Sensation and Perception (September 8th)

Sensation

Process by which our sensory receptors and nervous system receive and represent stimulus energies from the environment (response to a stimuli)

Perception

Process of organizing and interpreting sensory information (occurs farther up the neural chain in the brain)

Our perceptions don’t always match our…..

reality

Bottom-Up Processing

Analysis that begins with sensory receptors and works its way up to the brain

Top-Down Processing

Constructing perceptions from sensory input by drawing on your experiences and expectations

Parallel Processing

Processing many aspects of a problem simultaneously; the brain’s natural mode of information processing

Absolute Threshold

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

Ex. Weakest light or softest sound

Difference Threshold

Minimum difference between 2 stimuli required for detection 50% of the time.

Also known as just noticeable difference

Ex. How much louder does Sound 1 need to be than Sound 2 for you to say it is louder?

Weber’s Law

The principle that, to be perceived as different, 2 stimuli must differ by a constant minimum percentage

Sensory Adaptation

Diminished sensitivity as a consequence of a constant stimulus

Perceptual Set

A mental predisposition to perceive one thing and not another

Shape Constancy

Perceiving same shape despite changing orientation

Cones

Sense color in 3 different wavelengths

Rods

Sense black, white, and grey. Night vision. Can sense a broad spectrum of wavelengths

Color only exists in your……

perception

Young-Helmholtz Trichromatic Theory

Theory that the retina contains only 3 color receptors. Only a combination of these three allow you to perceive color

Afterimage

Image continuing to appear after exposure to image has ceased. Colors are inverted relative to original color

Opponent-Process Theory

Theory that opposing retinal processes (red-green, yellow-blue, black-white) enable color vision

Feature Detectors

Nerve cells in brain that respond to specific features of a stimulus

Ex. shape, angle, movement

Sensorineural Hearing Loss

Hearing loss caused by damaged hair cells in the cochlea or auditory nerve

Most common

Conduction Hearing Loss

Damage to mechanical system that conducts sound to cochlea

What entails the sensation of touch?

Temperature

Pressure

Vibration

Pain

Outer Ear

Auditory Canal

Ear Drum

Middle Ear

Bones of the middle ear: Malleus, incus, stapes

Inner Ear

Cochlea

Oval Window

Protruding Hair Cells

Auditory Nerve

Place Theory

Theory that we link pitches we hear with place where the cochlea’s membrane is stimulated

Frequency Theory

Theory that the rate of nerve impulses traveling up the auditory nerve matches frequency of a tone, enabling us to sense its pitch

The Volley Principle

The summing of individual neuron’s fire rate representing a sound’s frequency

Taste and smell detect chemical molecules, not….

Energy

What are the 5 tastes?

Sweet

Salty

Sour

Bitter

Umami

Perceptual Constancy

The brain’s ability to perceive familiar objects as unchanging