AP Psych 1.6 NEW

Sensation

The first step where body parts that detect light, sound, touch, taste, and smell pick up signals from the world. This step only detects the signal; it does not yet give it meaning.

Transduction

The change where a physical signal, like light or sound, is turned into an electric signal the head organ can use. Without this change, the head organ could not read signals from the world.

Perception

The step where the head organ organizes and gives meaning to signals it has picked up. This step turns raw signals into a clear picture of what is happening.

Absolute threshold

The smallest strength of a signal that a person can detect about half the time. If the signal is weaker than this level, it will usually go unnoticed.

Just-noticeable difference

The smallest change between two signals that a person can tell apart. If the change is smaller than this, the two signals will seem the same.

Sensory adaptation

A drop in how strongly a person notices a signal that stays the same over time. The body parts that detect signals get used to a steady signal and pay less attention to it.

Weber's Law

A rule that the smallest change a person can tell apart grows with the size of the starting signal. A small change is easy to notice in a quiet room, but hard to notice in a loud room.

Sensory interaction

The effect where one kind of signal changes how another kind is felt. For example, smell can change how food tastes, even though taste and smell use different body parts.

Synesthesia

A condition where a signal for one sense also triggers an experience in another sense. A person might see colors when hearing music, for example.

Retina

A thin layer at the back of the eye that turns light into electric signals. It holds the light-detecting units that start the seeing process.

Blind spot

A small place in the eye where the nerve leaves to go to the head organ. This place has no light-detecting units, so nothing can be seen from that exact place.

Lens

A clear, bendable part of the eye that focuses light onto the back layer. It changes shape to make near and far objects look sharp.

Accommodation

The change in shape of the eye's focusing part to make near or far objects look sharp. The focusing part gets thicker for near objects and thinner for far objects.

Nearsightedness

A seeing problem where close objects look clear but far objects look blurry. Light is focused in front of the back layer instead of right on it.

Farsightedness

A seeing problem where distant objects look clear but close objects look blurry. Light is focused behind the back layer instead of right on it.

Rods

Light-detecting units in the eye that work best in dim light. They help a person see in shades of gray and notice movement at the edges of sight.

Cones

Light-detecting units in the eye that work best in bright light. They help a person see colors and fine detail, especially in the middle of sight.

Ganglion cells

Units in the eye that collect signals from light-detecting units and send them onward. Their long fibers join together to form the nerve that goes to the head organ.

Light adaptation

The change where the eye gets used to bright surroundings after being in the dark. The pupil gets smaller, and the color units take over so glare feels less strong.

Dark adaptation

The change where the eye gets used to dim surroundings after being in bright surroundings. The pupil gets wider, and the dim-light units become more sensitive over about 20 to 30 minutes.

Trichromatic theory

An idea that seeing color starts with three kinds of color units in the eye. One kind responds most to red, one to green, and one to blue, and mixing their signals makes other colors.

Fovea

A tiny pit in the middle of the back layer of the eye with the most color units packed together. This pit gives the sharpest, clearest sight.

Photoreceptors

Units in the eye that turn light into electric signals for the head organ. They include the units for dim light and the units for color and detail.

Blue-short wavelengths of light

The color that comes from signals with a small length, about 450 nanometers. These signals are at the small end of the signals a person can see.

Green-medium wavelengths of light

The color that comes from signals with a middle length, about 500 nanometers. These signals sit between the small-length and long-length signals a person can see.

Red-long wavelengths of light

The color that comes from signals with a great length, about 650 to 700 nanometers. These signals are at the great-length end of the signals a person can see.

Opponent-process theory

An idea that color seeing works through pairs that work against each other. One pair is red against green, one is blue against yellow, and one is black against white.

Afterimages

Pictures that stay in sight for a short time after a person looks away from a strong image. They often show the opposite color because the color units get tired.

Ganglion cells (red/green, blue/yellow, black/white)

Units in the eye that are turned on by one color in a pair and turned off by the other color in that pair. There are three such pairs, and tiredness in one side can make the other side seem stronger.

Color vision deficiencies (Dichromatism, Monochromatism)

Problems with telling hues apart that happen when one kind of hue unit is missing or not working. In the most complete form, only shades of gray are picked up, with no hues at all.

Prosopagnosia (face blindness)

A problem where a person cannot recognize familiar people by looking at them, even though their eyes work normally. This problem is often linked to damage in a part of the head that handles recognizing people.

