AP Psych: Unit 1 (sensation)

sensation

the process by which our sensory receptors and nervous system that receive information of the world around us and represent stimulus energies from our environment. (vision, hearing, smell, taste, and touch)

perception

the process of organizing and interpreting sensory information to make sense of the world around us and enables us to recognize objects and events as meaningful. it involves the brain’s interpretation of sensory inputs and can be influenced by past experiences, expectations, and context.

transduction

the conversion of sensory stimuli into neural impulses that can be understood by the brain. transforming physical energy (ex. sights, smells, tastes) into neural impulses the brain can interpret.

absolute threshold

the minimum amount of stimulation required for a stimulus to be recognized by a sensory system. Represents the point at which a stimulus becomes noticeable to an individual. it’s the minimum stimulus energy needed to detect a particular stimulus 50% of the time

just-noticeable difference (JND)

the smallest change in a stimulus that can be detected by an individual when you can be certain it’s changed. the minimum difference between 2 stimuli required for detection 50% of the time.

weber’s law

perceived difference in a stimulus that must be proportional to the original intensity of the stimulus. to be perceived as different, 2 stimuli must differ by a constant minimum percentage.

sensory adaptation

process by which sensory receptors become less responsive to constant stimuli overtime

synesthesia

a condition in which stimulation of one sensory pathway leads to automatic, involuntary experiences in another sensory pathway.

retina

the light sensitive inner surface of the eye containing photoreceptor cells that convert light into neural signals by layers of neurons that begin processing visual information.

rods

photoreceptor cells in the retina responsible for vision in low light conditions and detecting motion (sensitive to movement). provides black and white vision, allowing us to see in dim conditions.

cones

photoreceptor cells in the retina responsible for color vision and detail in bright light. they enable us to perceive colors and fine details such as reading text.

fovea

central area of the retina responsible for sharp central vision. it contains a high concentration of cone cells (no rods), enabling detailed color vision. it’s the central focal point in the retina

blind spot

area on the retina where the optic nerve exits the eye, lacking photoreceptor cells. it’s a spot where vision is absent as there are no light sensitive cells to detect visual stimuli.

ganglion cells

neurons in the retina that receive visual information from bipolar cells and transmit it to the brain via the optic nerve. they play a crucial role in processing visual signals and relaying them to the brain for further interpretation.

lens

transport structure in the eye that focuses light onto the retina. it adjusts its shape to help the eye properly refract light, enabling clear vision at different distances.  

acommodation

the process by which the lens of the eye changes its shap to focus on objects at different distances. it allows for clear vision both of nearby and distant objects by adjusting the curvature of the lens.

nearsightedness

a common vision condition where close objects appear clear, but distant objects appear blurry. it occurs when the eyeball is too long or the cornea is too curved, causing light to focus in front of the retina instead of on it.

farsightedness

a vision condition where distant objects are seen more clearly than close ones. it happens when teh eyeball is too short or the cornea is too flat, causing light to focus behind the retina rather than directly on it.

trichromatic theory

theory proposing that color vision is based on three types of cone receptors, each sensitive to different wave lengths of light (red, green, blue). The brain combines signals from these cones to create the perception of a whole range of colors. 

opponent-process theory

theory proposing that color vision is based on pairs of opposing color processes (red-green, blue-yellow, black-white).

afterimages

visual stimulations that persist after a stimulus has been removed. they occur due to temporary overstimulation of cone cells in the retina, resulting in a brief perception of an inverted of complementary image.

dichromatism

a type of color vision deficiency where an individual has only 2 types of functioning cone cells instead of the normal 3. this condition typically results in difficulty distinguishing between certain colors, especially reds and greens.

momchromatism

a rare form of color blindness where an individual has only one form of functioning cone cell, or none at all. this results in the inability to perceive colors, seeing the world in shades of gray. 

blindsight

a phenomenon where individuals with damage to their visual cortex can respond to visual stimuli without consciously perceiving them. it suggests that some visual processing can occur unconsciously by passing traditional pathways in the brain.

prospagnosia

a neurological condition characterized by the inability to recognize familiar faces, including one’s own face, despite intact vision and intellect. it’s often referred to as face blindness

wavelength

the distance between sound wave peaks (shorter wavelength, higher pitch; bigger wavelength, lower pitch)

amplitude

the measure of the loudness of a sound wave, represented by the height of the peaks (greater amplitude, louder sound; lower amplitude, softer sound)

pitch perception

the brain’s interpretation of a the frequency of sound waves, determining whether a sound is high or low in tone (higher frequency, high pitch; lower frequency, low pitch)

place theory

the idea that different parts of the inner ear detect different sound frequencies

frequency theory

theory of pitch perception proposing that the frequency of a sound wave directly corresponds to the rate at which auditory nerve fibers fire.

volley theory

theory that auditory neurons fire in rapid succession to encode the frequency of sounds above 1000 Hz. it allows the brain to perceive pitches that exceed the firing rate of individual neurons. 

sound localization

the brain’s ability to determine the location of a sound source in space. it relies on cues such as differences in arrival time and intensity between the ears, as well as spectral cues to accurately locate sound.

conduction deafness

hearing impairment caused by problems with the outer or middle ear, such as damage to the ear canal

sensorineural deafness

hearing loss caused by damage to the inner ear or auditory nerve. results in difficulty hearing soft sounds and understanding speech.

sensory interaction

the principle that one fo out senses can influence another, such as when smell affects taste. it demonstrated how our sense work together to create our overall perception of the world. 

olfactory system

responsible for smell. special receptors in the nose detects smells and sends signals to the brain via the olfactory nerve. the thalamus helps process this info, allowing us to identify odors.

pheromones

chemical substances released by animals that trigger social or behavioral responses in others of the same species. plays a role in communication, mating, and territorial markings.

gustation

the sense of taste involving receptors on the tongue that detect different flavors (sweet, sour, salty, bitter, umami, oleogustus)

supertasters

people highly sensitive to taste, experiencing flavors more intensely, especially bitterness

medium tasters

people who have an average sensitivity to taste, experiencing flavors moderatley

nontasters

people less sensitive to taste, experiencing flavors less intensly than others

warm/cold receptors

specialized sensory neurons in the skin that detect changes in temperature. warm receptors respond to increases in temperature and cold receptors respond to decreases in temperature

pain

an emotional response to stimuli. when tissue is damages, there’s a pain response, however people can have that stimuli and feel it differently (more or less intensely)

gate control theory

a theory proposing that the experience of pain is modulated by a “gate” in the spinal cord. this gate can be opened to allow pain signals to be transmitted to the brain or closed to block them. 

phantom limb

sensation of pain or other feelings in a missing limb. occurs due to the brain’s continued perception of the limb even though it’s no longer there. can range from tingling to intense pain.

vestibular sense

the sense of body orientation and movement. it includes balance and spatial awareness. relies on receptors in the inner ear that detect changes in head position and movement.

kinesthesis

sense of body movement and position, including the awareness of muscle and joint sensations. allows perception and control of our body’s movements.

semicircular canals

fluid filled structures in the inner ear that detect rotational movements of the head. the play a crucial role in the vestibular sense.