Hand Function 7-24 Month Period

Original Editor - Robin Tacchetti based on the course by Pam Versfeld
Top Contributors - Robin Tacchetti, Jess Bell, Tarina van der Stockt, Kim Jackson, Ewa Jaraczewska and Jorge Rodríguez Palomino

Introduction

Hand function from 7-24 months can be divided into two periods.

During 7-12 month period infants continue to use their hands to explore the properties of objects, but are also learning to adapt their grasp to the shape and size of objects, and learn to reach for, grasp and move objects in many different ways.  In addition they start to use their hands for communication.

During 12 – 24 month period infants start to use their hands to explore the many different ways that objects can be grasped, moved and manipulated relative to one another to perform many tasks and goal directed actions.

The importance of experience in the development of hand function

When considering the development of hand function there are 2 important ideas that need to be kept in mind: cascades in development and perception-action loops with embedded exploration and selection.

Cascades in development

Development can be viewed as a cascade, with new behaviors building on established ones. At any moment, the whole child is a product of all the previous developments, and any new change begins with and must build on those previous developments.

The development of hand function clearly illustrates this principle: newborn spontaneous movements of the arms and hands are replaced by intentional use of the hands to explore surfaces and objects in ever more complex ways which allows the infant to start finding out how the hands can be used to pick up, move and manipulate objects to perform tasks to achieve a variety of goals.  

Perception-action loops with embedded exploration and selection

Infants will repeat a new task many times allowing for repeated opportunities to use information about the success of their actions to vary their movements, and over time select and reproduce what works.

Performing an action over and over again creates perception-action loops, with each repetition producing a slightly different sequence of movements and consequently slightly different sensory feedback.

Some variations in the pattern of movement will be more effective in achieving the goal, and over time will be selected when the task is performed again.

Corbetta et al. (2018) calls this process of repetition and adaptation perception-action loops with embedded exploration and selection. It is argued that the embedded exploration and selection process provide the fundamental mechanism by which the discovery and formation of new behaviors occur.

During the 7-12 period infants use their hands for 3 different functions

1. As part of the postural and locomotor systems including learning to balance in sitting, crawling and buttock shuffling, cruising.  
2. For communication and in social interactions
3. For picking up, moving and manipulating objects to explore their different properties and what can be done with them.

Hand behaviors seen in the 7-12 month period.

During the 7-12 month period infants continue to explore the properties of objects using a wide range of different and increasingly complex hand-object actions.  

These include:

• Shaking – especially toys that make a noise
• Banging – especially toys and surfaces that are hard.
• Patting, poking, stroking, flapping with the fingers
• Turning objects  over many times to inspect them from all angles  
• Passing objects  from one hand to the other
• Throwing and dropping objects becomes more common
• Picking up, moving and dropping small and large objects
• Mouthing objects

These hand-object interactions provide many opportunities for infants to learn to select a grasp  pattern that is suited to the action that is being performed.

Experience with handling and manipulating many different objects is important for learning to adapt the pattern of finger movement to suite the shape and size of different objects. This is the exploration phase and with repetition the most effective pattern is selected when encountering the same object at a later time.

Grasp  patterns commonly seen during this period:

• Hook grasp
• Power grasp
• Palmar grasp,
• Circular grasp
• Chuck grasp
• Key grasp    
• Pincer grasp          

Postural stability and hand use

At the beginning of the 7-12 month period when infants are still learning to sit independently, their head and trunk stability and balance are still insecure and arm actions are needed to maintain balance.

This means that some of the brain’s limited attention resources are required to balance, and hand actions, especially reaching beyond arm’s length are somewhat restricted.

However, the provision of external support will overcome this constraint and allow the infant to explore ways to interact with toys and other objects and to start reaching beyond arm’s length.                                                               

Detailed inspection and exploration of a toy

During 7-12 month period, when infants first encounter a new toy they will often systematically engage in a series of exploratory actions that provide them with information about the object

Actions include repeatedly shaking and banging the toy, turning a toy over, fingering it, mouthing and passing it from one hand to the other.

These varied actions provide the infant’s perceptual-motor brain with a detailed internal map of the toy – its size, shape, texture and the way the different parts move relative to one another.  

These exploratory actions provide experience in using a variety of grasp patterns to accommodate the shape and size of the toy.                  

These many exploratory actions infants engage in provide them with detailed information about the shape, size, weight and texture of objects as well as how different properties of objects allow for different actions – known as affordances.

So for instance balls are good for throwing, small balls can be thrown with one hand, but larger balls require a two handed grasp. Containers such as tubs and tins afford different actions and are good for putting toys into and can be tipped upside down to get the toys out again.

Ball activities provide a wide variety of experience

Playing with large and small balls provides infants with a wide variety of experience and knowledge about how ball behave. Importantly when a ball is thrown it lands and then rolls across the floor until something or someone stops its forwards motion.

