Midterm 1 Flashcards
what are sciences?
- systems of formal theories
- they construct their theories by testing opposing casual hypotheses (models)
what are hypotheses called
models: stated in mathematical or logarithmic form
predict unknown facts through logical (or mathematical) derivation from a model.
what are some universals of childhood?
- childhood fear of strangers
- classification of age
- sweets preferred
- thumb sucking
- turn taking
what is one purpose of developmental theories?
explaining the universals of childhood
what is a theory?
explains known facts and predicts unknown facts by identifying cause-effect relations that hold for the known and the unknown
ceteris paribus (all-other-things being-equal)
example of scientific theory
Darwin’s theory explains the known fact of species- differences as an effect of evolution by natural selection vs. Lamarckism which is the inheritance of acquired characteristics
Does experiment with rat tail length:
Predicts that any newly discovered population that is subject to selection rules differing from its ancestors will evolve different characteristics over time that can eventually lead to speciation - Lamarckism predicts that predicts that short tailed rats will predominate in one group if you cut off the tails of all the rats and interbreed them all
Lamarck’s hypothesis failed
Darwin’s worked
what is a model?
Models are provisional theories that posit mutually exclusive cause-effect relations
Cause-effect relations are established by testing competing models
How do we test a hypothesis?
1) choose the appropriate measurement
2) gather data using some method
3) use data yielded to draw a conclusion
What is measurement?
measure must be directly related to hypothesis!
measure must be reliable
- interrater reliability
- test-retest reliability
measure must be valid
- internal validity: are effects due to manipulated conditions? (e.g. advertising)
- external validity: does the test generalize? (preference for one sip isn’t the whole can)
what are characteristics of good measures?
1) reliable
2) valid
what does it mean to be reliable?
the degree to which independent measurements of a behavior under study are consistent
what is interrater reliability?
do observers agree?
indicates how much agreement there is in the observations of different rates who witness the same behavior
If we measure preference by facial expressions, observers probably won’t agree as much as if we measure preference by self- report.
what is test-retest reliability?
are measures consistent over time?
measures of a child’s performance on the same test, administered under the same conditions, are similar on two or more occasions
what does it mean to be valid?
refers to the degree to which is measures what it is intended to measure
reflect only what is manipulated, generalize outside the measurement setting
what is internal validity?
Are effects due to conditions manipulated?
refers to whether effects observed within experiments can be attributed with confidence to the factor that the researcher is testing
E.g. preference may come from product advertising or from product taste - A blind taste-test would be a better measure b/c it would eliminate brand loyalty as a variable and thus have higher internal validity than a bottle- to-bottle comparison
what is external validity?
does this test generalize?
refers to the ability to generalize research findings beyond the particulars of the research in question
you want to draw more general conclusions
to test its external validity, you’ll have to study participants from different backgrounds with different research methods
E.g. preferences for one sip might not generalize to preferences for a whole can
what are the two problems with correlation?
Hypothesis: Tobacco smoke contains substances that are toxic to human tissue when deposited by contact
1) ambiguous direction of causation (maybe the direction of causation is reversed. maybe people who have cancer are nervous which causes them to smoke)
2) potential third variable (correlation doesn’t mean causation)
what are characteristics of experimental design?
- random assignment
- experimental control
nonsmokers –> smokers –> high disease
vs
nonsmokers –> nonsmokers –> low disease
ONLY experimental designs will allow you to draw a conclusion about causation
examples of non-experimental designs?
1) no control, no pretest
2) no control, pre-post test
3) control, no random assignment
what are some problems for studying developmental causes
- problems of measurement:
1) old people misunderstand instructions
2) young children perseverating answers (repeating them over and over)
3) infants don’t pay attention - problems with age being confounded with non-age related factors (if a kid get’s better at cards over a span of 18 months you have to realize he’s also getting older)
what are three designs for examining development? (identifying age-related changes)
1) cross-sectional designs
2) longitudinal designs
3) microgenetic designs
what is a cross-sectional design?
you collect data from a population/subset at ONE specific point in time - used to describe characteristics that exist in a population, but not to determine cause-and-effect relationships between different variables - utilizes different groups of people who differ in the variable of interest (share other things like race, socioeconomic) - variable is not manipulated
you take measurements in 2000 of how racist the 5, 20, 40, and 80 year old populations are
You see that there is a change with age and that 80 y.o. had more racial sterotypes than 5 y.o.
