Sensation and Perception Flashcards

The conversion of one form of energy into another. In sensation, receptors convert stimulus energy such as light or sound waves into neural impulses.

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

Two stimuli must differ by a constant proportion, not a constant amount, to be perceived as different, so the just noticeable difference grows with the size of the stimulus.

Whether we detect a faint stimulus depends on our expectations, experience, motivation and alertness, not only on the stimulus strength.

Reduced sensitivity to an unchanging stimulus over time (e.g., no longer noticing the smell of a room after a few minutes).

Rods detect black, white and gray and work in dim light and peripheral vision. Cones detect color and fine detail in good light and cluster in the fovea.

The point where the optic nerve leaves the eye has no rods or cones, so no image is detected there.

The retina has three types of cones, most sensitive to red, green and blue light, and their combined activity produces every color we perceive.

Afterimages. Color is processed in opposing pairs (red-green, blue-yellow, black-white), so fatiguing one side of a pair makes you briefly see its opposite.

Neurons in the visual cortex that respond to specific features such as edges, lines and angles, discovered by Hubel and Wiesel.

Conduction loss is damage to the mechanical system that carries sound to the cochlea (eardrum, middle-ear bones). Sensorineural loss is damage to the cochlea's hair cells or the auditory nerve.

Different frequencies stimulate hair cells at different places along the cochlea's basilar membrane. It best explains high-pitched sounds.

The rate at which the auditory nerve fires matches the frequency of the sound wave. It best explains low-pitched sounds.

The spinal cord contains a neural gate that can block pain signals or let them through to the brain, which is why rubbing a bumped knee can ease the pain.

Head position and movement, using the semicircular canals and vestibular sacs in the inner ear, to keep you balanced.

The sense of the position and movement of your own body parts, from receptors in muscles, tendons and joints.

Bottom-up processing builds a perception from raw sensory input. Top-down processing interprets that input using expectations, knowledge and context.

A mental predisposition to perceive one thing and not another, shaped by expectations, context and experience.

The Gestalt tendency to see an object (the figure) standing out from its surroundings (the ground).

Closure.

A binocular depth cue: the greater the difference between the images on the two retinas, the closer the object.

A binocular cue based on how far the eyes turn inward to focus on an object. The more they converge, the nearer the object.

Linear perspective.

Perceiving objects as keeping the same size, shape, color and brightness even when the image on the retina changes with distance, angle or lighting.

Failing to see a visible object because attention is focused elsewhere, as when viewers counting basketball passes miss a person in a gorilla suit (Simons and Chabris).