Module Overview: From Sensory Input to Conscious Experience

Sensation

The process by which our sensory receptors and nervous system receive and represent stimulus energies from our environment.

Transduction

The transformation of stimulus energy into neural impulses that the brain can interpret.

Absolute Threshold

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

Difference Threshold (JND)

The minimum difference between two stimuli required for detection 50% of the time.

Weber’s Law

To be perceived as different, two stimuli must differ by a constant percentage, not a constant amount.

Sensory Adaptation

Diminished sensitivity as a consequence of constant stimulation.

Amplitude (in vision)

Determines the brightness of light.

Wavelength

Determines the hue (color) of light.

Cornea

The clear protective outer layer of the eye that helps focus light.

Pupil

The adjustable opening in the eye that allows light in.

Iris

The colored muscle that controls the size of the pupil based on light intensity.

Lens

Transparent structure that changes shape to focus images on the retina.

Retina

The light-sensitive inner surface of the eye containing receptor rods and cones.

Rods

Photoreceptors that detect black, white, and gray; function in low light.

Cones

Photoreceptors that detect fine detail and color; concentrated in the fovea.

Young-Helmholtz Trichromatic Theory

The theory that the retina contains three different color receptors for red, green, and blue.

Opponent-Process Theory

The theory that visual processing occurs in opposing pairs of colors.

Audition

The sense of hearing, involving sound wave vibrations.

Place Theory

Theory that different pitches trigger activity at different places along the cochlea.

Frequency Theory

Theory that the rate of nerve impulses matches the frequency of a tone, primarily for low pitches.

Gustation

The sense of taste, involving sensations of sweet, sour, salty, bitter, and umami.

Olfaction

The sense of smell, which directly connects to the olfactory bulb.

Gate-Control Theory

The theory that the spinal cord has a neurological 'gate' that can block or allow pain signals.

Vestibular Sense

The sense that monitors the head's position and movement, important for balance.

Kinesthesis

The system for sensing the position and movement of individual body parts.

Bottom-Up Processing

Analysis that begins with sensory receptors and works up to brain integration.

Top-Down Processing

Information processing guided by higher mental processes, based on experience.

Selective Attention

The process of focusing on a specific object in the presence of multiple stimuli.

Gestalt Principles

A set of principles describing how we organize visual elements into groups or wholes.

Circadian Rhythm

The biological clock that regulates the 24-hour cycle of physical, mental, and behavioral changes.