Psych/Soc Flashcards
binocular cues
Humans have two eyes which allow them to receive visual cues from their environment by ___________. These give them a sense of depth. Examples include:
- Retinal disparity
- Convergence
retinal disparity
Eyes are ~2.5 inches apart which allows humans to get slightly different views of objects of world around. Gives humans an idea on depth.
convergence
Gives humans an idea of depth based on how much eyeballs are turned:
- Things far away – muscles of eyes relaxed.
- Things close to us – muscles of eyes contracted.
monocular cues
Visual cues humans receive which they do not need two eyes for. These give humans a sense of form of an object. Examples include:
- Relative size
- Interposition (overlap)
- Relative height
- Shading and contour
- Motion paralax
- Constancy (size, shape, color)
relative size
The closer an object it is perceived as being bigger. Gives us an idea of form. Monocular cue.
interposition (overlap)
Perception that one object is in front of another. An object that is in the front is closer. Monocular cue.
relative height
Things higher are perceived to be farther away than those that are lower. Monocular cue.
shading and contour
Using light and shadows to perceive form depth/contours (e.g. crater/mountain).
motion parallax
“Relative motion.” Things farther away move slower,
closer moves faster. Monocular cue that gives a sense of motion.
constancy
Our perception of object doesn’t change even if the image cast on the retina is different. Different types of constancy include size constancy, shape constancy, color constancy.
size constancy
One that appears larger because its closer, we still think it is the same size.
shape constancy
A changing shape still maintains the same shape perception.
- Ex. A door opening means the shape is changing. But we still believe the door a rectangle
color constancy
Despite changes in lighting which change the image color falling on our retina, we understand (perceive) that the object is the same color.
sensory adaptation
Our senses are adaptable and they can change their sensitivity to stimuli (hearing, touch, smell, proprioception, sight)
hearing adaptation
Inner ear muscle: higher noise = muscle contract (this dampens vibrations in inner ear, protects ear drum.) Takes a few seconds to kick in! So does not work for immediate noises like a gun shot, but it works for being at a rock concert for an entire afternoon
touch adaptation
Temperature receptors get desensitized over time.
smell adaptation
Receptors in your nose get desensitized to molecule sensory information over time.
proprioception adaptation
The sense of the position of the body in space i.e. “sense of balance/where you are in space.”
- Experiment: goggles that make everything upside down and the perception of the world, and eventually you would accommodate over time, and flip it back over.
sight adaptation
Down regulation or up regulation to light intensity:
- Down regulation: light adaptation. When it is bright out, pupils constrict (less light enters back of eye), and the desensitization of rods and cones become desensitized to light)
- Up regulation: dark regulation. Pupils dilate-, rods and cones start synthesizing light sensitive molecules
down-regulation of sight adaptation
Light adaptation. When it is bright out, pupils constrict (less light enters back of eye), and the desensitization of rods and cones become desensitized to light)
up-regulation of sight adaptation
Dark regulation: Pupils dilate, rods and cones start synthesizing light sensitive molecules.
just noticeable difference (JND)
The threshold at which you’re able to notice a change in any sensation.
- E.g. A 2 vs. 2.05 lb weight would feel the same, but a 2 vs. 2.2 lb weight difference would be noticeable.
weber’s law
ΔI (JND)/I (initial intensity) = k (constant)
- E.g: 0.2/2 = 0.5/5 = 0.1, change must be 0.1 of initial intensity to be noticeable
If we take Weber’s Law and rearrange it, we can see that it predicts a linear relationship between incremental threshold and background intensity.
- ΔI=Ik
absolute threshold of sensation
The minimum intensity of stimulus needed to detect a particular stimulus 50% of the time.
- At low levels of stimulus, some subjects can detect and some can’t.
- Different than Just Noticeable Difference (JND) which is the smallest difference that can be detected 50% of the time
- Absolute threshold can be influenced by a # of factors (it’s not a fixed unchanging number. E.g: it is influenced by a variety of psychological states:
- Expectations – ex. Are you expecting a text.
- Experience (how familiar you are with it) – ex. Are you familiar of the phone’s text vibration sound.
