1.6 a,b,c sensation and perception

Sensation

The process by which our sensory receptors detect stimuli from the environment and send this information to the brain.

Sensory Receptors

Specialized cells that detect specific stimuli (like light or sound) and convert them into neural signals for the brain.

Perception

The process by which the brain organizes and interprets sensory information, turning raw sensations into meaningful experiences.

Transduction

The conversion of physical energy from stimuli (like light or sound waves) into electrical signals that the nervous system can interpret.

Absolute Threshold

The minimum stimulus intensity that a person can detect 50 percent of the time.

Difference Threshold (Just Noticeable Difference)

The smallest change in intensity between two stimuli that can be detected at least 50 percent of the time; also known as the just noticeable difference.

Weber’s Law

The principle stating that to perceive a difference between two stimuli, they must differ by a constant proportion rather than a fixed amount.

Habituation

A decrease in responding to a stimulus that remains constant, as the brain stops attending to unchanging information.

Difference Threshold (Just Noticeable Difference)

The smallest change in intensity between two stimuli that a person can detect 50 percent of the time.

Subliminal Stimuli

Stimuli that are below the level of conscious awareness; they are detected less than half the time and do not produce conscious perception.

Sensory Adaptation

Reduced responsiveness of sensory receptors after prolonged exposure to a constant stimulus, allowing us to focus on changes in the environment.

Top Down Processing

Perception that uses prior knowledge, expectations, and experiences to interpret incoming sensory information, influencing how we perceive stimuli.

Bottom Up Processing

Perception that begins with the raw sensory data, building up information from the smallest details to form a complete representation, without relying on prior knowledge.

Properties of Light

Characteristics of light waves, such as wavelength that determines color and amplitude that determines brightness.

Cornea

The clear, protective outer layer of the eye that helps focus incoming light by bending it toward the lens.

Aqueous Humor

The clear fluid located between the cornea and the lens that nourishes the eye and helps maintain its shape.

Iris

The colored muscle in the eye that controls the size of the pupil, regulating how much light enters.

Light properties

Light waves vary in wavelength (color) and amplitude (brightness).

Eye parts

Cornea (bends light), pupil (light entry), iris (controls pupil), lens (focuses light), retina (light-sensitive layer), fovea (central focus), optic nerve (to brain).

Rods vs. Cones

Rods = dim light/black-white; Cones = color & detail.

Visual accommodation

The lens changes shape to focus light on near or far objects.

Pupil

The opening in the center of the iris that changes size to control the amount of light entering the eye.

Lens

A transparent, flexible structure behind the pupil that changes shape to focus light onto the retina.

Farsighted/Nearsighted

Farsighted: image focuses behind the retina; Nearsighted: image focuses in front of the retina.

Blind spot

The point where the optic nerve leaves the eye; this area has no photoreceptor cells.

Retina

The light-sensitive inner surface of the eye containing photoreceptor cells (rods and cones) that convert light into neural signals.

Fovea

A small central depression in the retina where visual acuity is highest due to a high concentration of cones.