Chapter 4 Flashcards
Sensation
simple stimulation of a sense organ; basic registration of light , sound, pressure, odor, or taste as parts of your body interact with the physical world.
Perception
the organization, identification, and interpretation of as sensation in order to form a mental representation.
Sensation and Perception are-
Actual components you experience; but are 2 distinct tests that work together for an experience.
How do sensory receptors communicate through the brain?
Transduction
Transduction (where does it happen ?)
- occurs when many sensors in the body convert physical signals from the environment into encoded neural signals sent to the central nervous system.
- the eyes and ears
3 basic Tasks of Sensation and Perception ?
- Translate incoming info into neural impulses
- identify message components
- produce a stable interpretation
The human perceptual system is better at detecting __ in stimulation than the simple onset or offset of stimulation.
- changes
JND ( just noticeable difference)
- the smallest amount of change in a stimulus that can just barely be detected.
- Is CONSTANT
- not a fixed quantity
- proportional to the intensity of the stimulus.
JND was noticed by __
- Ernst Weber
What is “Weber’s law” ?
- The just noticeable difference of a stimulus is a constant proportion despite variations in intensity.
- Noticeable difference is the proportion of the size of the standard.
Example of “Weber’s law”?
- if you picked up a 1 ounce envelope and a 2 ounce after, you would notice the difference between them. But if you picked up a 20 pound package- then a 20-pound 1 ounce package, you’d detect no difference at all between them.
Sensory Adaptation
- Sensitivity to prolonged stimulation tends to decline over time as an organism adapts to current conditions.
- responds more strongly to changes in stimulation more so than constant
Light waves vary in…
- height and wavelengths.
3 physical properties of light waves
- Length ( determines what colors we see )
- Amplitude (how hight the peaks are, determines what we perceive as brightness)
- Purity (number of distinct wavelengths that make up light/ determines saturation or richness of the colors.)
light
translated to neural impulse where transduction happens.
Cornea
- Outer covering of the eye (light gray) (protective covering)
- clear smooth outer tissue where light first passes through
Pupil
- dark center of the eye (dilates to let light in) (or constricts to keep light out)
- hole in the colored part of the eye
iris
- colored part of the eye. (donut shaped muscle) ( controls constriction or dilation of the pupil)
- controls the amount of light that can enter your eye.
lens
- (green portion) if you have vision problems this is where it comes from. uses [accommodation]
accommodation
- process by which the eye maintains a clear image on the retina
- lens changes shape to focus nearby or faraway objects on the retina
retina
- light sensitive tissue lining the back of the eyeball
- where transduction happens
- light is translated into that neural impulse
- made up of “rods and cones”
myopia
- nearsightedness
- condition where eyeball is too long and images are focused in front of the retina
hyperopia
- farsightedness
- if eyeball is too short , images are focused behind the retina
2 types of photoreceptor cells
- rods
- cones
cones
-detect color , operate under normal daylight conditions, and allow us to focus on fine detail.
Rods
- become active under low-light conditions for night vision
- much more sensitive than cones
fovea
-an area of the retina where vision is the clearest and there are no rods at all.
similarity
- Regions that are similar in color, lightness, shape, or texture are perceived as belonging to the same object.
closure
- we tend to fill in missing elements of a visual scene, allowing us to perceive edges that are separated by gaps as belonging to complete objects.
continuation
- when edges or contours have the same orientation, we tend to group them together perceptually.
frequency (wavelength of the ear)
- how often the peak in air pressure passes the ear or a microphone , measured in cycles per second (Hertz Hz)
- perceived by humans as changes in (pitch)
Pitch
- how high or low a sound is
- changes in the physical frequency of a sound wave are perceived
amplitude (sound wave of the ear)
- refers to it’s height, relative to the threshold for human hearing
- corresponds to loudness
- ex.) sound of leaves rustling in the breeze
loudness
- corresponds to amplitude
- sound’s intensity
complexity (sound waves of the ear)
- mix of frequencies
- corresponds to timbre
timbre
- listener’s experience of sound quality or resonance
- offers us information about the nature of sound.
- same note played at the same loudness produces a perceptually different experience depending on whether out was played on a flute versus a trumpet
Pinna of the ear
-airtight flap of skin that vibrates in response to sound waves gathered by the pinna and channeled through the canal
Cochlea
- a fluid filled tube that is the organ of (auditory transduction)
basilar membrane
- structure in the inner ear that undulated when vibrations from the ossicles reach the cochlear fluid.
Haptic perception
active exploration of the environment by touching and grasping objects with our hands.
Touch
- mechanical energy
- different locations on the body project sensory signals to different locations in the somatosensory cortex in the parietal lobe.
- has a powerful effect on our decisions and judgments.
Smell / Olfaction
- least understood sense
- only one directly connected to the forebrain with pathways into the frontal lobe, amygdala , and other forebrain structures.
- smell has a close relationship with emotional and social behavior.
- Olfactory receptor neurons (ORNs), receptor cells that initiate the sense of smell
Taste / gustation
- hundreds of taste buds
- organ of taste transduction
- 5,000 to 10,000 taste buds fairly evenly distributed over the tongue, roof of the mouth , and upper throat.
pain
- fast acting (A) delta fibers transmit initial sharp pain one might feel right away from a sudden injury
- (C) fibers transmit longer-lasting, duller pain that persitis after initial injury.
- if (A) and (C) delta fibers are impaired in cases of congenital insensitivity to pain, that can be life threatening.
PAG ( periaqueductal gray)
- under high stress, naturally occurring endorphins can activate the PAG to send inhibitory signals to neurons in the spinal cord that then suppress pain signals to the brain
- activated through the action of opiate drugs, such as morphine.
absolute threshold
- the minimal intensity needed to just barely detect a stimulus in 50% of the trials.
- it’s a boundary between awareness and unawareness.
