IAT 201 QUIZ 1

Absolute threshold

The smallest amount of stimulation needed for detection by a sense.

Agnosia

Loss of the ability to perceive stimuli.

Anosmia

Loss of the ability to smell.

Audition

Ability to process auditory stimuli. Also called hearing.

Auditory canal

Tube running from the outer ear to the middle ear.

Auditory hair cells

Receptors in the cochlea that transduce sound into electrical potentials.

Binocular advantage

Benefits from having two eyes as opposed to a single eye.

Binocular disparity

Difference in images processed by the left and right eyes.

Binocular vision

Our ability to perceive 3D and depth because of the difference between the images on each of our retinas.

Bottom-up processing

Building up to perceptual experience from individual pieces.

Chemical senses

Our ability to process the environmental stimuli of smell and taste.

Cochlea

Spiral bone structure in the inner ear containing auditory hair cells.

Cones

Photoreceptors that operate in lighted environments and can encode fine visual details. There are three different kinds (S or blue, M or green, and L or red) that are each sensitive to slightly different types of light. Combined, these three types allow you to have color vision. Also: Photoreceptors of the retina sensitive to color, located primarily in the fovea.

Contrast

Relative difference in the amount and type of light coming from two nearby locations.

Contrast gain

Process where the sensitivity of your visual system can be tuned to be most sensitive to the levels of contrast that are most prevalent in the environment.

Dark adaptation

Adjustment of eye to low levels of light; process that allows you to become sensitive to very small levels of light so you can see in near‑absence of light.

Differential threshold

The smallest difference needed in order to differentiate two stimuli. (See Just Noticeable Difference (JND))

Dorsal pathway

Pathway of visual processing. The “where” pathway.

Flavor

The combination of smell and taste.

Gustation

Ability to process gustatory stimuli. Also called taste.

Just noticeable difference (JND)

The smallest difference needed in order to differentiate two stimuli. (See Differential Threshold)

Lateral inhibition

A signal produced by a neuron aimed at suppressing the response of nearby neurons.

Light adaptation

Adjustment of eye to high levels of light.

Mechanoreceptors

in the skin that respond to tactile stimulation.

Multimodal perception

The effects that concurrent stimulation in more than one sensory modality has on the perception of events and objects in the world.

Nociception

Our ability to sense pain.

Odorants

Chemicals transduced by olfactory receptors.

Olfaction

Ability to process olfactory stimuli. Also called smell.

Olfactory epithelium

Organ containing olfactory receptors.

Opponent-process theory

Theory proposing color vision as influenced by cells responsive to pairs of colors. Also: Theory of color vision that assumes there are four different basic colors, organized into two pairs (red/green and blue/yellow), and proposes that colors in the world are encoded in terms of the opponency (difference) between the colors in each pair. There is an additional black/white pair responsible for coding light contrast.

Ossicles

A collection of three small bones in the middle ear that vibrate against the tympanic membrane.

Perception

The psychological process of interpreting sensory information.

Phantom limb

The perception that a missing limb still exists.

Phantom limb pain

Pain in a limb that no longer exists.

Photoactivation

A reaction that occurs when light hits photoreceptors, producing a neural signal.

Pinna

Outermost portion of the ear.

Primary auditory cortex

Area of the cortex involved in processing auditory stimuli.

Primary somatosensory cortex

Area of the cortex involved in processing somatosensory stimuli.

Primary visual cortex (V1)

Brain region located in the occipital cortex responsible for processing basic visual information like detection, thickness, and orientation of simple lines, color, and small‑scale motion.

Principle of inverse effectiveness

The finding that for a multimodal stimulus, if the response to each unimodal component is weak, multisensory enhancement is large; if one component alone evokes a strong response, adding other components yields a relatively small enhancement.

Retina

Cell layer in the back of the eye containing photoreceptors.

Rods

Photoreceptors that are very sensitive to light and mostly responsible for night vision; located around the fovea.

Sensation

The physical processing of environmental stimuli by the sense organs.

Sensory adaptation

Decrease in sensitivity of a receptor to a stimulus after constant stimulation.

Shape theory of olfaction

Theory proposing that odorants of different size and shape correspond to different smells.

Signal detection

Method for studying the ability to correctly identify sensory stimuli.

Somatosensation

Ability to sense touch, pain, and temperature.

Somatotopic map

Organization of the primary somatosensory cortex maintaining a representation of the arrangement of the body.

Sound waves

Changes in air pressure. The physical stimulus for audition.

