Maternal Responsiveness and the Development of Directed Vocalizing in Social Interactions

For effective communication, infants must develop the phonology of sounds and the ability to use vocalizations in social interactions. Few studies have examined the development of the pragmatic use of prelinguistic vocalizations, possibly because gestures are considered hallmarks of early pragmatic skill. The current study investigated infant vocal production and maternal responsiveness to examine the relationship between infant and maternal behavior in the development of infants' vocal communication. Specifically, we asked whether maternal responses to vocalizations could influence the development of prelinguistic vocal usage, as has been documented in recent experimental studies exploring the relation between maternal responses and phonological development. Twelve mother–infant dyads participated over a six‐month period (between 8 and 14 months of age). Mothers completed the MacArthur Communicative Development Inventory when infants were 15 months old. Maternal sensitive responses to infant vocalizations in the previous months predicted infants' mother‐directed vocalizations in the following months, rather than overall response rate. Furthermore, mothers' sensitive responding to mother‐directed vocalizations was correlated with an increase in developmentally advanced, consonant–vowel vocalizations and some language measures. This is the first study to document a social shaping mechanism influencing developmental change in pragmatic usage of vocalizations in addition to identifying the specific behaviors underlying development.     

Stimulus-Stimulus Pairing of Vocalizations: A Systematic Replication

The current study replicated an enhanced stimulus-stimulus pairing (SSP) procedure used by Esch et al. (Journal of Applied Behavior Analysis 42: 42–225, 2009) for increasing vocalizations in children with autism. The enhanced SSP procedure consisted of pairing target vocalizations with high-preference items, interspersed target and nontarget trials, an observing response, and the presentation of the vocalizations in “motherese” speech. Results showed substantial increases in target vocalizations above baseline levels and above nontarget vocalizations for two of three participants.     

Assessing the Effects of Observational Conditioning and Response-Contingent Pairing on the Vocalizations of Children With Autism Spectrum Disorder

Children with autism spectrum disorder (ASD) often display impairments in communication, such as limited echoic behavior, few vocal-verbal responses, and a lack of functional communication. One potential way to foster the acquisition of vocal responses in individuals with disabilities is by conditioning vocalizations as reinforcers. Conditioning procedures include stimulus–stimulus pairing, response-contingent pairing (RCP), operant discrimination training, and observational conditioning (OC). However, previous research has not evaluated whether OC can be used to condition vocalizations as reinforcers. The current study assessed whether two conditioning procedures, RCP and OC, were effective in conditioning vocalizations as a reinforcer and also evaluated their effect on the rate of vocalizations. Participants included three children with ASD, ages 5–10 years old. During the conditioning phase, rates of vocalizations during the RCP and OC conditions and a control condition were compared within an adapted alternating-treatments design. Reinforcer assessments were completed in a multielement design, pre- and postconditioning, to assess whether the target vocalizations acquired reinforcing properties. A conditioning effect and an increase in the rate of vocalizations were observed for two of the three participants; however, the conditioning effect was minor for one participant. Overall, the results of this study indicate both the RCP and OC procedures may be beneficial in increasing vocalizations for some children and could be incorporated into clinical programs and further explored in future research.     

The Influence of Mouthing on Infant Vocalization

Although vocalization and mouthing are behaviors frequently performed by infants, little is known about the characteristics of vocalizations that occur with objects, hands, or fingers in infants' mouths. The purpose of this research was to investigate characteristics of vocalizations associated with mouthing in 6‐ to 9‐month‐old infants during play with a primary caregiver. Results suggest that mouthing may influence the phonetic characteristics of vocalizations by introducing vocal tract closure and variation in consonant production.     

