PSYC 352 Study Guide - Midterm Guide: Habituation, 6 Years, Externality

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7 Sep 2020
Core knowledge: infants’ understanding of object representation and babies’ abilities to make
sense of quantitative information
Perception: organization of the sensations
o Not just the stimulation of senses, but perceiving something (about the world… not just
of the world)
Cognition: what we do with perception
o After experiences organized with perceptual system, cognition refers to how we take
those representations and manipulate them, coming to conclusions about how to act
Why study infant cognition?
o We go from knowing almost nothing to being able to do so many things
All over the world, different things
o We do these things without really being told how to do them so where does knowledge
come from?
o Relevant to knowing ourselves but also relevant to advances in artificial intelligence,
computing, etc.
How to study infant cognition?
o Babies can't do much… no reaching prior to 5 months, locomotion before 7 months, no
point before 10-12 months
Basic Perceptual Abilities of Young Infants
Chemical senses (olfaction and taste) tend to develop early and are quite well developed shortly
after (and even before) birth
o Pregnant woman’s diet can influence taste preferences in newborn
Young infants can also tell the difference among a wide range of odors early in life and they
develop preferences for certain odors within the first week
o Discriminate their mothers from other women by smell and by the sound of their voices
Infants also experience pain at birth and respond to tactile stimulation
"Implicit" Methods
Take something that infants do naturally and then see if their behaviour changes or varies with the
introduction of various stimuli
Some of those things infants do naturally:
o Non-nutritive sucking
Asked pregnant women to read aloud one of three passages twice a day during
last 6 weeks of their pregnancies
Shortly after birth, neonates tested for which passage, if any, would have more
reinforcing value
Headphones places over babies’ ears, various passages played
Non-nutritive sucking (on pacifier) assessed as function of which passage being
Baseline sucking rate determined for each baby, then trained such that changes in
their rate of sucking determined whether they heard a familiar or novel passage
General finding was that familiar passage more reinforcing than novel passage
Reinforcing value of passage also independent of who recited it, an infant’s
mother or another woman
o Visual preference
Can develop set of principles/understandings about how their perceptual
experiences are organized, based off of what they have visual preferences for
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Fantz had infants look at different images at different ages, found high
contrast and high spatial frequency had higher rates of looking … But
most obviously high rate of looking was for faces
Able to show babies younger than 1 week can tell difference between
stimuli like schematic face, bull’s-eye pattern, un-patterned disk
Preference indicates infant looks at one object more than another,
synonymous with perceptual bias (not responding randomly)
In modern labs, put kids in front of two screens with different images,
observe which one they look at longer to figure out preference
o Habituation/dishabituation
Show infants object, take it away, show object, take it away -> Over
time, looking lengths at same stimulus starts to decline
When looking time gets to half the time of the original, that's
how you know they're habituated to the stimulus
Change stimulus, look to see if looking time increases again
Shows they're sensitive to the change, organizing experiences
in different way
Look to see if 5 month old infants sensitive to both person identity
when encoding world, and also their facial expressions (Bornstein & Arterberry)
Both are new expressions but person changes
o Can get infants to habituate to 1, 2, 4, 5
o Then present them with either the same woman with a new
expression, compared to a different woman with an expression in
the same point of the sequence (3)
o Both novel stimuli because they're faces the kid hasn’t seen
before, but new woman even more novel so if they're encoding
the identity more than the expression, they will dishabituate
o Found that infant dishabituated to woman on right, whereas
remained habituated to woman on left
Both are new expressions from different people but one is consistent
with habituation i.e. a smile, and other is not
o Different identities all along in habituation phase, for test either
show person with middle smile from sequence, compared to
another person with a completely different expression
o Do kids see both as equally novel because they're new people, or
is F seen as more novel because it's a completely different
o Found that individuals dishabituated to F more because they
recognized it was from a completely different sequence
Development of Visual Perception
Acuity in newborn children is poor (~20/400 to 20/600)
o Poor accommodation (focusing), but develops quickly (3 months)
o Undeveloped fovea (center of the retina with high concentration of cones, much less
sensitive to light, but gets better quickly (2 months)
Also poor with convergence (both eyes looking at same thing) and coordination (both eyes
moving together; 6 months)
Color vision poor until about 4 months
Visual acuity: Newborn: 20/660, 2 months: 20/300, 4 months: 20/160, 8 months: 20/80
o Acuity improves substantially over first year, but doesn't reach adult levels until 6 years
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To assess visual acuity, babies shown high-contrast patterns of various sizes like pattern of stripes
o If they look at striped pattern longer than at plain gray one, infer they can “see” the lines
o When they show no preference for any one pattern, assume cannot tell difference
between them
What Kinds of Things Do Babies Like to Look At?
Externality effect: tendency of young infants (1 months) to direct their attention primarily to
outside of a figure and to spend little time inspecting internal features
Moving things
High contrast -> Including outline/contour of an object (edges vs background)
Vertical symmetry
"Top-heavy" stimuli -> Most information in upper half, relative to lower half
Curvilinearity, and concentric design
Preferences that infants have for their looking are all characteristics of faces
o Usually moving, lots of contour, vertical symmetry, curvilinear
o Most of the information above a horizontal median rather than below
Infants show strong preference for faces
o Had infants lying down, looking at paddles with one of three designs (blank, schematic
face, or scrambled face), moved paddles around a bit, looking at to what extent they
would track it to i.e. angle of head, and how long they would track it for
Important to note scrambled face had all the same features of face i.e. top heavy,
vertical symmetry, curvilinear, but not in schematic organization to be facial
characteristics so while they like the scrambled face more than the blank face, not
as much as the schematic face even though technically, has all the same features
o Born with some notion of face schema
o Subcortical control until 2 months, then at 3 months as acuity improves and details
become relevant (and distracting) the face bias goes away for a little bit, and bias needs to
develop again (which it does, by around 6 months)
24 to 120 hour old babies preferred "mutual gaze" to eyes averted
Newborns prefer to look at upright faces when eyes are visible, but don't care about orientation
when eyes not visible
o Evidence for face schematic -> Expecting eyes on top of face which is why upside down
weird, but when you can't see components that contribute to facial schema, doesn't matter
Infants from birth oriented toward faces, or face-like stimuli
Shows how early/innate preferences help focus attention to stimuli that will later have adaptive
significance -> Evolutionary perspectives
Interesting Things From Textbook
Infants' perception of pain and how that's affected by their experience in the case of low
o For extremely low birthweight (2.2 lbs), response to pain affected by repeated painful
episodes often necessary for preterm patients
When tested at 8 months, number of invasive procedures they had from birth
associated with reduced facial and heart rate reaction to pain
o Other studies report children exposed to more pain as preterm infants experienced
increased sensation to pain in childhood and adolescence compared to full-term babies
o Self-reports indicate no increased prevalence of pain syndromes as adults
Whether infants prefer familiarity or novelty -> Goldilocks effect, differentiation
o Beginning around 2-4 months, psychological characteristics stimulus’ familiarity or
novelty exert increasing influence on whether and for how long it will be attended to
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