Читать книгу Lifespan Development - Tara L. Kuther - Страница 255

Piaget’s method of determining an infant’s understanding of object permanence relied on the infant’s ability to demonstrate it by uncovering a hidden object. Critics argue that many infants may understand that the object is hidden but lack the motor ability to coordinate their hands to physically demonstrate their understanding. Studying infants’ looking behavior enables researchers to study object permanence in younger infants with undeveloped motor skills because it eliminates the need for infants to use motor activity to demonstrate their cognitive competence.

One such research design uses a violation-of-expectation task, a task in which a stimulus appears to violate physical laws (Hespos & Baillargeon, 2008). Specifically, in a violation-of-expectation task, an infant is shown two events: one that is labeled expected because it follows physical laws and a second that is called unexpected because it violates physical laws. If the infant looks longer at the unexpected event, it suggests that he or she is surprised by it, is aware of physical properties of objects, and can mentally represent them.

In a classic study, developmental researcher Renée Baillargeon (1987) used the violation-of-expectation method to study the mental representation capacities of very young infants. Infants were shown a drawbridge that rotated 180 degrees. Then the infants watched as a box was placed behind the drawbridge to impede its movement. Infants watched as either the drawbridge rotated and stopped upon hitting the box or did not stop and appeared to move through the box (an “impossible” event). As shown in Figure 5.3, 4½-month-old infants looked longer when the drawbridge appeared to move through the box (the “impossible” unexpected event) than when it stopped upon hitting the box. Baillargeon and colleagues interpreted infants’ behavior as suggesting that the infants maintained a mental representation of the box, even though they could not see it, and therefore understood that the drawbridge could not move through the entire box.

Other researchers counter that these results do not demonstrate object permanence but rather illustrate infants’ preference for novelty or for greater movement (Bogartz, Shinskey, & Schilling, 2000; Heyes, 2014). For example, when the study was replicated without the box, 5-month-old infants looked longer at the full rotation, suggesting that infants looked at the unexpected event not because it violated physical laws but because it represented greater movement (Rivera, Wakely, & Langer, 1999). Nevertheless, studies that use simpler tasks have shown support for young infants’ competence. Four- and 5-month-old infants will watch a ball roll behind a barrier, gazing to where they expect it to reappear (von Hofsten, Kochukhova, & Rosander, 2007). When 6-month-old infants are shown an object and the lights are then turned off, they will reach in the dark for the object (Shinskey, 2012), suggesting that they maintain a mental representation of the object and therefore have object permanence earlier than Piaget believed.

Table 5.1