PSC ch.4

the minimum amount of a stimulus you need to perceive a sensation

detection of an reaction by sensory stimuli through sensory organs and transmission of response to the brain

sensory stimuli -> sensory organs -> brain

-biological impact

-processing and interpretation of sensory stimuli

-psychological impact that is driven by our present/past experience

the minimum amount of stimuli needed to perceive a difference

Webster believes that to perceive a difference, the stimuli must have different constant proportion and not have a constant amount

• example:
•   using extra $200 for laptop (unlikely to spend)
•                  vs.
•     using extra $200 for house (likely to spend)

detection of a stimulus depends partly on a person's:

• experiences
• expectations
• alertness
• motivation

the ability to respond visual stimuli without having any conscious visual experience

-it is densely packed with cones

-has the highest visual

to perceive a difference in arrival time of sound between the two ears

allow us to localize sound

the way neurons in the visual pathway respond to specific features of a stimulus

angle, shape, direction of movement

physical mixing of color to remove reflected wavelengths

combination of pigments

ex. mixing paints

you see color black

mixing of different wavelengths of light to increase reflected wavelengths

combining light to get white

we perceive familiar objects as having consistent color

even if changes in illumination alter the wavelengths being reflected

sensory information starts from low level to high level of processing area

low level = entry level sensation

information from higher order processing areas influences sensory information at low level areas

-we use our expectations and past experiences to interpret sensation

gustation (the action of tasting)

sweet, salty, sour, bitter, umami

sensory organs to taste include, tongue, mouth and throat

the cilia is a small hairlike receptor that sticks out to receive info

taste receptors in taste bud transmit signal along a cranial nerve through the thalamus, to other areas of the brain resulting perception

• Olfaction-the sense of smell
• the only sense that doesn't go to thalamus first

volatile chemicals act as stimulus energy

pathway to the brain glides along the olfactory nerve to areas of the cortex and amygdala

the nose and nasal passage

olfactory receptors, in the olfactory epithelium, transmit the signal to the olfactory bulb which transmits it along the olfactory nerve to areas of the cortex and amygdala

touch is stimulated through temperature and pressure

skin is a sensory organ for touch

receptors are found everywhere, mainly at base of hair follicles

• 2 type of fibers transduce pain signals
• fast fibers create sharp and immediate pain

short fibers create dull, chronic pain that makes the person remember not to make same mistake

temperature and pressure receptors in your skin transmit signal from brain stem to thalamus

stimulus like noise with different wavelength (noise), frequency (pitch) and amplitude (intensity)

• sound wave enters pinna
• moves down ear canal
• vibrates ear drum
• cause ossicles to vibrate
• vibrate oval window creating waves in cochlear fluid

• waves in fluid cause basilar membrane to move
• this bends hair cells
• moving hair cells transmit neural signal to auditory nerve

the pathway to the brain starts from the auditory nerve

going to thalamus

specifically to the medial geniculate nucleus

and the thalamus will transfer the wave to the auditory cortex

• rods
• cones

• Rods
• -found in periphery
• -respond to low light
• -night vision

• Cones
• -found in center
• -respond to high light
• -color vision
• -vision acuity

1. bleaching - light enters the eye and break down photopigments

2. causes membrane changes in photoreceptor

3. activates interneurons

4. interneurons work to exaggerate signals from photoreceptors

5. pass signals to ganglion cells

6. ganglion cells- first neurons in visual pathway with axons

7. collect info from a group of bipolar cells/interneurons

8.send signal to optic nerve

9.optic nerve sends signal from retina to brain

10. half of he nerves cross over at the optic chiasm

11. from optic chiasm signal goes to thalamus

12. info then sent to visual cortex

kinesthetic sense

vestibular sense

• position of your body and limbs in space 
• and in relation to one another

sense of balance

Monocular cues judge depth through the use of separate eyes

top down processing


linear perspective

parallel lines, width length decreases when distance increase

ex. train tracks

we perceive objects that are higher in our view as being farther away

objects that are farther away seem smaller on the retina than close objects of the same size