Chapter 5 Flashcards

(19 cards)

1
Q

Newborns’ sensory systems are all functioning.

A

But some more developed than others.

E.g.: touch and smell > vision.

At birth, a healthy baby’s five sensory systems are all functioning, but some are far more developed than others. Touch and smell are fully developed at birth, but a newborn’s vision is very limited, both in terms of acuity, and colour, and as we’ll see, develops gradually over the first year.

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2
Q

Methods for assessing sensory capabilities:

A
  1. Preferential looking (more time looking at stimulus = preference)

Newborns show preferences for upright faces and schematic faces

We’re going to start by looking at some of the techniques devised by developmental psychologists to measure infants’ sensory abilities. First we have the preferential looking paradigm, a version of which is displayed above. Typically, this paradigm involves two or more stimuli, including patterns or faces; if an infant spends more time looking at one stimulus over others, it’s assumed that they prefer that pattern or face. (Watch video at the link above to see how an eye tracking device is used to measure preferential looking in a laboratory.)

Research has found that newborns show a distinct preference for faces that are in an upright position over faces that are inverted, and for faces with features in their usual alignment over faces with the features scrambled. This suggests that babies are born with an innate predisposition to be attuned to human faces.

  1. Habituation/Dishabituation

Present Stimulus 1
B.P., heart rate increase
Responses decline when familiar with stimulus

Present Stimulus 2
If B.P., heart rate increase, suggests infant able to discriminate S2 from S1

Habituation is a very simple form of learning. At birth, the human brain is set up to be attracted to novelty. Babies tend to respond more strongly to something new that has entered their environment, which ensures that they will continually add to their knowledge base.

When you first present a stimulus to a baby (say, a cute stuffed animal, or a song), they will exhibit an increase in head or eye movements, and an increase in their heart rate and respiration rate as well. When a stimulus has become overly familiar, these measures will drop. This is the infant’s way of saying “I’m getting tired of seeing or hearing this stimulus - show me something else!”

If the stimulus changes – a new stuffie is introduced, or a new song comes on – and the infant starts reacting to it (i.e., paying attention to it, and their blood pressure and heart rate increase) dishabituation has occurred. In other words, this tells us that the infant is aware that the new stimulus is different from the first one. If, however, the infant fails to react to the second stimulus, this suggests they aren’t able to discriminate it from the first one – they think it’s the same stuffie, or the same song.

  1. High-Amplitude Sucking
    Establish baseline
    Measure rate of sucking in response to stimuli

High-amplitude sucking (pictured above) is another way of measuring habituation / dishabituation. This method involves giving an infant (up to 4 months old) a special pacifier, and measuring variations of the rate at which they suck on it. These responses are recorded on a computer which is hooked up to the pacifier by a cord. The researcher first establishes the infant’s baseline sucking rate. When an infant sucks faster than they did in the baseline phase, it triggers a stimulus to appear on a screen, or to be played on a stereo; if the infant finds the stimulus interesting, they can make it last by continuing to suck rapidly. Once the infant loses interest, the sucking rate goes down, and the stimulus is withdrawn. If the researcher then presents a new stimulus, and the infant’s rate of sucking increases, this suggests the infant was able to discriminate the new stimulus from the old one.

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3
Q

Hearing

A

Not fully developed at birth

3-day-olds can turn in general direction of sound, but have trouble “localizing” source

infants prefer consonant tones to dissonant ones

Prefer human speech which is slow, clear, high-pitched

Hearing is not fully developed at birth. Newborns, however, can hear a wide variety of sounds, and this improves greatly over first few months. Very young infants struggle to pinpoint the specific location of a sound in their environment. To localize a sound, you rely on the time the sound arrives at each ear (if the source is on your right, it will reach your right ear faster than your left ear), and the loudness of the sound (a source to your left will be louder at your left ear). The ability to identify the precise location of a sound improves greatly over the first six months.

Research has found that infants prefer consonant tones to dissonant tones. An example of a consonant tone is a major 5th (if you hum the first four notes of “Twinkle Twinkle Little Star,” the change from the second note up to the third note represents a major 5th). A minor 2nd, by contrast, is a dissonant tone (the theme from Jaws alternates between two notes, which are a minor 2nd), as is an augmented 4th (the first two notes of The Simpsons theme song). In case you’re wondering how this is tested, the researcher will draw an infant’s attention toward an audio speaker by flashing a light on it, then play music through the speaker. The length of time infants look at the speaker is taken as a measure of their interest in, or preference for, the music coming from the speaker.

