AP Psych Unit 10

Absolute Threshold

Absolute smallest amount of stimulation needed to first detect a sensory stimulus 50% of the time

Difference Threshold

Smallest amount needed to detect a difference/change in stimulation strength as determined by Weber’s Law

Weber’s Law

States the difference threshold is detected based on percentage changes - not by a constant amount

Sensory Adaptation

Weakened sensation after being constantly exposed to a stimulation

Signal Detection Theory

The detection of a sensory stimulus also involves our motivation to detect it

Transduction

Process of converting sensory stimulation into neural signals that our brain can interpret

Wave-Based Senses

Hearing + Vision

Chemical-Based Senses

Olfaction + Taste

Vision

Amplitude=Brightness

Frequency=Color/Hue

Hearing

Amplitude=Volume

Frequency=Pitch

Cornea

Protective outer layer of the eye - bend helps focus light onto retina

Pupil

Adjustable opening where light enters

Iris

Colored part of the eye - controls size of pupil by responding to light intensity

Lens

Behind the pupil - changes curvature to focus light on retina - called accommodation

Retina

Inner surface of eye containing photoreceptors (rods + cones)

Rods

Photoreceptors in the periphery of eyes (outer region)

Peripheral vision and dark adaptation

Detects black, white, and grey

Cones

Photoreceptors in the center of retina (fovea)

“Normally” lit conditions

Detects color in detail

Fovea (Foveal Vision)

Cluster of cones in the center of the retina

• Straight ahead vision

• Most acuity (sharpness, accuracy)

Optic Nerve

Once photoreceptors are stimulated, nearby bipolar cells then ganglion cells send action potentials to the brain via optic nerve

Causes a blind spot in our vision where ganglion cells leave the eye

Feature Detectors

Ganglion cells send information to specialized feature detector neurons in the visual cortex of the occipital lobe

Enables detections of stimuli like movement, edges, and faces

Young-Helmholtz Trichromatic Color Theory

States there are three types of cones that produce any color when stimulates in different combinations (red, green, blue)

Color Deficient Vision

“Color blindness” is due to a lack of functioning between two cones (red/green is most common)

Opponent Process Theory

States our photoreceptor cells (cones) come in color pairs like red/green, yellow/blue, black/white

Negative Afterimage Effect

Illusion after one color is stimulated - those cones will rest and the other color is “seen” after looking away

Process of Auditory Transduction

1. Sound waves enter the auditory canal

2. Hit the tympanic membrane (ear drum) which activates the middles ear (ossicles)

3. Middle ear (ossicles) transfers information to the oval window attached to the inner ear

4. Stimulates hair cells on basilar membrane of the cochlea

5. Cochlea sends action potentials to the temporal lobe

Outer Ear

Auditory canal and tympanic membrane (ear drum)

Function: Steps 1 + 2 of auditory transduction

Middle Ear (Ossicles)

Oval window and three bones (hammer, anvil, stirrup)

Function: Steps 2 + 3 of auditory transduction

Inner Ear

Cochlea + auditory nerve

Function: Steps 3 + 4 of auditory transduction

Additional function: Semicircular canals (vestibular sacs) help maintain balance)

Sound Localization

As a result of having two ears - process of determining the location of a sound by judging which ear was stimulated by sound waves first

Place Theory

Pitch depends on the place where the cochleas basilar membrane has been stimulated

Frequency Theory

Pitch depends on how many times the cochlea (frequency) sends a message to the brain

Conductive Hearing Loss

Damage to the middle ear or outer ear

Sensorineural Hearing Loss

Damage to the inner ear (cochlea or auditory nerve)

Smell/Olfaction

When 350+ molecules in the air reach olfactory receptor cells at the top of our nasal cavity to create 10,000+ odors - processed by the olfactory bulb

(females are superior)

Kinesthetic Sense

Sense for position and movement of individual body parts

Touch

Largest sense organ - mixture of pressure, warmth, cold and pain receptors (More sensitive regions are lips, palms)

Gate Control Theory

Pain theory - spinal cord is able to “block” signals of pain to the brain (massages)

Vestibular Sense

Sense related to our body orientation (balance, equilibrium)

Taste/Gustation

Involves several sensations (sweet, salty, sour, bitter, unmani)

Innate dislike of bitterness to protect from poisons

Sweet signals energy rich food

Receptors: Bumps on your tongue contains 300+ taste buds

Synesthesia

Neurological condition in which sensory input from one pathway (ex. vision) leads to the experience of another sense (ex. taste)