Even if that were the case you couldn’t say that it was because they were older- it could be because they are from different generations and grew up in different cultures
(bar graph)
what is a longitudinal study?
follow the same people from when they’re 5 to when they’re 80 (1925-2000): if you find the same thing, does this mean it’s showing the same results? well you should probably follow other 5 y.o. that were born 15 years later in a different generation and see if their results were also the same
(linear graph)
what is the microgenetic design?
- Choose children slightly younger than when a change normally takes place
- Provide experiences that are hypothesized to set the change in motion
- Observe the change while it is occurring
The strategy is to experimentally induce a developmental change - you make a change happen by manipulating causal variable - observe before, during, and after the change takes place - you see the change happening
Multiple tests in a short period of time, increased density of trials - can have multiple subjects like the math problem solving strategies experiment
what is the “positive effects of experience”?
the idea is that in the period E you have lots and lots of “special experiences” and what you should find is that the control group and experimental group should diverge - there should be immediate and delayed effects - what happens is that eventually they converge because there’s catch up growth - these special experiences are something that children will just encounter later
what are “negative effects of experience”?
hypothetical patterns of development resulting from the effects of “impoverishing” experience - experimental on isolation
why not make everything innate?
if everything was already hardwired then it’d be hard to adapt/learn - there’d be no plasticity and everything would be robotic - if the environment changes the only way for adaptation to occur would be at individual differences by chance
examples of innate abilities? not innate?
- Newborn colts can run moments after birth
- Newborn rats prefer sweet tasting foods to bitter ones
vs. - speaking english
-driving a car
what are the two theoretical limits on innateness?
1) Environmental change requires fast adaptation: supposed it was hardwired that when you see a bannana you go for it - the bannana used to be brown but now it’s yellow so you need to adapt
2) Genes are limited in number: true but it’s a theoretical limit - even with an limited number of genes you can get unlimited types of behaviors
what is plasticity?
the capacity of brain to change in response to experience or damage
what are three kinds of evidence that support plasticity?
1) Effects of general experiences that almost all normal infants have regardless of history, culture, child-rearing practices, etc. (experience-expectant plasticity)
2) Effects of specific, idiosyncratic experiences the child will have as a result of his or her own life circumstances (experience-dependent plasticity)
3) Recovery from brain damage
what is experience-expectant plasticity?
refers to the role of general human experience in shaping brain development - the normal wiring of the brain partly results from general experiences (everyone has them):
- patterned visual stimulation - voices and other sounds - movement - manipulation
When an expected experience is absent, the areas of the brain that would have normally become specialized as a result of that experience can be reorganized to serve some other function (deaf people have better peripheral stimuli)
These sources activate or stabilize some synapses and cause other synapses to be eliminated
experimental evidence of experience-expectant plasticity?
Experiments on cats and other mammals have shown that if a brain is chemically ‘silenced’ during fetal development, the mammal ends up with significant abnormalities –> it’s almost as if one sense took over to compensate for the missing one
By shutting off auditory stimuli, Mriganka Sur rewired the brains of ferrets so that signals from their eyes fed into their auditory cortex
Ferrrets could even move toward objects detectable by sight alone
its as if the cells of the auditory cortex were trained to be from the occipital cortex
written english vs. ASL experiment
evidence of experience-expectant plasticity
- normally the left hemisphere is used for language processing b/c of the brains expectations of spoken language
- when a language depends on perception of spatial location and motion (like ASL) areas within the right hemisphere are also part of the language systems of the brain –> when you shut down part of the brain it can be taken over by another part of the brain
Studies of visual processing in congenitally deaf individuals suggest that certain aspects of visual development are enhanced after auditory deprivation. These include the perception of and attention to peripheral visual space and to motion
what is experience-dependent plasticity?
proof of plasticity - brain is also wired by idiosyncratic experiences - experience can help select and preserve the synapses that the body produces
stimulus poor vs. stimulus rich environment - when the rats were in the rich environment they were interacting with each other more and they moved/saw more = better exercise –> more dendritic spines on cortical neurons, more synapses per neuron, thicker cortex, more supportive tissues (such as blood vessels and glial cells)
what are examples of experience dependent plasticity?
