulus

Dark adaptation

caused by the regeneration of rhodopsin, the photopigment in the rods

lateral inhibition

adjacent retinal cells inhibit one another; sharpens and highlights borders between light and ark areas

cornea

the cornea is the protective covering of the eye, where light first enters and is focused

pupil

the black part in the middle of the eye, the pupil acts like the shutter of a camera, and is controlled by the iris

iris

the iris is the colored disc surrounding the pupil that changes its dilation, allowing more or less light in

lens

the lens focuses light entering through the pupil (called accommodation), then flips and inverts the image and projects it onto the retina

retina

the upside-down and inverted image is projected onto the retina, where neurons are activated to interpret the image via transduction

the retina has several layers of cells involved in transduction

What are the parts of the retina?

-rods and cones

-fovea

-ganglion cells

-blind spot

When the sun sets and everything in the dark around you looks blush, are your rods or your cones activated?

Rods are activated.

Rods react to light, rather than color, with the exception of blue, which explains why we can only see shades of blue in the dark.

Cones are activated by other colors.

fovea

The fovea is an indentation in the retina. It is the eye's fixation point, or the part of the eye used when attending to detail.

Why do we have a "blind spot"?

the area where the optic nerve leaves the retina has not photoreceptors (rods or cones)

The optic nerve is comprised of axons from what?

ganglion cells

What is the lateral geniculate nucleus (LGN)?

it is the visual part of the thalamus that receives information from the optic nerve

Information from the left side of the retinas go to the left side of the brain, and information from the right side of the retinas go to the right side of the brain.

Where does the information get routed to each side?

optic chiasm

Since the optic chiasm, where this information intersects, is shaped like an X, an easy way to remember this is to remember that "chi" is the letter X in Greek.

After visual impulses are processed in the thalamus, where do they end up?

vision is ultimately processed by the occipital lobe

There are five feature detectors in vision, labeled V1 through V5. Who won the Nobel Prize for their discovery?

David Hubel and Torsten Wiesel

In the context of vision, what does each of the five feature detectors do?

V1 - mental image formation and imagination

V2 - illusory contours

V3 - location

V4 - color analysis and pattern recognition

V5 - motion and direction

What is the trichromatic theory?

It is the theory that the cones in our retinas perceive blue, green, and red, and are activated in combination to create a perception of all the colors in the visual spectrum.

When you look at the sun for a while and then look away, why is there a dark spot in you vision for a period of time?

This is called an afterimage.

Afterimages of red are green, and afterimages of blue are yellow and vice versa. The opponent-process theory states that when you look at something of one color, you inhibit its color pair, which you see when you look away.

Why would the opponent-process theory help explain color blindness?

The opponent process theory hypothesizes that the retina has its sensory receptors arranged in color pairs, and if a person is missing a specific pair, they will be unable to perceive either of those colors.

What characteristics of a sound wave determine what we actually hear?

The amplitude of a soundwave determines the loudness of a sound (decibels).

The frequency of a soundwave determines the pitch of a sound (hertz).

pinna

The pinna is the flap of skin outside the ear that helps capture and focus sound

eardrum

the eardrum or tympanic membrane concentrates sound energy, vibrating when sound from the ear canal hits it

ossicles

Ossicles are three tiny bones in the middle ear that connect the eardrum to the oval window

1. hammer (malleus)

2. anvil (incus)

3. stirrup (stapes)

The visual pathway that tells us what we are looking at is called the..

ventral stream

Which of the following are two competing theories of color vision that describe events that take place at different levels of the nervous system?

trichromatic vs opponent-process

Albert recently noticed that he has difficulty hearing people at crowded parties even though his hearing seems fine in quiet surroundings. He most likely has damage to his..

hair cells

Which of the following best states the major shortcomings of the place and the frequency matching (volley) theories of audition?

Place theory does not explain the coding of very low frequencies, whereas frequency-matching theory does not explain the coding of very high frequencies.

If adjacent lights flash on and off in sequence, individuals will often perceive apparent motion even though there is no motion. This experience is referred to as what?

the phi phenomenon

The full Moon looks much larger when it is on the horizon than when it is high in the sky. Which of the following is the best explanation for this phenomenon?

