Psych Unit 4

Sensation

Sensation

Process by which our sensory receptors and nervous system receive and represent stimulus energies

Perception

Process of organizing and interpreting sensory information to make sense of the world around us

Transduction

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

Absolute Threshold

The minimum amount of stimulation required for a stimulus to be detected by a sensory system

Just-Noticeable Difference

The smallest change in a stimulus that can be detected by an individual

Weber’s Law

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

Sensory Adaptation

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

Synesthesia

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

Retina

Light-sensitive inner surface of the eye containing photoreceptor cells that convert light into neural signals

Rods

Photoreceptor cells in the retina responsible for vision in low light conditions and detecting motion

Cones

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

Fovea

Central area of the retina responsible for sharp central vision

Blind Spot

Area on the retina where the optic nerve exits the eye, lacking photoreceptor cells

Ganglion Cells

Neurons in the retina that receive visual information from bipolar cells and transmit it to the brain via the optic nerve

Lens

Transparent structure in the eye that focuses light onto the retina and adjusts its shape to help the eye properly reflect light

Accommodation

Process by which the lens of the eye changes its shape to focus on objects at different distances

Nearsightedness

Vision condition where close objects appear clear, but distant objects appear blurry

Farsightedness

Vision condition where distant objects are seen more clearly than close ones

Trichromatic Theory

Theory proposing that color vision is based on 3 types of cone receptors, each sensitive to different wavelengths of lights

Opponent-Process Theory

Theory proposing that color vision is based on pairs of opposing color processes

Afterimages

Visual sensations that persist after a stimulus is removed

Dichromatism

Color vision deficiency where an individual has only two types of function cone cells instead of the normal three

Monochromatism

Rare form of color blindness where an individual has only one type of functioning cone cells, or none at all

Blindsight

Phenomenon where individuals with damage to their visual cortex can response to visual stimuli without consciously perceiving them

Prosopagnosia

Neurological condition characterized by the inability to recognize familiar faces, including one’s own face despite intact vision and intellect

Wavelength

Distance between sound wave peaks

Amplitude

Measure of intensity or loudness of a sound wave, represented by the height of its peaks

Pitch Perception

The brain’s interpretation of the frequency of sound waves, determining whether a sound is high or low in tone

Place Theory

Idea that different parts of the inner ear detect sound frequencies

Frequency Theory

Theory proposing that the frequency of a sound wave directly corresponds to the rate at which auditory nerve fibers fire

Volley Theory

Theory that groups of auditory neurons fire in rapid succession, or “volleys”, to encode the frequency of sounds above 1000 Hz

Sound Localization

The brain’s ability to determine the location of a sound source in space

Conduction Deafness

Hearing impairment caused by problems with the outer or middle ear

Sensorineural Deafness

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

Sensory Interaction

Principle that one sense can influence another, such as when smell affects taste

Olfactory Systems

Special receptors in the nose that detect smells and send signals to the brain via the olfactory nerve

Pheromones

Chemical substances released by animals (including humans) that trigger social or behavioral responses in the same species

Gustation

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

Supertasters

Highly sensitive to taste, experiencing flavors more intensely

Medium Tasters

Have an average sensitivity to taste

Nontasters

Less sensitive to taste, experiencing flavors less intensely

Warm/Cold Receptors

Specialized sensory neurons in the skin that detect changes in temperature

Pain

An emotional response to stimuli that varies from person to person

Gate-Control Theory

Theory proposing that the experience of pain is modulated by a neural “gate” in the spinal cord

Phantom Limb

Phenomenon where there is a sensation of pain or other feelings in a missing limb

Vestibular Sense

The sense of body orientation and movement, including balance and spatial awareness

Semicircular Canals

Fluid-filled structures in the inner ear that detect rotational movements of the head

Kinesthesis

The sense of body movement and position, including the awareness of muscle and joint sensation

Perception

Process by which our brain organizes and interprets sensory information

Bottom-Up Processing

Way our brain makes sense of info, starting with the small details

Top Down Processing

Interpreting sensory information based on the larger context, prior knowledge, and expectations

Selective Attention

Process of focusing on a specific aspect of information while ignoring others

Cocktail Party Effect

Ability to focus on a single conversation in a noisy environment, while bringing out other stimuli

Inattentional Blindness

When an individual fails to notice and unexpected stimulus in their visual field when their attention is elsewhere

Change Blindness

Failure to notice large changes in the environment when the change occurs simultaneously with a visual disruption

Schemas

Mental frameworks that help us organize and interpret information in the world around us

Perceptual Set

A tendency to perceive or notice some aspects of the available sensory data and ignore others

Gestalt Psychology

How we perceive whole objects or figures (gestalts) rather than just a collection of parts

Figure Ground

The ability to distinguish an object from its surroundings

Binocular Depth Cues

Visual information that requires both eyes to perceive depth and distance

Retinal Disparity

When each eye sees a slightly different picture because of their separate positions on our face

Convergence

When our eyes move inward toward each other to focus on a closer object

Monocular Depth Cues

Visual indicators of distance and space that can be perceived using just one eye

Relative Clarity

A depth cue where objects that appear clear and more detailed perceive closer, and less clear objects seem farther away

Relative Size

A visual cue where objects closer to us appear larger, while further objects appear smaller

Texture Gradient

The way we perceive texture to become denser and finer as it recedes into the distance

Linear Perspective

A depth cue where parallel lines appear to converge as they recede into the distance

Interposition

Occurs when one object overlaps another, leading us to perceive the overlapping object as closer

Perceptual Constancies

Our brain’s ability to see objects as unchanging, even when the image on our retina changes

Shape Constancy

Ability to perceive an object as having the same shape, even when our angle of view or distance changes

Size Constancy

Our perception that an object remains the same size, even when its distance from us changes

Color Constancy

Ability to perceive colors of objects as stable under varying light conditions

Apparent Movement

The perception of motion when there isn’t any actual movement