AP Psych - Unit 3

Sensation:

Sensory receptors receiving and representing stimuli from your environment. (OBJECTIVE)

Ex: Putting a pickle on your tongue gives everyone the same sensation.

Perception:

Organizing and interpreting sensory information; gives meaning to sensation. (SUBJECTIVE)

Ex: Everyone perceives the taste of a pickle on their tongue differently - good, bad, sour, etc.

Sensory Receptors:

Specialized nerve endings that respond to stimuli.

Bottom-Up Processing:

Starts at sensory receptors and works up to higher levels of processing.

Top-Down Processing:

Constructs perceptions from sensory input based on experience and expectations.

Selective Attention:

Focusing conscious awareness on a particular stimulus.

Cocktail Party Effect:

We only capture what we deem important; You can listen to one person and drown out everyone else in the room. But, if someone says your name, your mind brings that person into your conscious awareness (you have programmed yourself into deeming your name important).

Inattentional Blindness:

Failing to see visible objects when our attention is directed elsewhere.

What are the two forms of inattentional blindness?

Change blindness and choice blindness.

Change Blindness:

Failing to notice changes in the environment.

Choice Blindness:

People are blind to their own choices and preferences.

Change Deafness:

Failing to notice changes in sound/voices.

What do all of our senses do?

Receive, transform, and deliver sensory information.

Transduction:

Converting one form of energy into another.

- Sensory receptors transform stimulus energies (light, air, and vibrations) into neural impulses your brain can interpret.

Absolute Threshold:

The minimum stimulation needed to detect a particular stimulus 50% of the time. Edge of awareness.

Ex: Hearing tests in elementary school test for the lowest note that you can identify 50% of the time.

Difference Threshold:

The minimum difference between two stimuli required for detection 50% of the time.

AKA: Just noticeable difference (JND)

Weber’s Law:

Two stimuli must differ by a constant percentage (NOT amount).

Two lights= 8% - Two weights= 2% - Two noise frequencies= 0.3%

Signal Detection Theory:

Assumes that our stimulus detection DOESN’T depend on one single absolute threshold. Our detection depends on our experience, expectations, motivation, and alertness.

What does the Signal Detection Theory measure?

Rejections, misses, and false alarms.

What is an example of the Signal Detection Theory? (4 parts)

Hit: hear your cell phone and answer it

Miss: cell phone rings, but you don’t hear it

False Alarm: “hear” your phone ring, but when you go to answer it, you see that there was never a call

Correct Rejection: don’t hear your phone ring so you don’t check for a call

Subliminal Stimuli:

Stimuli so weak, that they are below our absolute threshold for conscious awareness. (they can still influence our behaviors)

Priming:

The activation (often unconsciously) of certain associations, thus predisposing someone’s perception, memory, or response.

(behaviors can be primed, but there is no evidence suggesting they can be persuaded to change)

Sensory Adaptation:

Diminished sensitivity as a consequence of constant stimulation to an unchanging stimulus.(sight is different because your eyes are constantly moving, so sight is always changing)

Ex: getting into a cold pool, you get used to the water after bit

Gestalt:

German for “whole”. Emphasizes the tendency to integrate pieces of information into meaningful wholes. Our brain filters incoming information and constructs perceptions of that.

Figure-Ground:

Organizing the visual field into objects (figures) that stand out from their surroundings (ground).

Grouping:

Organizing stimuli into coherent groups.

Proximity:

Grouping nearby figures together.

Continuity:

Perceiving smooth continuous patterns.

Closure:

Filling in the gaps to perceive complete, whole objects.

Depth Perception:

Ability to see three dimensional objects even though the images that strike our retinas are two dimensional.

Visual Cliff:

Experiments that have babies crawl out onto glass over a drop off most refused to do so, indicating they could perceive depth (danger- evolutionary).

Binocular Cues:

Depth cues that depend on both eyes.

Convergence:

Inward angle of the eyes focusing on a near object.

Retinal Disparity:

Eyes are 2.5 inches apart; retinas get slightly different images, so when comparing the 2, it allows your brain to judge how close an object is. (movie makers use this to make 3D movies)

Monocular Cues:

Depth cues available to either eye alone.

What are the two types of Binocular Cues?