Size judgment is based on visual cues between the viewer and the image of the Moon

A security screener is an airport checks by hand everything that seems suspicious. It is critical that she never let any potentially dangerous item through her security checkpoint. In terms of signal detection theory, this screener is likely to make..

a larger number of hits and a large number of false alarms

Melvin has a set of Von Frey hairs of different diameters. He starts by pressing a thin hair against a participant's toe and continues with increasingly thicker hairs until the participant feels pressure. Melvin then starts with a thick hair and uses increasingly thinner hairs until the participant does not feel pressure. Melvin is using the method of..

limits

oval window

compresses the fluid in the cochlea and connects the middle ear to the inner ear

cochlea

fluid filled, small, and coiled, like a snail's shell, and converts vibrational activity into neural energy

organ of Corti

The part within the cochlea that actually converts soundwaves into neural energy. The hair cells attached to the basilar membrane on the cochlea move in response to the compression of fluid, which causes transduction in the organ of Corti, sending neural information to the brain.

What is place theory?

This theory believes that pitch processing is activated spatially on receptors in the cochlea, the same way that a piano's notes are arranged spatially.

A higher pitch would move hair cell on a certain part of the cochlea that a lower pitch would not.

What is frequency theory?

This theory (or volley theory) says that we hear different pitches because of the frequency at which the hair cells in the cochlea fire.

When you go to a loud concert and stand by the speakers, what kind of deafness are you causing for yourself?

nerve deafness

Loud noises damage the hair cells on the cochlea, preventing them from firing for any sounds at all, so no neural impulses reach the brain.

What kind of deafness is caused when one of the mechanisms used to move sound from the outer ear to the cochlea is damaged?

conduction deafness

What sensory modality responds to pressure or temperature?

touch

If you stub your toe, then fall down and break your wrist, which one will you feel more, and what theory predicts this?

You will feel your broken wrist more than your stubbed toe, which is predicted by the "gate-control" theory.

This theory hypothesizes that pain messages are prioritized and the high-priority messages will be delivered first, while the low-priority messages will be shut out, like a swinging gate.

Pain killers also help close the gate, as will natural endorphins in the brain.

What are papillae?

the bumps on your tongue that hold taste buds

What are the five different tastes we perceive?

1. salty

2. sweet

3. bitter

4. sour

5. umami (savory or meaty tastes)

What is another word for "taste"?

gustation

What makes smell different from the other senses? Why do certain smells trigger memories?

It is not processed through the thalamus.

Instead, nerves of the olfactory bulb connect with the amygdala and hippocampus, which are attached to memory and emotional response.

What sense is responsible for motion sickness on a roller coaster?

The vestibular sense responds to your body's orientation in space. There are canals in your ear that are filled with fluid, and the position of that fluid tells your brain where you are. If you are on a bumpy, looping roller coaster, your vestibular sense may be confused, causing nausea and dizziness.

What is the kinesthetic sense in charge of?

This keeps track of specific body parts and where they are in space, using receptors in joints and muscles.

What is the absolute threshold?

It is the smallest stimulus consciously perceptible at least 50% of the times encountered.

Stimuli below this are considered subliminal.

If your parents ask you to turn down the tv, what determines how much you have to turn it down before they notice a change in volume?

The difference threshold (or just-noticeable difference) is the amount a stimulus needs to change before the change can be detected. For hearing, the change must be 5%.

What is the Weber-Fechner law?

It asserts that the amount of stimulus change needed to perceive a difference is proportional to the intensity of the existing stimulus.

If there is one candle in a room and another candle is added, you will notice a difference in brightness. However, if there are 17 candles one birthday cake, an 18th candle will likely not be noticeable.

What theory takes into account the things that distract us from perceiving a stimulus?

Signal detection theory acknowledges the motivation to perceive a certain stimulus, like smelling delicious food when we're hungry, or not noticing a friend in a crowded room.

What is top-down processing?

This process uses information we already have in our brains to fill in gaps in the things we sense. It can frequently overrule the more primitive areas of our brains.