Infants prefer human speech that is slow, clear, and high-pitched, with a rising tone at the end of phrases and sentences. (If this were a live lecture, you would get to hear me give a silly demonstration of this!) This mode of speech is commonly referred to as “motherese” or “fatherese,” and it’s believed that infants prefer it in part because it eases their perceptual learning.

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4
Q

Vision

A

Newborns are very nearsighted

able to:
- scan their surroundings
- perceive patterns and distinguish among forms
- show a preference for faces
- distinguish mother’s face

Newborns have poor visual acuity; they perceive an object at a distance of 20 feet away as clearly as adults perceive objects at 400 to 600 feet. Acuity reaches near-adult levels at 6-8 months. Infants can scan their environments, but their eye movements tend to be slow and inaccurate. Infants show a preference for patterned stimuli (e.g., a checkerboard pattern, as seen above) to plain stimuli, although they will see the pattern differently than an adult will. Once infants are able to distinguish between faces and non-faces, they show a preference for faces, including a strong preference for their mother’s face over a stranger’s face. This is something that makes sense from an evolutionary perspective, given how dependent an infant is on his or her caregivers for survival.

Newborns respond to light and track moving objects with eyes; perceive few colours

Concentrate on edges

3-mo.-olds concentrate on interior of face; better at perceiving colour

Newborns perceive few colours. One-month-olds can differentiate blue from gray, and red from green. By 3 to 4 months, infants are able to perceive colors similarly to adults. A newborn’s vision is so poor that his or her mother’s face will appear to be blurry, even at a couple feet away. When looking at faces, one-month-old infants concentrate on outside edges - light/dark contrasts which signals the edge of an object. Three-month-olds are able to take in all of the facial features, looking at the eyes, nose, and mouth of someone’s face. Watch the video clip at the link above for a more detailed explanation of how vision develops in infants (and brighten your day by looking at cute babies!)

Perception of faces shaped by perceptual narrowing

6-mo.-olds: generalists (recognize other-race & other-species faces just as well as same-race faces)

9-mo.-olds: specialists (superior recognition for same-race faces)

Infants spend about 15 minutes of every hour they’re awake looking at faces. Not surprisingly, they show a preference for their own caregivers’ faces over those of other people. Over the course of their first year, infants’ perception of faces is shaped by their experiences through a process known as perceptual narrowing. Over this time, infants become face specialists, becoming better at discriminating amongst the kinds of faces they’re frequently exposed to in their environments. Research shows that six-month-olds are just as good at discriminating between faces of monkeys, faces of people from other races, and people from their own race. By nine months, however, they have a great deal of difficulty telling the difference between one monkey face and another, and between faces of people from unfamiliar racial or ethnic groups.

Children with ASD scan faces in atypical manner

Griffin et al. (2021)

Meta-analysis of 112 studies

On average, 80% of ASD individuals perform worse than typical individuals on tests of face recognition

Whereas typically developing children will focus on the eyes and the mouth when looking at a face, children with Autism Spectrum Disorder (ASD) tend not to look at specific features, and tend to look away from faces more often (see face-tracking patterns comparing non-ASD individuals and ASD individuals above). Griffin and colleagues identified 112 studies involving face recognition representing over 5,000 participants, and compared the performance of ASD and non-ASD individuals using a statistical technique known as a meta-analysis. The researchers found, on average, over 80 percent of ASD individuals performed worse than typical individuals on tests of face identity processing. Spending less time looking at faces, and not looking at the areas of faces that give the most information regarding a person’s emotional state means that those with ASD often struggle in social interactions, both in terms of recognizing other people and in terms of accurately reading their facial expressions.

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5
Q

Depth Perception

A

Visual cliff studies show that children as young as 6 weeks react with interest to differences in depth

At 7 mo’s, show wariness of deep side of the cliff

The visual cliff (see above) is a device designed by Gibson and Walk. It consists of a Plexiglass covered table with two sides: a “shallow side” (checkerboard pattern just under the glass), and a “deep side” (checkerboard pattern several feet beneath the glass). By the age of seven months, most infants show hesitation to cross over to the deep side; this coincides with the time at which most infants are able to crawl. It’s to our evolutionary advantage to be wary of heights once we are able to propel ourselves around. Interestingly, whether or not they do cross the cliff can be influenced by the expression on a parent’s face (smile = cross; fear = avoid). (See video clip at link above.)

