Jessa Reed, Kathy Hirsh-Pasek, and Roberta Michnick Golinkoff

24Meeting Children Where They Are: Adaptive Contingency Builds Early Communication Skills

Abstract: Communication competence in preschoolers begins in infancy. By offering both prompt and meaningful responses to children’s communicative bids, caregivers support emerging language (e.g., vocabulary) and social skills so that preschoolers can become savvy conversationalists. Here we introduce the idea of adaptive contingency as a shared mechanism that sustains adult and child interactions and promotes communication competence across four developmental periods: early and later infancy, toddlerhood, and the preschool years. Adaptive contingency is expressed differently over time, accommodating children’s growing cognitive, social, and motor skills. With infants, caregivers scaffold exchanges by mirroring infants, establishing expectations of reciprocity and turn-taking. In the second half of the first year, caregivers capitalize on infants’ explorations, offering input that builds upon (rather than mirrors) their actions. Toddlerhood is characterized by shared referential contexts between adult and child (i.e., common ground) that facilitate vocabulary growth. Finally, conversations during the preschool years allow young children to practice budding pragmatic skills. Although the content and quality of caregivers’ input change over time, adopting a panoramic view reveals the import of adaptive contingency (prompt timing and meaningfulness) as the foundation for a series of cascading behaviors between adult and child that fosters communication competence.

Keywords: parent-child interactions, contingency, word learning, language development, pragmatic skills, communication competence

Words are also actions, and actions are a kind of words.

Ralph Waldo Emerson

A child’s first word is a moment to be celebrated. Across cultures, babies’ earliest vocabularies often consist of words to describe family members (e.g., “daddy”) as well as functional terms such as “hi” (Tardif et al., 2008). The transition from babbling may feel abrupt, like a green shoot that emerges above ground from the pea planted below. Much, however, is going on beneath the surface, and science is beginning to chart that development. Through the Human Speechome Project, for example, Roy and colleagues pioneered an approach that allowed the “birth” of a word to be monitored through continuous recordings of a child at home from birth to three years (Roy, Frank, DeCamp, Miller, & Roy, 2015). Eight million words were transcribed, and in his Ted Talk, Roy (2011) chronicled the emergence of the word “water” in his son’s lexicon. The word did not suddenly appear; the longitudinal recordings demonstrate its nascent form in babbles and abbreviated attempts. The outcome – here, baby’s growing vocabulary – is rooted in a process that unfolds over time and is shaped by interactions with supportive caregivers.

How can caregivers foster children’s emerging communication competence? Before this question can be addressed, it is imperative to recognize that communication consists of more than just words. First, effective communication consists of talking and listening (Ironsmith & Whitehurst, 1978). Second, eye gaze and gestures are part of our arsenal for communicating with others (Tomasello, 2008). Even as young as 9 months, infants recognize that pointing is a useful tool to communicate with others (Krehm, Onishi, & Vouloumanos, 2014). Third, words are not the only means by which we communicate. Infants’ earliest exchanges are infused with positive affect. When speaking to babies, for example, caregivers use a particular style of infant-directed speech that conveys affective information (for a recent review, see Golinkoff, Can, Soderstrom, & Hirsh-Pasek, 2015; see also Soderstrom, 2007). The “conversational duets” (Hirsh-Pasek et al., 2015) that caregivers have with children, in which they seamlessly integrate nonverbal behaviors (e.g., eye gaze, smiles, and gestures) and words during back-and-forth exchanges, lay the basis for communication competence. In this chapter, we introduce the concept of adaptive contingency – defined as prompt and meaningful responses to children’s bids – and argue that adaptive contingency is the foundation of communication that sustains these duets.

Central to our thesis is the idea that communication competence in preschoolers is a result of a developmental process that begins in early infancy and embodies both language development (e.g., vocabulary and grammar) and the social skills that support language. For example, longitudinal work by Adamson and colleagues (Adamson, Bakeman, Deckner, & Nelson, 2012, 2014) demonstrates the predictive power of early interactions on later communication development. After defining adaptive contingency, we address how caregivers foster communication competence through adaptive contingency during four developmental periods: early infancy (birth to six months), later infancy (6 months to 1 year), toddlerhood (1–3 years) and the preschool years (3–5 years). The dyadic exchanges within each period are structured to support developmentally appropriate communication skills.

Adaptive Contingency

The literature on caregiver-child interactions is replete with terms and constructs that address complementary facets of the dyadic relationship. For example, Feldman (2015) defined infant-caregiver synchrony as the “the online coordination of social behavior between parent and infant in the gaze, vocalization, affect, and touch modalities” (p. 394). Responsiveness captures the timely and appropriate feedback to children during the next stage of development (Landry, Smith, & Swank, 2006; Tamis-LeMonda, Bornstein, & Baumwell, 2001), when gross motor milestones such as sitting independently and crawling allow children to interact with their environments in new ways. Children’s first birthdays mark yet another transition in the nature of parent-child interactions. Emerging theory-of-mind skills allow young toddlers to participate in episodes of joint attention, in which dyads mutually share a common focus, as when a fire truck roars by or a jack-in-the-box unexpectedly pops. Initially, children jointly attend to an object or event when the shared referent is physically present; when a puppy passes by, toddlers cannot help but point it out to their nearby caregiver. In time, preschoolers begin to reminisce about the past or anticipate future events. These conversations are a sophisticated form of joint engagement (Adamson et al., 2014), in which parent-child dyads are no longer limited to the here-and-now.

While at first glance, these constructs appear to be mere stepping stones along the way to mature communication, a panoramic lens across the four developmental periods reveals a common thread – adaptive contingency. Critically, we will argue that each of these constructs, however, captures a particular moment of adaptive contingency across time. Prompt and meaningful responses to a child depend on where that child is developmentally. This idea is well captured in developmental psychopathology (Cicchetti, 1993; Sroufe & Rutter, 1984) where the term heterotypic continuity is used to describe the way a process or behavior is expressed differently over time (e.g., Lavigne, Gouze, Bryant, & Hopkins, 2014). Here we offer a dynamic approach to understanding the ways in which caregivers foster adaptive contingency but do so differently across development.