Convergence and Retinal Disparity.

Motion Perception:

Shrinking objects are retreating; enlarging objects are approaching. (Large objects appear to move more slowly than smaller objects)

Stroboscopic Motion:

Brain perceives continuous motion in rapid series of slightly varying images. (movies flash 24 pictures per second).

Phi Phenomenon:

Movement illusion created when two or more adjacent lights blink on or off in quick succession.

Ex: strobe lights at haunted forest.

Restored Vision:

If the visual cortex is not stimulated early on in life, it will lack the experience it needs to interpret visual stimuli if vision is restored.

Sensory Resrictions:

There is a critical period for normal sensory and perceptual development which must be used early in life or it will be lost. (doesn’t seem to have permanent harm).

Perceptual Adaptation:

In vision, the ability to adjust to an artificially displaced or inverted visual field.

Ex: adjusting to different prescription glasses.

Perceptual Constancies:

Perceiving objects as unchanging even as illumination and retinal images change; Top-down process.

What are the 5 types of perceptual constancies?

Color, brightness, relative luminance, shape, and size.

Color Constancy:

Even if the lighting changes, we perceive colors as the same.

Brightness Constancy:

Even if the lumination changes, we perceive objects as having the same brightness.

Relative Luminance:

The amount of light an object reflects relative to its surroundings.

Shape Constancy:

Even if an object moves and our retinas see a different image, we perceive objects as the same shape.

Size Constancy:

Even if our distance from an object varies, we perceive it as the same size.

What determines the intensity of a light’s wave?

The amplitude or height. The greater the amplitude, the brighter the color. The smaller the amplitude, the duller the color.

Cornea:

The eye’s clear, protective outer layer covering the pupil and iris.

Pupil:

The adjustable opening in the center of the eye through which light enters.

Iris:

A ring of muscle tissue that forms the colored portion of the eye around the pupil and controls the size of the pupil opening.

Lens:

The transparent structure behind the pupil that changes shape to help focus images on the retina.

Retina:

The light-sensitive inner surface of the eye, contains rods and cones, plus layers of neurons that begin processing visual information.

Optic Nerve:

The nerve that carries neural impulses from the eye to the brain.

How does sight work? (step by step)

Light enters the eye through the cornea. The light hits the pupil, which adjusts in response to the light (the iris is actually made up of muscles that control the pupil opening). The light then goes through the lens, which helps the images focus on the retina. Then, the rods and cones in the retina turn the light into electrical impulses, which then go to the optic nerve. The optic nerve takes those messages to the brain’s occipital lobe.

What is a blind spot?

The area in the optical nerve that has no receptor cells. With no receptor cells there, the light cannot be turned into electrical impulses/sent to the occipital lobe, therefore, nothing can be seen through a blind spot.

Rods:

Periphery of retina, black/white, sensitive in dim light, and located outside/around the retina. 120 million.

Cones:

Center of retina, color/white/detail, unresponsive in dim light, and located in the fovea/center of ret. 6 million.

Young-Helmholtz-Trichromatic (three-color) Theory:

The retina contains 3 types of color receptors: some most sensitive to red, some to green, and some to blue. When stimulated in combination, they can produce perceptions of any color.

What makes someone color deficient?

They lack one of the three color receptors, thus they can’t perceive that color/colors requiring that receptor.

Afterimages:

Images you see after staring at an image for a long time.

Opponent-Process Theory:

There are three pairs of opponent colors: Green and Red, Blue and Yellow, White and Black. The brain can only process one color from these pairs at a time. A cell could activate when it sees green and deactivate when it sees red. So, once the brain gets used to staring at the green for awhile, it suppresses that signal. So when you look away, the afterimage is red because the cell activating the green got worn out.

Explain the two types of color processing:

Three color theory=There are 3 color receptors that combine wavelengths to make all of the different colors.

Opponent process theory= there are opponent colors that control color by using three different complexes with opposing actions.

What are the two stages of color processing?

Retina cones respond to different color stimuli.

Cone’s responses are processed by opponent process cells.

Prosopagnosia:

Face blindness; not being able to recognize yourself (photos/videos) or other’s faces.

