AP psych

Unit 3 sensation and perception

Sensation

bringing in sensory stimuli from the environment to the brain

Perception

Organizing & interpreting sensory info

Transduction

Converting an environmental energy into a neural impulse

Absolute Threshold

the minimum amount of energy needed to detect the presence of a stimulus (50% of the time)

Just noticeable difference (JND)(AKA difference threshold)

the minimum amount of energy needed to detect a change in a stimulus or the difference between two stimuli (50% of the time)

Weber’s Law (related to JDN)

JND is a fixed proportion of the intesiry of the stimulus

The greater initial intensity of a stimulus the more it is going to take to notice

Sensory adaptation

decline in sensitivity to stimuli that are presented at a constant level (our sensory neurons become less responsive)

Sensory Interaction

Occurs when one sense impacts another (taste and smell)

Synesthesia

Cross-talk of the senses   (KIKI- Sharp object)

Amplitude

Brightness/intensity

Wavelength

color/hue

Short Wavelengths

blues

Long Wavelengths

reds

Visual Process

Light wave - cornea - iris + pupil - lens - retina - photoreceptors - bipolar cells - ganglion - forms the optic nerve - optic disk - thalamus - occipital lobe

Accomodation

the ability of the lens to bend light rays in order to focus the image (based on the objects location on th retina)

Nearsightedness

Occurs when the lens bends too much causes the image to fall in front of the retina

Farsightedness

occurs when the lens doesn’t bend enough causes the image to fall in behind the retina

Photoreceptors

Sensory receptors for vision ~ responsible for transduction

Cones

Color vision; helps us to see in the daytime/bright loghting; located in the center of the retina

Fovea

Center of the retina, highest concentration of cones; greatest visual activity (detail)

Rods

Detect black white and gray sensitive to movement more sensitive in dim lighting; located on the outher edge of the retina (peripheral vision)

Bipolar cells

Receive visual signals from photoreceptors (rods & cones) help to see contrast and edges

Ganglion Cells

Signals sent from bipolar cells; axons of ganglion cells bumdle together to form the optic nerve

Optic nerve and Optic disk

The optic nerve leaves the eye at the optic disk

Blindspot

Where the optic nerve leaves the eye there are no rods and cones, which creates a blind spot

Feature detectors

Specialized cells that respond to specific features of more complex stimuli (edges, lines, angles)

Parallel Processing

Processing visual information is done simultaneously (as opposed to serial processing)

Blindsight

A condition in which a person can respon to a visual stimulus without consciously experiencing it

Prosopagnosia (face blindness)

the inability to recognize human faces

Visual agnosia

the inability to recognize objects

Young-Helmholtz Trichromatic Theory

there are 3 types of receptors (cones) with different sensitivities to different wavelengths that can create all colors: red green blue

Color Blindness

Lack one of the three (or more in rare cases two) types of cones

(supports the Trichromatic theory of color vision)

Dichromatism

Only 2 cone types are functional

Monochromatism

Only one type of cone is functional

Opponent Process theory

Color perception is determined by the activity of 3 opponent systems: yellow-blue red-green black-white

Occurs in the ganglion cells

Afterimages

an image that continues to appear in the eyes after a period of exposure to the original image

Supports the opponent process theory of color vision

figure-ground

figure-the object

Ground- the background or surroundings in which the object occurs

Closure

filling in the gaps to perceive a completed image

Proximity

Objects close together are grouped together

Similarity

grouping based on shared characteristics

Perceptual constancies

Pereving object as unchanging (having consistent color,size, shaoe, brightness, ect.) even as illumination and retinal images change

Visual Cliff (what is it and what was learned)

Apparatus used to to test depth perception in infants

Depth perception is largely innate

Binocular depth cues

Retinal (binocular) disparity'

depth perception guided by the different images seen by each eye

Convergence

sensing the eyes converging (turning inward) as they focus on closer objects

Linear perspective (monocular depth cues)

parallel lines appear to converge in the distance

Relative Size

Closer objects appear larger that far away objects