AP Psychology Topic 1.6 - Sensation

Absolute threshold

The minimum amount of stimulus energy needed for a person to detect a stimulus 50% of the time.

Difference threshold

The smallest difference between two stimuli that a person can detect.

Just Noticeable Difference

The smallest difference between two stimuli that a person can detect, also known as the difference threshold.

Sensation

The process of detecting physical energy from the environment and converting it into neural signals.

Sensory adaptation

The process where sensitivity to an unchanging stimulus decreases over time.

Sensory interactions

The way one sense can influence another sense, such as the smell affecting taste.

Signal detection theory

A theory that predicts how and when we detect the presence of a faint stimulus amidst background noise.

Synesthesia

A condition where one sense is simultaneously perceived as if by one or more additional senses, like tasting colors.

Transduction

The conversion of physical energy into neural signals that can be interpreted by the brain.

Weber’s Law

A principle stating that the difference threshold is a constant fraction of the original stimulus intensity.

Accommodation

The process by which the eye adjusts its focus by changing the shape of the lens.

Afterimage

A visual illusion that occurs when a person looks at an image for a long time and then looks away, creating a seemingly residual image.

Blind spot

An area in the visual field that cannot be seen due to lack of photoreceptors in the optic disc.

Blindsight

A phenomenon where individuals with damage to the visual cortex can respond to visual stimuli without consciously perceiving it.

Color blindness

A condition where a person is unable to distinguish certain colors, often due to missing cone receptors in the eyes.

Cones

Photoreceptor cells in the retina responsible for color vision and seeing in bright light.

Dark adaptation

The process by which the eyes become more sensitive to low levels of light in darkness.

Dichromatism

A type of color blindness where a person can only see two primary colors instead of three

Farsightedness

A vision condition where distant objects are seen clearly, but close objects appear blurry, due to the eye's shape.

Fovea

The central part of the retina that provides the clearest vision and is responsible for sharp central vision.

Hue

The aspect of color that is determined by the wavelength of the light being perceived.

Intensity

The amount of energy in a light or sound wave, perceived as brightness or loudness.

Monochromatism

A rare condition where a person only sees in shades of one color, often associated with a lack of cone receptors.

Nearsightedness

A vision condition where close objects are seen clearly, but distant objects appear blurry, due to the eye's shape.

Opponent-process theory

A theory of color vision that suggests color perception is controlled by opposing pairs: red-green, blue-yellow, and black-white.

Optic chiasm

The point in the brain where the optic nerves from each eye cross and project information to the opposite side of the brain.

Optic Nerve

The nerve that transmits visual information from the retina to the brain.

Photoreceptor

Specialized cells in the retina (rods and cones) that convert light into neural signals.

Prosopagnosia

A neurological condition characterized by the inability to recognize faces, even familiar ones.

Retina

The light-sensitive layer at the back of the eye that contains photoreceptors.

Rods

Photoreceptor cells in the retina that are sensitive to low light levels and do not detect color.

Trichromatic theory

A theory of color vision that proposes three types of cones in the retina, each sensitive to red, green, and blue light.

Wavelength

The distance between successive peaks of a wave, which determines the color perceived in light.

Amplitude

The height of a wave, which influences the perceived loudness of sound.

Audition

The sense of hearing.

Conduction deafness

Hearing loss due to problems with the structures of the ear that conduct sound waves.

Frequency

The number of waves that pass a point in a second, determining the pitch of a sound.

Frequency Theory

A theory suggesting that the rate of nerve impulses traveling up the auditory nerve matches the frequency of a tone, aiding pitch perception.

Nerve Deafness

Hearing loss caused by damage to the inner ear or the auditory nerve.

Pitch

The perceived frequency of a sound, which determines how high or low it sounds.

Place Theory

A theory that explains pitch perception based on the location of stimulation along the cochlea.

Sensorineural deafness

Hearing loss resulting from damage to the inner ear or auditory nerve.

Sound localization

The ability to determine the origin of a sound in the environment.

Volley theory

A theory that explains how groups of neurons can fire in succession to encode high frequencies of sound.

Bitter

One of the five basic tastes, often associated with toxic substances.

Chemical sense

The senses of taste and smell that respond to chemical stimuli.

Gustation

The sense of taste, primarily involving taste buds on the tongue.

Medium taster

A person who can perceive certain tastes at a standard level of intensity.

Nontaster

A person who has a reduced ability to taste certain flavors.

Oleogustus

A proposed taste modality for the flavor of fat.

Olfaction

The sense of smell, which detects airborne chemicals.

Pheromone

A chemical substance produced and released into the environment by an animal to affect the behavior or physiology of others of its species.

Salty

One of the five primary tastes, typically from sodium ions.

Sour

One of the five primary tastes, often linked to acidity.

Supertaster

A person who experiences taste sensations more intensely than the average person.

Sweet

One of the five primary tastes, associated with sugars and certain other substances

Umami

A savory taste, often associated with monosodium glutamate (MSG) and protein-rich foods.

Gate-control theory of pain

A theory suggesting that non-painful input can close the nerve gates to painful input, thereby reducing the perception of pain.

Kinesthesis

The sense that provides feedback about body position and movement through sensors in muscles and joints.

Kinesthetic Sense

Another term for kinesthesis; the awareness of body position in space.

Phantom Limb Pain

The sensation of pain that feels like it's coming from a limb that has been amputated.

Vestibular Sense

The sense that provides information about balance and spatial orientation through structures in the inner ear.