1) Violinists with years of practice have increased cortical representation of the fingers of the left hand
2) Skilled Braille readers also have enlarged cortical representation of the hand they use to read Braille text
more synapses don’t make you necessarily smarter - you have to have the right synapses at the right place at the right time
what is recovery from brain damage?
proof of plasticity - recovery from brain damage shows that plasticity differs with age
- Very early damage (during neurogenesis and neuron migration) results in profound deficits like for pregnant women during Heroshima
- Later damage (during synapse generation and elimination) is ‘best’ because plasticity is highest
- better for kids to have brain damage than adults because immature parts of the brain can take over the parts that were lost
- some problems/deficits only show up at later ages though
what are some limits of plasticity?
subcortical structures seem much less plastic (lower level structures seem to be less plastic)
- hippocampus
- amygdala
- hypothalamus
what does the hippocampus do?
consolidates memories and supports mental maps
what does the amygdala do?
colors experience with emotions
what does the hypothalamus do?
the source of the sex drive and other appetites
what is the old development claim?
William James
babies have to learn to see the world, no experience in the womb
without perceptual experience, infants are born into a “blooming buzzing confusion”: he means that children would literally think the world was constantly blooming
what used to be the dominant view on development?
perceptual development required sensory input
what is psychological atomism?
the doctrine that the mind constructs its awareness by of reality by mixing sensations (like brightness and solidity) through “mental chemistry” (associations)
they had an idea that our most basic experiences (like a table) are not actually the basics - they’re composed of something still more basic - the most basic form of experience was these atoms called sensations called primary ideas
who invented psychological atomism?
john locke, bishop berkley, wilhelm wundt, hermann helmholtz
what was the atomists’ thought experiment?
Suppose a man born blind, and taught by his touch to distinguish between a cube and a sphere… Suppose the cube and sphere placed on a table and the blind man to be made to see: …[could he] by his sight, before he touched them… distinguish and tell which is the globe, which the cube?
Molyneux and Locke agreed that he wouldn’t be able to tell - but you can make an argument for either case - you couldn’t find out the difference between experiences in one modality vs. the other because this experience is impossible - the only other option was to consider it in infants but you never know what a baby thinks
what is the “proof” of psychological atomism?
the argument for ambiguity
the image on retina does not provide information about size, distance, or even shape (Berkley)
decreasing an objects distance causes an increase in retinal image size
different sized objects with the same visual angle have the same retinal size (a small object that’s close looks to be the same size as a big object that’s far away)
when an object is getting closer to you all your retina sees is that the object is growing in size (blooming)
what is the view of modern cognitive scientists on development?
do not assume that“in the womb” =“no experience
fetal experience and sensory structures?
Sensory structures (i.e., receptors and nerves) for experiencing the world are present (in some form) during fetal development
touch in the womb
- the fetus’s body parts come in contact with one another
- an 18 week old fetus sucks its thumb, grasps its umbilical cord, rubs its face
taste in the womb
- the fetus can detect the flavors of the amniotic sac
- preferences for sweets is already present
they directly injected blue die into the amniotic fluid which was either sweet or unflavored (sacarine) as the baby drinks the blue die and excretes it into the mom’s pee - she will either excrete alot of blue or a little - those with sugar dye peed a bright blue which indicates they prefer it - we have an innate preference for sweets
smell in the womb
- the fetus seems to detect the smells of the amniotic fluid, which are influenced by what the mother eats.
- newborns turn more to cotton pads soaked in their own amniotic fluid than to control pads
amniotic fluid has sort of a fecal smell - each women’s is slightly difference based on what mom eats - the result is that each fetus environment has its own unique smell - how do we know that the fetus knows what that scent is? they put two pads next to a newborn, one with its mothers amniotic fluid and another with a different women’s- they must have been able to smell it previously and thus had a preference for it
hearing in the womb
some sounds can reach the fetus better than others such as: mom’s heart beat, breathing, swallowing, voice (it’s actually noisy on the inside and quite on the outside = crying)
during the last trimester the baby hears:
- external noises elicit changes in movement and heart rate
- when the mother starts speaking the fetus’ heart rate briefly decelerates (indicating detection of novelty)
low frequency tones like dad’s voice isn’t heard well but in the last trimester the baby can hear all of these because they elicit changes in movement and heart rate of the fetus
hearing in the womb in the third trimester
In the 9th month, fetuses can learn to recognize some of what they hear
measured babies heart rate based on phonetic switch: you see if babies can detect if the phoneme has switched - shows they’re able to hear
when you’re presented with a stimulus again and again and again - either you have sensory adaptation (you’re no longer able to sense something) or you have habituation: when a person effectively ignores a stimulus that is changing a little bit until they are no longer aware of it (you forget you’re wearing socks) and when you wiggle your toes and feel your socks again that’s dishabituation (regain awareness)
habituation in the womb
hearing in the womb
Lecanuet et al. (1987):
36- 40 weeks GA,
DV: heart rate
IV: phonetic switch (babi/ biba vs babi/babi; vv)
Results: 79%of19fetuses recovered in babi/biba; 71% of 14 fetuses in biba/babi
DeCasper & Spence (1986)
Fetuses were read“Cat in the Hat”vs“The King, the Mice, & the Cheese”; tested after birth
IV: story,familiarityofstory
DV: preferential sucking
Moms would read to their unborn babies - they were tested after birth to see which of the two stories they wanted to hear by taking a recording of the new story vs. the old story and whenever the baby would suck on the pacifier it would read a story - initially they preferred the new one to the old one - but after a couple of days they wanted the familiar instead of the new - it shows they can differenciate (began with novelty and moves to a familiarity preference)
sight in the womb
the fetus may react to a bright light shown against the mother’s tightly stretched abdominal skin, but its visual experience is very slight
in priniciple, they baby has the ability to detect brightness differences but other than that there’s no visual stimulus in the womb
does in the womb = no experience?
