Abstract

SILVA, Laísla Camila da; MARQUES, Inara  and  MEDINA-PAPST, Josiane. Effect of object weight and experience on the organization of object management tasks in infants of 10 months of age. J. Hum. Growth Dev. [online]. 2019, vol.29, n.2, pp. 192-199. ISSN 0104-1282.  http://dx.doi.org/10.7322/jhgd.v29.9419.

INTRODUCTION: CLittle is known about the real impact the practice of manipulating objects on the development of infants perception-action and it is assumed that this newly acquired knowledge is useful for planning future actions. OBJECTIVE: To analyse the effects of controlled practice on the tasks of reaching and transporting objects in 10-month-old infants when the weight of the object was changed. METHODS: Sixteen infants were divided into two groups: heavy/light group (HLG) and light/heavy group (LHG). The task consisted in reaching, grasping, and lifting a lighter or heavier bar 9 times. On the tenth trial, the object weight was switched to the heavier or lighter weight object (whichever was opposite to the object weight experienced in the first 9 trials) to assess whether infants had learned and adapted their object-directed movement strength to the initial weight condition practiced during the first 9 trials. RESULTS: No significant differences were found when comparing the reaching and lifting phases within groups (LHG, P = 0.06 and HLG, p = 0.41). However, group comparisons revealed that HLG infants presented increased velocity peak (p = 0.01) during the trials CONCLUSION: The reaching and object lifting trials of the infants throughout the attempts were very variable, indicating that, possibly, at 10 months of age, infants present transitions from one organizational state to another. However, it is necessary to carry out more detailed investigations on reaching and lifting actions of objects to understand the processes involved in these transition periods.

Keywords : infant behavior; motor skills; infant.

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