(Week 3) Sensation & Perception

Absolute threshold

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

Difference threshold

The point at which one can tell the difference between two stimuli.

Weber's Law

The principle that perceiving differences is on a logarithmic rather than linear scale.

(Its not the amount of change, but the percentage of change that matters)

Transduction

The process of transforming sensory energy into neural messages.

Signal detection theory

A theory predicting how and when a person will detect a weak stimulus based on context and psychological state.

Hue

The color or shade that we see, determined by the wavelength of light. (Determined by the length and height)

Amplitude

The amplitude of a light wave determines its brightness or intensity. (Amount of energy in a given light wave)

Saturation

The richness or purity of color, determined by the number of distinct wavelengths.

Chromostereopsis

The visual effect where pure colors appear at different distances, even though both colors are at the same distance from the eye.

Feature detectors

Specialized nerve cells that respond to specific features like shape, angle, and movement.

Parallel processing

The brain's ability to simultaneously process multiple aspects of a visual stimulus.

Binocular cues

Depth cues that require both eyes to perceive distance.

Monocular cues

Depth cues that do not require both eyes to perceive distance.

Gestalt principles

Organizational principles guiding how we perceive forms, such as proximity, similarity, and closure.

Top-down processing

Cognitive processing in which the brain uses pre-existing knowledge to interpret sensory information.

Bottom-up processing

Perception that starts with the stimulus and builds up to a final perception.

Affordances

The meanings and uses of objects in our environment that guide behavior.

Paréidolia

The tendency to see meaningful patterns, such as faces, in random stimuli.

High amplitudes vs Low amplitudes

High amplitudes in light waves result in greater brightness or intensity, while low amplitudes lead to dimmer light.

Pure spectral color

A color that is derived from a single wavelength of light, not mixed with any other color, appearing at the highest saturation.

Retina

The thin layer of tissue at the back of the eye that contains light-sensitive cells (rods and cones) responsible for converting light into neural signals.

Cones

Photoreceptor cells in the retina responsible for color vision and function best in bright light conditions.