PSY Chapter 4 Key Terms

Sensation

simple stimulation of a sense organ. It is the basic registration of light, sound, pressure, odor, or taste as parts of your body interact with the physical world

Perception

is the organization, identification, and interpretation of a sensation in order to form a mental representation

Transduction

when sense receptors convert physical signals from the environment into neural signals that are sent to the central nervous system

Sensory Adaptation

sensitivity to prolonged stimulation tends to decline over time as an organism adapts to current (unchanging) condition

Psychophysics

methods that systematically relate the physical characteristics of a stimulus to an observer’s perception

Absolute Threshold

the minimal intensity needed to just barely detect a stimulus in 50% of the trials

Sensitivity

how responsive we are to faint stimuli

Acuity

how well we can distinguish two very similar stimuli

Just Noticeable Difference (JND)

the minimal change in a stimulus (e.g., its loudness or brightness) that can just barely be detected

Weber’s Law

for every sense domain, the change in a stimulus that is just noticeable is a constant proportion despite variation in intensities

Signal Detection Theory

the response to a stimulus depends both on a person’s sensitivity to the stimulus in the presence of noise and on a person’s decision criterion

Retina

a layer of light-sensitive tissue lining the back of the eyeball

Accommodation

the process whereby the eye maintains a clear image on the retina

Cones

detect color, operate under normal daylight conditions, and allow us to focus on fine detail

Rods

become active only under low-light conditions, for night vision

Fovea

an area of the retina where vision is clearest and there are no rods at all

Blind Spot

a location in the visual field that produces no sensation on the retina

Area V1

the part of the occipital lobe that contains the primary visual cortex.

Color-Opponent System

pairs of cone types (channels) work in opposition

Visual Receptive Field

the region of the visual field to which each neuron responds

Visual Form Agnosia

the inability to recognize objects by sight

Binding Problem

how the brain links features together so that we see unified objects in our visual world rather than free-floating or miscombined features

Parallel Processing

the brain’s capacity to perform multiple activities at the same time

Illusory Conjunction

a perceptual mistake whereby the brain incorrectly combines features from multiple objects

Feature-Integration Theory

focused attention is not required to detect the individual features that make up a stimulus (e.g., the color, shape, size, and location of letters), but it is required to bind those individual features together

Attention

the active and conscious processing of particular information

Perceptual Constancy

even as aspects of sensory signals change, perception remains constant

Perceptual Organization

process of grouping and segregating features to create whole objects organized in meaningful ways

Monocular Depth Cues

aspects of a scene that yield information about depth when viewed with only one eye

Binocular Disparity

the difference in the retinal images of the two eyes that provides information about depth

Apparent Motion

perception of movement as a result of alternating signals appearing in rapid succession in different locations

Biological Motion Perception

our ability to perceive biological motion critical for identifying individuals and various socially relevant features, such as their emotional state, personality characteristics, whether they are vulnerable to attack, or are engaging in deceptive actions

Spatial Acuity

ability to distinguish two stimuli that are very close together in space

Temporal Acuity

ability to distinguish two stimuli that are very close together in time

Multisensory

stimulating multiple senses at the same tim

Ventriloquist Illusion

The fact that you depend on your visual system for reliable information about spatial location

Change Blindness

when people fail to detect changes to the visual details of a scene

Synesthesia

When one attribute of a stimulus, such as its sound or shape, leads to the conscious experience of an additional attribute, often in a different sensory modality than the initiating stimulus

Inattentional Blindness

a failure to perceive objects that are not the focus of attention

Sound Waves

changes in air pressure unfolding over time

Pitch

how high or low a sound is

Loudness

the perception of a sound’s intensity

Timbre

the quality of sound that allows you to distinguish two sources with the same pitch and loudness

Cochlea

a fluid-filled tube that contains cells that transduce sound vibrations into neural impulses

Basilar Membrane

a structure in the inner ear that moves up and down in time with vibrations relayed from the ossicles, transmitted through the oval window

Traveling Wave

the up-and-down movement that sound causes in the basilar membrane

Inner Hair Cells

specialized auditory receptor neurons embedded in the basilar membrane

Area A1

the primary auditory cortex in the temporal lobe

Place Code

the brain uses information about the relative activity of hair cells (e.g., which ones are more active and which are less active) across the whole basilar membrane to help determine the pitch you hear

Temporal Code

the brain uses the timing of the action potentials in the auditory nerve to help determine the pitch you hear