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6
Q

Taste and Smell

A

Newborns prefer sweet tastes and smells
E.g.: breast milk

Averse to sour, bitter, and salty tastes

Foul odors

Newborns will make the same facial expressions as adults in response to sweet, bitter, and salty tastes, showing a strong preference for sweet. These reactions are important for survival, as the “food” that best supports an infant’s early growth is sweet-tasting breast milk. Many toxic substances are bitter tasting. Babies will display odour preferences as well: bananas and chocolate will give a baby a pleasant, relaxed expression, while rotten eggs will make an infant frown.

Once infants start eating solid foods, around five to six months, they start to like salty tastes more. Preferences change readily through experience; it was not uncommon for my daughters to enjoy a food one day, and want nothing to do with it a couple days later!

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7
Q

Touch

A

Helps stimulate early physical growth

Newborns sensitive to pain

Explore objects with hands / mouth

Touch is also well-developed at birth, and helps to stimulate early physical growth, as we saw with special infant stimulation (aka “kangaroo care”) for children born prematurely or underweight. An adult’s soft caresses induce infants to smile (starting at around four to six weeks) and become more attentive to the adult’s face.

A newborn experiencing pain will respond with a high-pitched, stressful cry, which is distinct from the “I’m hungry” or “I’m tired” cry, accompanied by a dramatic rise in heart rate and blood pressure.

When a child is able to grasp and hold onto objects (by about four months), they often run their lips and tongue over the surface of the object, then remove the object to look at it. Pictured above is my daughter Keira, as an infant, with her well-chewed stuffed rat!

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8
Q

Intermodal Perception

A

The ability to perceive an object or event by more than one sensory system simultaneously.

In intermodal perception, we make sense of light, sound, odour, taste, and tactile information by perceiving them as integrated wholes. We come to expect that these properties go together. For example, as an infant we learn the relation between our mother’s or father’s face and the sound of their voices (or between an animal and the sound it makes, as learned by playing with the “see n’ say” toy).

The ability to perceive an object or event by more than one sensory system simultaneously.

Intersensory redundancy theory: infants learn best when stimuli presented to multiple sensory modes
(e.g., watching someone play instrument: sight + sound)

According to the Intersensory Redundancy Theory, infants are more apt to pay attention to a stimulus if it’s presented to more than one sense at a time. For example, a parent playing a guitar for their infant is going to simultaneously stimulate her auditory system with sound, and her visual system with the movement of the parent’s fingers. And this would be more stimulating to the infant than merely hearing a song on the radio (without visuals) or watching someone play an instrument (without audio). As another example, a parent might place their infant’s hand on the back of the family dog so he would get the double sensory experience of seeing what fur looks like and how soft it feels.

E.g., McGurk effect
- Occurs when visual information influences the way we hear a phoneme
- “Ba” misheard as “va” when lips appear to be saying “va”
- 5 mo.-olds experience this illusion

Children as young as five months old treat the “va” sound as familiar after watching the McGurk stimuli (the sound of a person saying “ba” played while that person’s lips are moving as if to say “va”), even though they haven’t actually heard “va.” This suggests that infants are able to integrate auditory and visual information together (and are thus able to be tricked the same way older children and adults are by this effect!)

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9
Q

The Process of Attention

A

Processes that allow people to control input from environment and regulate behaviour

  1. Orienting network
    Determines which stimuli will be processed

Right from the beginning, newborns are attracted to moving stimuli, but have trouble tracking them, as their eye movements are jerky. This ability to scan the environment is important because it’s one of the few ways that infants have active control over what they observe and learn.

Recall that infants easily habituate to stimuli that are repeated, but show renewed interest when something novel is presented. This is an orienting process; attention seems to be automatically captured by interesting or novel stimuli, as a way for the infant to learn about their environments.

  1. Alerting network
    Prepares infant to detect & respond to incoming stimuli
  2. Executive network
    Shift attention from one stimulus to another; ignore distracting stimuli

When an infant hears a sound like the front door opening, followed by the sound of Mom’s or Dad’s voice saying hello, an alert is triggered, and they will direct their attention to the door in anticipation of them coming in.

Infants’ and toddlers’ selective attention, their ability to more deliberately choose what to focus on and ignore other stimuli, is not very good, as their executive network (largely located in the prefrontal cortex) has yet to fully develop. To keep a toddler occupied, you have to keep switching activities every few minutes or so, which can give parents fits in waiting rooms and airports!