Temporal Coordination of Social Exchanges: Prompt Timing Matters

Timing is the first necessary component of successful social interactions. Adult conversation partners quickly adapt to one another, converging on a shared rhythm (e.g., Manson, Bryant, Gervais, & Kline, 2013). Indeed, the transition from one speaker to another is shorter than other reaction time measures because we anticipate what the other person will contribute to the exchange (Magyari, Bastiaansen, de Ruiter, & Levinson, 2014). Cross-cultural observations demonstrate that parents around the globe and their 5.5-month-old infants engage in temporally coordinated interactions (Bornstein, Cote, Haynes, Suwalsky, & Bakeman, 2012). Evidence that temporal contingency helps to sustain social interactions can be found through two complementary lines of research. The first examines what happens after a caregiver responds contingently to an infant’s initial bid and finds that contingency carries an exchange forward by prompting back-and-forth turn taking. For example, Dix, Cheng, and Day (2009) reported toddlers between 14 and 27 months were more likely to make additional bids for attention to their caregivers if infants’ smiles moments before were promptly acknowledged in some way by caregivers.

A second line investigates the consequences when the timing of social interactions is “off.” Longer latencies to respond reveal our distraction or otherwise disengagement from the conversation at hand. Do young children perceive these “hiccups” when interacting with others? Experimental manipulations suggest that they do. For instance, Henning and Striano (2011) delayed the video feed of parents interacting with their 3-month-old infants via closed circuit television and found infants smiled less relative to the live video feed condition. Relatedly, mothers with depression have been found to respond less contingently to their children, with cascading effects on the child. In a longitudinal design, Yan and Dix (2014) asked mothers to rate their depressive symptoms and the degree to which their child withdraws from social interactions via the Child Behavior Checklist. Assessments began when children were two years and continued until first grade. Additionally, parent-child interactions were coded for mutual responsiveness (Kochanska, 1997). Structural equation modeling revealed that maternal depression at 24 months predicted both higher withdrawal scores and lower ratings of mutual responsiveness. Withdrawal scores and mutual responsiveness ratings then predicted maternal depression, one year later. This pattern ultimately predicted children’s social skills, school success, and conduct problems in first grade. When the timing is not quite right, there can be profound consequences on both in-the-moment engagement as well as later behavioral outcomes that affect children’s communication competence.

Children “Make Sense” of Meaningful Input

Adaptive contingency also requires the relevance or meaningfulness of caregivers’ responses to the child’s focus. In her intentionality model, Bloom (1993, 2000) argued that language results from the confluence of two processes – engagement and effort, and the principle of relevance is a driving force behind children’s engagement. Bloom (2000) draws upon Fauconnier’s (1985) brick wall analogy to explain how relevance facilitates engagement. When building a wall, any brick will work in any spot. At any one moment in the building process, the next brick to be laid must go in a particular spot (not helter-skelter). Likewise, as children engage in their world, relevant responses “fit” in that moment.

Grice’s (1975) principles influence what information we share with others as well as the inferences we make about others’ communicative intentions. We expect our conversational partners to be truthful (principle of Quality), relevant, and concise (Quantity principle), and these same rules apply to our own contributions to the exchange. Meaningful input adheres to these principles. Even when semantic content is absent – as in the case of caregivers interacting with their newborns – the meaningfulness dimension can be flexibly applied to refer to the affective nature of these earliest exchanges. For example, the earliest exchanges in infancy are characterized by synchrony (Feldman, 2007a, 2007b). Here, caregivers and infants engage in tightly coupled back-and-forth exchanges (Jaffe, Beebe, Feldstein, Crown, & Jasnow, 2001). An infant’s smile begets one in return from an attuned caregiver, who mirrors the infant in affect and hence in emotional meaning. Caregivers can “read” an infant’s affective state and respond appropriately, reflecting how even prelinguistic exchanges are infused with meaning (Papoušek, 2007). These synchronous interactions are highly rewarding for children and caregivers. Feldman, Gordon, and Zagoory-Sharon (2010) found increased levels of oxytocin (associated with social rewards; Feldman, 2012) in both parents and 4- to 6-month-old infants following a face-to-face interaction, with higher levels of oxytocin predicted by the degree of shared affect during the exchange.

Just as temporal contingency facilitates back-and-forth exchanges, so too does meaningful input. Dunham, Dunham, Tran, and Akhtar (1991) tested this idea directly with the help of a friendly robot. In their paradigm, the robot always responded promptly to the two-year-old participants. The content of the robot’s contributions, however, either built upon the child’s topic or was completely irrelevant. Imagine asking the robot about trains, only to have it respond that there is a frog under the table. How frustrating! Did the toddlers mirror our imagined frustration? Indeed they did, evidenced by fewer conversational turns with the untoward robot. Timing alone cannot sustain a social exchange. Consequently, adaptive contingency refers to the prompt delivery of meaningful content; the two dimensions depend upon one another.

It Takes Two: The Bidirectionality of Adaptive Contingency

Critical to our conceptualization of adaptive contingency is its dyadic, bidirectional nature. Parents most effectively teach communication competence when they meet children where they are developmentally (for a review, see Harrist & Waugh, 2002). As a result, the mechanism of adaptive contingency must take into consideration children’s current social, cognitive, and motor competencies for caregivers to provide prompt and meaningful content in that moment. By adopting a developmentally appropriate approach to adaptive contingency, its expression within each developmental period reflects how caregivers offer prompt and meaningful responses that take into account children’s current level of functioning and current emotional states.