Myopia:

Nearsightedness (can only see nearby objects)

Hyperopia:

Farsightedness (can only see far away objects)

Astigmatism:

A defect in the eye/lens caused by an imperfection in the curvature of the lens.

What are the parts of the outer ear?

Pinna and Auditory Canal

What are the parts of the middle ear?

Tympanic Membrane, Hammer/Anvil, and Stirrup

What are the parts of the inner ear?

Hair Cells, Organ of Corti, Basilar Membrane, Oval Window, and Cochlea

Pinna:

Collects sound waves and channels them into the ear canal.

Auditory Canal:

Helps amplify sound.

Tympanic Membrane:

Sound transmission and amplification.

Hammer/Anvil:

Magnifies the vibrations and relays that information to the inner ear.

Stirrup:

Conduction of sound vibrations to the inner ear.

Hair Cells:

Primary sensory receptor cells in the inner ear. Converts/transduces sound into electrical signals to get taken to the brain.

Organ of Corti:

Transduction of auditory signals from sound waves.

Basilar Membrane:

Supports hair cells, serves as a base layer of the Organ of Corti, and propagates sound vibrations to interpret sound.

Oval Window:

Membrane covered opening that covers the entrance to the cochlea. Leads to the movement of fluid in the cochlea and activation of receptors for hearing.

Cochlea:

Converts sound waves into electrical impulses that get sent to the brain.

What are the different parts of the cochlea?

Hair cells, the basilar membrane, and the auditory nerve.

What does the height/amplitude of sound waves indicate?

The loudness of the sound

What does the length/frequency of sound waves indicate?

The sound’s pitch.

What pitch does each wave produce?

Long wave= low pitch

Short wave= high pitch

How are sound waves measured?

In decibels. Every 10 decibels increase a tenfold in intensity.

What is the absolute threshold for hearing?

Zero (0) decibels.

Where do hair cell movements trigger impulses? Where does the thalamus send this information for recognition and interpretation?

In adjacent nerve cells, whose axons converge, making the auditory nerve. The auditory nerve takes the information to the thalamus, which then sends it to the auditory cortex in the temporal lobe.

Sensorineural hearing loss:

Damage to the hair cell receptors/auditory nerve. People hear sound but have trouble interpreting it. Causes: heredity, aging, prolonged exposure to loud noise, or rarely, disease damaged hair cells.

MORE COMMON type

Conduction hearing loss:

Damage to the mechanical system, eardrum and middle ear bones, that takes sound waves to the cochlea. Hard to hair soft sounds, and loud sounds are muffled.

Causes: clogged ear, hole in eardrum, ear infection, etc.

LESS COMMON type

For now, what is the only way that hearing can be restored? How does this process work?

Getting a Cochlear Implant (bionic ear). The implants translate sounds into electrical signals that (when wired to the cochlea’s nerves) conveys sound information to the brain.

Place Theory:

We hear different pitches because different sound waves trigger neural activity in different pace along the cochlea’s basilar membrane. The brain recognizes pitch by identifying the specific place on the membrane that is producing the signal.

ONLY WORKS for HIGH PITCH sounds because the signal is always closer to the beginning of the basilar membrane. But, low pitch sounds can be anywhere from the middle to the end of the basilar membrane, so it isn’t accurate enough to determine the pitch.

Frequency Theory (temporal):

The brain reads pitch by monitoring the frequency of neural impulses going up the auditory nerve. The basilar membrane vibrates at the same rate as the soundwaves, which triggers neural impulses to the brain at the same rate. Ex: 100 waves per second= 100 pulses per second up the auditory nerve. If exceeding 1000 pulses per second, neurons combine frequencies (volley principle).

Volley Principle:

If the frequency of a sound is over the limit of 1 neuron (1000 pulses per second), then neural cells can combine frequencies, shooting while others reload, to achieve the correct frequency of the sound.

Why is it better to hear with two ears rather than one?

So you can locate where sounds are coming from and quickly.

Why is the brain constantly being fooled by what is sees?

Because: we perceive the world not exactly as it is, but as it is useful for us to perceive it.

How does the brain use shadows to perceive the world?

We trust shadows to perceive an objects position and behavior in space.

Wha tis the difference between color and light?

Color is a construct of our brain, while light exists in the physical world.