Unit 1: Biological Bases of Behavior (Sensation Edition)

sensation ("detecting and encoding")

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

transduction

the conversion of sensory stimuli into neural impulses that can be understood by the brain

perception ("interpretation")

the process of organizing and interpreting sensory information to make sense of the world around us. it involves the brain's interpretation of sensory inputs, which can be influenced by past experiences, expectations, and context

absolute threshold

the minimum amount of stimulation required for a stimulus to be detected by a sensory system. it represents the point at which a stimulus becomes noticeable to an individual at least 50% of the time

just-noticeable difference

the smallest change in a stimulus that can be detected by an individual. it's the minimal difference needed for a person to perceive that a change has occurred

sensory adaptation

the process by which sensory receptors become less responsive to constant stimuli over time

weber's law

the perceived difference in a stimulus must be proportional to the original intensity of the stimulus

synesthesia

"to perceive together," is 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

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

visual/optic nerve

the nerve that carries neural impulses from the eye to the brain (cross to opposite side of brain, once inside the brain, visual information is sent via a number of structures to the occipital lobe at the back of the brain for processing)

lens

transparent 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

accommodation

the process by which the lens of the eye changes its shape to focus on objects at different distances. it allows for clear vision of both 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 the eyeball is too short or the cornea is too flat, causing light to focus behind the retina rather than directly on it

photoreceptors

specialized cells in the retina that convert light energy into electrical signals, allowing us to see. they are responsible for detecting and transmitting visual information to the brain

rods

photoreceptor cells in the retina responsible for vision in low light conditions and detecting motion. they provide black-and-white vision and are highly sensitive to light, allowing us to see in dim environments

cones (blue, green, red)

photoreceptor cells in the retina responsible for color vision and detail in bright light. they enable us to perceive colors and fine visual details, such as reading text or distinguishing between different hues

trichromatic theory

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

opponent-process theory

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

fovea

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

afterimages

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

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

dichromatism

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

monochromatism

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

prosopagnosia

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

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, bypassing traditional pathways in the brain

wavelength

the distance between sound wave peaks. shorter wavelengths mean higher-pitched sounds, while longer wavelengths mean lower-pitched sounds

pitch

the perceived highness or lowness of a sound, which is determined by the frequency of the sound wave

amplitude

the measure of the intensity or loudness of a sound wave, represented by the height of its peaks. greater amplitude corresponds to louder sounds, while lower amplitude indicates softer sounds

loudness

the perceptual characteristic of a sound's intensity or volume, determined by the amplitude of the sound wave

pitch perception

the brain's interpretation of the frequency of sound waves, determining whether a sound is high or low in tone. higher frequencies are perceived as higher pitches, while lower frequencies are perceived as lower pitches

place theory

idea that different parts of the inner ear detect different sound frequencies. high pitches are sensed near the entrance, low pitches near the end

volley theory

a theory of pitch perception proposing that groups of auditory neurons fire in rapid succession, or "volleys", to encode the frequency of sounds above 1000Hz. this allows the brain to perceive pitches that exceed the firing rate of individual neurons

frequency theory

a theory of pitch perception proposing that the frequency of sound wave directly corresponds to the rate at which auditory nerve fibers fire. higher frequency sounds lead to faster firing rates, resulting in higher perceived pitches

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 sounds

conduction deafness

hearing impairment caused by problems with the outer or middle ear, such as damage to the ear canal, eardrum, or middle ear bones. it typically results in difficulty hearing soft sounds and can often be treated medically or surgically (temporary)

sensorineural deafness

hearing loss caused by damage to the inner ear or auditory nerve. it results in difficulty hearing soft sounds and understanding speech, and is often permanent. common causes include aging, exposure to loud noise, and certain medical conditions

olfactory system

responsible for smell. special receptors in the nose detect smells and send signals to the brain via the olfactory nerve. the thalamus helps process this information, allowing us to identify different odors

thalamus

a relay station in the brain that processes and relays sensory information, such as sight, sound, touch, and taste, to the cerebral cortex

pheromones

chemical substances released by animals, including humans, that trigger social or behavioral responses in others of the same species. they play a role in communication, mating, and territorial marking

gustation

the sense of taste, involving receptors on the tongue that detect different flavors

sweet

associated with sugars and generally pleasurable taste

sour

caused by acidic substances, often associated with citrus fruits

salty

tastes primarily from salt, enhancing flavor

bitter

often found in plant-based foods, can be unpleasant in high concentrations

umami

savory taste associated with amino acids and protein-rich foods like meat and cheese

oleogustus

a proposed taste sensation for detecting fat, still debated within the scientific community

taste receptors

specialized cells located on the tongue and in the mouth that detect different tastes

superstasters

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

medium tasters

have an average sensitivity to taste, experiencing flavors moderately

nontasters

less sensitive to taste, experiencing flavors less intensely than others

sensory interaction

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

warm/cold receptors

specialized sensory neurons in the skin that detect changes in temperature. warm receptors respond to increases in temperature, while cold recepetors respond to decreases. they help us perceive and regulate our body's temperature

pain

a more difficult concept than others. it is in fact not a sensation but an emotional response to stimuli

gate control theory

a theory proposing that the experience of pain is modulated by a neural "gate" in the spinal cord. this gate can open to allow pain signals to be transmitted to the brain or close to block them

phantom limb

sensation of pain or other feelings in a missing limb. it occurs due to the brain's continued perception of the limb, even though it's no longer there. phantom limb sensations can range from tingling to intense pain and are thought to results from the process of plasticity in the somatosensory cortex following amputation

vestibular sense

the sense of body orientation and movement, including balance and spatial awareness. it relies on receptors in the inner ear that detect changes in head position and movement, helping to maintain stability and coordinate bodily movements

semicircular canals

fluid-filled structures in the inner ear that detect rotational movements of the head. they play a crucial role in the vestibular sense, helping to maintain balance and coordination by sending signals to the brain about changes in head position and movement

kinesthesis

the sense of body movement and position, including the awareness of muscle and joint sensations. it allows us to perceive and control our body's movements providing feedback to the brain about the position and orientation of body parts