Empirical evidence for caregivers’ intuitive modification of their language offers a portrait of how caregivers might adjust their responses to children at varying levels of development. Sokolov (1993) analyzed three longitudinal corpora from the Child Language Data Exchange System and found support for this transactional process in the ways parents modify their language input to introduce and reinforce grammatical concepts such as auxiliary verbs and pronouns. Sokolov offers this example, in which a caregiver expands a child’s “Lilly fix” into a more complete “Lilly will fix it” (1993, p. 1019). As children begin to form more grammatically complete sentences, caregivers need to add less to children’s utterances. Instead, caregivers adopt different ways of building upon children’s language to bolster emerging skills (also see Hirsh-Pasek, Treiman, & Schneiderman, 1984). For instance, pronouns are practiced as caregivers substitute a child’s “I do it” by affirming, “Yes, you do it.” Further support comes from Adamson, Bakeman, and Brandon (2015), who asked caregivers to provide novel labels (e.g., felly, nupa) to their children during semi-structured lab-based interactions. Some families had toddlers diagnosed with autism spectrum disorders, while others had children with Down syndrome. There was also a sample of typically developing children, who were younger (18 months) to better equate the three diagnostic groups on language scores. While caregivers were fairly consistent in their strategies to teach the novel target words to their children across all groups, differences did emerge in the strategies used by caregivers depending on where children were developmentally. For example, when introducing a new word to a child with autism, parents engaged in more attention management strategies, whereas children with Down syndrome heard more frequent repetitions of the target words themselves.

Two programs of research also highlight the bidirectional nature of adaptive contingency. Tamis-LeMonda et al. (2001) observed dyads longitudinally. The ways in which children engaged during the semi-structured free play session changed from 9 to 13 months, with more frequent play behaviors (instead of mouthing or manually manipulating objects) as one example. Relatedly, caregivers responded differentially over time to their children. They were more likely to describe what was unfolding to the infant at 9 months but instead offered more frequent play prompts at 13 months. This pattern consequently predicted various language milestones. For example, contingent and meaningful verbal responses to play behaviors in the form of questions at 13 months predicted when children began to talk about the past, a more advanced language milestone. A child pretends to feed a doll; her mother responds by asking whether the child remembers who came over for dinner last night. This sequence is an example of the tailored responses that depend on children’s current competencies. If the child does not yet have words, then reminiscing is not as facilitative as offering a label when the child attends to the doll. Adaptive contingency meets the child where he or she is developmentally. Evaluating only the caregiver’s contributions will not offer a complete picture; instead, adaptive contingency takes into account the child’s contributions in order to determine what will be most appropriate.

A second program of research that illuminates the bidirectional nature of adaptive contingency is that which studies how caregivers respond differentially to walkers and crawlers. Research by Adolph and colleagues (Adolph & Tamis-LeMonda, 2014; Karasik, Tamis-LeMonda, & Adolph, 2014) and Iverson (2010) has identified different patterns of parental responsiveness to infants’ gestural bids, depending on the child’s current locomotion style. For example, the most likely response to a walking child’s socio-communicative showing gesture with a toy in hand was a prompt to do something with that object. A walking child who showed a block to her mother by extending the object in the air was likely to hear the mother suggest a particular way to play with that block. On the other hand, caregivers were less likely to offer any kind of feedback following a crawling child’s socio-communicative bid. Karasik and colleagues also examined how children made their bids – either while in motion or while still. Crawlers overwhelmingly made stationary bids, but in the rare instances of bidding while locomoting, caregivers were more likely to offer an action gesture, such as a prompt to place the block on top of the tower. As such, this study was the first to empirically demonstrate how motor skills affect children’s engagement in their environments, which “sets in motion a cascading effect that ultimately affects the language infants hear” (Karasik et al., 2014, p. 394). Once again, we find evidence for the bidirectional nature of adaptive contingency. The child’s current developmental status affects how the caregiver responds, which in turn affects the child, with adaptive outcomes linked to responses that are tailored to where the child is developmentally.

Woven across developmental time is adaptive contingency, and the panoramic lens allowed us to distill a common thread from within each particular developmental period that draws on different constructs in the evolution of communication competence. In the sections that follow, the ways in which caregivers scaffold children’s emerging communication competence within each developmental period are reviewed. Moving from early to later infancy, toddlerhood then the preschool years, the foundational skills for communication competence are laid through temporally contingent and meaningful exchanges between children and their caregivers.

Fostering Communication Competence in Early Infancy

In this earliest developmental period, caregivers are largely responsible for sustaining dyadic interactions, providing contingent responses during infants’ limited bouts of sustained attention. “Serve and return” is a common (and apt) metaphor to describe this early dynamic (Shonkoff & Bales, 2011). For example, when an infant vocalizes (his “serve”), the caregiver can coo in response (the “return”). By providing temporally and meaningfully contingent responses to infants’ gaze, smiles, and vocalizations, caregivers are effectively keeping their analogous game of social tennis in play. Research has demonstrated that infants as young as six weeks old participate in contingent back-and-forth exchanges, coordinating their eye gaze in response to caregivers’ vocalizations (Crown, Feldstein, Jasnow, Beebe, & Jaffe, 2002). Biological rhythms such as heart rate become co-regulated during moments of shared affect and proto-conversations (Feldman, Magori-Cohen, Galili, Singer, & Louzoun, 2011).

Defining Adaptive Contingency via Synchrony

Studies that examine the first glimpses of adaptive contingency in infancy refer to the “back and forth” exchanges by examining synchrony. Synchrony refers to the moment-by-moment coordination of caregivers and infants (Feldman, 2007a). The timescale coupling infant actions with responses from the caregiver is quite narrow, often measured in milliseconds, with evidence for both universal patterns and cultural variation in structure and timing of these earliest exchanges (Gratier, 2003; Van Puyvelde, Loots, Gillisjans, Pattyn, & Quintana, 2015). Gratier’s observational work with mother-infant (2- to 5-month olds) dyads from France, India, and the United States, as well as a cohort of Indian families who immigrated to America, revealed that overall levels of synchronous behaviors and vocal matching or rhythmic structure (e.g., the “beat” of the interaction) are relatively similar across the globe. Some variations did emerge, however. For example, Indian mother-child dyads had a greater proportion of overlapping speech (9.4 %) than either the American (5.1 %) or French (3.2 %) families. Perhaps relatedly, Indian dyads had the shortest between-speaker pause, relative to their American and French cohorts. The cohort of Indian immigrants living in California highlights the role of culture: Their scores on a variety of measures fell in between those of native dyads living in India and America.

