Sensation & Perception Vocab List

Sensation

The process by which our sensory receptors and nervous system receive and represent stimulus energies from our environment. 

Bottom-Up Processing

Information processing that begins with the sensory receptors and works up to the brain’s integration of sensory information. Detects lines, angles and colors that form the images. Ex ) reading a new book and figuring out what the words and sentences mean as you go.

Top-Down Processing

Information processing guided by higher-level mental processes, as when we construct perceptions drawing on our experience and expectations. Our brains organize and interpret information to use as context. Ex ) ability to make sense of misspellings when texting.

Prosopagnosia

Also known as “facial blindness”. Cognitive disorder of face perception where the ability to recognize faces is impaired. Ex ) a patient couldn’t recognize his wife from her face, but could by her voice.

Blindsight

A neurological condition where someone can perceive the location of an object, despite having damage to the visual cortex.

Transduction

Transforms energy into neural impulses the brain can interpret. ex) skunks molecules enter your nose which sends neural impulses that are interpreted by your brain as very unpleasant.

Absolute Threshold

The minimum stimulation necessary to detect a particular light, sound, pressure, taste or odor. ex) if i can hear a very high pitch sound but someone else cannot, then the sound is above my absolute threshold and below the other person’s absolute threshold.

Just Noticeable Difference

The smallest amount by which two sensory stimuli can differ for us to be able to tell them apart. While we can detect the differences between the two stimuli, we sometimes cannot determine the degree of difference. Ex ) the smallest difference in sound for us to perceive a change in the radio's volume.

Weber’s Law

The degree to which stimuli need to be different for the difference to be detected. The stimuli must differ by a constant proportion / percentage not a constant amount. Ex ) in car radio you can’t tell much difference between volume 20 & 25 but you can 5 & 10.

Sensory Adaptation

Diminished sensitivity as a consequence of constant stimulation. Ex ) you smell something bad in the classroom immediately and after staying for 30 minutes you no longer notice the smell.

Light’s Wavelength

The distance from one wave peak to the next, determines its hue we experience. Shorter = more blue, medium = more green, longer = more red

Light’s Wavelength Amplitude

Determines its intensity, the amount of energy the wave contains, intensity influences brightness.

Lens

Changes shape to help focus images on the retina.

Accommodation

To focus the rays, the lens changes its curvature and thickness.

Retina

A layer of tissue at the back of the eye. Cells capture visual information that is transduced to the brain for processing.

Fovea

The central point in the retina

Nearsightedness

If the lens focuses the image on a point in front of the retina, you can see near objects clearly but not distant objects.

Farsightedness

If the lens focuses the image on a point behind the retina, you see distant objects better than near objects.

Photoreceptors

Convert light into electrical signals that are sent to the visual nerve for brain processing.

Rods

Retinal photoreceptors that detect black, white and gray and are sensitive to movement. Concentrated on the sides.

Cones

Retinal photo receptors that detect color and are located in the fovea. Concentrated near the center of the retina.

Ganglion cells

Retinal neurons whose axons form the optic nerve, the last stop before visual info leaves the eye

Visual Nerve (Optic nerve)

Carries neural impulses from the eye to the brain.

Blind spot

Where the optic nerve leaves the eye there are no receptor cells.

Trichromatic Theory

Three types of cones : blue (short wavelength), green (medium wavelength) and red (long wavelength). Can make millions of combinations of colors.

Opponent-Process Theory

Sensory receptors come in pairs : red/green, blue/yellow, and black/white.

Afterimages

When certain ganglion cells in the retina are activated, while others are not.

Monochromats

Have total color blindness, their worlds look like black and white movies. Only have rods or one kind of cone that can’t do all the work.

Dichromats

Have trouble distinguishing red from green because they have just two kinds of cones.

Amplitude

The perceived loudness of the sound waves. The height of the wave.

Pitch

The length of the wave distinguishes the tone experience of high or low.

Cochlea

A snail shaped tube in the inner ear. The incoming vibrations cause it to vibrate, jostling the fluid that fills the tube.

Vestibular Sense

Located above the cochlea in the inner ear and is our sense of body movement and position enables our sense of balance. 

Semicircular Canals

Contains fluid and moves in response to the movements of your head. ex) when the fluid inside moves a lot you will be dizzy especially after spinning.

Conduction Deafness

Can be caused by damage to the eardrum or middle ear bones that conduct sound waves to the cochlea.

Sensorineural Deafness

Damage to the cochlea’s hair cells or the auditory nerve. 

Place Theory

Presumes that we hear different pitches because different sound waves trigger activity at different places along the cochlea’s basilar membrane. The brain determines a sound’s pitch by recognizing the specific place that is generating the neural signal. (high pitches).

