AP Psychology Unit 4

Sensation

The process by which sensory receptors and the nervous system detect and receive stimulus energy from the environment.

Absolute Threshold

The minimum amount of stimulation needed to detect external stimulus 50% of the time.

Transduction

The process of converting sensory energy into neural signals the brain can interpret.

Just-Noticeable Difference (JND)

Minimal change in a stimulus that can just barely be detected.

Sensory Adaptation

Decreased/diminished sensitivity to a constant stimulus over time.

Weber's Law

The principle that the JND is a constant proportion of the original stimulus.

Sensory Interaction

One sense can influence another.

Synesthesia

A condition where one sense triggers another sense involuntarily.

Energy Senses

Detect a type of energy that gives information about the environment.

Chemical Senses

Providing information about the chemical composition of substances.

Signal Detection Theory

Predicts how and when a person detects a signal.

Retina

Light-sensitive layer at the back of the eye that contains rods, cones, and layers of neurons that process visual information.

Cornea

Eye's clear protective outer layer.

Iris

Forms colored portion of eye; controls size of the pupil opening.

Pupil

Opening of the eye through which light enters.

Photoreceptors

Rods/Cones... where transduction occurs in vision.

Optic Disk/Blind Spot

Area on the retina without photoreceptors where the optic nerve exits.

Optic Nerve

Carries visual information from the retina to the brain.

Lens

Focuses light onto the retina by changing shape.

Accommodation

The modification of existing mental structures to make sense of new information or experiences that don't fit into current understandings.

Rods

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

Cones

Photoreceptors that detect/enable color perception and fine detail; function in bright light.

Fovea

Central point in the retina where cones are concentrated for sharp vision.

Trichromatic Theory

The idea that color vision is based on three cone types (red, green, blue).

Opponent Process Theory

The theory that color vision is based on opposing pairs (red-green, blue-yellow, black-white).

Afterimages

Visual images that remain after looking away from a stimulus.

Ganglion Cells

Neurons in the retina that send visual information to the brain via the optic nerve.

Dichromatism

Color blindness where one cone type is missing.

Protanopia

Lack of red cone cells (red-green color blindness).

Deuteranopia

Lack of green cone cells (red-green color blindness).

Tritanopia

Lack of blue cone cells (blue-yellow color blindness).

Monochromatism

Total color blindness; only shades of gray seen.

Prosopagnosia

Inability to recognize faces.

Blindsight

Ability to respond to visual stimuli without consciously seeing them.

Pinna

Visible outer ear on either side of your head; helps pinpoint and locate sound.

Ear Canal

Where sound travels to reach eardrum.

Tympanic Membrane (Ear Drum)

Vibrates at a rate that corresponds to the sound's frequency, transmits to ossicles.

Ossicles

Three bones (hammer, anvil, stirrup) that pick up eardrum vibrations, amplify them, and pass them along to the cochlea in the inner ear.

Cochlea

A coiled - fluid-filled tube through which sound waves are transduced into nerve impulses.

McGurk Effect

The interaction of vision and hearing.

Conductive Hearing Loss

Problem transferring sound waves anywhere along the route through the outer or middle ear.

Pitch

How high or low a sound is, determined by frequency.

Amplitude

Height of a sound wave; determines loudness.

Intensity (Loudness)

Size of amplitude relates to perceived loudness.

Place Theory

Different sound frequencies stimulate different spots on the cochlea's membrane.

Volley Theory

Neural cells alternate firing to match the frequency of a sound.

Frequency Theory

Pitch is determined by the rate of nerve impulses matching sound frequency.

Sound Localization

The brain's ability to determine where a sound is coming from.

Conduction Deafness

Hearing loss caused by damage to the mechanical system of the ear.

Sensorineural Deafness

Hearing loss caused by damage to hair cells or auditory nerve.

Olfaction

Sense of smell.

Pheromones

Chemical signals that affect behavior or physiology of others.

Olfactory System

The system responsible for detecting and processing odors.

Gustation

Sense of taste.

Super Taster

Someone with more taste buds and sensitivity to flavors.

Warm/Cold Receptors

Nerve endings that detect temperature changes.

Gate Control Theory

The spinal cord contains a 'gate' that controls pain signals to the brain.

Phantom Limb Sensation

Feeling sensations in a limb that has been amputated.

Vestibular Sense

It is a sense responsible for the body's balance and spatial orientation.

Semicircular Canals

Structures in the inner ear that detect rotational movement.

Kinesthetic Sense

Sense of body position and movement of body parts.

Perception

The process of organizing and interpreting sensory information into meaningful objects/events.

Depth Perception

Ability to gauge length, width, and depth, and to judge how far away an object is.

Monocular Cues

Cues to help us perceive depth without needing both eyes.

Binocular Cues

Depth cues that require both eyes.

Bottom-Up Processing

Perception starts with sensory input and builds up to sensory interpretation.

Top-Down Processing

Perception based off previous events, previous experience and expectations affect the detection and analysis of information from the senses.

Schemas

Mental frameworks that help organize information.

Perceptual Sets

A mental tendency to perceive things a certain way.

Context Effects

Environment influences perception.

Grouping (Gestalt)

The perceptual tendency to organize stimuli into coherent groups.

Proximity (Gestalt)

Perceive objects as belonging together when they are close to one another.

Similarity (Gestalt)

Group objects that have similar characteristics.

Phi Phenomenon

An optical illusion where a series of stationary images shown in rapid succession are perceived as a single, continuous moving object.

Closure (Gestalt)

Filling in missing parts of an image to see it as complete.

Figure-Ground (Gestalt)

Differentiating an object (figure) from its background (ground).

Selective Attention

Focusing on one stimulus while ignoring others.

Cocktail Party Effect

Ability to focus on one voice among many.

Change Blindness

Failing to notice a change in the environment.

Inattentional Blindness

Failure to see objects in the visual field when attention is directed elsewhere.

Retinal Disparity

Difference between images seen by each eye; used for depth perception.

Convergence

Eyes move inward to focus on a close object.

Relative Clarity

Nearby objects are clearer than more distant objects.

Texture Gradient

Detailed textures appear closer; less detail means farther away.

Linear Perspective

Parallel lines appear to meet at a distance.

Perceptual Constancies

Recognizing objects as the same even when appearance changes.

Apparent Movement

Perceiving motion when none exists.

Extra Sensory Perception

Perception without sensory input.

Perceptual Adaptation

Adjustments of how we adapt to the environment and filter out distractions.

Color/Light Constancy

Our ability to perceive an object as the same color regardless of the environment.

Size Constancy

Objects remain same size regardless of distance.

Relative Height

Near objects are low in visual field; more distant are higher up.

Relative Size

An object that appears larger than another object believed to be of the same size is judged to be closer.

Interposition

Objects that are obscured by other objects are perceived as being farther away.