The tightly coupled structure of synchronous interactions at the millisecond level reflects infants’ more general cognitive ability to detect temporal contingencies in their environment. Initially, infants prefer perfect contingencies (Zmyj & Klein-Radukic, 2015). A perfect temporal contingency exists when a stimulus is always met with a response; the consequent splash that follows after jumping in a puddle is an example. Perfect contingencies can be expressed in “if-then” statements. “If I jump in this puddle, then there will be a splash” (mud optional). In the classic Rovee and Rovee (1969) mobile paradigm, infants distinguished between mobiles activated by their leg kicks – a perfect contingency – and when mobile activation was not contingent on their actions. Social contingencies are imperfect, for not every single infant action is met with a corresponding response from the environment. Evidence that infants can detect social contingencies emerges by age 2 months (Bigelow & Rochat, 2006).

Before reviewing how adaptive contingency contributes to children’s fledgling communication competence, it is necessary to address a critical gap in the literature. Research during this earliest development period has focused almost exclusively on the temporal rather than on the meaningful dimension of adaptive contingency. The findings discussed below come from research designs that confound timing with the presence of meaningful content. Only the timing of responses has been observed or manipulated experimentally, not the content. For example, Bigelow and Power (2014) coded whether or not a caregiver smiled back at infants within one second of an infant’s smile. Meaningfulness – here defined as an appropriate affective response to the child’s own smile – is held constant.

It remains an open question as to whether or not timing alone drives dyadic interactions in this earliest developmental period. Nevertheless, we maintain the relevance of our central thesis that timing and meaningfulness matter, even in the first few months. We draw on work concerning maternal mind-mindedness, or the extent to which mothers infer or attribute intentionality to very young infants (Meins, 2013). This literature finds that appropriate comments – not just any talk about infants’ mental states – are predictive of infants’ later development (Meins et al., 2012). Bigelow, Power, Bulmer, and Gerrior (2015) provide compelling evidence, effectively closing the hypothesized loop between maternal mind-mindedness and meaningfulness via mirroring behaviors. In their paradigm, mothers first engaged in a short face-to-face interaction with their 5-month-old infants. Afterwards, the mothers watched the interaction with an experimenter, and their comments related to infants’ mental states were coded. Mind-mindedness positively correlated with how the caregivers interacted with their babies, suggesting that “in mirroring the infants’ behavior, mothers recognize and respond appropriately to their infants’ mental states” (Bigelow et al., 2015, p. 265). The work on mind-mindedness carves the space for us to consider how the appropriateness of responses may be an undercurrent responsible – in tandem with timing – for successful parent-child interactions in early infancy.

Laying the Foundation for Fluid Turn-Taking through Adaptive Contingency

Adult conversational partners will converge on a mutual pace, matching pause durations in between speaker changes, for instance (Stivers et al., 2009). Failure to make these micro-adjustments in conversational rhythms can lead to lower ratings on a variety of social outcomes, such as likeability and perceived engagement (Crown, 1982; Koudenberg, Postmes, & Gordijn, 2013; Warner, Malloy, Schneider, Knoth, & Wilder, 1987). Prior to babbling, infants will coordinate eye gaze with maternal vocalizations (Crown et al., 2002), demonstrating perhaps the earliest evidence of nascent interpersonal timing. Indeed, Crown and colleagues write, “The temporal coordination between the adult and the 6-week-old infant is a shared rhythmic behavior” (2002, p. 19). By four months, parent-child interactions exhibit several of the hallmark features of coordinated interpersonal timing, such as matching the length of pause between speakers (Beebe, Alson, Jaffe, Feldstein, & Crown, 1988). This is a critical foundational communication skill. Difficulty in maintaining fluid conversational rhythms – a skill that emerges in infancy – has recently been identified as a risk factor for later language delays (Northrup & Iverson, 2015). Northrup and Iverson pinpointed several features of dyadic interactions at 9 months that predicted lower language scores at age 3 years among a high-risk cohort of younger siblings of children with autism spectrum disorders, including a higher proportion of overlapping speech and less convergence on mutual pause duration between speaker changes (i.e., from mother-to-child and from child-to-mother).

Expectations for the tight coupling of infant-caregiver behaviors are formed as a result of these early social interactions. Experimental manipulations of caregiver responsiveness via delayed video feed during closed circuit television interactions (Henning & Striano, 2011; Stormark & Braarud, 2004) or the Still-Face paradigm (Bigelow & Walden, 2009; Goldstein, Schwade, & Bornstein, 2009; Mcquaid, Bibok, & Carpendale, 2009) reveal that infants respond differentially to perturbations during what was expected to be a naturally unfolding, fluid exchange. For example, infants smiled less when contingencies were manipulated. Dyads construct a turn-taking structure, and naïve observers can differentiate mother-child from stranger-child dyads (Bigelow, Power, Mcquaid, Ward, & Rochat, 2008). Using eyetracking technology, Thorgrimsson, Fawsett, and Liszkowski (2015) designed a study in which infants watched as one actor initiated verbal contact with a second individual onscreen via speech or non-speech (e.g., cough) sounds. In line with their hypothesis that infants would expect (and thereby anticipate) the back-and-forth structure of conversations, infants shifted their gaze more quickly toward the as-of-yet silent partner in the speech condition, relative to the non-speech stimuli. Bornstein, Putnick, Cote, Haynes, and Suwalsky (2015) studied mother-infant interactions in 11 different countries in North and South America, Europe, Africa, and Asia when infants were 5.5 months old. Across cultures, dyads engaged in protoconversations characterized by temporal contingency; infant vocalizations predicted maternal talk in response. This cross-cultural look suggests that participating in synchronous exchanges is a human universal that sets the stage for reciprocity.

Recent work suggests that synchrony also has a direct impact on infants’ affect (MacLean et al., 2014). Second-by-second coding of parent-child interactions during the Still Face paradigm revealed real-time change in infants’ affect following moments of mutual gaze. In line with a developmental systems approach (Molenaar, Sinclair, Rovine, Ram, & Corneal, 2009), such “in the moment” consequences of synchrony can be integrated with findings that link high-quality parent-child interactions in early infancy to later developmental outcomes (e.g., Lickenbrock & Braungart-Rieker, 2015). Prospective studies demonstrate how early exchanges marked by prompt and meaningful responses to infants’ socio-communicative bids – what we refer to as adaptive contingency – have a lasting impact on later development, in line with the thesis of this chapter. The roots of communication competence begin in infancy.

