16-18

What is sensation?

The process by which sensory receptors and the nervous system receive and represent stimuli from the environment.

What is perception?

The process of organizing and interpreting sensory information, enabling us to recognize meaningful objects and events.

What is bottom-up processing?

Analysis that begins with the sensory receptors and works up to the brain’s integration of sensory information.

What is top-down processing?

Information processing guided by higher-level mental processes, such as constructing perceptions based on experience and expectations.

What is selective attention?

Focusing conscious awareness on a particular stimulus.

What is inattentional blindness?

Failing to notice changes in the environment, a form of inattentional blindness.

What is transduction in sensation?

The conversion of one form of energy into another; the transformation of stimulus energies into neural impulses the brain can interpret.

What does psychophysics study?

Relationships between the physical characteristics of stimuli and our psychological experience of them.

What is the absolute threshold?

The minimum stimulus energy needed to detect a particular stimulus 50% of the time.

What is signal detection theory?

A theory predicting how and when we detect the presence of a faint stimulus amid background stimulation.

What is the difference threshold?

The minimum difference between two stimuli required for detection 50% of the time, also known as the just noticeable difference (JND).

What is Weber’s law?

The principle that to be perceived as different, two stimuli must differ by a constant minimum percentage.

What is sensory adaptation?

Diminished sensitivity as a consequence of constant stimulation.

What is a perceptual set?

A mental predisposition to perceive one thing and not another.

What is extrasensory perception (ESP)?

The controversial claim that perception can occur apart from sensory input.

What is parapsychology?

The study of paranormal phenomena, including ESP and psychokinesis.

What is wavelength?

The distance from the peak of one light wave to the peak of the next, determining color.

What is hue?

The dimension of color determined by wavelength.

What is intensity in the context of light?

The amount of energy in a light wave, influencing perceived brightness.

What is the function of the cornea?

The eye’s clear, protective outer layer that covers the pupil and iris.

What is the pupil?

A small adjustable opening in the center of the eye through which light enters.

What is the iris?

A ring of muscle tissue that forms the colored portion of the eye and controls pupil size.

What is the lens of the eye responsible for?

Changing shape to focus images on the retina.

What is the retina?

The light-sensitive inner surface of the eye containing receptors and neurons that process visual information.

What is accommodation in vision?

The process by which the eye’s lens changes shape to focus on near or far objects.

What are rods?

Retinal receptors that detect black, white, and gray, necessary for peripheral and night vision.

What are cones?

Retinal receptors concentrated near the center of the retina that detect fine detail and color.

What does the optic nerve do?

Carries neural impulses from the eye to the brain.

What is a blind spot?

The point where the optic nerve leaves the eye, creating a blind spot due to no receptor cells.

What is the fovea?

The central focal point in the retina where the eye’s cones cluster.

What does Young-Helmholtz Trichromatic Theory explain?

The retina contains three types of color receptors (red, green, blue) that combine to perceive color.

What is the Opponent-Process Theory?

The theory that opposing retinal processes enable color vision (red-green, yellow-blue, white-black).

What are feature detectors?

Nerve cells in the visual cortex that respond to specific features of stimuli like shape, angle, or movement.

What is parallel processing?

Processing many aspects of a problem simultaneously, the natural mode of information processing for vision.