Psych 125Human Development

Christopher GadeOffice: 1031-G

Office hours: Tu 12-1:30 and by apt.Email: gadecj@gmail.com

Class: T 1:30-4:20 Room 2210

Starting Off…

• Let’s turn in those first assignments!

Looking at Motor, Sensory, and Perceptual Development

• So far we’ve examined how our bodies change and grow, how our environment and body throughout development relate to health changes, and how our nervous system grows and then declines with age.

• In today’s class, we’ll focus on the last physical related topic of development– Motor development– Sensory/perceptual development

Movement/Touch and the Nervous System• The value of Movement

and Touch– Interact with the

environment– Detect danger/injuries– Derive pleasure from the

environment

• Our Basic Systems– Nervous system– Motor and sensory systems

Our Sensory

and Motor System

More on Nerves• Action/Sensory Nerve– Cranial– Spinal• Sensory (afferent) root• Motor (efferent) root

Examining Motor Development: How Do We Get There?

• Maturation – Motor development that results from an unfolding of growth through experience and genetics in a predictable pattern

• Dynamic systems theory – a theory thatattempts to explain maturation by examiningthe combination of perception and action– Perception – identification and recognition of a desirable

stimulus in the environment– Action – attempts to coordinate movement in order to

obtain that desirable stimulus

An Early Bag of Tricks: Reflexes• Despite being very vulnerable at birth, newborns

do have a few motor skills that can help increase their chances of survival.– Reflexes – built-in physical reactions to stimuli

• What are the reflexes that we’ve identified– Rooting reflex – a stroke of the cheek causes the

infant’s head to turn toward the contact– Sucking reflex – any object placed in the mouth causes

an instant sucking motion– Moro reflex – when startled, infants arch their back,

throw back their heads, & fling out their arms and legs

More on Reflexes• Other reflexes that we’ve identified– Palmar grasp – touching the palm of the hand with an

object causes the infant to grasp around that object– Plantar grasp – touching the sole of the foot causes

the toes to spread open and footto curve inward

– Stepping reflex – feet on a flatsurface will cause infant to“walk”

– Swimming – infants placed inwater will stroke with legs andarms while holding their breath

Any others?• A lot of our reflexes at birth persist throughout life– Coughing– Sneezing– Blinking– Shivering– Yawning

• The ones listed previously usually disappear at about 3-4 months of age– Sucking exception– Development issues and the continuation of reflexes

What About What We’re Not Born With?• Gross motor skills – skills that involve large-muscle activities

• Posture– 2 weeks – hold our heads– 2 months – able to sit while supported– 6 months – able to sit on own– 8-9 moths – able to pull ourselves up to a stand– 10-12 months – able to stand

• Walking– At about 1 year, infants begin to attempt to walk, the big challenge

is learning how to shift their weight between feet when they are moving them

– This is a continual learning process, with terrain and angles all needing to be learned

Later Gross Motor Development• 1-2– Standing along easily– Coordinating movement– Climbing steps– Walking quicker

– Squat without falling– Walk backward– Kick and throw a ball– Jump

Later Gross Motor Development• 3-4– Hopping– Running– Run to jump

• 4-5 – walk down stairs– Coordinate movements

• 5-adolescence– Development centers around experience– Smoother behaviors and coordination are a result of

repeated actions

Adolescence to Adulthood and Beyond• Our motor system continues to be capable of

getting better and better as we age into early adulthood

• At about 30, our motor systems startto decline

• Note: As mentioned earlier, this decline can be very rapid, or very slow, depending upon our levels of activity and health as we age

Development of Fine Motor Skills

• The ascent– Our fine motor skills greatly increase into adulthood

due to new connections and myelination– Experience helps in fine motor skill growth

• The descent– Once we reach adulthood, our fine motor skills often

decline just like our gross motor skills– Neural noise – irregularities in neural activity in the

central nervous system– More use of fine motor skills greatly slow the decline– Oftentimes, fine motor skills are close to those of

younger adults, but require more time

Moving On…

• Now onto the second part of today’s class,

Sensory and perceptual development

Sensation and Perception• Sensation: the conversion of energy from the

environment into a pattern of responses by the sensory receptors

• Perception: the interpretation of that information.

• In order to understand how we interact with the environment, we need to understand both parts.

Let’s See How Good We Are At This• Tasks to show how

this works

– Pick up an object• Eyes closed• Eyes open

– Catch an object

– Clap in unison

Specific Types of Sensory Development

• In this section, we’re going to focus our discussion of sensation and perceptual growth on twocategories

– Vision– Hearing– Touch– Taste/

Olfaction

Visual Development: Looking at the Eye

• The eye has a number of parts that are critical to our ability to sense the visual stimuli in our environment

– The lens

– The fovea (rods andcones)

Vision at Birth• Because most of our eye’s structures aren’t fully

formed, newborns have extremely limited vision– Visual acuity – ability to see things at a distance• 20/240 at birth• 20/40 by 6 months• Close to normal by about

1 year– Color vision – ability to

detect colors• 4-8 weeks can detect color• 3-4 months can show

color preferences

Visual Development: Looking at the Mind

• The brain also plays a critical role in our interpretation of stimuli– Perceptual constancy –

ability to perceive objects as the same across different shades, shapes, and sizes• Starts to form at 3 months• Develops until early

adolescence

Another Development of the

Mind in Vision

• Depth perception – a combination of the ability to pick up on information presented by the lens, our ability to interpret colors, and understand binocular cues (information about depth that we gain through the use of both eyes)– 2-4 months of age display

a basic understanding of depth

Later Vision Development• Childhood– By 3 to 4 we begin to detect color boundaries much better– By 4 to 5 our eye muscles become flexible enough to focus on

information up close• Adolescence to adulthood– Unlike most other types of development, very few physical

changes take place in vision during this stage• Adulthood on– As we age, we begin to lose a lot of visual functions

• Visual acuity• Response to glare• Dark adaptation• Color vision• Depth perception

Hearing Development• Unlike vision, our hearing is fairly in tact not only

at birth, but even up to two months before birth– Sound/voice identification– Locating ability– Range of frequency– Range of volume

• As we age, our ability to hear declines first at the higher and lower end of the frequency spectrum, then as we get into our late 70’s early 80’s, all frequencies decline

The Frequency Range of Hearing

Looking Back at Today…• Up to today, we had examined how our bodies

change and grow, how our environment and body throughout development relate to health changes, and how our nervous system grows and then declines with age.

• In today’s class, we focused on the last physical related topic of development– Motor development– Sensory/perceptual development

In Our Next Class• We’ll be having our first exam…

• Details– 40-60 multiple choice questions– Questions based on the lectures, but information

covered in the text AND in lecture will have a very good chance of being in the exam

– Class is over after the exam– No phones or bags open during the exam