AP Psychology - Unit 3

Sensation

The process by which we receive physical energy from the environment and encode it into neural signals.

Perception

The process of organizing and interpreting sensory information, enabling us to recognize meaningful objects and events.

Bottom-Up Processing

Information processing that starts by noticing individual elements and then zooms out to appreciate the whole picture.

Top-Down Processing

Information processing guided by our thoughts or higher-level mental processes - we move from the general concept to the specific example.

Process of Sensation

Reception, transduction, transmission

Reception (Step 1)

Stimulation of sensory receptor cells by energy (sound, light, heat)

Transduction (Step 2)

Transforming this cell stimulation into neural impulses

Transmission (Step 3)

Delivering this neural information to the brain to be processed

Absolute Threshold

The minimum level of stimulus intensity needed to detect a stimulus half the time

Signal Detection Theory

Refers to whether or not we detect a stimulus, especially amidst background noise.

Subliminal

Below our threshold for being able to consciously detect a stimulus

Difference Threshold

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

Weber's Law

Refers to the principle that for two stimuli to be perceived as different, they must differ by a constant minimum percentage and not a constant amount (e.g. 1/100th of the weight, not 2 ounces).

Sensory Adaptation

diminished sensitivity as a consequence of constant stimulation

Perceptual Set

What we expect to see, which influences what we do see. Example of top-down processing .

Extrasensory Perception (ESP)

the controversial claim that perception can occur apart from sensory input; includes telepathy, clairvoyance, and precognition

Opponent-Process Theory

The theory that opposing retinal processes (red-green, yellow-blue, white-black) enable color vision.

After-image effect

Staring at a yellow, green, and black flag and when looking away, you see red, white, and blue

Accommodation

the process by which the eye's lens changes shape to focus near or far objects on the retina

Cornea

outer covering of eye

Iris

colored part of eye that contracts/expands to let in more/less light

Lens

bends to allow light can be focused on central point retina

Pupil

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

Retina

the light-sensitive inner surface of the eye that contains the receptor rods and cones plus layers of neurons that begin the processing of transduction for vision.

Rods

retinal receptors that detect black, white, and shades of gray that are necessary for peripheral and twilight vision when cones don't respond. The human eye has around 120 million rods.

Cones

retinal receptors that are concentrated near the center of the retina that detect colors and details and that function in the daylight or in well-lit conditions. The human eye has around 6 million cones.

Fovea

the central focal point in the retina, around which the eye's cones cluster

Bipolar Cells

specialized neurons that connect the rods and cones w/the ganglion cells

Ganglion Cells

specialized neurons that connect to the bipolar cells. The bundled axons of the ganglion cells form the optic nerve.

Optic Nerve

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

Blind Spot

the point at which the optic nerve leaves the eye, creating a "blind' spot because there are no receptor cells located there.

Process of Transduction

Visual transduction is the process in the eye whereby absorption of light in the retina is translated into electrical signals that ultimately reach the brain

Transduction (Step 1)

1. Lights enters and hits retina which triggers photochemical reaction in rods and cones at back of retina

Transduction (Step 2)

2. Chemical reaction in turn activates bipolar cells

Transduction (Step 3)

Bipolar cells activate ganglion cells which form the optic nerve and that transforms to visual cortex in brain

What cells are mainly in center of retina?

Cones

Order of Visual Transduction

Cornea -> Iris Expands -> Hits Pupil -> Fovea -> Bipolar Cells -> Ganglion Cells -> Optic Nerve -> Thalamus -> Occipital Lobe

Visual Information Processing

Once neural signals enter the optic nerve, they are sent through the thalamus to the visual cortex.

Turning Neural Signals into Images

Some ganglion cells in the eye send signals directly to the visual cortex in response to certain features such as visual patterns, certain edges, lines, or movements.

Parallel Processing

the brain's natural mode of information processing many things at once, such as color, motion, form, and depth.

Visual Processing

scene -> retinal processing -> feature detection -> parallel processing -> recognition

Frequency

the number of complete wavelengths that pass a point in a given time and determines pitch - corresponds to our perception of pitch

Pitch

a tone's highness or lowness. The shorter the waves, the higher the pitch; the longer the waves, the lower the pitch.

Amplitude

the strength of a wave. This is measured from peak to trough. The taller the wave, the louder the sound; the shorter the wave, the softer the sound.

Timbre

the sound of a tone. It allows you to distinguish between two similar sounds - complexity corresponds to this perception...

Young-Helmholtz Trichromatic Theory

According to this theory, there are three types of color receptor cones--red, green, and blue. All the colors we perceive are created by light waves stimulating combinations of these cones.

Color Blindness

People missing red cones or green cones have trouble differentiating red from green

Figure-Ground Perception

the perception of figures against a background

Gestalt

a meaningful pattern/configuration, forming a "whole" that is more than the sum of its parts.

What are three of the ways we group visual information into wholes?

Proximity, continuity, and closure.

Depth Perception

The ability to see objects in three dimensions although the images that strike the retina are two-dimensional; allows us to judge distance.

Retinal disparity (binocular cue)

Each eye sees a slightly different image because they are about 6 cm apart (on average). Your brain puts the two images it receives together into a single three-dimensional image

Convergence (binocular cue)

When looking at a close-up object, your eyes angle inwards towards each other (you become slightly cross-eyed). The extra effort used by the muscles on the outside of each eye gives a clue to the brain about how far away the object is. If you hold your finger 20 cm in front of your eyes, your muscles need to work a lot harder than when your finger is 50 cm away.

Interposition (monocular)

The partial blocking of one object by another object, leaving the viewer with the perspective that the blocking object is closer.