Infants and toddlers are drawn to the movement of the ball and learn to visually track the moving ball as well as predict where it will be at a future time.  Predicting where a ball will be at a future time is important for learning the catch a ball.  

Picking up small objects

Around about 10-11 months infants start to take an interest in picking up very small objects.

And will also use the extended forefinger to poke at small objects they encounter.

The first attempts to pick up small objects usually involves bending and extending the fingers using a raking action.

Over time infants start to use a key or pincer grasp for picking up small objects.  

In a key grasp the object is held between the thumb pad and the side of the forefinger.

In a precision grip the object is held between the pads of the thumb and the forefinger.  This requires more thumb opposition.

Social interaction and communication gestures

By the end of the 7-12 month period infants have learned a range of social interaction and communication gestures.  These include making requests, visual and arm pointing, waving, imitating actions of social partners and the start of pretend play.

They will often have learned to clap their hands, raise arms for hooray, and give a high five.

By 12 months infants have also started to play pretend games and quickly learn to pretend to talk on a mobile phone and pretend feeding a doll.  

Autism Navigator Resources

A wonderful source of evidence informed information about the development of social and  communication skills.

https://babynavigator.com/resources/

https://babynavigator.com/wp-content/uploads/2021/04/Milestones-that-Matter-Most-from-1-24-Months.pdf

The 12-24 month period

During this period infants learn to use visual attention, motor planning and reach, grasp, hold, transport and manipulation abilities to perform a range of goal directed actions.

Here are some of the hand tasks toddlers master in the second year

• Stacking blocks, building towers

• Fitting objects through apertures – posting objects

• Fitting and taking off lids

• Pulling apart and pushing together

• Throwing and intercepting (catching) balls

• Retrieving objects from a container and tipping objects out of a container.

• Lifting, moving and carrying large or heavy objects

• Using a spoon for feeding self

• Finger feeding

• Drinking from a cup

       

   

Task structure

Learning to perform more complex goal oriented tasks requires an understanding of the structure of the task and how to combine several different hand-object–surface interactions to complete a task.

The structure of a task refers to the series of the actions needed to complete the task including:

• Visual information gathering needed for planning movements

• Anticipatory and compensatory postural responses  in response to limb movements
• The sequence of movements needed to complete the task

Fitting lids onto bottles

There are several steps in fitting a lid onto a bottle

1 Turn the lid upside down and then grasp it around its edge

2 Position the lid over the mouth of the bottle

3 Fit the lid onto the bottle and then push it down or twist it to complete the action.    

Fitting lids and taking them off is usually a bimanual action, with one hand holding the bottle and the other hand manipulating the lid.

       

   

Posting activities

Inserting or posting objects through small openings or into small spaces is another activity that toddlers enjoy doing. In homes with mobile toddlers this interest often leads to lost keys and other objects that toddlers’ value highly such as cell (mobile) phones and car keys.

Toddlers also take great pleasure in activities that involve posting small balls, rods and flat disks into holes in the lids of containers. In these activities the size and shape of the holes and objects being posted can be varied to suit the abilities of the toddler.

The structure of posting  a disk through a slot task

1. Visual search locates the position of the disk.
2. The disk is picked up using a grip that aligns the disk vertically.
3. Visual attention is shifted to the slot in the posting box
4. The hand is moved to bring the disk vertically above the slot and aligned with its angle
5. The position and alignment of the disk is adapted if necessary.
6. The disc is inserted

 

Toddlers are very busy people

Toddlers are very busy people and in a safe and nurturing environment will often move quickly between different parts of the physical environment, spending short periods of time interacting with interesting objects and toys that they encounter or engage in play that mimics caregiver activities.

In the kitchen for instance drawers and cabinet doors are opened and closed, and contents unpacked. Pots and pans may be used for pretend cooking activities for a brief period of time, before the toddler moves off to find something else to play with.

In natural setting such as their homes and day care setting infants will move around the environment, engaging with  many objects for brief periods of time.

Corit Herzberg and colleagues from New York University (NYU) conducted a study using frame-by-frame video analyses of spontaneous activity of forty  13-23 month old infants in two 2 hour  home visits. Regardless of age, for every infant and time scale, across 10,015 object bouts, object interactions were short (median = 9.8 s) and varied, with transitions among dozens of toys and non-toys, with this activity consuming an average to 60% of the infants' time.

The authors of the NYU study suggest that this exuberant object play, creates immense amounts of brief, time-distributed, variable interactions with objects and may optimally promote learning about object properties and functions, motor skill acquisition, and growth in cognitive, social, and language domains.

An important insight provided by this study is that infants naturally learn about their environment using a strategy of brief exploratory interactions with many play and non-play objects. This flitting from one activity to another is not a sign of poor attention span, but rather an indication of employing their time in the most effective way to learn about the properties and affordances of many objects.

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Resources:

• Infant Action Lab

• Skills for Action: Perception-action loops are the basic structure underlying infant learning