- Motivation – ex. Are you interested in the response of the text
- Alertness – Are you awake our drowsy. Ex. You will notice text if you are awake
subliminal stimuli
Stimuli below the absolute threshold of sensation.
somatosensation: types
Temperature (thermoception)
Pressure (mechanoception)
Pain (nociception)
Position (proprioception)
somatosensation: intensity
How quickly neurons fire for us to notice.
- Slow = low intensity, fast = high intensity.
somatosensation: timing
Neuron encodes 3 ways for timing: non adapting, fast adapting, or slow adapting
- Non-adapting- neuron fires at a constant rate
- Slow-adapting - neuron fires in beginning of stimulus and calms down after a while
- Fast-adapting - neuron fires as soon as stimulus start…then stops firing. Starts again when stimulus stops).
non-adapting somatosensory neuron
Neuron fires at a constant rate during stimulation
slow-adapting somatosensory neuron
Neuron fires in beginning of stimulus and calms down after a while
fast-adapting somatosensory neuron
Neuron fires as soon as stimulus start … then stops firing. Starts again when stimulus stops.
somatosensation: location
Location-specific stimuli by nerves are sent to brain. Relies on dermatomes.
vestibular system
A type of sensation. Balance and spatial orientation
- Comes from both inner ear and limbs.
- Focus on inner ear - in particular the semicircular canals (posterior, lateral, and anterior; each orthogonal to each other)
- Canal is filled with endolymph, and when we rotate the fluid shifts in the semicircular canals – allows us to detect what direction our head is moving in, and because we can detect how quickly the endolymph is moving we can determine the strength of rotation.
- Otolithic organs (utricle and saccule) help us to detect linear acceleration and head positioning. In these are CaCO3 (Calcium carbonate) crystals attached to hair cells in viscous gel. If we go from lying down to standing up, they move, and pull on hair cells, which triggers action potential. These would not work very well w/o gravity! Buoyancy can have effects as well, particularly without visual cues on which way is up/down.
- Also contribute to dizziness and vertigo (when you or objects around you are moving when they are not)
- Endolymph doesn’t stop spinning the same time as we do, so it continues moving and indicates to brain we’re still moving even when we’ve stopped – results in feeling of dizziness.
semicircular canals
Posterior, lateral, and anterior
- Each orthogonal to each other
- Part of inner ear structure
endolymph
Fluid in the inner ear: when we rotate, this fluid shifts in the semicircular canals, allowing us to detect what direction our head is moving in, and because we can detect how quickly the fluid is moving, we can determine the strength of rotation.
otolithic organs
utricle and saccule
- Help us to detect linear acceleration and head positioning. In these are CaCO3 (Calcium carbonate) crystals attached to hair cells in viscous gel. If we go from lying down to standing up, they move, and pull on hair cells, which triggers AP. These would not work very well w/o gravity! Buoyancy can have effects as well, particularly without visual cues on which way is up/down.
signal detection theory
Theory that looks at how we make decision under conditions of uncertainty – discerning between important stimuli and unimportant “noise”
- Origins in sonar – is signal a small fish vs. large whale.
- Its role in psychology – Imagine being given a list. Then a second list. Now experimenter asks, which words on the second list were on the first. Person has to have uncertainty as they are not sure whether a certain word is exact or similar than the one in the first list. (Which words on second list were present on first list.)
- Real world example – traffic lights. It’s foggy day & you have to decide when to start driving. How strong does a signal have to be for you to drive? Signal is present or absent (red).
- Options: hit/miss/false alarm/correct rejectio
- Hit, the subject responded affirmative when a signal was present
- False Alarm, the subject perceived a signal when there was none present;
- Correct Rejection, a correct negative answer for no signal
- Miss, a negative response to a present signal
hit (signal detection theory)
The subject responded affirmative when a signal was present
false alarm (signal detection theory)
The subject perceived a signal when there was none present
correct rejection (signal detection theory)
A correct negative answer for no signal
miss (signal detection theory)
A negative response to a present signal
conservative strategy (signal detection theory)
Always say no unless 100% sure signal is present. Bad thing is might get some misses.
liberal strategy (signal detection theory)
Always say yes, even if get false alarms.
bottom up processing
Begins with stimulus. Stimulus influences what we perceive (our perception).