Blindsight

The ability to respond to visual signals without being aware of them. This can happen after damage to the visual part of the head, even though the person says they notice nothing.

Wavelength of sound = pitch

The length of a vibration that decides how high or low a tone seems. Shorter vibrations seem higher, while longer vibrations seem lower.

Amplitude of wave = loudness

The height of a vibration that decides how strong a tone seems. Taller vibrations seem stronger, while smaller vibrations seem weaker.

Place theory

An idea that how high or low a tone seems depends on which spot inside the ear's spiral tube vibrates most. High tones vibrate most near the start of the tube, while low tones vibrate most near the far end.

Frequency theory

An idea that how high or low a tone seems depends on how often nerve signals fire. The firing rate matches the vibration rate, and this works best for low tones.

Volley theory

An idea that groups of nerve units take turns firing to match a tone that is too fast for one unit alone. By firing in turns, the group can keep up with fast vibrations.

Sound localization

The skill of telling where a tone is coming from by comparing the two ears. The head organ uses small differences in timing and strength between the ears to judge direction.

Conduction deafness

A hearing loss caused by damage to the outer or middle ear that stops vibrations from reaching the inner ear. The problem is in how vibrations are carried, not in the nerve or inner ear itself.

Sensorineural deafness

A hearing loss caused by damage to the tiny hair units in the inner ear or to the nerve that carries hearing signals. This kind of loss is often lasting and cannot be fixed by making vibrations louder.

Chemical senses

The two ways of detecting molecules in the air and in food and drink. These ways let a person smell and taste, and they work by reacting to tiny particles.

Olfaction

The way of detecting smells through receptors in the nose. Signals go straight to the smell part of the head organ and to parts linked to feelings and memory.

Thalamus-smell is not processed here

Unlike other ways of detecting the world, nose signals skip the relay station in the middle of the head. They go straight to the scent part and to parts linked to feelings and memory.

Pheromones

Chemical signals released by one living thing that change the actions or body state of others of the same kind. These signals are picked up without conscious thought and can affect mating or alarm.

Gustation

The way of detecting tastes through receptors on the tongue and in the mouth. Signals from these receptors tell the head organ about sweet, sour, salty, bitter, and savory flavors.

Types of taste: sweet, sour, bitter, salty, umami, oleogustus

Six basic flavors a person can detect through receptors on the tongue. They include flavors from sugar, acids, sharp plant compounds, cooking crystals, savory foods, and fats.

Taste receptors (linked to sensitivity to taste)

Tiny detectors on the tongue that react to chemicals in food and drink. How many of these detectors a person has can change how strong flavors seem.

Supertasters, nontasters, medium tasters

People differ in how many tongue detectors they have and how strong flavors seem to them. Some people notice flavors very strongly, some notice them weakly, and most fall in between.

Chemical senses-sensory interaction

The effect where smell and flavor work together to create what a person experiences as flavor. Much of what seems like flavor actually comes from the nose, not just the tongue.

Touch

The way of feeling pressure, heat, cold, and pain through receptors in the skin. These receptors send signals that tell the head organ what is pressing on or harming the skin.

Hot = warm and cold receptor activation

A feeling of heat that can happen when both heat-detecting and chill-detecting detectors fire at the same time. The head organ reads this combined firing as heat, even though no single heat source is there.

Pain (body, brain)

An unpleasant feeling that starts with signals from hurt or harm and is built up in the head's thinking organ. Attention, feelings, and expectations can make this feeling stronger or weaker.

Gate control theory

An idea that a passage in the back cord can open or close to let hurt signals through to the head organ. Large-fiber signals, attention, and feelings can help close the passage and lower the hurt feeling.

Phantom limb sensation

A feeling that a missing arm or leg is still there, sometimes with itching or hurt. This happens because the head organ's map of the body still includes the missing part.

Vestibular sense

The way of knowing balance and which way the head is turned or tilted. Receptors in the inner ear send signals that help a person stay steady and know their position.

Semicircular canals

Three fluid-filled tubes in the inner ear that detect turning movements of the head. When the head turns, fluid moves inside these tubes and signals the turn.

Kinesthesis

The way of knowing where body parts are and how they are moving, without looking at them. Receptors in muscles, tendons, and joints send signals about position and movement.