only for sight!
touch, smell, taste, and hearing are all developed in the womb and they’re born with preferences
what is a mature visual system?
- Adult normal acuity is 20/20
- Adults find edges and internal features
- Adults see distinct objects
- Adults perceive depth
visual acuity at birth?
at birth, visual acuity is about 20/400; by 8 months, infants’ vision is comparable to adults
the change occurs due to the maturation of the size, shape, and arrangement of the cones in the fovea (which are highly sensitive to resolution)
what is visual acuity?
maturation is the key to visual acuity
Schematic representations of cone size, shape, and spacing in adults (a) and infants (b). Difference results in infants only catching 2% of light on fovea (vs. 65% in adults)
although visual acuity doesnt normally improve with experince, visual acuity can decline with experience - althought visual acuity is highly heritable, reading increases the risk for needing glasses
visual scanning
infants are attracted to moving stimuli but their eye movements aren’t smooth
jerky movements because of immature fovea since cones aren’t developed and there’s just a few big ones and in an adult the size, shape, and arrangement is bigger
As the fovea matures (by 2 - 3 months), infants can track moving objects smoothly if the objects are moving slowly.
Infants’ visual scanning ability is limited to focusing on perimeters or corners.
what is a contour?
in visual scanning, babies are biased towards perimeters and contours
contours: there’s a contrast in brightness - we have cells in our visual cortex that respond to contrast which is sufficient to detect contrast (innate the baby already has it)
how does a baby look at a face vs. an adult?
baby: looks at places of high contrast to find out more about the shape
(bottom-up knowledge)
adult: looks at the hairline to tell gender
looks at mouth to tell their attitude/emotions
scans areas that have high value about social interactions (top-down knowledge)
what is pattern perception?
Pattern perception requires visual acuity, visual scanning, and the ability to analyze and integrate the separate elements of a visual display.
Kanisza Square: is it four circles with a square in the middle or 4 separate pac man figures?
babies and the kanisza square
8 month old babies stare longer at the kanisza square, like they think it’s weird, which shows that they not only can see the Kanizsa square but can interpret it as a real object which can act as an occluder
5 month olds cannot do this (the 5 month stares longer at the image where the first part is two pac men and then second is the kanisza square)
perceiving objects
Our retinal images of people and objects change as they move behind occluders, move away from us, or toward us
can they tell an object retains its characteristics despite the retinal image? (a person doesn’t look like they’re floating just because you can’t see their legs)
okay great we have patterns and contrast but it doesn’t matter if we can’t perceive objects as a whole
what are the three characteristics that involve perceiving objects?
1) segregation ambiguity
2) shape ambiguity
3) size/distance ambiguity
movement and ambiguous segregation
image 1: a rod with a block in front of it
image 2: two smaller rods with a gap between them
image 3: a full rod
if the baby understands more than just the retinal image they should see the second rod instead of the third and understand that even though the block was in front of it, it was just covering up the rod, not that the rod was actually in two pieces
object segregation and knowledge
As infants get older (8 mo), general knowledge aids in ambiguous object segregation
the ability to segregate has it’s limits when the objects get more complex
the image of a tube with a box in front of it…the baby probably can’t tell that those are two separate things and will rotate them together
shape ambiguity
tilted trapezoid or rectangle?
you reach for things that are closer so they tested the babies to see if they reached for things that are nearer - put a tilted rectangle near a baby and see if they think it’s a trapezoid and vice versa
based off of if the babies reach for an object - they’ll reach for things that are closer so based off that you can determine if a baby is seeing a rectangle or trapezoid
which experiment tested for size/distance ambiguity?
