PSYC 104 Chapter 4- Sensation & Perception

Sensation

The process of detecting physical energy from the environment and converting it into neural signals.

Perception

The process of organizing, interpreting, and making sense of sensations.

Transduction

Conversion of one form of energy into another, such as light into neural signals.

Bottom-up Processing

Sensory analysis that begins with input and moves to the brain's integration of the information.

Top-down Processing

Using experiences and expectations to interpret sensory information.

Psychophysics

The study of the relationship between physical characteristics of stimuli and our psychological experience of them.

Absolute Threshold

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

Difference Threshold

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

Subliminal Threshold

Stimulation that is below one's absolute threshold for conscious awareness.

Sensory Adaptation

Diminished sensitivity to a stimulus as a result of constant exposure.

Perceptual Set

A mental predisposition to perceive one thing over another, influenced by experience and expectations.

Contextual Effects

Influence on perception caused by the surrounding context or setting.

Motivation and Emotion

Our perceptions can be influenced by our current emotional state or motivation.

Transduction in Vision

The eye converts light energy into neural messages that the brain processes.

Light

A form of electromagnetic energy that stimulates the sense of vision.

Wavelength

The characteristic of light that determines the color (hue) perceived.

Intensity (in light)

The amount of energy in a light wave related to brightness.

Cornea

The transparent tissue that allows light to enter the eye.

Iris

A muscle that regulates the size of the pupil to control how much light enters.

Lens

Focuses light onto the retina.

Retina

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

Rods

Receptor cells that detect black, white, and gray; crucial for peripheral and night vision.

Cones

Receptor cells that detect color and are concentrated in the fovea.

Optic Nerve

Carries visual information from the retina to the brain.

Blind Spot

The point where the optic nerve exits the eye and no receptor cells are present.

Fovea

The central focal point in the retina where cones are concentrated.

Visual Cortex

The area in the brain where visual information is processed.

Trichromatic Theory

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

Opponent-Process Theory

Suggests that we have opposing retinal processes (e.g., red-green, blue-yellow) for color vision.

Figure-Ground

The organization of the visual field into objects (figures) that stand out from their background.

Proximity (grouping principle)

Grouping nearby figures together.

Continuity (grouping principle)

Perceiving smooth, continuous patterns.

Closure (grouping principle)

Filling in gaps to create a complete object.

Binocular Cues

Depth cues that depend on the use of two eyes.

Retinal Disparity

The difference between the images received by each eye; greater disparity indicates a closer object.

Monocular Cues

Depth cues available to each eye alone.

Relative Height

We perceive objects higher in our visual field as farther away.

Linear Perspective

Parallel lines appear to converge with distance.

Lightness Constancy

The perception that the color and brightness of objects remain the same under changing illumination.

Size-Distance Relationship

Objects of similar size appear different in size based on their distance from the viewer.

Kant's view on perception

Kant believed perception is inborn and we are hardwired to organize sensory information.

Locke's view on perception

Locke believed perception is learned through experience.

Sensory Deprivation

The result of lack of sensory input, which can impair development of perceptual abilities.

Perceptual Adaptation

The ability of our visual system to adjust to artificially displaced or inverted visual fields.