Superadditive effect of multisensory integration

The finding that responses to multimodal stimuli are typically greater than the sum of the independent responses to each unimodal component.

Synesthesia

The blending of two or more sensory experiences, or the automatic activation of a secondary sensory experience due to aspects of the primary sensory stimulation.

Tastants

Chemicals transduced by taste receptor cells.

Taste receptor cells

Receptors that transduce gustatory information.

Top-down processing

Experience influencing the perception of stimuli.

Transduction

The conversion of one form of energy into another.

Trichromatic theory

Theory proposing color vision as influenced by three different cones responding preferentially to red, green, and blue.

Trichromacy theory

Theory that proposes all color perception is based on the combination of three different color signals (same concept as trichromatic theory).

Tympanic membrane

Thin, stretched membrane in the middle ear that vibrates in response to sound. Also called the eardrum.

Ventral pathway

Pathway of visual processing. The “what” pathway.

Vestibular system

Parts of the inner ear involved in balance.

Vestibulo-ocular reflex

Coordination of motion information with visual information that allows you to maintain your gaze on an object while you move.

Weber’s law

States that just noticeable difference is proportional to the magnitude of the initial stimulus.

What pathway

Pathway of neural processing responsible for recognizing what is around you.

Where-and-How pathway

Pathway of neural processing responsible for knowing where things are in the world and how to interact with them.

Human perception

Human perception is not an accurate reflection of what is “out there” in the world. It is biased by our experience, the current context, and our goals.

Past experience and priming

bias our perceptual systems to detect/NOT certain objects and events. Repeated perception of an event over a short interval can cause habituation, increasing the chances that we will miss later occurrences of the event. With long‑term experience, we develop frames for familiar situations that make us perceive things that aren’t there or miss things that are.

Attentional blink

Because our attention has limited capacity, when it is overloaded we can miss other objects and events.

Dual nature of perception

Perception operates in two ways simultaneously:

1. Our perception of whole objects and events is based on our perception of the parts.

2. Our perception of the parts is based on our perception of the whole.

Gestalt principles of visual perception

Principles most relevant to user‑interface design:

Proximity

Objects near each other (relative to other objects) appear grouped, while those farther apart do not.

Similarity

Objects that look similar appear grouped.

Continuity

Our visual perception is biased to perceive continuous forms rather than disconnected segments.

Closure

Our visual system automatically tries to close figures that are open so they are perceived as whole objects rather than separate pieces.

Symmetry

Our visual system parses complex scenes in a way that reduces their complexity by recognizing symmetries in the scene.

Figure/Ground

Our mind separates the visual field into the figure (foreground) and ground (background).

Common Fate

Objects that move together are perceived as grouped or related.

Terse, structured presentation

Presenting information in a terse, structured manner makes it easier for people to scan, understand, and remember. Eliminate needless words and repetition. Use bullets and numbered lists instead of paragraphs of text.

Visual hierarchy

Breaking content up into clearly labeled sections and subsections is a “best practice” way to structure information.

Accessible hierarchical structuring

using section headings and labels that screen readers can recognize as headings, helps people with visual impairments find their desired content.

Chunking

Chunking data—such as phone numbers, credit card numbers, serial numbers—helps people scan, enter, and remember it.

Emotion and perception

Our perception of objects and events can be biased by our emotional state.

Evolutionary hacks and bugs

Our perceptual system—particularly our visual system—includes evolutionary hacks and bugs that cause us to misperceive certain stimuli.

Goals and plans

Our goals and plans strongly influence what we pay attention to and therefore what we perceive.

Design implications

By following design guidelines based on how human perception works, designers can create applications, websites, and appliances that are a good fit with the people who will use them.

G

Short for "general factor" and is often used to be synonymous with intelligence itself.

Intelligence

An individual's cognitive capability. This includes the ability to acquire, process, recall and apply information.

IQ

Short for "intelligence quotient."This is a score, typically obtained from a widely used measure of intelligence that is meant to rank a person's intellectual ability against that of others.

Norm

Assessments are given to a representative sample of a population to determine the range of scores for that population. These "norms" are then used to place an individual who takes that assessment on a range of scores in which he or she is compared to the population at large.

Standardize

Assessments that are given in the exact same manner to all people. With regards to intelligence tests standardized scores are individual scores that are computed to be referenced against normative scores for a population (see "norm").

Stereotype threat

The phenomenon in which people are concerned that they will conform to a stereotype or that their performance does conform to that stereotype, especially in instances in which the stereotype is brought to their conscious awareness.