Slater, Maddock, and Brown Experiment (1990)
perceptual constancy!
one block was small and closer to the baby while the other was bigger and farther away
what did the slater, haddock, and brown experiment discover?
perceptual constancy!
shape and size constancy in new borns = innate ability
how do babies have perceptual constancy?
depth cues!
conclusion on William Jame’s hypothesis?
- babies do not perceive objects that change distance to change shape
- babies do not perceive objects that change distance to change size
- humans do not require sensory experience to avoid a “blooming, buzzing confusion” –> the only possible way for this to be true is for newborns to perceive depth
what experiment was used to determine depth perception in babies?
the visual cliff
early studies suggest that babies didn’t perceive depth until they began to crawl
when testing mountain goats, they put them on a table and the baby goats would freeze - they said it must be because they realized there’s a depth difference between the ground and the table - then they said they could do the same thing with babies but with a table
is the visual cliff effect in determining depth perception?
no - crawling experience probably isn’t necessary for depth perception
new born rates never cross over to the deep side. when placed on the deep side of the visual cliff, pre-crawling 3-month olds show decelerated heart rate whereas crawling 12-month olds show increased heart rate - tells us about whether babies can see heights and if they fear them
What is Berkley’s funny idea of the visual system?
there’s only one eye in this image - but there’s an angle of dissperity between two eyes - the difference of what’s happening between your left and right eye gives you information about depth
what are the depth cues used by infants?
1) convergence
2) optical expansion
what is convergence?
turning inward of the eyes so they point to the same point in space
when your eyes hurt when you bring something closer to you - this happens in babies
what is optical expansion?
visual image increases as it comes closer and it occludes more of the background
trying to cover Dr. Opfer’s head with my thumb - if i move my thumb closer it covers more of his head
the fact that newborns can use optical expansion to cue depth is evidence against the blooming buzzing theory because they don’t see everything coming at them all the time - it tells them the object is coming closer and not increasing in size
which experiment demonstrated conversion and optical expansion cues in newborns?
In Slater’s studies both conversion and optical expansion cues were present, allowing depth to be registered and thus allowing size and shape constancy
what is binocular disparity?
depth cue used by infants
The two eyes do not send the same signals to the brain because there are different retinal images of the object in each eye.
Closer objects generate greater binocular disparity
(the picture of the two football players)
binocular disparity in relation to distance?
if you have three images all at the same distance then they’ll yield the same optical disparity
at different distances, the closer the object the
greater the retinal disperity - what this means is that if there were a cell in the brain that could code retinal disparity then you could register depth directly without the need for learning - these cells were recently found! that’s how you know depth innately
what is stereopsis?
the process by which the visual cortex combines the different neural signals from each eye to create depth perception
using both your eyes to perceive depth
what are binocular disparity cells?
what they find is that the response of this cell is perfectly proportion to the degree of disperity from the two eyes - it codes retinal disperity and makes stereopsis possible
when stereopsis is achieved it means that the binocular disparity cells are mature
when does stereopsis begin?
it begins suddenly around 4 months and is completed within a couple of weeks (newborns registered depth but just not through stereopsis)
Achievement of this process signals the maturation of the binocular disparity cells in the visual cortex
what are monocular cues? examples?
perceptual cues of depth that can be perceived by one eye alone
1) relative size
2) object interposition
what is relative size
Objects that are larger appear to be closer to us than smaller objects
what is object interposition?
Near objects partially occlude objects that are farther away
the larger object looks closer - other clues that tell you the larger one is closer is the brightness and the occlusion of the image in the background by the image in the foreground
what is adult vision like?
- normal acuity is 20/20
- find edges and internal features
- see distinct objects
- perceive depth
what is adult hearing like?
- localize the source of the sound
2. detect rhythm and melody in music
what is adult perception?
- combination of hearing and vision
- they combine information from different modalities
which experiment disproves the “blooming BUZZING confusion”?
when there’s a sound the baby doesn’t know where it’s coming from - this is false due to the clicker experiment - the baby doesn’t just hear clicking coming from everywhere, it localizes it
when does an infant achieve adult auditory perception?
5-8 years
what is auditory localization?
newborns can turn toward the direction of sound
infant music perception?
4-mo: prefer consonance to dissonance
4.5 mo: prefer Mozart w/o pauses
5 mo: detect melody
mary had a little lamb via flute or obo - if you bore them with flute and then play it with the obo they stay bored