The effects of tact training on stereotypic vocalizations in children with autism

This study was a systematic extension of Karmali, Greer, Nuzzulo-Gomez, Ross, and Rivera-Valdes (2005) and Ahearn, Clark, MacDonald, and Chung (2007). We investigated the effects of a tact correction procedure on stereotypic vocalizations in 4 children diagnosed with autism who ranged in age from 6 to 16 years. Participants had limited vocal verbal repertoires and were primarily dependent on prompts for the emission of appropriate vocalizations. A multiple-baseline design across participants was used. Data were collected on instances of stereotypic vocalizations and independent tacts during baseline conditions and on instances of stereotypic vocalizations, independent tacts, and echoic-tacts during intervention. Procedural integrity and social validity data were also obtained. The results indicated a decrease in stereotypic vocalizations for 3 of the 4 participants and a slight increase in appropriate vocal verbal behavior (i.e., tacting) for all participants. The study provides support for the use of tact correction procedures to decrease stereotypic vocalizations and increase appropriate vocalizations in children with autism.     

The Effects of Contingent Caregiver Imitation of Infant Vocalizations: a Comparison of Multiple Caregivers

The present study replicated and extended the Pelaez et al. (Journal of Applied Behavior Analysis 44:33–40, 2011) study, which examined the reinforcing effects of mothers’ contingent imitation of their infants’ vocalizations. Three infants aged 7–12 months who could vocalize sounds but not words participated with two caregivers for each infant (i.e., triads). During the intervention phase, the caregivers were asked to immediately imitate all vocalizations emitted by the child for a 3-min period. During the yoked control phase, the caregivers listened to an audio recording from the preceding condition and provided vocalizations non-contingently on the infants’ responses. The procedures yielded different results across participants; one infant emitted a higher frequency of vocalizations during the contingent imitation phases over the control phases, and the other two infants showed higher rates of responding during the control phases. However, all infants emitted more imitative return vocalizations during contingent reinforcement conditions compared with the yoked control condition.     

Evaluating Stimulus-Stimulus Pairing and Direct Reinforcement in the Establishment of an Echoic Repertoire of Children Diagnosed with Autism

Many children with autism do not imitate adult vocalizations, an important skill in learning to talk. Pairing adult vocalizations with preferred stimuli has been shown to increase free-operant vocalizations but effects are temporary; thus, direct reinforcement may be necessary to establish durable vocal behaviors. In Experiment 1, directly reinforced echoic responses did not increase following stimulus-stimulus pairings in three children with autism. Similarly, pairings did not increase free-operant vocalizations in Experiment 2, a replication of Miguel et al. (2002). Experiment 3 demonstrated that shaping increased vowel frequency for one participant. Results suggest that variables are yet to be delineated that influence effectiveness of a stimulus-stimulus pairing procedure on vocalization frequency and acquisition of a verbal operant following such pairings.     

Human Non-linguistic Vocal Repertoire: Call Types and Their Meaning

Recent research on human nonverbal vocalizations has led to considerable progress in our understanding of vocal communication of emotion. However, in contrast to studies of animal vocalizations, this research has focused mainly on the emotional interpretation of such signals. The repertoire of human nonverbal vocalizations as acoustic types, and the mapping between acoustic and emotional categories, thus remain underexplored. In a cross-linguistic naming task (Experiment 1), verbal categorization of 132 authentic (non-acted) human vocalizations by English-, Swedish- and Russian-speaking participants revealed the same major acoustic types: laugh, cry, scream, moan, and possibly roar and sigh. The association between call type and perceived emotion was systematic but non-redundant: listeners associated every call type with a limited, but in some cases relatively wide, range of emotions. The speed and consistency of naming the call type predicted the speed and consistency of inferring the caller’s emotion, suggesting that acoustic and emotional categorizations are closely related. However, participants preferred to name the call type before naming the emotion. Furthermore, nonverbal categorization of the same stimuli in a triad classification task (Experiment 2) was more compatible with classification by call type than by emotion, indicating the former’s greater perceptual salience. These results suggest that acoustic categorization may precede attribution of emotion, highlighting the need to distinguish between the overt form of nonverbal signals and their interpretation by the perceiver. Both within- and between-call acoustic variation can then be modeled explicitly, bringing research on human nonverbal vocalizations more in line with the work on animal communication.     