Frequency Theory

Suggests the brain reads pitch by monitoring the speed of neural impulses traveling up the auditory nerve. The speed in which the neural signal moves. ex) a 100 Hz tone would be signaled by 100 impulses per second in the auditory nerve. Cannot fire more than 1000 per second. (low pitches).

Volley Theory

Like soldiers who alternate firing so that some can shoot while others reload, neural cells can alternate firing. By firing in rapid succession, they can achieve a combined frequency above 1000 waves per second. (medium pitches)

Localizing Sound

You can easily point to the sound when it comes from either side because the sound is more intense, but struggle when it comes directly ahead, behind, above, or below.

Skin Senses

Sensitive to pressure, warmth, cold and pain.

Kinesthesis

System for sensing the position and movement of individual body parts. Millions of position and motion sensory in your body provide constant feedback to your brain.

Gate-control Theory

The spinal cord contains a neurological gate that blocks pain signals or allows them to pass on to the brain.

Phantom Limbs

The brain can also create pain. When it lacks the normal sensory input from a missing limb, the brain may misinterpret and amplify spontaneous but irrelevant central nervous system activity.

Gustation

Our sense of taste.

Taste Sensations

Sweet, sour, bitter, salty, meaty (umami), and oleogustas (fat).

Supertasters

Have double the amount of taste buds than others, enabling them to experience more intense tastes.

Nontasters

Have less taste buds than others, so they experience less than average tastes

Olfactory Receptor

Respond selectively and instantly alter the brain through their axon fibers.

Pheromones

Secreted chemical substances outside of the body (urine, seat, semen, breast milk) by animals and humans that trigger a social and s3xual reaction.

Synesthesia

As we attempt to decipher our world, our brain blends inputs from multiple channels.

Sensory Interaction

Principle that one sense may influence another. 

Perception

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

Selective Attention

When you focus conscious awareness on a particular stimulus.

Cocktail-Party Effect

The ability to focus one;s listening attention on a single talker among a mixture of conversations and background noises, ignoring other conversations. ex) especially if you hear your name mentioned

Inattentional Blindness

Failing to see visible objects when our attention is directed elsewhere. ex) turning into a parking lot and only focusing on other cars, a driver fails to see a bicyclist riding down the sidewalk. The driver only hears a thud and first sees the bicyclist on the ground near her left front fender.

Change Blindness

Failing to notice changes in the environment.

Perceptual Set

Our experiences, assumptions, and expectations give us our _____ ___. ex) by a 6-1 margin, preschool children thought french fries tasted better when served in a mcdonalds bag rather than a plain white bag.

Gestalt Psychology

Focused on how we group objects together. We innately look at ways to integrate pieces of information into meaningful holes.

Figure Ground Relationship

The organization of the visual field into objects (the figures) that stand out from their surroundings (the ground). Ex ) words are the figure and paper is the ground.

Proximity

Group objects that are close together as being part of the same group.

Closure

Like top-down processing we fill gaps in if we can recognize it.

Similarity

Our minds naturally group similar things together, even if they are not physically together

Binocular Cues

Judging depth depends on the use of both eyes. Better for the distance of nearby objects.

Retinal Disparity

By comparing retinal images from the two eyes, the brain computes distance. The greater the disparity (difference) between the two images, the closer the object. Because our eyes are about 2.5 inches apart, our retinas receive slightly different images of the world.

Convergence

Uses both eyes to focus on the same object. As an object comes closer,our eyes have to come together to keep focused on the object. As the eye looks at an object further away, the eyes move further apart to focus^.

Monocular Cues

Using one eye to gauge distance. Give the illusion of depth on flat or two dimensional surfaces.

Linear Perspective

Parallel lines appear to meet in the distance.

Relative Clarity

Because more light passes through objects that are farther away, we perceive these objects as hazy, blurry or unclear. Nearby objects by contrast appear sharp and clear.

Texture Gradient

Moving toward or away from an object changes our perception of its smoothness or texture. When a wall is viewed from a distance, we will perceive it as smooth. Ex) Viewing the same wall up close will reveal greater texture and detail.

Interposition

If one object partially blocks our view of another, we perceive it as closer.

Relative Size

If we assume two objects are similar in size, most people perceive the one that casts the smaller retinal image as farther away.

Perceptual Constancy

Perceiving objects as unchanging (consistent color, brightness, shape, and size) despite the stimuli change that occur. Ex) when a door is unopened it looks like a rectangle, when you open it slightly it looks like a trapezoid.

Apparent Movement

An illusion of motion or change in size of a visual stimulus. Visual phenomenon that tricks the brain into seeing motion that isn’t there. Ex ) flip books