Chapter 10: Sensory-Perceptual Development & Chapter 11: Perception & Action in Development

Laterality & Lateral Dominance & Direction

• Laterality: Awareness that one’s body has two distinct sides that can move independently
• Lateral Dominance: Consistent preference for use of one eye, ear, hand, or foot instead of the other
• No research suggests that it is more advantageous to have a more lateralized brain
• Directionality: Ability to project the body’s spatial dimensions into surrounding space and grasp spatial concepts about the movements or locations of objects in the environment

Perception of the Body

(Body Awareness)

• Recognition, identification and differentiation of location, movement, and interrelationships of body parts and joints
• Awareness of spatial orientation and perceived location of the body in the environment

Tactile Localization

• The ability to identify without sight the exact spot on the body that has been touched
• Relatively mature by age 6
• Children improve their ability to locate touches, but little is known about threshold discrimination for touches

Perception of

Objects

• Infants are sensitive to the size and shape of an object
• Size consistency: The perception of an actual object size despite the size of its image as projected in our retina
• Shape consistency: The perception of actual object shape despite its orientation to a viewer

As a parent, what are some of the ways you might use touch to communicate with your baby?

Perception of

Objects

• Figure and ground perception: Ability to see an object of interest as distinct from the background
• Whole and part perception: Ability to discriminate parts of a picture or an object from the whole., yet integrate the parts into the whole, perceiving them simultaneously
• Very young children have difficulty integrating objects that form a whole
• Before 9, only see the “nuts and bolts”

Kinesthetic Sensation

• Proprioceptors: Collective name of various kinesthetic receptors located in the periphery of the body (somatosensors & Vestibular apparatus)
• Somatosensors: Receptors under the skin, in the muscle, at the muscle-tendon junctions, and in joint capsules and ligaments
• Vestibular apparatus: Receptors located in inner ear
• Many infantile reflexes stimulated through kinesthetic receptors

Perception of Space

Perception of Objects

• Depend on three-dimensional space
• Must perceive depth and distance
• Depth perception: A person’s judgement of the distance from self to an object or place in space
• Retinal Disparity: The difference in images received by the two eyes as a result of their different locations
• Cues about depth and distance in our environment are often derived from the two eyes being in different locations or from movement of the head

• Size, shape, and motion
• Concept of object is “relative”
• Perception of edges and boundaries helps us extract an object or figure from the background environment

Perception of

Motion

Kinesthetic Sensation

• Cortical cells fire according to direction, location, and speed of an object on the retina
• Early in infancy, infants lack adult sensitivity to motion
• Direction not perceived until 8 weeks of age
• Velocity is difficult at slower speeds by age of 6 weeks
• Infants perceive motion, but direction and velocity are better perceived with advancing age

Visual Sensation

• As age changes, changes in visual system occur naturally
• Presbyopia: Gradual loss of accommodation power to focus on near objects.
• Age related maculopathy: Disease affecting the central area of the retina that provides detailed vision
• Signs indicating a visual problem:
• Lack of coordination in hand-eye tasks
• Squinting
• Under or-overreaching for objects
• Unusual head movements to align one’s gaze with a particular object

Visual Perception

• Relative position of the body part to each other
• Position of body in space
• Body’s movements
• Nature of objects that body comes in contact with

• Depend heavily in the performance of motor skills
• Three types:
• 1. Space
• 2. Objects
• 3. Motion

Visual Sensation

As a parent, why would you think it is important to have your child’s vision checked regularly? For what activities would vision be important in this age group?

• Acuity: Sharpness of sight
• First month of life, visual system is functional at a level approximately 5% of eventual adult activity
• Differentiate facial features from a distance of 20 feet in
• At about 6 months of age, visual systems perceive adequate detail to assist in task
• By age of 10, have vision anomaly score at the desired level of 20/20

Kinesthetic

Development

Visual Development

Sensation

Perception

Auditory Development

• Infants respond to tactile stimuli (vibrations)
• Absolute threshold: Minimal detectable sound that a hearer can sense at least half of the time a signal is sounded
• Differential threshold: Closest that two sounds can be yet still allow the hearer to distinguish them at least 75% of time

• Location
• Differences between sounds
• Patterns
• Auditory figure and ground

• Sensation: Neural activity triggered by a stimulus that activates a sensory receptor and results in sensory nerve impulses traveling the sensory nerve pathways to the brain
• Perception: Multistage process that place in the brain and includes, selecting, processing, organizing, and integrating information received from the senses

• Sensory information and perceptual information are highly integrated
• Don’t simply receive information from the environment but act to obtain information

Chapter 10:

Sensory-Perception

Development

Chapter 11:

Perception & Action

in Development

Brain derived Neurotropic & Growth Factors

Contemporary Views

• Motor development and cognitive development may be more interrelated than previously thought
• Prolonged development of the prefrontal cortex
• Functional imaging of the brain
• About half of children with ADHD have motor coordination problems
• Children with dyslexia or specific language disorder frequently have motor deficits
• Children with autism frequently have motor impairments

• Strengthen neurons and helps with neuron loss (memory)
• Exercise increases metabolic substances in the brain that can help build new neurons, especially in brain areas important to learning and memory
• Allows brain centers to continue adapting to new experiences

Self-Produced

Locomotion

• Animal studies support the notion that movement is necessary for normal perceptual development
• Self produced locomotion appears to facilitate the development of depth perception
• Development of spatial perception: Enables one to deal efficiently with spatial properties, dimensions, and distances of objects and object relations in the environment
• Development of surface texture and slope

Postural Control

&

Balance

• The timing of development trends in balance is related to the type of balance under task consideration
• As children grow, they rely more on kinesthetic information and less on visual information for balance