Monocular Cue

(depth perception that requires only ONE eye; more limited but still possible) that help use judge distance

Linear Perspective (monocular)

Parallel lines appear to converge at a vanishing point on the horizon. The closer the lines are, the greater the distance

Relative Size (monocular)

If two objects are roughly the same size, the object that looks the largest will be judged as being the closest to the observer.

Relative Height (monocular)

We perceive objects higher in our field of vision as farther away.

RELATIVE CLARITY (monocular)

Clear objects appear closer than blurry or fuzzy objects. The further something is from us, the less detail it conveys.

LIGHT AND SHADOW (monocular)

Nearby objects reflect more light to our eyes than distant ones. If there are two identical objects, the dimmer one seems farther away. Shading (shadows) also produces a sense of depth because our brains assume that light comes from above.

TEXTURE GRADIENT (monocular)

When you're looking at an object that extends into the distance, such as a grassy field, the texture becomes less and less apparent the farther it goes into the distance. As you look out over a scene, the objects in the foreground have a much more apparent texture.

MOTION PARALLAX (monocular)

Objects closer to use appear to move faster than those farther away. When you're riding in a car, for example, the nearby telephone poles rush by much faster than the trees in the distance. This visual clue allows you to perceive the fast moving objects in the foreground as closer than the slower moving objects off in the distance.

What helps produce a sense of depth?

SHADING - SHADOWS

Perceptual constancy

Our ability and need to perceive objects as unchanging even as changes may occur in distance, point of view, and illumination. Our brain makes adjustments and interpretations without our awareness to perceive the objects as the same, because otherwise our world view would not make sense.

Color Constancy

perception that the color of an object remains the same even if lighting conditions change

Size Constancy

tendency for the brain to perceive objects as the same apparent size regardless of their distance from us

Shape Constancy

when our viewing angle changes or an object rotates and we still perceive the object as staying the same shape; EXAMPLE: the doors to the right become more trapezoidal but we still perceive a rectangle

Lightness Constancy

when our perception of the whiteness, blackness, and grayness of objects remains constant no matter how much the illumination has changed (we see a constant proportion of lightness)

Stroboscopic Effect

the perception of motion produced by a rapid succession of slightly varying images

Phi phenomenon

an illusion created when two or more adjacent lights blink on and off in succession, creating the perception of movement (lighted signs, illusions)

Perceptual Adaptation

This refers to the ability of the body to adapt to an environment by filtering out distractions. For example, someone who lives near a train can perceptually adapt such that they can ignore the train whistle in order to sleep at night.

The ______ collects sound and funnels it to the eardum

Outer ear

What happens in the middle ear?

Sound waves hit the eardum and move the hammer to amplify the vibrations...then the vibrations go to cochlea.

What happens in inner ear?

Waves of fluid move from the oval window over the cochlea's "hair" receptor cells and they send signals through the auditory nerves to the temporal lobe of the brain.

Conduction Hearing Loss

hearing loss caused by damage to the mechanical system, such as the three bones, that conducts sound waves to the cochlea. A hearing aid may help amplify sounds for someone who has conduction hearing loss.

Sensorineural Hearing Loss

hearing loss caused by damage of the cochlea's receptor cells or to the auditory nerves. It is also called nerve deafness and hearing loss can be benefitted from cochlear implant.

What do hearing aids do?

Amplify sounds striking the eardrum, ideally amplifying only softer sounds or higher frequencies.

Loudness

more intense sound vibrations which causes a greater number of hair cells to send signals to the brain.

Softness

only activate certain hair cells

Place theory

links pitch we hear with the place where the cochlea's membrane is stimulated. This theory can explain how we high-pitched sounds, but now how we hear low-pitch sounds because the neural signals generated by low-pitched sounds are not so neatly localized on the basilar membrane.

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 its pitch.

Volley principle

Neural cells alternate firing. By firing in rapid succession, they can achieve a combined frequency.

Localization (Sound)

Sounds usually reach one of our ears sooner, and with more clarity, than they reach the other ear.
The brain uses this difference to generate a perception of the direction the sound was coming from.

Cochlear implant

a device for converting sounds into electrical signals and stimulating the auditory nerve through electrodes threaded into the cochlea.

What are the four different components of the sense of touch?

Cold, Warmth, Temperature, and Pain

Nociceptors

sensory receptors that detect hurtful temperatures, pressure, or chemicals.

Pain circuit

signals that travel to the spinal cord, up through small nerve fibers, which then conduct pain signals to the brain.

Gate-Control Theory

the theory that the spinal cord contains a neurological "gate" that blocks pain signals or allows them to pass on to the brain. The "gate" is opened by the activity of pain signals traveling up small nerve fibers and is closed by activity in larger fibers or by information coming from the brain.

Endorphins

the body's natural painkillers

Phantom Limb Sensation

feeling sensations or movement in limbs that have been removed

What are psychological influences on pain?

Distraction and culture and social contagion

Social contagion

We feel more pain if other people are experiencing pain. This occurs either out of empathy/mirroring, or a shared belief that an experience is painful.

Cultural influences

We may not pay attention as much to pain if we see a high level of pain endurance as the norm for our family, peer group, or culture.

What are the five basic senses?

Sweet, salty, sour, bitter, and umami (taste of meat)

Sensory interaction

the principle that one sense may influence another, as when the smell of food influences its taste.

Synaesthesia

when perception in one sense is triggered by a sensation in a DIFFERENT sense.

Humans have 350 different types of _______ allowing us to detect about 10,000 different odors.

Smell receptors

How does the sensations of smell take a shortcut to the brain?

By going through the thalamus

Kinesthesis

the system for sensing the position and movement of individual body parts.

Vestibular sense

the sense of body movements and position, including the sense of balance...Changes in head position move fluid within the vestibular canals of the inner ear to activate hair cells. Information is sent primarily to the cerebellum, the region of the brain that coordinates movement.