AP Psychology Sensation and Perception

Sensation

The process by which our sensory receptors and nervous system receive and represent stimulus from our enviroment

Transduction

conversion of stimulus energy into neural impulse for interpretation (energy → sensory receptors → neural impulse → brain)

Absolute threshold

The point at which you initially detect the stimuli (-55mV)

Just-noticeable difference

The minimum difference between two stimuli required for detection

Weber’s Law

to be perceived as different, two stimuli must differ by a certain percentage (ex. adding one pound of weight to a 100 pound dumbbell might not be noticed, but adding it to a 10 pound dumbbell would)

Sensory adaptation

Diminished sensitivity/less frequent firing of nerve cells as a consequence of prolonged exposure to a stimuli

Sensory interaction

The principle that one sense can influence another

Synesthesia

Stimulation of one sense triggers experiences in another

Retina

back layer of the eye. transduction occurs here

Blind spot

place where the optic nerve leaves the eye (no rods or cones)

Lens

helps focus the light/image

Accomodation

when your lens changes its shape (curvature/thickness) to focus

Nearsighted

lens focuses the image on the point in front of the retina and cant see far objects (aka myopia)

Farsighted

lens focuses light past the retina and cant see near (hyperopia)

Rods

sensitive in darkness, concentrated in the peripheral, and see black and white

Cones

sensitive in light, see color and fine details

Trichromatic (Young-Helmholtz) theory

The retina contains three color receptors (red, green, and blue) which when stimulated allow us to see any color

Opponent-process theory

opposing retinal processors enable color visions (ex. cells stimulated by green are inhibited by red)

Fovea

where cones are located

Afterimages

the visual perception that remains after a stimulus has been removed, caused by the fatigue of retinal photoreceptors or ongoing neural signaling

Ganglion cells

activated by bipolar cells. their axons turn into the optic nerve

Color vision deficiencies

a condition where people cannot see colors the way others do, most commonly involving difficulty distinguishing between red and green

Occipital lobe

It receives visual input from the eyes and processes it to allow you to see the world.

Prosopagnosia

a neurological disorder characterized by the inability to recognize familiar faces

Blindsight

the ability to respond to visual information without consciously seeing it, often occurring after damage to the brain's primary visual cortex

Wavelength of sound

Short wavelengths are high frequency (pitched) sound. Long wavelengths are low frequency (pitched) sounds

Amplitude of light

tells us the intensity of the light

Amplitude of sound

Large amplitude is loud sounds. Small amplitude is soft/quiet sounds

Place theory

a model of auditory perception that explains how we hear different pitches by the location of stimulation along the membrane in the inner ear (most applicable to high frequency)

Frequency theory

proposes that the pitch of a sound is determined by the rate at which the auditory nerve fires (most applicable to low frequency)

Sound localization

Sound waves strike one ear slightly sooner and more intensely. Losing hearing in one ear makes it more difficult to locate sound

Conduction deafness

Damage to the mechanical system (eardrum and middle ear bones)

Sensorineural deafness

Damage to cochlea hair cell receptors or auditory nerve

Chemical senses

Olfaction and gustation

Thalamus

Sensory gateway: it receives almost all sensory information (except for smell) and relays it to the cerebral cortex for interpretation

Pheromones

Olfactory chemical messages. Some serve as sexual attractants

Gustatory cells

Sweet: energy source
Sour: potentially toxic acid
Bitter: potential poisons
Salty: sodium essential to physiological processes
Umami: proteins to grow and repair tissue
Oleogustus: fats for energy, insulation, and cell growth

Taste receptors

(taste buds) linked to sensitivity of taste. detect molecules from food and other substances, allowing the sensation of taste and triggering responses like digestion or immune reactions

Supertasters

higher number of taste buds, experience taste intensely (25% of the population)

Nontasters

have fewer taste buds (25% of the population)

Medium tasters

average sensitivity of flavors (50% of the population)

Temperature receptor activation

involves specialized receptors that convert thermal stimuli into neural signals, which are then processed by the brain to influence our psychology, including attention, mood, and behavior

Pain (gate control theory)

Pain signals are not transmitted directly to the brain but are modulated by a “gate” in the spinal cord

Phantom limb syndrome

When a person is missing a limb, the brain may misinterpret and increase nervous system activity

Gustation

action of tasting (receptors in taste buds)

Olfaction

action of smelling (receptors in nasal cavities)

Vestibular sense

the body's sensory system, located in the inner ear, that controls balance and spatial orientation

Kinesthesis

the ability to feel the position and movement of one's body and limbs without needing to see them. Relies on receptors in muscles, joints, and tendons that send feedback to the brain, enabling coordinated and balanced movements

Bottom-up processing

involves analyzing sensory information in a sequential and detail-oriented manner, from the simplest to the more complex elements
. It is also known as data-driven processing.

Top-down processing

our brains use prior knowledge, expectations, and context to interpret and understand sensory information

Perceptual set

a mental predisposition to perceive one thing and not another (influenced by context, experience, motivation, emotion, culture)

Gestalt closure

we fill in gaps to create a complete/whole object

Gestalt proximity

we group nearby figures together

Gestalt figure-ground

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

Gestalt similarity

we group together objects that seem alike/similar

Gestalt principles:

proximity, closure, similarity, figure-ground

Selective attention

our tendency to focus on just a particular stimulus among the many around us

Cocktail party effect

ones ability to focus on one voice among many

Change blindness

failure to notice changes in the enviroment

Inattention blindness

failing to see visible objects when our attention is directed elsewhere

Binocular depth cues

Retinal disparity and convergence

Monocular depth cues

Relative clarity, relative size, texture gradient, linear perspective, interposition

Retinal disparity

the slight difference in the images our two eyes receive due to their separation, which allows the brain to judge depth and distance

Convergence

A binocular depth cue where the brain uses the inward turning of the eyes to judge distance. When you look at something close, your eyes angle inward more, and the brain understands this increased muscle effort means the object is near

Relative clarity

a depth perception cue where objects that are sharper and more detailed appear closer, while hazier or blurrier objects appear farther away

Relative size

a comparison of an object's size to another object

Texture gradient

a visual cue where the texture of a surface appears to change from coarse up close and smooth as it recedes into the distance

Linear perspective

parallel lines appear to converge as they recede into the distance

Interposition

one object partially blocking another is perceived as being closer

Perceptual constancy

the tendency to perceive objects as having consistent properties, like shape, size, and color, even when the sensory input (like the object's distance or angle) changes

Stroboscopic motion

an illusion of continuous movement experienced when viewing a rapid series of still images

Phi phenomenon

illusion of movement created when two or more adjacent lights blink on and off in quick succession

Autokinetic effect

illusion of movement of a still spot in a dark room

Cochlea

House the receptors for hearing. Hair moves with sound vibration → electrical impulse

Transduction in the Ear

Soundwave → cochlea → hair cells → auditory nerve → thalamus → auditory cortex

Transduction in the Eyes

light/stimulus → rods and cones in the retina → neural impulse → ganglion cells → optic nerve → thalamus → occipital lobe

Retina is to eye as

cochlea is to ear

Thalamus in smell

bypassed

Semi-circular canals in ear

Three fluid-filled loops (anterior, posterior, and horizontal) that detect rotational head movements, such as nodding yes or shaking your head no

wavelength (frequency) of light

short are blue tone and long are red tone