Unit 1B AP Psychology Sensation and Perception

Sensation

Sensation

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

Absolute Threshold

The minimum stimulation needed to detect a particular stimulus 50% of the time.

Just-Noticeable Difference (JND)

The minimum difference a person can detect between two stimuli 50% of the time.

Weber's Law

States that the just noticeable difference (JND) between two stimuli is a constant proportion of the original stimulus, meaning that as the intensity of a stimulus increases, the noticeable difference also increases proportionally.

Sensory Adaptation

The diminished sensitivity to a stimulus as a result of constant exposure.

Sensory Interaction

The principle that one sense may influence another, such as how smell can affect taste.

Synesthesia

A condition in which one sense is simultaneously perceived as if by one or more additional senses, like seeing colors in response to sounds.

Wavelengths

The distance between successive peaks of waves, determining the hue of visual light.

Retina

The light-sensitive layer of tissue at the back of the eye that contains photoreceptors (rods and cones).

Blind Spot

The point where the optic nerve leaves the eye, creating a _______ as there are no receptor cells there.

Visual Nerve (Optic Nerve)

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

Lens

The transparent structure behind the pupil that changes shape to help focus images on the retina.

Accommodation

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

Nearsightedness

A condition where close objects are seen clearly, but distant objects appear blurry.

Farsightedness

A condition where distant objects are seen more clearly than close ones.

Fovea

The central focal point in the retina around which cones are concentrated.

Photoreceptors

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

Transduction

The process of converting one form of energy into another, such as light into neural signals.

Rods

Photoreceptors that detect black, white, and gray; necessary for peripheral and low-light vision.

Cones

Photoreceptors that function in daylight or in well-lit conditions; detect fine detail and color.

Trichromatic Theory

The theory that the retina contains three different color receptors (red, green, blue) which combine to produce the perception of color.

Opponent-Process Theory

Theory that opposing retinal processes (e.g., red-green, blue-yellow) enable color vision.

Afterimages

Visual impressions that persist after the removal of the stimulus that caused them.

Ganglion Cells

Cells in the retina that receive visual information from photoreceptors and transmit it to the brain.

Dichromatism

A type of color blindness where one of the three basic color mechanisms is absent or not functioning.

Monochromatism

Total color blindness, where only one type of photoreceptor is functioning.

Prosopagnosia

The inability to recognize familiar faces, often due to brain damage.

Blindsight

A phenomenon in which people with certain kinds of brain damage can respond to visual stimuli they do not consciously see.

Pitch

The highness or lowness of a sound, determined by the frequency of sound waves.

Amplitude

The height of a sound wave, determining its loudness.

Loudness

The perception of the intensity of a sound, related to its amplitude.

Pitch Perception

The ability to distinguish different pitches, or frequencies, of sound.

Place Theory

Theory that different areas of the cochlea respond to different frequencies, determining pitch.

Volley Theory

Suggests that neurons in the cochlea fire in rapid succession to achieve perception of higher frequencies.

Frequency Theory

Theory that pitch is determined by the frequency of impulses along the auditory nerve.

Conduction Deafness

Hearing loss caused by damage to the mechanical system that conducts sound waves to the cochlea.

Sensorineural Deafness

Hearing loss caused by damage to the cochlea's receptor cells or auditory nerves.

Sound Localization

The process by which the location of a sound is determined.

Olfactory System

The sensory system for smell.

Thalamus

Brain structure that relays sensory information to the cerebral cortex (all senses except smell).

Pheromones

Chemical signals released by organisms to communicate with others of their species.

Gustation

The sense of taste.

Taste Receptors

Sensory receptors on the tongue that respond to different tastes.

Umami

A savory taste sensation triggered by amino acids in protein-rich foods.

Oleogustus

A proposed taste for fatty acids, representing the taste of fat.

Supertasters

People with heightened sensitivity to taste.

Medium Tasters

Individuals with average taste sensitivity.

Nontasters

People with a reduced ability to detect flavors.

Gate Control Theory

Proposes that the spinal cord contains a neurological 'gate' that blocks or allows pain signals to pass to the brain.

Phantom Limb Sensation

The perception of sensations in a limb that has been amputated.

Vestibular Sense

The sense of body movement and position, including balance.

Semicircular Canals

Structures in the inner ear involved in maintaining balance.

Kinesthesis

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

Perception

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