Building a perception of an object by mentally compiling all of its features is called what?

bottom-up processing or feature analysis

This is slower than top-down processing, but is more thorough and less prone to mistakes.

What are the four Gestalt rules of perception?

1. proximity

2. continuity

3. similarity

4. closure

proximity

items close together are easy to perceive as being part of the same group

continuity

items that form a continuous pattern are easier for the mind to see as part of the same group

similarity

items that look alike are more likely to be seen as being in the same group

closure

items that form a known image are easier to group together, even if there are some gaps within the image

While objects frequently remain the same, the way we view them does not. What allows us to still recognize an item despite the changes in how we see it?

Constancy allows this to happen. There are 3 types of constancy:

1. size constancy

2. shape constancy

3. brightness (or color) constancy

What prevents us from thinking an object is actually changing in size as we walk toward it?

Size constancy helps take distance into account when calculating the size of an object.

What allows us to see different properties of an object form different angles but know it is still the same object?

Though an understanding of the object has to exist to begin with, the principle of shape constancy allows our brains to recognize that, even if we see a piano from behind instead of looking at its keys, it is still a piano.

brightness constancy (or color constancy)

allows use to know that the color of an object does not change, even though the light hitting it does change

Eleanor Gibson terrified babies by pioneering what experiment? What does this experiment measure?

She pioneered the visual cliff experiment, which measures depth perception in babies.

A baby is placed on one end of a table and tries to cross to the other side. However, the middle of the table appears hollow, like a cliff, and babies who refuse to cross the cliff can perceive depth.

binocular cues vs monocular cues

binocular cues are used to perceived depth, and require use of both eyes, while monocular cues only require use of one eye

Two pins are placed so close to each other on a subject's finger that they are perceived as a single point. This is because the pins have not reached the

two-point threshold

In touch perception, the two-point threshold refers to the amount of distance between two pins necessary for each to be perceived as a distinct sensation.

When extremely excited, Marsha has a harder time throwing darts than when she is mildly excited. This behavior is consistent with which of the following?

The Yerkes-Dodson law

This law centers around performance and arousal. The main thing to remember regarding it is that individuals tend to perform best with a moderate level of arousal.

Too much or too little arousal results in poorer performance.

The appearance of afterimages of different colors than the original stimulus is used as support for

opponent process theory

Edward Hering's opponent process theory for color vision posits that color is perceived through the action of three opponent processes, one for red-green, one for blue-yellow, and one for black-white.

Afterimages (also known as the McCollough effect) that appear after staring at a color for a long time provide support for the opponent process theory.

Fechner

quantified Weber's statement of the relationship between stimulus and sensation

Watson said that the goal of behaviorism is to predict the response if the stimulus is known and to predict the stimulus is the response is known.

Which of the following are used by Watson to study behavior?

-simple observation

-conditioned reflex studies

-instrumental control studies

-verbal reports on visceral reactions

"I see a bear, my heart starts racing, I start trembling, and I begin to run. From these bodily responses, I understand that I am afraid."

This understanding of emotion is consistent with

the James-Lange theory

This theory states that emotional attributions are based on physiological sensations.

According to Helmholtz and Young, the neural basis for pitch perception is

the location on the basilar membrane that vibrates

These people should be associated with the place theory of pitch perception. This theory contrasted with the frequency theory of pitch perception.

Place theory holds that the location on the basilar membrane that vibrates determines the perceived pitch.

Frequency theory holds that the frequency at which the basilar membrane vibrates as a whole determines perceived pitch.

Which statement best summarizes current views on feature detectors in the auditory and visual systems?

feature detectors have been clearly demonstrated in both modalities

Afferent pathways are involved in which of the following sensory systems?

-visual

-tactile

-kinesthetic

-auditory

-olfactory

Afferent pathways ascend to the brain, and consequently are closely connected to any sensory system.

Efferent pathways exit the brain and are more involved in motor skills and funcitoning.

Two-point discrimination is assessed in the study of

cutaneous sensitivity

This refers to the ability to perceive two tactile points as distinct from each other. It is associated with cutaneous sensitivity and touch perception.