Fostering Communication Competence in Older Infants

Emerging motor, social, and cognitive skills in the second half of the first year allow children to begin to autonomously explore their environments and make communicative bids to caregivers. When infants reach developmental milestones such as sitting independently and gesturing to show, the nature of parent-child interaction adapts to dynamically reflect these co-evolving roles. Caregivers once mirrored infants’ earliest socio-communicative bids (smile for smile, coo for coo) via processes of attunement. Now, in this next developmental window, caregivers capitalize upon babies’ developing sense of initiative by providing labels for those objects and events that have captured their children’s attention. This responsive style has been linked to positive child language outcomes (Bornstein & Tamis-Le-Monda, 1997; Goldstein & Schwade, 2009).

Defining Adaptive Contingency via Responsiveness

A critical element of communication competence is the ability to express oneself verbally. Frustration builds when children are unable to verbalize their desires or needs to caregivers or peers, which can lead to behavioral challenges (Carpenter & Drabick, 2011). Caregivers can facilitate word learning in later infancy (approximately 9 to 18 months) through adaptive contingency in the form of responsiveness (Baumwell, Tamis-LeMonda, & Bornstein, 1997; Lohaus, Keller, Ball, Elben, & Voelker, 2001). Here, caregivers respond contingently (operationally defined as within a 1- to 5-second window following infants’ initiations) and appropriately. How do we define appropriateness? Goldstein and Schwade (2009) tackled this question directly in their longitudinal investigation of early parent-child interactions and later language development. Infants, when approximately 9 months old, begin to engage in object-directed vocalizations, whereby they make vocalizations while manually exploring new objects in their environments. For example, while holding and turning a toy train in her hands, an infant can babble, “gaga.” Such vocalizations signal a readiness to learn (Goldstein, Schwade, Briesch, & Syal, 2010). Caregivers, in response to these vocalizations, can either offer a proximal label (i.e., shaping the infant’s “gaga” into “game”) or an object match label (i.e., labeling “train” in response to the infant’s object-directed vocalization of “gaga”). Through their prospective design, Goldstein and colleagues found that a particular responsive style predicted higher language scores several months later – that of proffering object match labels that corresponded with the child’s visual focus. This finding directly aligns with our thesis that only temporally contingent and meaningful responses will benefit language growth, with the corollary that the relevance of input depends on the child’s current functioning.

Adaptive Contingency Encourages Communication Engagement

Responsiveness not only shapes children’s word learning but also the likelihood that children will engage in verbal communicative exchanges, even before they can use words. Participating in these proto-conversations sets the foundation for later conversations and signals intentionality as well as agency. Gros-Louis and colleagues have offered empirical support for this developmental pattern through both observational (Gros-Louis, West, & King, 2014) and experimental (Miller & Gros-Louis, 2013) designs. Observational data come from Gros-Louis and colleagues, who followed dyads longitudinally from 8 to 14 months, and found that contingent feedback from caregivers increased infants’ communicative use of prelinguistic vocalizations. In a classic ABA design, Miller and Gros-Louis directed caregivers to first engage naturally with their infants (the A component of the study). In the experimentally manipulated B portion of the experiment, caregivers were instructed to either respond to children’s bids (i.e., provide meaningful input that builds upon the previous utterance) or redirect them (i.e., shift the child’s focus to something new and unrelated). This design revealed real-time changes in infants’ behaviors, demonstrating how sensitive infants are to maternal styles of interactions. This is one of the few studies to experimentally manipulate the meaningfulness of input, such that caregivers either followed the child’s focus or introduced something unrelated. The results suggest that not just any response will sustain a dyadic interaction. Instead, the meaningfulness of the caregiver’s content as a function of the child’s focus must be taken into account. By responding promptly with meaningful content, caregivers model how to share a common focus, effectively sustaining the exchange as children then continue to add to the unfolding interaction.

Fostering Communication Competence in Toddlerhood

The transition from dyadic (i.e., caregiver-child) to triadic (i.e., caregiver-child-shared object) interactions marks another shift in the evolution of adaptive contingency across developmental time. Longitudinal observations document the emergence of joint attention prior to children’s first birthdays, but it is not until toddlerhood that dyads spent a significant portion of their time together engaged in joint attention (Carpenter, Nagell, & Tomasello, 1998). This ability to jointly attend allows children who once directed their caregivers’ attention to actively participate in sustaining a shared focus.

Defining Adaptive Contingency via Joint Attention

Common ground, or the shared referential context (Clark, 1996; Tomasello, 2008), is co-constructed by communicative partners. For example, when dyads share a common task – whether playing with dinosaurs or cleaning up – there is a joint focus through which input is filtered, as if the common ground provides a lens that makes salient only that which is temporally contingent and meaningful in that particular moment. Work by Bourdais, Danis, Bacle, Santolini, and Tijus (2013) demonstrates how 13-month-olds (but not their 10-month-old peers) point to share information with caregivers, such as the location of a hidden toy. This finding highlights the tightly coupled connection between developing socio-cognitive skills such as theory of mind and the development of communication competence. When children recognize that their experience and knowledge are not implicitly available to others, theory of mind begins to develop. Pointing to inform is, as Liszkowski, Carpenter, and Tomasello (2007) write, “already a fully communicative act involving an understanding of mental states … infants understand others as persons who have psychological relations toward the environment with specific knowledge states and attitudes about it” (p. F6). Consequently, children can become more active partners in dynamic social interactions.