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10
Q

Attention

A
  1. Executive network

E.g., play board game without getting distracted by other toys

Develops throughout childhood

Pre-schoolers (age 3 to 4) more strategically deploy their attention to what they choose to examine. The have better selective attention, can ignore some distractions, and sustain their attention for a longer period of time. The average pre-schooler can play a board game or watch a half hour TV show like Octonauts or Paw Patrol without getting too bored. This is related to increasing myelination of the brain structures involved in attention.

Development of selective and sustained attention

In this experiment, children were given a task to do, such as putting together Lego blocks to replicate a model in front of them. Some children did this task with no distraction, while others performed it in the presence of a television that occasionally came on, and a third group of children did the task with a TV on continuously in the background. As seen above, when there wasn’t any distraction, the performance of 4-year-olds was only slightly better than that of 3.5-year-olds. This difference was much more pronounced when there was an intermittent distraction, suggesting that 4-year olds have developed a greater ability to sustain their attention, and can avoid periodic disruptions. In general, poor performance was related to looking at the distracting stimuli (what was on TV) in the distraction conditions.

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11
Q

ADHD

A

Two main types:

1) inattentive
Trouble staying focused; easily distracted

2) hyperactive / impulsive
Interrupts, intrudes; can’t wait for turn

Often resulting in academic and social problems

Children with inattentive ADHD have trouble staying focused on a task that requires mental effort for more than a few minutes. They can be distracted easily by both external stimuli and their own thoughts (i.e., daydreaming). Children with hyperactive / impulsive ADHD, by contrast, are more prone to fidgeting, squirming, and running around from one place to another. Some ignore social rules (e.g., interrupting conversations, or not waiting for others before taking their turn), and might lash out with hostility when frustrated, having difficulty inhibiting action in favour of thought. In some cases, people are diagnosed with combined ADHD (i.e., they have symptoms consistent with both subtypes of ADHD).

Children with ADHD tend to score 7-15 points lower on IQ tests and other standardized tests, not because they are less intelligent, but because they have difficulty concentrating.

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12
Q

ADHD: Causes

A

Genetic factors: Monozygotic twin concordance rates are 55%

Research suggests impairment in the connection between the frontal lobes and the limbic system

Identical twins are more likely to both have ADHD than are fraternal twins, suggesting a genetic factor, but the rate of concordance is 55 percent, which points to the importance of environmental factors as well. Current research continues to focus on the frontal lobe (specifically, circuits that allow people to inhibit their actions), but has also implicated the basal ganglia’s involvement in regulation of motor behavior and impulse control.

The brain image of a person with a history of ADHD shows lesser overall activation (at the red and white levels), especially in the frontal and limbic regions.

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13
Q

ADHD: Sex Differences

A

Prevalence: 3-7% of Canadian children (using DSM-V criteria)

Boys: 4 X as likely to be diagnosed

Girls more often diagnosed with inattentive ADHD

Controversy: some “symptoms” may reflect behaviour that’s normal for boys of a young age

On average, boys mature later than girls. Boys are also more likely than girls to be diagnosed with ADHD. Most diagnoses of ADHD occur after children are introduced to a school setting, be it preschool, kindergarten, or elementary school. This raises the possibility that hyperactive / impulsive ADHD is sometimes a misdiagnosis when applied to boys who have simply not matured enough to sit still in the classroom or that boys are not socialized to sit still, but to act and be physical. There would perhaps be fewer diagnoses if school settings did not require as much sitting or focused attention in the younger grades.

By contrast, inattentive ADHD is diagnosed more often in girls, but some researchers believe that its frequency is underdiagnosed. It’s much easier for a teacher to notice a child who is frequently getting up and acting out in the classroom (i.e., exhibiting symptoms of hyperactive / impulsive ADHD) than to notice a child who’s quiet and has tuned out. But the consequences for girls with inattentive ADHD can be just as negative if they aren’t accurately diagnosed and treated for their symptoms.

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14
Q

Treatment of ADHD

A

Stimulant medication (increases frontal lobe activity)
If regulated, improve attention, academic performance, peer relations for about 70%

Best outcomes for children given medication combined with behavioural therapy

Stimulant medications such as Adderall and Ritalin can improve a child’s capacity to sustain attention, while inhibiting “off-task” behaviour. But drugs alone can’t teach children to compensate for inattention and impulsivity. Interventions tend to be most successful when they model and reinforce appropriate academic and social behaviour. Family interventions are important as well; parents of children with hyperactive / impulsive ADHD are more likely to react punitively and inconsistently, a child-rearing style that we will see is ineffective. Family interventions involve training parents to be more patient, and adopt an authoritative (firm, but fair and warm) parenting style.

