January 7,
1999 Vol. 18 No. 7

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    [amanda woodward], by jason smith  
    Amanda Woodward adjusts the cameras in the lab where she observes babies for her studies on learning and development.

    Woodward discovers babies develop reasoning skills as early as 5 months

    By William Harms
    News Office

    New research by Amanda Woodward, Assistant Professor in Psychology, shows that babies begin to develop social reasoning skills as early as 5 months of age.

    Woodward demonstrates for the first time that young babies have the ability to understand the purpose of some of their adult care givers’ actions. Infants begin to expand their reasoning skills at 5 months and have more fully developed reasoning skills by 6 to 9 months, according to her paper, “Infants Selectively Encode the Goal Object of an Actor’s Reach,” published in the December issue of the journal Cognition.

    Researchers have found that babies are aware of many features of their environment and understand early that two objects cannot occupy the same space. Until Woodward’s research, however, scholars have been unable to establish when babies begin developing the ability to reason about human behavior. Woodward’s study disputes views of other researchers who have contended that because infants younger than 9 or 12 months do not reliably follow points or gaze, they do not understand action as directed at an object.

    “Early in life, infants begin to set up a system of knowledge of human action that has features in common with more mature understandings, and that is distinct from their knowledge of inanimate object motion,” Woodward writes. “This system of knowledge likely provides the foundation on which later knowledge is built.”

    Understanding intentions is a crucial part of a child’s ability to make sense of the world. As a child grows, the ability to reason also grows. Making inferences about the actions of others is a common experience for adults, who intuitively reason, for example, that when they see someone stop and look at the ground and move toward a spot, that person has seen something and has the goal of exploring the item further. When reasoning about other people’s actions, adults focus on underlying intentions rather than the physical motion that takes place.

    Using a visual habituation technique, Woodward conducted a series of experiments to find out if babies make distinctions between people and objects and if they are able to determine if an action made by a person has a purpose.

    For the experiments, researchers placed the babies on seats or on their mothers’ laps across from a stage. Babies saw an actor who moved and grasped either a multicolored ball or a white teddy bear that were sitting side by side. After habituation, the positions of the toys were switched, and babies saw test events in which there was a change in either the path of motion taken by the actor’s arm or the object that was grasped by the actor.

    Once babies have been habituated to an event they will look longer at another event that seems novel to them. Thus, infants’ attention to the change in path versus the change in goal object indicated which feature, path or goal was more central to the event from the babies’ points of view.

    In the first experiment, 32 9-month-old infants were tested. Half of the babies saw a hand grasp one of the toys, and the other half saw a decorated rod touch one of the toys. When babies saw the hand grasp the toy, they paid specific attention to the relation between the hand and the goal object. That is, they seemed to think that the goal was a key feature of the event. When the babies saw the rod touch the toy, they did not pay special attention to the goal object for the same length of time.

    In a second experiment, 5-month-olds were tested. Like the 9-month-olds, the younger infants differentiated between the human hand and the rod.

    Woodward finally conducted an experiment with 6-month-olds to determine if infants were paying attention to the goal object because of the grasping motion or because it involved a person. Half of the babies watched as a claw tool grasped a toy, and the other half watched as a hand grasped a toy. As in previous studies, babies who saw the hand grasp the toy focused on the relation between the hand and the object. In contrast, babies who saw the claw grasp did not do this. If anything, babies in this group attended more to the path of motion taken by the claw.

    “Taken together, these findings indicate that young infants distinguish in their reasoning about human action and object motion, and that by 6 months, infants encode the actions of other people in ways that are consistent with more mature understandings of goal-directed action,” Woodward wrote in her paper.

    Woodward said reasoning skills likely develop as part of the normal experiences of an infant. The development may be related to other growth for infants as they reach 6 months and begin to sit up by themselves and perform other physical actions for the first time. As babies become able to act on the world in new ways, their understanding of action may be enriched.

    “Babies don’t require special training to develop this reasoning ability,” Woodward said. “It’s something that seems to come naturally, which is important because these reasoning skills are fundamental to the way we live.”

    Woodward is among a group of researchers with the Early Childhood Initiative at the University, an innovative program to study early childhood development and policy. It is funded through a two-year, $875,000 grant from the Robert R. McCormick Tribune Foundation.

    Woodward’s work on social reasoning also was funded by the John Merck Fund.