Children use common ground to make inferences about speakers’ communicative intent (Egyed, Király, & Gergely, 2013; Grassmann, Stracke, & Tomasello, 2009; Liebel, Behne, Carpenter, & Tomasello, 2009; Schulze & Tomasello, 2015). To test this notion, experimental studies traditionally present toddlers with an ambiguous request, nested within a jointly shared activity. Evidence for the use of common ground emerges if children respond appropriately to ostensive requests but indiscriminately to accidental requests. Schulze and Tomasello’s work with 18-month-olds demonstrates this. While child and experimenter worked together on a puzzle, a puzzle piece was suddenly discovered to be missing. The experimenter held up a large key, which had previously been used to open boxes together. Did the toddlers infer that the key could be used to reveal the missing piece, hidden inside? Only when the experimenter used ostensive communicative signals via joint attention did the young participants rely on their knowledge of the key (information within the common ground space) and act accordingly to sustain the ongoing joint activity. These findings highlight children’s active participation in communicative exchanges that depend, in part, on temporal coordination and meaningful input.

Building Lexicons on Common Ground

Successful dyadic interactions require social coordination, whereby partners flexibly monitor one another, complementing actions in pursuit of a common goal. At first, supportive caregivers bear the responsibility through heavy scaffolding during unfolding interactions (Adamson & Bakeman, 1984). Initially, children’s word learning is optimized when caregivers follow the child’s focus, instead of redirecting them (Dunham, Dunham, & Curwin, 1993; Hollich, Hirsh-Pasek, & Golinkoff, 2000; Tomasello, 1988; Tomasello & Farrar, 1986; Tomasello & Todd, 1983).

By their first birthdays, typically developing children are seasoned joint attenders, following caregivers’ shifts in eye gaze and points. By then, child and caregiver are jointly responsible for establishing and maintaining a joint focus that is built upon a foundation of temporal and meaningful exchanges. For example, as children’s social cognition skills emerge, they actively contribute to joint attention (Baldwin, 1991, 1993; Baldwin et al., 1996; Moore, Angelopoulos, & Bennett, 1999). Toddlers begin to rely on referential cues from speakers (e.g., eye gaze) when mapping a novel label to an object. They check to see what the speaker is attending to when labeling, recruiting nascent theory-of-mind skills to facilitate word learning. The degree to which dyads coordinate during structured lab-based tasks predicts how well the children learn novel labels for unfamiliar referents (Pereira, Smith, & Yu, 2008). It is likely that the ability to fully engage during dyadic interactions paves the way for rapid word learning.

Indeed, this active participation from both partners reflects children’s evolving role in the creation and maintenance of common ground, a critical component of communication competence. Communication is a collaborative act (Tomasello, 2008), and toddlers at this stage in development contribute a shared commitment to the unfolding joint activity. As in a game of ping-pong or tennis, dyads establish a rhythm as they jointly pursue a common goal. If one player refuses to play, progress is halted; we would cajole or otherwise pursue our partner to get back in the game. As in earlier developmental periods, timing alone cannot sustain the rhythm of interaction. Where previously caregivers responded appropriately to infants’ affective signals, meaningful responses in this later developmental period need to be semantically related to the shared focus.

Toddlers likewise demonstrate an understanding that collaborative acts require both partners, and will attempt to re-engage experimenters who seem to suddenly become uninvolved (Hamann, Warneken, & Tomasello, 2012; Warneken, Gräfenhain, & Tomasello, 2012). As evidence has amassed in support of toddlers’ collaborative proclivities, recent research has begun to tackle the question of individual differences. With a sample of German toddlers, Schuhmacher and Kärtner (2015) asked what could account for variability in toddlers’ likelihood to collaborate. Relevant to this chapter is the finding that the quality of previous peer-to-peer interactions at the start of the study predicted toddlers’ decisions either to play with a peer or alone on a subsequent task. Again, we find evidence that children are sensitive to the quality of engagement of their social partners.

To bolster children’s communication competence within this developmental epoch, caregivers can employ a variety of strategies to provide rich lexical input within meaningful social exchanges. Consequently, children can glean cues from their shared common ground in order to make sense of the new input. Among a vulnerable yet understudied population – families experiencing housing instability – O’Neil-Pirozzi (2009) drew upon different parental strategies to augment dyadic engagement. Parents in the intervention were trained on particular strategies designed to build upon children’s utterances and promptly recast them into more sophisticated sentences while also eliciting children’s participation in the ongoing dialogue. Various intervention programs, such as Parent-Child Intervention Therapy (Garcia, Bagner, Pruden, & Nichols-Lopez, 2015) and The Incredible Years Parent-Toddler Programme (Gridley, Hutchings, & Baker-Henningham, 2015), offer converging evidence that through prompt and meaningful responses – here, reformulations that build upon children’s contributions – children’s language skills improve relative to their peers in wait-list controls.

Consider the relative challenge in discerning children’s focus when embedded within a dynamic, visually complex (e.g., a well-stocked play room) environment. “Gimme that” can be an opaque request when possible contenders compete – is the child referring to the dinosaur figurine on the left or his copy of the Velveteen Rabbit beside it on the shelf? In order to provide meaningful content within this developmental period, caregivers must be particularly attuned to their shared common ground. Within the context of jointly constructing a jungle scene with blocks, the once-ambiguous “gimme that” request becomes clear. Otherwise, a comment about Margery Williams’ (1922) classic – however good-intentioned – can potentially disrupt the ongoing activity because of its inappropriateness. Imagine asking for directions and getting the time in return; there is little room for a conversation to build. In addition to remaining attuned to children’s communicative intentions, open-ended questions is another strategy for caregivers to use in order to reinforce children’s developing communication competence, for they require children to put ideas into words without fear of making mistakes (Whorrall & Cabell, 2016).

When Technology Falls Short: The Case for Adaptive Contingency

Children’s television programming offers a test case for the role of adaptive contingency within this developmental period. Although shows such as Dora the Explorer and Blue’s Clues attempt to engage viewers via questions, pauses, and affirmations, this style of media relies on contingency, not adaptive contingency. Television can only offer generic timing and content whereas children’s language development depends on prompt timing and meaningful content that is tailored to each particular child. Roseberry, Hirsh-Pasek, and Golinkoff (2014) capitalized upon Skype technology to contrast word learning under three different conditions: live (control), Skype, and video. Only live and Skype interactions preserved adaptive contingency, and it was only in those conditions that children demonstrated word learning at test. Critically, the same content was presented in the yoked video condition, demonstrating how the two elements (temporal coordination and meaningful content) work together. This finding echoes McGillion and colleagues’ (2013) observational data, in which only the frequency of maternal responses that were both temporally prompt and semantically relevant to the child (as opposed to either prompt or relevant) predicted children’s language scores months later.

