AP Psych Sensation and Perception

Unit 1 Part 2

Bottom-up processing

Sensory receptors throughout the body register information about the external environment and send it up to the brain for processing.

Top-down processing

Using your knowledge, experience, or context to understand and interpret sensory perceptions.

Sensation

The detection of external stimuli via the five senses, and the transmission of this information to the brain.

Perception

The process of organizing and interpreting sensory information so that it makes sense.

Transduction

Conversion of sensory input into electrical impulses the brain can use to process information.

Absolute threshold

The weakest amount of a stimulus that a person can detect 50% of the time.

Difference threshold

The minimum amount something needs to change before a person notices the change 50% of the time.

Weber's Law

States that, for an average person to perceive a difference, two stimuli must differ by a constant percentage, not a constant amount.

Sensory adaptation

When constantly exposed to an unchanging stimulus, we become less aware of it.

Selective attention

Focusing your awareness on one particular task or stimulus.

Cocktail party effect

The ability to focus auditory attention on a particular voice or sound while filtering out others.

Inattentional blindness

Failing to see visible objects when our attention is directed elsewhere.

Change Blindness

(a form of inattentional blindness) failing to notice changes in the environment because your attention is directed elsewhere.

Gestalt theory

Tendency to integrate pieces of information into meaningful wholes.

Proximity

Grouping nearby figures.

Similarity

Grouping similar objects.

Closure

Filling in gaps to create a complete object.

Figure-ground

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

Monocular cues

Depth cues that only require one eye.

Binocular cues

Depth cues that depend on the use of both eyes.

Visual cliff

A model of a cliff with a 'drop-off' area that is covered by glass.

Rods

In retina, black and white and peripheral vision and motion, allows you to see in dim light.

Cones

In fovea, detect color and fine detail, work poorly in dim light.

Accommodation

The process by which the lens changes shape to focus near or far objects on the retina.

Lens

Transparent structure behind the pupil that changes shape to help focus images on the retina.

Retina

Light-sensitive inner surface of the eye, contains rods and cones

Optic nerve

The nerve that carries neural impulses from the eye to the brain

Blind spot

The point at which the optic nerve leaves the eye creates this because no receptor cells are located there. The brain fills in the gaps in the incomplete retinal images to perceive a relatively complete picture of the world.

Afterimage

A visual illusion in which retinal images persist even after the stimulus has been removed. Ex. By staring at green, we tire our green response. When we then stare at white (which contains all colors, including red), only the red part of the green-red pairing will fire normally.

Trichromatic theory

Explains how we detect color in the retina. Three different kinds of cones respond only to red, blue, and green and other colors are perceived through the mixing of signals from the cones.

Opponent-process theory

Explains how colors are processed in the brain. Three types of cells can only detect the presence of one color at a time because the two colors oppose one another. (Red-green) (yellow-blue) (white-black)

Dichromatism and monochromatism

Color vision deficiency involves damage or irregularities to one or more cones or ganglion cells (red/green, blue/yellow)

Wavelengths

Distance from one wave peak to the next.

Pitch

Low frequency= bass, high frequency=high pitch

Amplitude (loudness)

Height of waves, Loud = high amplitudes, Soft = low amplitudes

Place theory

Says that higher and lower tones excite specific areas of the cochlea basilar membrane. We process pitch based on which part of the cochlea responds to incoming sound waves. The front of the cochlea responds to higher pitches and the deeper areas of the cochlea respond to lower pitches.

Frequency theory

The brain detects pitch by monitoring the frequency of neural impulses traveling up the auditory nerve. The basilar membrane vibrates with the incoming sound wave. This triggers neural impulses at the same rate as the sound wave's frequency.

Conduction hearing loss

Caused by damage to the structures that conduct sound waves through the outer and middle ear (eardrum, ossicle bones, auditory canal)

Sensorineural hearing loss

Caused by damage to the cochlea, cannot be reversed

Sound localization

How we identify where sounds in our environment are coming from.

Gate control theory

Theory that the spinal cord contains a neurological "gate" that blocks pain signals or allows them to pass to the brain.

Phantom limb

The sensation that a missing or amputated limb is still attached. The parts of the sensory cortex that sense the limb can experience electrical activity that tricks the brain into thinking it's still there.

Olfaction (smell)

Olfactory receptors instantly alert the brain of smells through their axon fibers. Smell bypasses the thalamus and is processed in areas connected to the limbic system.

Pheromones

Produce chemical messages for the olfactory system.

Sweet

This flavor signals that a food is an energy source

Sour

This flavor signals that a food is a potentially toxic acid

Salty

This flavor signals that a food is sodium essential to physiological processes

Bitter

This flavor signals that a food could be a potential poisons

Umami

This flavor signals that a food contains proteins to grow and repair tissue

Oleogustus

This flavor signals that a food contains fats for energy, insulation, and cell growth

Kinesthesia

The system for sensing the position and movement of individual body parts. Interacts with vision to help you keep your balance.

Vestibular sense

Monitors the head's position and movement so the body knows its position in space. Fluid in the semicircular canals of the inner ear moves when your head rotates or tilts.

Synesthesia

Where one sort of sensation (such as hearing sound) produces another (such as seeing color).