Mapping the feel of the arm with the sight of the object: on the embodied origins of infant reaching

Abstract

For decades, the emergence and progression of infant reaching was assumed to be largely under the control of vision. More recently, however, the guiding role of vision in the emergence of reaching has been downplayed. Studies found that young infants can reach in the dark without seeing their hand and that corrections in infants' initial hand trajectories are not the result of visual guidance of the hand, but rather the product of poor movement speed calibration to the goal. As a result, it has been proposed that learning to reach is an embodied process requiring infants to explore proprioceptively different movement solutions, before they can accurately map their actions onto the intended goal. Such an account, however, could still assume a preponderant (or prospective) role of vision, where the movement is being monitored with the scope of approximating a future goal-location defined visually. At reach onset, it is unknown if infants map their action onto their vision, vision onto their action, or both. To examine how infants learn to map the feel of their hand with the sight of the object, we tracked the object-directed looking behavior (via eye-tracking) of three infants followed weekly over an 11-week period throughout the transition to reaching. We also examined where they contacted the object. We find that with some objects, infants do not learn to align their reach to where they look, but rather learn to align their look to where they reach. We propose that the emergence of reaching is the product of a deeply embodied process, in which infants first learn how to direct their movement in space using proprioceptive and haptic feedback from self-produced movement contingencies with the environment. As they do so, they learn to map visual attention onto these bodily centered experiences, not the reverse. We suggest that this early visuo-motor mapping is critical for the formation of visually-elicited, prospective movement control.

Learning to reach with “sticky” or “non-sticky” mittens: A tale of developmental trajectories

“…This was revolutionary to the field of motor development but contemporary research has not fully supported all aspects of Piaget's theory (Bahrick & Lickliter, 2000;Clifton et al, 1993;McCarty, Clifton, Ashmead, Lee, & Goubet, 2001;Meltzoff & Moore, 1977;Pogetti, Souza, Tudella, & Teixeira, 2013;Slater, Quinn, Brown, & Hayes, 1999;Streri & Gentaz, 2003). As of today, it is still not clear how infants exactly figure out how to coordinate their bodies, actions, and intentions to manage the first successful contact with an object, and repeat this action over time, although accounts on how this may come about have been suggested (see Corbetta, Thurman, Wiener, Guan, & Williams, 2014;Piaget, 1952;White et al, 1964, for past and more current accounts).…”

“…Given the complexity of such behavior, how then do infants just all of a sudden put these elements together to produce successful reaches? From a systems perspective, this does not happen all of a sudden; infants have been working on learning to reach since the day they were born through multiple sensory-motor experiences (Corbetta & Thelen, 1999;Corbetta et al, 2014). Here the term learning refers not simply to a change in behavior as a result of past experiences but more specifically to infants' continuous exploration of their body and its capabilities, and to the subsequent selection of successful movement patterns within the particular task context.…”

“…Indeed, in using these perspectives it is assumed that the learning to reach process begins from the earliest days of life, through embodied pre-reaching and spontaneous arm movements, where consequential outcomes of self-generated arm activities are used to draw how to move the arms and how to select reachinglike movements when presented with a reaching-specific context (Corbetta & Thelen, 1999;Corbetta et al, 2014;Thelen & Corbetta, 2002). Another key way infants select successful reaching movements is through repeated experience and exposure to the reaching-specific context which allows for active reaching attempts toward objects, exploration of the properties and consequences of their arm movements, and selection of those movements that prove to be the most successful, or valuable.…”

The neural dynamics of goal-directed arm movements: A developmental perspective

“…Learning to reach is a critical developmental milestone and infants work very hard at it. Many processes need to be in place in order to successfully reach: The mapping from visual space to a body-centered motor space must work [5]. Body-centered information about the target or movement plan must be translated into joint and muscle space.…”

Learning to reach after learning to look: A study of autonomy in learning sensorimotor transformations

“…However, this complexity is revealed in developmental studies, which establish that it takes human infants many weeks of intensive (and highly motivated) practice to develop the ability to direct their hands toward interesting objects [1]. The problem of generating a motor plan that directs the hand to a visually perceived object obviously requires learning the sensorimotor transformation between the the visual and the arm systems [2].…”