- No preconceived cognitive constructs of the stimulus (never seen it before)
- Data driven. And the stimulus directs cognitive awareness of what you’re looking at (object)
- Inductive Reasoning: always correct.
top-down processing
Uses background knowledge influences perception.
- Ex. Where’s Waldo
- Theory driven. Perception influenced by our expectation
- Deductive Reasoning: Ex. creating a cube when it’s not there! Not always correct.
gestalt principles
Tries to explain how we perceive things the way we do.
- Imagine watching a basketball game on TV. Why don’t we tell ourselves that we’re looking at bunch of still pictures rather influence ourselves that it’s some fluid realistic representation of basketball game?
- Similarity
- Pragnanz
- Proximity
- Continuity
- Closure
- Symmetry
- Law of Common Fate
- Law of Past Experiences
- Contextual Effects
similarity (gestalt principle)
Items similar to one another grouped together by brain.
- Ex: The brain automatically organizes these squares and circles in columns, and not in rows.
praganz (gestalt principle)
Reality reduced to simplest form possible.
- Ex. Olympic rings, where the brain automatically organizes these into 5 circles, instead of more complex shapes.
proximity (gestalt principle)
We naturally group the closer things together rather than things that are farther apart.
- Ex: We group things that are close to each another together.
continuity (gestalt principle)
Lines are seen as following the smoothest path.
- Ex: You group the line together!
closure (gestalt principle)
Objects grouped together are seen as a whole. Your mind fills in the missing information.
- Ex. You fill in the triangle even though there is none.
symmetry (gestalt principle)
The mind perceives objects as being symmetrical and forming around a center point.
law of common fate (gestalt principle)
For example, if there are an array of dots and half the dots are moving upward while the other half are moving downward, we would perceive the upward moving dots and the downward moving dots as two distinct units.
law of past experiences (gestalt principle)
Under some circumstances, visual stimuli are categorized according to past experiences. If two objects tend to be observed within close proximity, or small temporal intervals, the objects are more likely to be perceived together. For example, the English language contains 26 letters that are grouped to form words using a set of rules. If an individual reads an English word they have never seen, they use the law of past experience to interpret the letters “L” and “I” as two letters beside each other, rather than using the law of closure to combine the letters and interpret the object as an uppercase U
structure of the eye
- Conjunctiva: thin layer of cells that lines the inside of your eyelids from the eye.
- Cornea: transparent thick sheet of fibrous tissue, anterior 1/6th; starts to bends light, first part of eye light hits.
- Anterior chamber: space filled with aqueous humour, which provides pressure to maintain shape of eyeball; allows nutrients and minerals to supply cells of cornea/iris.
- Pupil: the opening in the middle of the iris. The size of the pupil can get bigger/smaller based on the iris relaxing/contracting respectively. The pupil modulates the amount of light able to enter the eyeball.
- Iris: Gives the eye color. The muscle that constricts/relaxes to change the size of the pupil.
- Lens: bends the light so it goes to back of eyeball – focuses light specifically on the fovea of the retina. Adjust how much it bends the light by changing its shape, using the suspensory ligaments.
- Suspensory ligaments: attached to a ciliary muscle. These two things together form the ciliary body, what secrets the aqueous humor.
- Posterior chamber: area behind the iris to the back of lens; also filled with aqueous humor.
- Vitreous chamber: filled with vitreous humour, a jelly-like substance to provide pressure to eyeball and gives nutrients to inside of eyeball.
- Retina: inside, back area filled with photoreceptors, where the ray of light is converted from a physical waveform to a electrochemical impulse that the brain can interpret.
- Macula: special part of retina rich in cones, but there are also rods.
- Fovea: special part of macula. Completely covered in cones, no rods. *Rest of the retina is covered in primarily rods.
- Cones: Detect color and discern high level of detail in what you are observing. Cone shaped.
- Rods: Detect light. Rod shaped.
