Infants and Children in Context. Tara L. Kuther

For example, in Jewish cultures, a boy is circumcised on the eighth day after birth in a ritual celebration known as a bris, in which the boy is welcomed as a member of the community. Parents’ decisions are also influenced by social factors such as whether the father is circumcised and the desire that the child resemble his peers (Bo & Goldman, 2008). The decision is complicated, as parents weigh health risks and benefits with contextual factors such as religious and cultural beliefs, as well as personal desires, to determine what is best for their child.

      Description

      Figure 4.15 Rates of Circumcision Performed, 1979–2010

      Source: Owings et al. (2013).

      Notes: Rates represent circumcisions performed during the birth hospitalization. Circumcision is identified by International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) procedure code 64.0.

      What Do You Think?

      1 In your view, what are the most important considerations in making a decision about whether to circumcise a newborn boy?

      2 Imagine that you had a newborn boy. Would you choose to circumcise your son? Why or why not? ●

      Smell and Taste

      Smell and taste receptors are functional in the fetus and preferences are well developed at birth (Bloomfield, Alexander, Muelbert, & Beker, 2017). Just hours after birth, newborns display facial expressions signifying disgust in response to odors of ammonia, fish, and other scents that adults find offensive (Steiner, 1979). Within the first days of life, newborns detect and recognize their mother’s odor (Macfarlane, 1975; Marin, Rapisardi, & Tani, 2015). Infants are calmed by their mother’s scent. Newborns who smelled their mother’s odor displayed less agitation during a heel-stick test and cried less afterward than infants presented with unfamiliar odors (Rattaz, Goubet, & Bullinger, 2005). Familiar scents are reinforcing and can reduce stress responses in infants (Goubet, Strasbaugh, & Chesney, 2007; Nishitani et al., 2009; Schaal, 2017). For example, the scent of breast milk can slow heart rate in premature neonates who are under stress (Neshat et al., 2016).

      Infants show innate preferences for some tastes (E. S. Ross, 2017). For example, both bottle-fed and breastfed newborns prefer human milk—even milk from strangers—to formula (Marlier & Schaal, 2005). Newborns prefer sugar to other substances, and a small dose of sugar can serve as an anesthetic, distracting newborns from pain (Gradin, Eriksson, Schollin, Holmqvist, & Holstein, 2002). Experience can modify taste preferences, beginning before birth: Fetuses are exposed to flavors in amniotic fluid that influence their preferences after birth (Beauchamp & Mennella, 2011; Forestell, 2016). In one study, the type of formula fed to infants influenced their taste preferences at 4 to 5 years of age (Mennella & Beauchamp, 2002). Infants who were fed milk-based formulas and protein-based formulas were more likely to prefer sour flavors at 4 to 5 years of age compared with infants who were fed soy-based formulas, who, in turn, were more likely to prefer bitter flavors.

      Intermodal Perception

      All stimuli we encounter involve more than one type of sensory information. For example, we see a dog but we also hear its bark. Not only are infants able to sense in multiple modalities, but they are able to coordinate their senses. Intermodal perception is the process of combining information from more than one sensory system (Johnson & Hannon, 2015). Sensitivity to intermodal relations among stimuli is critical to perceptual development and learning—and this sensitivity emerges early in life (Lewkowicz, Leo, & Simion, 2010). That is, infants expect vision, auditory, and tactile information to occur together (Sai, 2005). For example, newborns turn their heads and eyes in the direction of a sound source, suggesting that they intuitively recognize that auditory and visual information co-occur and provide information about spatial location (Newell, 2004).

      Newborns show a preference for viewing their mother’s face at 72, 12, and even just 4 hours after birth (Pascalis, Dechonen, Morton, Duruelle, & Grenet, 1995). It was once believed that infants’ preference for their mother’s face was innate. Are infants born knowing their mother’s face? In one study, neonates were able to visually recognize their mother’s face only if the face was paired with their mother’s voice at least once after birth (Sai, 2005). Thus, intermodal perception is evident at birth because neonates can coordinate auditory (voice) and visual stimuli (face) to recognize their mother. They quickly remember the association and demonstrate a preference for her face even when it is not paired with her voice.

      Infants integrate touch and vision very early in life. In one classic study, 1-month-old infants were presented with a smooth-surfaced pacifier or one with nubs on it. After exploring it with their mouths, the infants were shown two pacifiers—one smooth and one nubbed. The infants preferred to look at the shape they had sucked, suggesting that they could match tactile and visual stimuli (Meltzoff & Borton, 1979). In another example, 8- to 31-day-old infants fitted with special goggles were presented with a virtual object created by a shadow caster (Bower, Broughton, & Moore, 1970). The virtual object was an illusory object that could be seen by the infant but not touched. When the infant reached for the object, his or her hand felt nothing and flailed through the air. Infants exposed to the virtual object attempted to reach for it and became distressed when they did not feel it, suggesting that vision and touch are integrated and infants expect to feel objects that they can see and reach. Infants’ ability to integrate sensory information has implications for learning as discussed in the Lives in Context feature.

      Lives in Context: Biological Influences

      Intermodal Perception and Learning

      Infants can integrate information from multiple senses from birth. Do they process sensory information in similar ways as older children and adults? We cannot be certain of how they make sense of intermodal sensations; however, fMRI research suggests that when very young infants (11–36 days old) are perceiving intermodal stimuli, they show activity in similar sensory regions of the brain as adults (Sours et al., 2017).

      Infants are particularly responsive to touch (recall kangaroo care in Chapter 3). When given soft brush strokes to the skin of their leg, 11- to 36-day-old infants show similar neural responses as children and adults in areas linked with sensory, social, and affective processing (Tuulari et al., 2019). Infants’ early sensitivity to touch and its links with socio-affective brain regions may play an important role in development.

      Infants’ sensitivity to touch and their ability to integrate auditory with tactile information may aid learning. In one set of studies, researchers examined the integration of tactile and auditory senses in 5- to 7-month-old infants (Lew-Williams, Ferguson, Abu-Zhaya, & Seidl, 2019). Specifically, infants listened to abstract patterns of tones while being touched on the knee or elbow. The infants were more likely to learn auditory sequences when the accompanying touches matched the auditory pattern. The findings suggest that social touch not only arouses infants but also influences how they process stimuli and learn.

      Touch, particularly caregivers’ touch, promotes learning. For example, in one study, 4-month-old infants habituated to a face while their forehead was either stroked with a soft paintbrush, stroked by a caregiver, or was not stroked. The infants who were stroked by caregivers looked significantly longer than their peers when shown a new face, suggesting that caregiver touch promoted learning (Della Longa, 2019). Social touch is rewarding and may play a special role in learning, as suggested by a recent study of 7- to 8-month-old infants (Tanaka, Kanakogi, Kawasaki, & Myowa, 2018). In this study, infants heard a short string of syllables while being tickled (multisensory) or while not being tickled. When infants were tickled while listing to the string of syllables, they displayed more brain activity in regions of the brain related to sensory processing and attention than when they listened without being tickled. In