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Julie Campbell

Mentor Department



When does consistency in role-differentiated bimanual manipulations appear during infancy? According to Piaget (1952), at 1 to 4 months, infants' actions are accidental, at 4-8 months their actions become repetitive to gain environmental responses, and at 8-12 months, they become purposeful. Role-differentiated bimanual manipulations (RDBMs), are actions in which each hand performs a complimentary, but different action to perform a goal on the object. RDBMs first appear as simple actions or accidental relations between objects. The ability to perform difficult RDBMs begins to appear around 9-10 months (Babik & Michel, 2016). In the current study, we examined the consistency of performing RDBM actions across the 9- to 14- month age period. Ten infants (5 male), from 9- to 14-months were observed during a play situation. A researcher presented 32 toys to an infant and demonstrated the RDBM action before handing the toy to the infant. RDBM actions occur when infants used one hand to stabilize the object and one hand to manipulate them. No actions were coded if infants did not play with the toy or only used one hand. Videos were analyzed for the number of successful and attempted RDBMs that occurred. Successful RDBMs were defined as occurring when the expected action was performed on the object. Attempts were defined as incomplete actions (an object not completely pulled out from inside a cup, but dropped back in). A t-test will be conducted to find out if each infant performed significantly more successful RDBMs than attempted RDBMs at each month. The hypothesis is that performing a significant proportion of successful RDBMs at 9 months will predict more months overall (7 months total) in which the infant will display success at RDBM. The results of this study would support Piaget's (1952) theory that accidental actions develop into purposeful actions. Infants in this study may demonstrate a similar developmental trend if it is found that there is a significant increase in the frequency of successful RDBMs performed across infancy. The results we expect to see are that the overall number of RDBM actions in early months will predict successful RDBM's in later months. Piaget (1952) shows that 8-12 month olds actions become purposeful as they start to imitate observed behaviors of others. Babik and Michel (2016) found that RDBM actions appear around 9 months. Our study supports these theories as we expect to see consistent RDBM actions after 9 months of age.



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