sensation? and perception

Sensation

Process which stimulated receptors like your eyes and ears create a pattern of neural messages that represent stimuli in our brain, giving rise to our initial experience of stimulus.

Transduction

The process of converting energy from the environment and changing it to a neural impulse for the brain to read.

Absolute threshold

Minimum amount of energy the sense organ can detect.

Just-noticeable difference

Smallest change in energy that the sense organ can detect, or the amount of change needed to tell that two things are different.

Sensory adaptation

Your sensitivity weakens as you become used to the stimulus, e.g., noticing a unique smell at a friend's house then not noticing it after a few seconds.

Weber's law

The change in a stimulus that is just noticeable in a constant ratio of the original stimulus.

Sensory interaction

One sense influences another, for example, smell influences taste.

Synesthesia

Condition where the stimulation of one sense generates a simultaneous sensation in another, e.g., colors being associated with sound.

Retina

Where sensory receptors for vision are contained; holds rods and cones.

Blind spot

A hole in the retina where the optic nerve leaves the eye to enter the brain.

Optic nerve

A bundle of nerve fibers that carries visual information from the retina to the brain.

Lens

The part of the eye that bends to focus incoming light.

Accommodation

Process where the eye lens changes shape to focus light on the retina.

Nearsightedness

Refractive error that makes far-away objects look blurry.

Farsightedness

Refractive error that makes near objects appear blurry.

Photoreceptors

Light-sensitive cells in the retina that convert light energy into neural energy.

Rods

Retinal receptors that detect black, white, and gray; sensitive to movement and necessary for peripheral vision.

Cones

Retinal receptors concentrated near the center of the retina, functioning in daylight or well-lit conditions, giving rise to color sensations.

Trichromatic theory

Theory of color that suggests the retina contains three types of color receptors sensitive to red, green, and blue.

Opponent-process theory

Theory that some color combinations, such as reddish-green or yellowish-blue, can never be seen.

Afterimages

Occurs when certain ganglion cells in the retina are activated while others are not.

Ganglion cells

Projection neurons of the retina that convey information from other retinal neurons to the rest of the brain.

Dichromatism

A condition where a person is blind to red-green or yellow-blue.

Monochromatism

Total color blindness.

Prosopagnosia

Face blindness; inability to recognize familiar faces.

Blindsight

The ability to respond to visual stimuli even when there is no conscious awareness of the stimuli.

Wavelength

Distance between the peak of one light or sound wave to the peak of the next.

Pitch

A tone's experienced highness or lowness that depends on frequency.

Amplitude

Height of a wave or the physical strength of a wave, relating to volume.

Loudness

The perceived intensity of sound, related to amplitude.

Frequency theory

Theory that the perception of pitch depends on the rate at which the entire basilar membrane vibrates.

Sound localization

The ability to determine the location of a sound source due to the different arrival times of sound at each ear.

Conduction deafness

Inability to hear due to damage of the structures of the middle or inner ear.

Sensorineural deafness

Inability to hear due to a deficit in the body's ability to transmit impulses from the cochlea to the brain.

Olfactory system

The sense of smell, which interacts with receptor proteins associated with hairs in the nose.

Pheromones

Chemicals secreted by an individual that influence social and sexual behaviors of others of the same species.

Gustation

The sense of taste, identified on a specialized region of the parietal lobe somatosensory cortex.

Taste receptors

Receptors in the mouth that detect different taste sensations, including umami, sweet, sour, bitter, and salty.

Supertasters

People whose sense of taste is greater in intensity than average.

Medium tasters

Individuals with an average ability to sense different flavors.

Nontasters

Individuals who have less taste perception than most.

Warm/cold receptors

Skin senses connected to the somatosensory cortex, responsible for detecting temperature.

Gate control theory

Theory that explains pain control by proposing that we have a neural 'gate' that can block incoming pain signals.

Nociceptors

Sensory receptors that respond to painful stimuli.

Phantom limb

Perceived sensation that occurs after the removal of a limb, where the individual believes the limb still exists.

Vestibular sense

The sense of body orientation and balance, linked to gravity, with receptors located in the inner ear.

Semicircular canals

Three fluid-filled bony channels in the inner ear that help provide information about orientation and balance.

Kinesthesis

The sense that provides constant sensory feedback about the position and movement of the body.

Proprioception

The perception or awareness of the position and movement of one's body.

Pitch perception

Ability to distinguish tones played at differing frequencies.

Place theory

Theory that pitch perception depends on the area of the basilar membrane that is vibrating.

Volley theory

Theory suggesting that groups of neurons respond to sound by firing action potentials slightly timed differently to encode greater frequencies of sound.