Similarly, when adaptive contingency is momentarily disrupted because of an interrupting cell phone call, children fail to learn novel words (Reed, Hirsh-Pasek, & Golinkoff, under review). In this within-subjects design, mothers taught their children two novel words, one at a time. The experimenters instructed mothers to answer the lab’s cell phone in order to receive instructions concerning when to teach each word. Additionally, the experimenter mentioned that sometimes they would simply chit-chat, as if they were friends in the real world. The teaching of one word was uninterrupted whereas a cell phone conversation interrupted the mother while she taught the other word (order counterbalanced). During this interruption, experimenters chatted with the mothers about her morning coffee routine before ending the call with a reminder to continue to teach the target word. The design allocated 60 seconds for each teaching period; the interrupted teaching period consisted of two 30-second windows. Toddlers’ preference for a target action depended on whether or not the teaching was interrupted. Children only learned the novel word in the absence of interruptions.

Fostering Communication Competence in the Preschool Years

The final developmental hub of early childhood – that of the preschool years – reflects yet another shift in the way adaptive contingency works between caregivers and their increasingly independent children. Adamson and colleagues (2014) describe this period as the transition “from interactions to conversations” (p. 941). Prospective observations of parents and their children revealed that dyadic exchanges became more balanced over time from 3.5 years to 5.5 years.

Defining Adaptive Contingency via Conversations

Children become increasingly adept at navigating the common ground with their interlocutors. For instance, Schmerse, Lieven, and Tomasello (2015) investigated how preschoolers handle potentially ambiguous requests from experimenters that required them to select one among three similar objects such as three spoons that differed only in size. Three-year-olds preferentially selected a particular object that had been shared previously with the experimenter only in response to a prompt with a definite article (e.g., “Where is the pencil?”). There was no preference when an indefinite article was used (i.e., a/ an). These budding conversationalists recognize subtle differences in communicative intent, relying on their shared experience with the experimenter to interpret grammatical input.

Adaptive Contingency Fuels Conversations: Practicing Pragmatic Skills

Successful communicative exchanges demand that partners fluidly and flexibly alternate between speakers and listeners. Further, listening cannot be a simply passive task; adult conversationalists engage in a phenomenon known as “back channeling” to signal active engagement (e.g., “mhm”, “uh-huh”). Before preschoolers exhibit such skills, they must first recognize and acknowledge the differences inherent to speaker and listener roles (Nilsen & Graham, 2012).

Preschool children demonstrate emerging understanding of the complementary different roles that speakers and listeners fulfill during conversations. For example, Nilsen and Mangal (2012) manipulated the social context between child and experimenter, such that sometimes the dyad shared the same visual scene while other times they did not. The experimental task required that children request particular stickers from the experimenter; such requests were not immediately fulfilled by the adult, thereby necessitating the child to “repair” the request (Golinkoff, 1986). This paradigm revealed that children were sensitive to the state of the listener, offering more detail in their initial request when the dyad did not share the same visual information. Second, the way in which the experimenter signaled her lack of understanding differentially affected children’s follow-up requests. Only when the adult offered the wrong sticker did children provide new information to distinguish the target from non-targets; simply expressing confusion (e.g., “Huh?”) did not. Adaptive contingency in the preschool years reflects how partners actively monitor how well they understand (and are understood by) one another.

Turn-taking skills are further refined in this developmental period. Following a U-shape trajectory, perceptions of temporal contingency depend once again on a time frame measured in milliseconds, mirroring that which is found among the earliest dyadic instances of synchrony. In this final developmental hub (i.e., 3–5 years), conversations between children and caregivers are structured quite similarly to those between grown-ups; overlapping speech is relatively rare (Bedrosian, Wanska, Sykes, Smith, & Dalton, 1988; Craig & Washington, 1986).

Children make considerable gains in pragmatic skills or meaningfulness as well (Clark, 2014). First, Gricean principles are taken into account when evaluating the meaningfulness of speakers’ input, although a mature grasp of all is not in place until the elementary years (Eskritt, Whalen, & Lee, 2008). Second, children begin to use “referential pacts” with communication partners (Graham, Sedivy, & Khu, 2014; Köymen, Schmerse, Lieven, & Tomasello, 2014; Matthews, Lieven, & Tomasello, 2010). When we talk, we consistently use particular labels across time with specific individuals – what are known as “referential pacts” in the literature. For example, before heading to the park, we may ask our sibling to run upstairs and grab our running shoes from our closet after she finds her keys. Later that day, we will continue to refer to those sneakers as our running shoes, even when the adjective is no longer necessary to distinguish them from the other possible pairs, as when they are the only pair in the car, post-jog. When asked to direct their peers to re-construct a particular order of pictures from behind a screen, preschoolers will establish such referential pacts to aid performance when the three pictures are similar. Further, such labels are maintained across trials, even when pictures now come from different categories, such as clothing, animal, and food (Köymen et al., 2014). Third, cultural knowledge becomes part of the implicit common ground (Liebal, Carpenter, & Tomasello, 2013). In Liebal and colleagues’ experimental study, pairs of pictures were presented to children. Experimenters’ prompts of “What is that?” elicited different patterns of responses, depending on whether the question’s prosody signaled recognition or uncertainty. Children preferred the culturally shared image from within the pair when the experimenter’s prosody suggested that he already knew the answer. Again, we find evidence that partners tailor their responses, with preschoolers providing what they inferred would be an appropriate and meaningful response to the experimenter’s inquiry, depending on the communicative intent behind the question.

