Source: Turk-Browne et al., 2008.
Figure 5.4 A-Not-B Error
The infant continues to look for the ball under Place A despite having seen the ball moved to Place B.
Deferred Imitation Tasks
Another method of studying infants’ capacities for mental representation relies on deferred imitation, the ability to repeat an act performed some time ago. Piaget (1962) believed that infants under 18 months cannot engage in deferred imitation because they lack mental representation abilities. Yet laboratory research on infant facial imitation has found that 6-week-old infants who watch an unfamiliar adult’s facial expression will imitate it when they see the same adult the next day (Meltzoff & Moore, 1994). Six- and 9-month-old infants also display deferred imitation of unique actions performed with toys, such taking a puppet’s glove off, shaking it to ring a bell inside, and replacing it over a 24-hour delay (Barr, Marrott, & Rovee-Collier, 2003).
When infants engage in deferred imitation, they act on the basis of stored representations of actions—memories—a contradiction of Piaget’s beliefs about infants’ capabilities (Jones & Herbert, 2006). Many researchers now suggest that deferred imitation, along with object permanence itself, is better viewed as a continuously developing ability rather than the stage-like shift in representational capacities that Piaget proposed (Miller, 2016).
For example, a 3-year longitudinal study of infants 12, 18, and 24 months old showed that performance on deferred imitation tasks improved throughout the second year of life (Kolling, Goertz, Stefanie, & Knopf, 2010). Between 12 and 18 months, infants remember modeled behaviors for several months and imitate peers as well as adults (Hayne, Boniface, & Barr, 2000). They also imitate across contexts, imitating behaviors that they learn in child care at home (Patel, Gaylord, & Fagen, 2013).
Increases in imitative capacity are observed with development up to 30 months of age. In addition, imitative capacity increases when shorter sequences of action are used, for example, a sequence of fewer than eight unique actions (Kolling, Goertz, Stefanie, & Knopf, 2010; Kressley-Mba et al., 2005). Furthermore, research following infants from 9 to 14 months of age suggests that individual differences in imitation are stable; children who show lower levels of imitation at 9 months of age continue to score lower on imitation at 14 months (Heimann & Meltzoff, 1996). These gradual changes suggest that infants and toddlers increase their representational capacities in a continuous developmental progression.
Core Knowledge Theory: An Alternative Perspective
Developmental psychologists generally agree with Piaget’s description of infants as interacting with the world, actively taking in information, and constructing their own thinking. However, most researchers no longer agree with Piaget’s belief that all knowledge begins with sensorimotor activity. Instead, infants are thought to have some innate, or inborn, cognitive capacities. Conservative theorists believe that infants are born with limited learning capacities such as a set of perceptual biases that cause them to attend to features of the environment that will help them to learn quickly (Bremner, Slater, & Johnson, 2015). Alternatively, the core knowledge theory proposes that infants are born with several innate knowledge systems, or core domains of thought, that promote early rapid learning and adaptation (Spelke, 2016).
According to core knowledge theorists, infants learn so quickly and encounter such a great amount of sensory information that some prewired evolutionary understanding, including the early ability to learn rules, must be at work (Spelke, 2016). Using the violation-of-expectation method, core knowledge researchers have found that young infants have a grasp of the physical properties of objects, including the knowledge that objects do not disappear out of existence (permanence), cannot pass through another object (solidity), and will fall without support (gravity; Baillargeon, Scott, & Bian, 2016). Infants also display early knowledge that liquids are nonsolid substances able to pass through grids (Hespos, Ferry, Anderson, Hollenbeck, & Rips, 2016).
Infants are also thought to have early knowledge of numbers (Spelke, 2017). Five-month-old infants can discriminate between small and large numbers of items (Christodoulou, Lac, & Moore, 2017). Even newborns are sensitive to large differences in number, distinguishing nine items from three, for example, but newborns show difficulty distinguishing small numbers from each other (two vs. three items) (Coubart, Izard, Spelke, Marie, & Streri, 2014). Comparative research has shown that animals display these systems of knowledge early in life and without much experience (Piantadosi & Cantlon, 2017), suggesting that it is possibl—and perhaps evolutionarily adaptiv—for infants to quickly yet naturally construct an understanding of the world (Bjorklund, 2018). Increasingly, infants are viewed as statistical learners, able to quickly identify patterns in the world around them (Saffran & Kirkham, 2018).
Much core knowledge research employs the same looking paradigms described earlier, in which infants’ visual preferences are measured as indictors of what they know, and this approach has come under criticism. Critics argue that it is unclear whether we can interpret looking in the same way in infants as in adults. Such measures demonstrate discrimination—that young infants can tell the difference between stimuli—yet perceiving the difference between two stimuli does not necessarily mean that infants understand how the two stimuli differ (Bremner et al., 2015). Others have suggested that infants are not detecting differences in number but rather differences in area (Mix, Huttenlocher, & Levine, 2002). For example, it may be that the infant differentiates nine items from three not because of the change in number but simply because nine items take up more space than three. More recent research has shown that 7-month-old infants can differentiate changes in number and area, are more sensitive to changes in number than area, and prefer to look at number changes than area changes (Libertus, Starr, & Brannon, 2014). Infants apply basic inferential mechanisms to quickly yet naturally construct an understanding of the world (Xu & Kushnir, 2013).
Overall, Piaget’s theory has had a profound influence on how we view cognitive development. However, infants and toddlers are more cognitively competent than Piaget imagined, showing signs of representational ability and conceptual thought that he believed were not possible. Developmental scientists agree with Piaget that immature forms of cognition give way to more mature forms, that the individual is active in development, and that interaction with the environment is critical for cognitive growth. Today, electronic media are an important part of almost everyone’s environment. Do infants interact with electronic media? The Lives in Context feature examines whether infants can learn from electronic media.
Lives in Context
Baby Videos and Infant Learning
Infants and toddlers learn more from interaction with their parents and other caregivers than they do watching infant-directed educational content.
iStock/LucaLorenzelli
Infants and toddlers spend 1 to 2 hours a day engaged with screen media, including television and tablets, and are exposed to over 5 hours daily of background television intended for adults (Courage, 2017). Infant-directed videos and programming, which offer educational content embedded in an engaging video format, are often advertised as aids to babies’ brain development, intelligence, and learning (Fenstermacher et al., 2010; Vaala & LaPierre, 2014). Most parents