Dev. Part 2 Motor Development

Principles of Motor Development

Proximodistal direction of development

• Trunk to extremities

Cephalocaudal direction of development

• Head to foot

Reflexes

• Involuntary actions in response to external stimulation (blinking, swallowing…)

Types of Reflexes

• Primitive reflexes: These are basic, survival orientated reflexes that ensure essential functions

  • Survival reflexes: Such as breathing, blinking, and swallowing

• Evolutionary reflexes: Reflexes that may have been evolved for survival in earlier stages of human development

  • Palmar grasp: where babies instinctively grasp objects placed in their palms

  • Startle reflex: A sudden reaction, like flinching to a loud noise

• Postural Reflexes: Reflexes that help maintain body posture and balance

  • These reflexes assist in maintaining posture like swimming, where babies automatically move their limbs in water to keep afloat

Gross Motor vs. Fine Motor Development

Gross Motor Development

• Refers to the development of large muscle movements and overall body coordination

• Milestones in gross motor development occur when there is significant growth in motor skills or brain development that allows individuals to perform actions involving larger muscle groups

  Example: Crawling, walking, running…

Fine Motor Development

• Involves smaller, more precise hand and finger movements

• Fine motor skills are crucial for tasks that require detailed control

  Example: Picking up small objects, writing, or manipulating

Biological Considerations in Motor Development

Predictable Time Frame

• Motor development follows a general predictable timeline across all children

• There are typical ages when certain motor skills develop (like crawling…)

Motor Skills Are Universal

• Motor skills develop similarly across all individuals, regardless of cultural background

• This universality means that basic motor skills are not influenced by culture, although how they are practiced can vary culturally

Physically Impaired Children

• Children with significant physical disabilities still develop motor skills in a similar order to typically developing children

• While engagement with motor tasks may be limited due to their impairments the sequence with which remains unchanged

Twin Concordance

• Greater concordance refers to the degree to which twins show similar motor development

Experimental Considerations in Motor Development

Institutional Studies

• Children in orphanages are placed in environments designed to be sterile and devoid of physical affection (e.g., minimal physical touch like hugging)

Hopi Indians

• Among the Hopi and other Native American communities in the Southwestern United States, motor practice for babies wasn't practiced

• Babies were often swaddled tightly, which limited their physical movement

• This suggests that in some cultures, motor development may not be actively facilitated or practiced in the same way as in other cultures, possibly leading to differences in the pace or style of motor development

Cross Cultural Studies

• Researchers like ‘Super’ studied motor development in various Kenyan communities, focusing on how cultural practices influence development

• They found that in communities where gross motor milestones (like walking) were actively practiced and supported by the entire community, children reached motor milestones faster

Two Theories of Motor Development

Brain to Behaviour View

• Motor development is primarily driven by genetics, with experiences influencing it to some extent

• Infants are controlled by innate reflexes that facilitate their interaction with the environment, allowing them to gradually develop more complex motor skills

High Motor Skills (reflexive movements)

• Controlled by subcortical brain regions (below the cortex)

  Example: Reflexes like the stepping reflex, which appears at birth but disappears around 4-5 months, at around 8-9 months babies start showing behaviours related to active walking

Low Motor Skills (more controlled actions)

• Involve cortical mechanisms, meaning the higher level brain regions (the cortex) are involved in inhibiting or guiding motor actions

• These motor skills are more deliberate and less reflexive

Dynamic System View

• This view emphasizes the holistic nature of motor development, considering multiple factors in the environment that influences motor skills

Environmental Constraints

• Researchers found that motor development might be influenced by external factors, such as weight or physical constraints

  Example: Babies who gain weight may have difficulty displaying the stepping reflex because their added weight slows down their leg movements

• The dynamic systems view proposes that motor development involves a complex interplay between biological factors (like muscle strength and neurological development) and environmental conditions (like weight or physical support)

Physical Changes in Adulthood

Aging involves both primary aging and secondary aging

Primary Aging

• The natural, gradual changes that occur with aging (decline in sensory abilities like vision and hearing, reduced muscle mass, and slower metabolism)

Secondary Aging

• Aging caused by lifestyle choices, environmental factors or diseases (smoking related issues, obesity related issues) these factors can significantly impact physical and emotional wellbeing

Stages of Aging

• Aging is often categorized into stages

  • Chronological ages: The number of years a person has lived

  • Functional age: How well a person functions in daily life

    Example: A 70 year old might function physically and mentally like a 50 year old due to health and lifestyle factors

Demographic Shifts

• The proportion of older adults is increasing globally compared to younger age groups like emerging adults and young children

• This disproportionate growth is due to factors like longer life expectancy and declining birth rates in many regions

• This demographic trend has significant implications for healthcare, social services, and economic systems, as an aging population may require more support while fewer young people are entering the workforce

Senescence

What is Senescence?

• Refers to the natural physical decline associated with aging, it is part of the body’s biological processes, requiring ongoing care and maintenance as we grow older

• Physical changes

  • These changes are normal and universal

  • Outward signs: Visible changes like greying of hair, wrinkles and changes in body compositions

Influence of Media on Perception of Aging

• Media shapes our expectations and norms about aging, influencing what we believe is "acceptable" or "ideal."

• These societal messages can create pressure to conform to specific standards, affecting self-image and confidence as we age

Psychosocial Factors and Gender differences

• Aging is often perceived differently for men and women:

  • Men: Physical signs of aging, such as graying hair, may be viewed as signs of wisdom or distinction.

  • Women: Visible aging may be more stigmatized, with greater pressure to maintain a youthful appearance.

• These perceptions are rooted in cultural norms and can impact how individuals experience aging emotionally and socially

Brain Change and Cognitive Decline

Neural Loss and Cognitive Decline

• Neural loss: As we age, these is a natural reduction in the number of neurons and neural connections in the brain, which can lead to:

  • Memory loss; Difficulty recalling information or forming new memories

  • Functional Decline: Challenges in preforming cognitive tasks or multitasking

Brain Efficiency and Decline

• Brain Decline: The brain’s overall functionality decreases with age

• Metabolic’s Differences

  • The brain’s energy diminishes, changes in glycolysis (the process that produces energy for the brain)

Lifestyle Effects

• Unhealthy Habits Habits such as drinking alcohol, smoking, and eating poorly contribute to faster brain and cognitive decline.

• These lifestyle choices can exacerbate natural aging processes by increasing the risk of diseases like diabetes, which further affect brain health

Vascular and Cardiac Changes

As we age

• Blood vessels: They shrink and become less flexible, reducing blood flow to the brain and other organs

• Heart function: The heart becomes less efficient at pumping blood, further diminishing the supply of oxygen and nutrients to the brain