|
|
  |
|
| |||||||||||||||||||||||||||||||||
|
|||||||||||||||||||||||||||||||||
|
Infants’ convergence to more useful
information in the control of catching John van der Kamp & Geert Savelsbergh |
 |
||||||||||||||||||||||||||||||||
|
Proponents of the ecological approach
argue that underlying each action there is a lawful coupling between
movement and visual information. The environment contains a manifold
of informational variables that differ in the degree to which they
are useful in the control of action. An informational variable is
considered more useful if it can be exploited across a larger
variety of situations without resulting in performance decrements.
By contrast, the variable is considered less useful if its use leads
to accurate performance in only one or few situations. Similar as
for learning in adults (e.g. Fajen, 2005; Jacobs & Michaels, 2002),
this implies that development in the control of action would be
characterized by a convergence to more useful information (Van der
Kamp, Oudejans & Savelsbergh, 2003). With respect to intercepting moving objects, our studies (Van Hof, Van der Kamp, Savelsbergh, 2006; 2008) demonstrate that improvements between 3 and 9 months of age infants learn to deal with a larger variety of situations (e.g. object speeds and sizes). In particular, Van Hof et al. (2008) presented infants with objects that approached with speeds varying between 10 and 200 cm/s. We found that with age, infants became better catchers; they managed to intercept balls with higher speeds. This development was associated with a shift from a using a distance strategy (i.e. movement onset occurs when the object is at a fixed distance) to using a time strategy (i.e. movement onset occurs when the object is at fixed time) in the way the infants controlled their catching action. |
We will present analyses that scrutinize
the optical variables involved in the infants’ control of action.
These analyses indicate that the shift in control strategy reflects
the convergence from less useful information (e.g., the optical
angle subtended on the retina by the moving ball which is dependent
on the balls speed) to more useful information (e.g., the rate or
relative rate of change of the optical angle, which is independent
of ball speed). References Fajen, B.R. (2005). Perceiving possibilities for action: On the necessity of calibration and perceptual learning for the visual guidance of action. Perception, 34, 717-740. Jacobs, D.M., & Michaels, C.F. (2002). On the apparent paradox of learning and realism. Ecological Psychology, 14, 127-139. Van der Kamp, J., Oudejans, R., & Savelsbergh, G.J.P. (2003). The development and learning of the visual control of movement: An ecological perspective. Infant Behavior & Development, 26, 495-515. Van Hof, P., Van der Kamp, J., & Savelsbergh, G.J.P. (2006). Three- to eight-month-old infants’ catching under monocular and binocular vision. Human Movement Science, 25, 18-36. Van Hof, P., van der Kamp, J. & Savelsbergh, G. (2008). The relation between infants’ perception of catchableness and the control of catching. Developmental Psychology, 44, 182-194. |
||||||||||||||||||||||||||||||||
|
|
|||||||||||||||||||||||||||||||||