- Choroid – pigmented black in humans, is a network of blood vessels that helps nourish the retina. It is black, so all light is absorbed here. Some animals have a different colored choroid which gives them better night vision.
- Sclera – Light usually absorbed by the time it gets to this. The whites of the eye, thick fibrous tissue that covers posterior 5/6th of eyeball (cornea covers the anterior 1/6). Attachment point for muscles. Extra layer of protection and structure of eyeball. Lined with the conjunctiva.
conjunctiva
Thin layer of cells that lines the inside of your eyelids from the eye.
cornea
Transparent thick sheet of fibrous tissue
- Anterior 1/6th
- Starts to bend light
- First part of eye light hits
anterior chamber
Space filled with aqueous humour, which provides pressure to maintain shape of eyeball
- Allows nutrients and minerals to supply cells of cornea/iris.
aqueous humor
The clear fluid filling the space in the front of the eyeball between the lens and the cornea.
- Provides pressure to maintain shape of eyeball.
pupil
The opening in the middle of the iris.
- Can get bigger/smaller based on the iris relaxing/contracting respectively.
- Modulates the amount of light able to enter the eyeball.
iris
The muscle that constricts/relaxes to change the size of the pupil.
- Gives the eye color.
lens
Bends the light so it goes to back of eyeball
- Focuses light specifically on the fovea of the retina.
- Adjusts how much it bends the light by changing its shape, using the suspensory ligaments.
suspensory ligaments
Attached to a ciliary muscle - these two things together form the ciliary body, what secrets the aqueous humor.
posterior chamber
area behind the iris to the back of lens; also filled with aqueous humor.
vitreous chamber
Filled with vitreous humour, a jelly-like substance to provide pressure to eyeball and gives nutrients to inside of eyeball.
retina
Inside, back area filled with photoreceptors, where the ray of light is converted from a physical waveform to a electrochemical impulse that the brain can interpret.
macula
Special part of retina rich in cones, but there are also rods.
fovea
Special part of macula. Completely covered in cones, no rods.
- **Rest of the retina is covered in primarily rods.
choroid
Pigmented black in humans, is a network of blood vessels that helps nourish the retina. Because it is black, all light is absorbed. Some animals have a different colored choroid which gives them better night vision.
sclera
Usually absorbs by the time the light gets to this. The whites of the eye, thick fibrous tissue that covers posterior 5/6th of eyeball (cornea covers the anterior 1/6). Attachment point for muscles. Extra layer of protection and structure of eyeball. Lined with the conjunctiva.
Marr’s 4 stages of vision
phototransduction cascade (PTC)
Makes the brain recognize that there is light entering the eyeball. The process of making the light –> neural impulse by turning off a rod:
- Light hits rods (which causes rod to turn off) –> bipolar cell (turns on) –> retinal ganglion cell (turns on) –> optic nerve –> BRAIN
- The phototransduction cascade is the process of rod turning from ON –> OFF
Detailed process:
- Inside rod are a lot of optic disks stacked on top of one another.
- A lot of proteins on the disks. One of the proteins is rhodopsin (on a cone the same protein is called a photopsin), a multimeric protein with 7 discs, which contains a small molecule called retinal (11-cis retinal). When light hits, it comes through pupil and hits the retina, then it hits rods, some of the light hits rhodopsin (which contains the retinal) and causes the retinal to change conformation from bent to straight conformation (11-trans retinal).
- When retinal changes shape, rhodopsin changes shape (closely linked molecules). This begins the cascade.
- Next, there’s a molecule called transducin made of 3 different parts – alpha, beta, gamma that is attached to the rhodopsin typically.
- When the rhodopsin changes shape, transducin breaks from rhodopsin, and alpha subunit binds to another disk protein called phosphodiesterase (PDE).
- PDE takes cGMP and converts it to regular GMP. [So when light hits, lower concentration of cGMP and increases concentration of GMP].