How do caregivers facilitate communication competence among children who have a relative mastery of basic conversation skills? Research suggests that when caregivers talk about mental states (e.g., wishes, desires), children’s language and theory of mind skills benefit (Adrian, Clemente, Villanueva, & Rieffe, 2005; Turnbull, Carpendale, & Racine, 2008). Similarly, when the goal of communication is to craft stories and preserve them (in the tradition of oral histories and story-telling), then parent-child interactions centered on reminiscing become paramount. The literature has distinguished between high and low elaborators (reviewed in Cleveland, Reese, & Grolnick, 2007), in which caregivers who are highly elaborative utilize open-ended questions, drawing the child into the active construction of the memory. Here again optimal engagement depends on adaptive contingency, whereby the quality and content of the exchange shapes the ways in which such conversations influence children’s development. Cross-cultural work with the Māori culture in New Zealand (Reese & Neha, 2015) reveals that although talking about the past may be a human universal, the focus of these conversations may be culturally dependent. Indeed, while American and other European cultures may emphasize specific events in a child’s life (e.g., “Remember when we went to Kiawah Island when you were 4?”), reminiscing among Māori parent-child dyads tends to center around family historical events. The data, however, hinted of a shift toward a more child-centered approach, perhaps “Because contemporary Māori parents frequently ascribe to multiple ethnicities (Morton et al., 2013), it could be that parents are simultaneously adopting European and Māori reminiscing practices with their children” (Reese & Neha, p. 107). This work reflects the role of culture (for more cross-cultural differences in content and style of parent-child reminiscing, see Schroder, Kärtner, & Keller, 2015).

These more advanced forms of communication competence – from repairing to reminiscing – depend on social exchanges infused with temporal and meaningful contingency. Implicit in these studies is the assumption that communicative partners will respond promptly and appropriately to one another. While exchanges in infancy are highly scaffolded by caregivers, interactions in the preschool years look less like a game of “follow the leader.” Instead, as if putting together train tracks, dyads share a common goal and adapt in real time to accommodate one another. There is no set path for either the train track or the conversation about its construction; instead, pieces (and words) are flexibly chosen in response to what came before.

How might the case for adaptive contingency and its role in communication competence be tested in the preschool years, when timing and meaning are so often conflated? One possible test case that remains yet unexplored are the ways in which disorganized attachment might affect various language outcomes via inconsistent or inappropriate responses. When children do not form expectations of reciprocity in infancy and toddlerhood, how might their social exchanges with caregivers differ in the preschool years, when the default may not be to view one’s contributions through the lens of common ground? This remains an open question that will further refine our understanding of the complementary dimensions of timing and meaningfulness across development.

Current Challenges and Future Directions

This chapter has argued that parents foster communication competence in their children through adaptive contingency during social interactions that embrace both temporal and meaningful contingency. We argued that across developmental epochs, seemingly very different constructs like synchrony and joint attention share adaptive contingency as a core theme. We further argued that the nature of temporal and meaningful contingency will need to adapt across developmental time such that meaningfulness for the young infant might rest on emotional attunement between partners, whereas meaningfulness during exchanges with toddlers will undoubtedly be more related to semantic consistency of message.

Though this heterotypic view is suggested when looking across studies within the vast literature in early communication, future research will be charged with the task of teasing apart these two dimensions to determine the relative weight of timing and meaningfulness at each point in development for each element of communication competence. For example, caregivers’ strategy of vocal matching in early infancy to reinforce particular sounds and patterns in their native language (Papoušek & Papoušek, 1989) relies on both dimensions. To reinforce the development of interpersonal timing, however, would temporal contingency alone be sufficient? In the later years, perhaps the semantic relevance of input can carry conversations forward, even when responses lag or are otherwise temporally delayed.

Given that social exchanges dynamically unfold over time, timing and meaningfulness undoubtedly reinforce one another. The appropriateness of responses often depends upon their timely delivery. A first step may be to examine how children of all ages respond to meaningful input that follows various windows of silence. Is there a certain point after which children no longer perceive caregivers’ responses as meaningful? By decoupling the two dimensions, future research can identify whether they have additive or multiplicative effects on various language and communication outcomes.

A challenge for this work also concerns the ways in which coding systems capture and measure real-time adaptive contingency. It is considerably more difficult when the dyad serves as the unit of analysis instead of coding one particular individual or another. Nonetheless, bidirectional constructs deserve to be operationalized as such. While measures have been developed to capture the quality of parent-child interactions at the global (or macro) level (for a recent review, see Funamoto & Rinaldi, 2015; Hirsh-Pasek et al., 2015), analyses at the micro-level are still in their infancy. Leading the field in this aim are Smith, Yu, and colleagues, with their head-mounted eye-trackers (reviewed in Smith, Yu, Yoshida, & Faucey, 2015). This methodology allows researchers to collect two streams of visual data (from the child and from the caregiver) that then can be overlapped to identify episodes of shared attention (Yu & Smith, 2013). Advances in neuro-imaging will uncover the neural networks engaged when infants and children perceive and participate in temporally contingent and meaningful exchanges, providing new insights into adaptive contingency.

Finally, though this chapter highlighted the social foundations of adaptive contingency, we realize that there is a wealth of evidence that points to non-social processes at work when children learn language. Statistical learning is but one well-studied phenomenon that children rely on (for a recent review, see Smith, Suanda, & Yu, 2014). Similarly, mechanistic, bottom-up approaches to word learning minimize the role of dyadic social engagement (Pereira, Smith, & Yu, 2014; Smith et al., 2014), although new models that integrate social and non-social mechanisms have gained increased recognition in the field (Frank, Goodman, & Tenenbaum, 2009; Goldstein et al., 2010). As the field moves forward, cross-talk among those who ascribe to a constructivist approach and those who adopt a reductionist perspective will only strengthen and deepen our understanding.

Concluding Thoughts

Well before children utter their first words, adults are laying the foundation for language and for learning through their dyadic communicative exchanges. Terms used to define these early interactions – synchrony, responsiveness, and joint attention (among many other terms) – often mask the inherent constancy across developmental epochs as communication takes shape. Adaptive contingency, the idea that temporal and meaningful contingency might be the essential ingredients that drive early communication across time – is offered as a new framework for investigating the communicative competence that undergirds early language. Future research should more fully explore how each of these constructs jointly and independently contributes to this competence as the child grows.

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