Sensation and Perception Flashcards
What is the psychology definition of Sensation?
Transduction; conversion of physical, electromagnetic, auditory, and other information from our internal and external environment to electrical signals in the nervous system
What is the psychology definition of Perception?
Processing the information to make sense of its significance
What is the difference between Sensation and Perception?
Sensation is merely information as a electrical signal from both outside and inside; Perception is processing this information to understand what is going on.
What are Sensory receptors?
Neurons that respond to stimuli and trigger electrical signals
What is Psychophysics?
Relationship between nature with perception and Sensation
What is Ganglia?
Collection of neuron cell bodies found outside of CNS; They receive signals from the nerve endings and transmit the information to CNS.
What are the 7 common receptors?
Photoreceptors Hair cells(hearing, rotational and linear acceleration) Nociceptors Thermoceptors Osmoreceptors Olfactory receptors Taste receptors
What is a threshold?
Minimum amount of stimulus that renders a difference in perception
What is the difference between Absolute threshold and Threshold of conscious perception? What happens when the stimulus is below each threshold?
Absolute threshold is the minimum stimulus energy required to activate a sensory system; Threshold of conscious perception is the minimum energy required to catch one’s attention and consciousness
Absolute threshold: if below, the signal is not transduced, not reaching the CNS
Threshold of conscious perception: If below, the signal is still transduced and reaches the CNS but maybe to quick or subtle that it doesn’t catch one’s attention
What is jnd and how is it related to Weber’s law? Give an example.
jnd: just noticeable difference(jnd) is the minimum difference in magnitude between two stimuli before one can perceive this difference. But Weber’s law states that instead of the mere difference between the two values, the ratio of: (diff b/w two values / original value) is more important.
ex. if jnd is 0.68% from the ratio, then we apply it to various values: 1000Hz and 1006.8Hz is the difference that one can distinguish, not 1000 and 1003Hz.
What is signal detection theory and what type of bias does this bring?
Theory that states perception of stimuli can be affected by nonsensory factors such as experience, memory, motives, and expectation.
It brings out Response bias which states one’s tendency to systematically respond to a stimulus in a particular way due to nonsensory factors.
A basic signal detection experiment may have catch trials, noise trials, hits, misses, false alarms, and correct negatives. What do these terms mean?
catch trials: signal presented
noise trials: signal not presented
hits: correctly perceives the signal
misses: fails to perceive the signal
false alarms: perceives a signal when none was given
correct negatives: doesn’t perceive the signal when none was given
How does sensory adaptation affect a difference threshold?
adaptation -> increases threshold because we are now “used to it”
List the function of each structure:
- Cornea
- Iris
- Lens
- Ciliary muscle
- Canal of Schlemm
- Pupil
- Sclera
- Vitreous
Cornea: gathers and focuses the incoming light
Iris: divides the front of the eye into anterior and posterior chamber; controls the size of the pupil
Lens: refracts the incoming light to focus it on the retina
Ciliary muscle: produces aqueous humor; accommodation of the lens
Canal of Schlemm: drains aqueous humor
Pupil: allows passage of light from anterior to posterior chamber
Sclera: provides structural support
Retina: Detects images with Cones and Rods
Vitreous: Transparent gel behind the lens that supports retina
List the structures in the visual pathway, from where light enters the cornea to the visual projection areas in the brain
Cornea -> Pupil -> Lens -> Vitreous -> Retina(rods and cones -> bipolar cells -> ganglion cells) -> Optic nerve -> Optic chiasm -> Optic tract -> Lateral geniculate nucleus(LGN) of thalamus -> radiations through parietal and temporal lobes -> visual cortex(in occipital lobe)
What is a characteristic of Optic chiasm?
has fibers that cross from nasal side of the retina
What is the difference between cones and rods?
cones: pick up colors(blue, green, red; short to long wavelengths)
rods: pick up black and white(light or dark)
What is parallel processing?
ability to simultaneously analyze and combine information regarding color, shape, and motion
In feature detection, what type of cells are responsible for color? Shape? Motion? what is the difference between the cells that are responsible for shape and motion?
Color: Cones
Shape: Parvocellular cells; high color and spatial resolution but low temporal resolution
Motion: Magnocellular cells; low spatial resolution but high temporal resolution
What does outer ear consist of(3)?
Pinna(auricle), External auditory canal, Tympanic membrane
What does middle ear consist of(2)?
Ossicles(malleus, incus, stapes)
Eustachian tube
What does Inner ear consist of(2)? what is the difference between the two?
Bony labyrinth. filled with Perilymph
Membraneous labyrinth: filled with Endolymph
What does Membraneous labyrinth consist of and what are their functions?
Cochlea: works with basilar membrane to distinguish sounds of low and high pitch
Vestibule(2): Utricle and Saccule, sensitive to linear acceleration
Semicircular canals(3): three of them with half circular loops, sensitive to rotational acceleration
List the structures in Auditory pathway
Pinna -> external auditory canal -> tympanic membrane -> malleus -> incus -> stapes -> oval window -> perilymph in cochlea -> basilar membrane -> basilar membrane -> hair cells -> vestibulocochlear nerve -> brainstem -> medial geniculate nucleus(MGN) of thalamus -> auditory cortex(temporal lobe)
How does the organization of the cochlea indicate the pitch of an incoming sound?
Basilar membrane is tonotopically organized: high-pitched sounds cause vibrations at the base of cochlea(outer), whereas low-pitched sounds cause vibrations at the apex of the cochlea(inner)
List the structures in the olfactory pathway.
Nostrils -> nasal cavity -> olfactory nerve(chemoreceptors) -> olfactory bulb -> olfactory tract
Both smell and taste are sensitive to chemicals what is different about the types of chemicals each one can sense?
Smell: volatile compounds, gaseous
Taste: dissolved compounds
What are the four main modalities of somatosensation?
Pressure, Temperature, Vibration, Pain
which lobe is responsible for somatosensory?
somatosensory cortext is in parietal lobe
What is the difference between Bottom-up processing and Top-down processing?
Bottom-up(data-driven) processing gathers information using parallel processing and feature detection, then integrated into one cohesive whole. -> slower but less prone to mistakes
Top-down processing depends on experience and expectations to make conclusion and make one cohesive whole -> faster but prone to mistakes
Describe each of the Gestalt principles:
- Proximity
- Similarity
- Good continuation
- Subjective contours
- Closure
- Pragnanz
Proximity: close to each other -> one unit
Similarity: similar -> grouped together
Good continuation: same pathway -> grouped together
Subjective contours: seeing invisible edges
Closure: space surrounded by lines -> enclosed
Pragnanz: Perceptual organization will always be as regular, simple, and symmetric as possible
What is somatosensation?
Kinesthetic sense?
Vestibular sense?
Chemoreception?
- various modalities of touch
- ability to tell where one’s body is in space
- detection of linear and rotational acceleration in the middle ear
- sensing chemicals in the environment
Difference between signal detection and Feature detection?
signal detection: when a stimulus is given, one tries to find/seek if it is what one expected it to be(stimulus -> investigate). Picks up a stimulus(signal) -> looks for it
Feature detection: Investigate -> finds. Detail gathering then finds.