- Na+ channels on the rods allow Na+ ions to come in, cGMP bound to Na+ channel, keeps the channel open and hence “ON” - HOWEVER as cGMP concentration decreases (due to the PDE which converts it into GMP), Na+ channel closes and cell turns “OFF”
- When Na+ channels become unbound of cGMP, less Na+ enters the cell, then cell hyperpolarization turns it “OFF”
- Bipolar cells:
- When there’s high levels of light, light hits rod, it is turned off –> ON-CENTER bipolar cells actived (OFF-CENTER bipolar cells inactived) –> ON-CENTER retinal ganglion cells activated –> signal to optic nerve to brain
- When it’s dark, rod is turned on –> OFF-CENTER bipolar cells actived (ON-CENTER bipolar cells inactived) –> OFF-CENTER retinal ganglion cell –> sends signal to optic nerve to brain
differences between rods and cones
- A photoreceptor is a specialized nerve that can take light and convert to neural impulse.
- Inside rods are optic discs, which are large membrane bound structures – thousands of them. In membrane of each optic disc are proteins that fire APs to the brain.
Differences b/w rods and cones:
- MORE RODS THAN CONES (each eye has 120M rods vs. 6M cones or 20x more rods than cones.) More important to see light than detail initially!
- Cones are concentrated in the fovea.
- Rods are 1000x more sensitive to light than cones. Better at detecting light – telling us whether light is present i.e. black/white vision.
- Cones detect color primarily but also some light (three types : 60% Red, 30% Green, 10% Blue)
- Rods have slow recovery time vs. cones have fast recovery time. Takes a while to adjust to dark – rods need to be reactivated. Cones adapt to change quickly (fire more frequently)
photoreceptor distribution in retina
- Where optic nerve connects to retina, blind spot – no cones or rods
- Rods are found mostly in periphery
- Cones are found primarily in the fovea, and few dispersed through the rest of eye
- At the fovea (dimple in retina) - there no axons in way of light so get higher resolution
- At the periphery - light has to go through bundle of axons and some energy lost. So at fovea light hits cones directly. At the periphery, less light gets to the rods.
visual field processing
- How our brain makes sense of what we’re looking at. Right side of body controlled by left side, vice versa. How does it work in vision?
- All right visual field goes to left side of brain; all left visual field goes to right side of brain.
- Ray of light from the left visual field hits the NASAL side of the left eye and hits the TEMPORAL side of the right eye
- Vice versa for light from the right visual field. Ray of light from the right visual field hits the NASAL side of the right eye and hits the TEMPORAL side of the left eye
- Optic nerves from each eye networks the electrical signal to the brain and converge from each eye at the optic chiasm and then break off and dig deeper into the brain
- Now….all light from the nasal side of both eyes cross to the other side so left nasal info goes to the right side and vice versa.
- On the other hand, all axons leading from the temporal side DO NOT CROSS the optic chiasm.
- What it effectively does, is the right visual field goes to the left brain and the left visual field goes to the right side of the brain (see diagram)
feature detection
When looking at an object, you need to break it down into its component features to make sense of what you are looking at. There are 3 things to consider when looking at any object: color, form, and motion:
-
Color:
- Cones
- Trichromatic theory of color vision, three types of cones: RED (60%), GREEN (30%), BLUE (10%)
- Remember, red objects reflect red, green objects reflect green, and blue objects reflect blue
- If object reflects red –> red light hits red cone –> fire axon potential –> brain is like OH RED!!
-
Form:
- We need to figure out boundaries of the object and shape of the object.
- Parvocellular pathway: good at spatial resolution (boundaries and shape—high levels of details), and color. But poor temporal (can’t detect motion—only stationary.)
- Cones responsible
- Acronym: Pink Pyramid (a type of “form”/”shape”) = Parvocellular pathway
-
Motion:
- Magnocellular pathway: has high temporal resolution (think time, motion) resolution [encodes motion]. But has poor spatial resolution; no color).
- Rods responsible.
- Acronym: Motion = Magnocellular pathway
sound (auditory waves) pathway
Sound (auditory waves) pathway:
- First hit outer part of ear, known as the pinna.
- Then the sound gets funneled from the pinna to the auditory canal (also known as external auditory meatus).
- Then from the auditory canal they hit the tympanic membrane (also called the eardrum).
