Different grasps for different tasks
When we talk about grasping, we mean movements of the wrist, fingers and thumb. When grasping, the wrist helps the thumb and fingers approach an object in the right direction, spread as widely or narrowly as necessary to surround the object, and then close together to grasp it.
Our hands use a variety of combinations of the fingers, thumb and wrist when grasping different objects
You’ll notice that your toddler will pick up a ball differently than an object with a handle. Likewise, they may need to use two different hand grasps when taking something out of a jar.
Before grasping, your toddler needs to think about the object they want to pick up and figure out how to move their wrist, thumb and fingers to do so.
When picking smaller items up, they may just use their fingertips and thumb, whereas when they pick up a teddy, a much larger grasp will be needed.
Over the coming months and years, your toddler will master a variety of grasps.
Sensory guiding and cognitive cues
Through playing and exploring, your toddler has gained a deeper knowledge of what toys and objects are and what they may be used for. Having this understanding makes it easier for them to successfully choose a grasp for picking up toys and other items.
You might also see them adjust their grasp as they keep hold of toys while moving around, while eating, or when playing.
When they use different grasps and adjust how they hold objects, your toddler is solving problems and making decisions.
Estimation
Before your toddler picks up an object, they will think about its size and shape. They rely on their vision to help guide decisions about how to grasp.[1]
They might not be able to calculate the weight of an object at this point, so they will still need to alter their hold if the object is heavy.
Trial, error and time
It takes a planned sequence of movements to be able to reach for and pick up an object.[2] Your toddler might try to pick something up several times before they work out which grasp will be best.
With lots of practice, your toddler will come to learn which hand grasp will work best in a variety of different situations.
References:
[1] Bosco A, Daniele F, Fattori P. Reaching and grasping actions and their context shape the perception of object size. Journal of Vision. 2017 Oct;17(12):10. DOI: 10.1167/17.12.10. PMID: 29053780.
[2] Ruitenberg, M.F.L. (2013) Sequential Motor Skill: Cognition, Perception, and Action. Marit Ruitenberg.