Lifespan Development. Tara L. Kuther

and perceived function and behavior (Bornstein & Arterberry, 2010; Mandler & McDonough, 1998; Oakes, 2010).

      Researchers also use sequential touching tasks to study the conceptual categories that older infants create (Perry, 2015). Infants are presented with a collection of objects from two categories (e.g., four animals and four vehicles) and their patterns of touching are recorded. If the infants recognize a categorical distinction among the objects, they touch those from within a category in succession more than would be expected by chance. Research using sequential touching procedures has shown that 12- to 30-month-old toddlers organize objects first at a global level and then at more specific levels. They categorize at more inclusive levels (e.g., animals or vehicles) before less inclusive levels (e.g., types of animals or types of vehicles) and before even less inclusive levels (e.g., specific animals or vehicles) (Bornstein & Arterberry, 2010). Infants’ and toddlers’ everyday experiences and exploration contribute to their growing capacity to recognize commonalities among objects, group them in meaningful ways, and use these concepts to think and solve problems.

      Recognizing categories is a way of organizing information that allows for more efficient thinking, including storage and retrieval of information in memory. Therefore, advances in categorization are critical to cognitive development. The cognitive abilities that underlie categorization also influence language development as words represent categories, ways of organizing ideas and things. In the Applying Developmental Science feature, we look at the baby signing movement, which proposes that infants can apply gestures as symbols in order to communicate.

      As shown in Table 5.2, information processing capacities, such as attention, memory, and categorization skill, show continuous change over the first 3 years of life (Rose, Feldman, & Jankowski, 2009). Infants get better at attending to the world around them, remembering what they encounter, and organizing and making sense of what they learn. Infants’ emerging cognitive capacities influence all aspects of their development and functioning, including intelligence. Cognitive development is also influenced by the contexts in which infants and children live.

      Applying Developmental Science

      Baby Signing

      Although signing may not accelerate language development, it offers opportunities for parent-infant interaction and play.

      AP/Justin Hayworth

      Few things are as frustrating for a parent as trying to decipher their baby’s cry. What does she need? Is she hungry? Cold? Does she have a wet diaper? Is she hurt? Imagine how nice it would be if infants could communicate their needs! Is baby signing the answer?

      The baby signing movement promotes early communication between infants and parents by teaching infants to communicate with symbolic gestures. The assumption behind baby signing is that the cognitive and gross motor skills needed for signing develop before the relatively fine motor control of the mouth, tongue, and breath needed to articulate speech (Goodwyn & Acredolo, 1998). The roots of baby signing lie in research conducted by Linda Acredolo and Susan Goodwyn. Their research has shown that babies readily acquire symbolic gestures when exposed to the enhanced gestural training that they refer to as baby signs (Acredolo, Goodwyn, & Abrams, 2009). They propose that the rewards of baby signing include larger and more expressive vocabulary, advanced mental development, improved parent–child relationships, and fewer tantrums and behavior problems (Acredolo & Goodwyn, 1988; Goodwyn & Acredolo, 1998). Based on their findings, Acredolo and Goodwyn created a signing program for infants with videos, classes, books, and cue cards (Acredolo et al., 2009). Parents who read about the benefits of teaching signs to their infants often embrace the practice. Numerous companies have been created to promote and sell baby signing materials. Most advertise benefits such as facilitating spoken language, reducing tantrums, and increasing IQ.

      It is generally recognized that gesture and language are linked and that babies naturally make early gestures that precede their use of language (Iverson & Goldin-Meadow, 2005). Sensitive responses from caregivers tend to result in more pointing and gesturing from infants, suggesting that gestures are a form of communication (Vallotton, Decker, Kwon, Wang, & Chang, 2017). But is baby signing effective in accelerating language and cognitive development? One review of 33 websites associated with various baby signing products revealed that all promoters claimed benefits such as faster language development, and many claimed to foster cognitive and emotional development, including higher IQs, improvements in parent–child interactions, and fewer child tantrums. Yet almost none provided evidence to support these claims. Those that did referred to case studies (such as Acredolo & Goodwyn, 1985) and opinion articles rather than experiments (Nelson, White, & Grewe, 2012). A review of research studies examining the outcomes of baby signing programs found that although some of the studies suggested some benefits, nearly all contained methodological weaknesses such as a lack of control groups or no random assignment. It was concluded that evidence to support these claims was insufficient (Johnston, 2005).

      More recently, a longitudinal study tested the effects of baby signing products. Infants were followed from 8 months of age until 20 months of age (Kirk, Howlett, Pine, & Fletcher, 2013). Babies were randomly assigned to one of three conditions: baby sign training, verbal training (i.e., mothers modeled words without signs), and nonintervention. At 20 months of age, the language development was similar for all babies, regardless of intervention. Encouraging gestures did not result in higher scores on language measures, providing no support for the claims of baby signing proponents.

      Nevertheless, many parents report that baby signing has improved their child’s ability to communicate, cognitive ability, and overall parent–infant interactions (Doherty-Sneddon, 2008; Mueller & Sepulveda, 2014). For example, although U.K. infants enrolled in a baby signing class showed no differences in language development compared with their nonsigning peers, mothers who enrolled their infants in the baby signing class tended to use more mental terms and refer to thinking (“You want the toy, huh?”) in their infant-directed interactions (Zammit & Atkinson, 2017). Baby signing may not have research support for accelerating language development, but if it promotes frequent parent–infant interaction, does not rush or pressure infants, and is helpful in parents’ estimation, there is no reason to discourage its use.

      What Do You Think?

      Should we encourage parents to teach their babies how to sign? Why or why not?

Table 5.2

      Thinking in Context 5.2

      1 What kinds of toys and activities would you recommend to caregivers who want to entertain infants while helping them develop skills in attention, memory, or categorization?

      2 Recall from Chapter 1 that an important theme of development is that it is influenced by multiple contexts. How might contextual influences, such as family, neighborhood, sociocultural context, and even cohort or generation, influence attention, memory, categorization, and/or other aspects of cognition?

      3 What are some of the challenges in studying how infants think and what they know? How have researchers addressed these issues? Can you identify criticisms to information processing researchers’ methods, findings, or conclusions?

      Individual Differences in Infant Intelligence

      At its simplest, intelligence refers to an individual’s ability to adapt to the world. Of course, different people have different levels of intelligenc—an example of the concept of individual differences or variation from one individual to another. Intelligence tests are used to measure these differences; they include questions that measure memory, pattern recognition,