- As pressurized wave hits eardrum, it vibrates back and forth, causing 3 bones to vibrate in this order:
- Malleus (hammer)
- Incus (anvil)
-
Stapes (stirrup)
- *[acronym: MIS]
- *Three smallest bones in the body.
- *These bones combined are also referred to as the ossicles.
- Stapes is attached to oval window (aka elliptical window). The oval window then vibrates back and forth.
- As it gets vibrated, it pushes fluid and causes it to go in/around cochlea (a round structure lined with hair cells).
- At tip of cochlea (inner most part of circle), where can the fluid now go? It can only go back, but goes back to the round window (circular window) and pushes it out.
- The reason doesn’t go back to oval window, is because in middle of cochlea is a membrane – the organ of Corti (includes the basilar membrane and the tectorial membrane).
- As hair cells (cilia) move back and forth in the cochlea – electric impulse is transported by auditory nerve to the brain.
- Place theory posits that one is able to hear different pitches because different sound waves trigger activity at different places along the cochlea’s basilar membrane.
- The above process of fluid going around the cochlea keeps occurring till the energy of the sound wave dissipates and stops moving. Occurs more = more hair cells vibrate.
cochlear implants
A surgical procedure that attempts to restore some degree of hearing to individuals with sensorineural narrow hearing loss – aka **nerve deafness**
- Individuals who have a problem with conduction of sound waves from cochlea to brain.
- Receiver goes to a stimulator, which reaches the cochlea.
- Receiver receives info from a transmitter. Transmitter gets electrical info from the speech processor. Speech processor gets info from microphone.
- Sound -> microphone -> transmitter (outside the skull) sends info to the receiver (inside skull). Then it sends info to the stimulator, into the cochlea, and cochlea converts electrical impulse into neural impulse that goes to brain. Restores some degree of hearing.
organ of corti (details)
Let’s unroll the cochlea. Stapes – moving back and forth at same frequency as stimulus. It pushes the elliptical window back and forth.
- There’s fluid inside the cochlea, which gets pushed around cochlea, and comes back around. Organ of Corti splits cochlea into 2 – the upper and lower membrane.
Cross section of Organ of Corti
- Upper and lower membranes, and little hair cells. As fluid flows around the organ, it causes hair cells to move back and forth.
- At the upper membrane: The hair cells/cilia are called the hair bundle and it is made of little filaments. Each filament is called a kinocilium. Tip of each kinocilium is connected by a tip link which is attached to gate of K+ channel. When the tip links get pushed back and forth by endolymph movement, they stretch and allows K+ to flow inside the cell from the endolymph (which is K+ rich)
- Ca2+ cells get activated when K+ is inside, so Ca2+ also flows into the cell, and causes an AP, which then activates a spiral ganglion cell, which then activates the auditory nerve.
auditory processing
How does the cochlea distinguish between sounds of varying frequencies and how is this distension maintained by the brain?
- Brain relies on cochlea to differentiate between 2 different sounds: Base drum has low frequency, whereas bees have high frequency.
- We can hear frequencies between 20-20000Hz.
- The information from the base drum and bees hits the cochlea.
- Brain uses basilar tuning – there are varying hair cells in cochlea and allows brain to distinguish between high and low frequency sounds. Hair cells at base (start of cochlea) of cochlea are activated by high frequency sounds, and those at apex (end of cochlea) by low frequency sounds. THNK: long wavelengths can travel farther.
- As sounds of different frequencies reach the ear, they will stimulate different parts of the basilar membrane.
- Apex = 25 Hz (low freq, HIGH wavelength)
- Base = 1600 Hz (high freq, LOW wavelength)
- As sound enters the cochlea, it travels and activates the hair cell that matches its frequency and it is mapped to a particular part of the brain. The primary auditory cortex (part of temporal lobe…acronym: hear Time Ticking = Temporal Lobe) receives all info from cochlea. It is separated by regions which detect different frequencies (0.5 kHz – 16 kHz).
- If this didn’t occur, brain wouldn’t be able to distinguish between different sound frequencies.
- So with basilar tuning, brain can distinguish different frequencies – tonotopical mapping