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15
Q

Motor development

A

Over the first year of life, a child shows gains in both gross and fine motor development. As well, their bones become harder and stronger, less vulnerable to being broken.

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16
Q

Gross Motor Skills

A

Gross Motor Skills:
-Involve large muscles of the body and make locomotion (crawling, walking, etc.) possible

Dynamic Systems Theory

Motor development stems from confluence of several factors:
Increase in strength
Balance / posture
Perceptual skills
Motivation

In the olden days, it was believed that infants’ motor development was governed by brain maturation. Nowadays, there is a different perspective, known as dynamic systems theory, according to which motor development is the result of a combination of many different factors.

Each distinct skill – rolling over, sitting up, crawling, standing with support, walking with support, standing and walking alone – requires a child to re-calibrate their balance, as different muscle groups are used. In terms of motivation, you can see the role of motivation in watching an infant make a determined effort to walk when they could move around much more efficiently by crawling. Practice is also vital to infants’ gradual mastery over their initially weak muscles and precarious balance. One study of 12- to 19-month-old infants in New York City found that they averaged 2,368 steps (and 17 falls!) per hour.

2-3 (yrs.): can run, kick a ball, climb on furniture
3-4: can ride tricycle, stand on one foot
4-5: can skip, throw ball overhand, run smoothly
5-6: ride bike without training wheels; gallop, skip, jump

As children gain motor skills, they increase their ability to explore their environment, adding to the variety of experiences they can have (and adding to the headaches parents experience, as they have to child-proof the entire house!)

Most three-year-olds are able to walk up stairs by alternating feet, and down stairs leading with one foot. (Mastering staircases occurs sooner in children who live in buildings with staircases.) Three-year-olds aren’t yet adept at catching a ball – they will try to trap it against their chest, rather than using both hands.

A four-year-old is able to throw a ball with full body rotation (transferring their weight from their back foot to their front foot); as a result, the ball goes much faster and further.

Five-year-olds usually have a good enough sense of balance that allows them to ride a bike without training wheels. But there are individual differences (my older daughter wasn’t able to do this until age 7, while my younger daughter mastered it at age 4).

17
Q

Progression of Locomotion

A

These are the average ages at which infants achieve the motor milestones listed. Parents eagerly await the progression of their infant to the next stage, and can wonder if something’s wrong if their infant hasn’t reached a milestone by the average month. But not all babies crawl – some learn to walk without having crawled at all!

Sitting without support

Standing with assistance

Hands and knee crawling

Walking with assistance

Standing alone

Walking alone

18
Q

Motor Development

A

Fine Motor Skills:
Involve the development and coordination of small muscles

Reaching and grasping
Poor at 3 mo’s; adept at 6-9 mo’s

Manual dexterity
By 12 mo’s, can use thumbs in opposition to fingers

My daughter Sophie here is about nine months old, at which age she was able to pick up an item with both hands. This ability further necessitates the need to childproof – if you look away for two seconds, they have something else in their hands, guaranteed to be put in their mouth, or spilled all over the floor!

By the time a child turns one, they can use their fingers to pick up smaller morsels of food – bananas, small chunks of sweet potato, cake, etc. – but it only makes it to their mouth about 50 percent of the time! This improves as children become more adept at using their thumbs.

19
Q

Fine Motor Skills

A

2-yr-olds: use spoon & fork; turn book pages
3-y-o’s: feed self well;
4-y-o’s: draw person; dress self well
5-y-o’s: print letters; tie shoes

From age two to five, a child’s fine motor skills improve, but not to same level of confidence as their gross motor skills. (Side note: I still draw people at about the same level as a four-year-old – sadly, I never progressed beyond this!)

Children under the age of two are unable to turn book pages without tearing them, which is why younger babies are given board books.

Five-year-olds have enough control of their fingers to be able to colour between the lines with crayons. A child’s printing also becomes much more legible at this age. Five-year-olds can learn to tie their shoelaces, although most pre-schools and kindergartens now mandate that children not wear shoes with laces to school (to save the teachers time when getting kids ready for recess and hometime!)

That brings us to the end of the unit on physical development. After the midterm, we will begin our in-depth look at cognitive development, from infancy through adolescence!