Learning While Babbling: Prelinguistic Object‐Directed Vocalizations Indicate a Readiness to Learn

Two studies illustrate the functional significance of a new category of prelinguistic vocalizing—object‐directed vocalizations (ODVs)—and show that these sounds are connected to learning about words and objects. Experiment 1 tested 12‐month‐old infants’ perceptual learning of objects that elicited ODVs. Fourteen infants’ vocalizations were recorded as they explored novel objects. Infants learned visual features of objects that elicited the most ODVs but not of objects that elicited the fewest vocalizations. Experiment 2 assessed the role of ODVs in learning word–object associations. Forty infants aged 11.5 months played with a novel object and received a label either contingently on an ODV or on a look alone. Only infants who received labels in response to an ODV learned the association. Taken together, the findings suggest that infants’ ODVs signal a state of attention that facilitates learning.     

Infant vocalizations elicit simplified speech in childcare

Infant babbling has an important social function in promoting early language development by attracting caregiver attention and prompting parents' contingent, simplified speech, which is more learnable for infants. Here, we demonstrate that prelinguistic infant vocalizations also create learning opportunities for infants in childcare settings by eliciting simplified and more learnable linguistic information during teacher-infant interactions. We compared the rates and complexity of contingent and non-contingent verbal interactions of 34 childcare teachers during a one-on-one free play interaction with a familiar infant under their care (M = 12.6 months old). As compared to non-contingent utterances, teachers' contingent utterances included fewer unique words, a higher proportion of single-word responses, and a shorter mean length of utterances. Teachers did not change their response length based on infants' syllable type and were equally likely to respond to vowels and consonant-vowel vocalizations. Sources of individual differences in the simplification effect related to infant behaviors and teacher characteristics are discussed. The results parallel previous findings demonstrating the simplification effect in parent-infant interactions. That teachers also show this simplification effect when responding to infant vocalizations suggests the power of infant prelinguistic vocalizations for organizing caregiver attention in various settings to elicit simplified, learnable language.     

“Did I just do that?”—Six-month-olds learn the contingency between their vocalizations and a visual reward in 5 minutes

It has been shown that infants can increase or modify a motorically available behavior such as sucking, kicking, arm waving, etc., in response to a positive visual reinforcement (e.g., DeCasper & Fifer, 1980; Millar, 1990; Rochat & Striano, 1999; Rovee-Collier, 1997; Watson & Ramey, 1972). We tested infants to determine if they would also change their vocal behavior in response to contingent feedback, which lacks the social, emotional, and auditory modeling typical of parent-child interaction. Here, we show that in a single five-minute session infants increase the rate of their vocalizations in order to control the appearance of colorful shapes on an iPad screen. This is the first experimental study to demonstrate that infants can rapidly learn to increase their vocalizations, when given positive reinforcement with no social element. This work sets the foundations for future studies into the causal relationship between the number of early vocalizations and the onset of words. In addition, there are potential clinical applications for reinforcing vocal practice in infant populations who are at risk for poor language skills.     

Extending the Assessment of Functions of Vocalizations in Children with Limited Verbal Repertoires

The current study examined the effectiveness of an experimental functional analysis for assessing the functions of emergent vocal-verbal behavior in children with developmental disabilities. Experiment 1 consisted of a systematic replication of Lerman et al. (2005). Participants were 3 children with developmental disabilities, between the ages of 2 and 5 years, with limited vocal-verbal repertoires, who could emit at least two clear vocalizations. Results indicated that for all participants, targeted vocalizations functioned as mands, tacts, or both. The purpose of Experiment 2 was to address some of the limitations of Experiment 1 while using a different experimental design. Results of Experiment 2 suggested that participants'' targeted vocalizations served as tacts, echoics, or both. Results are discussed in terms of the utility of this methodology for the selection and development of effective language interventions as well as implications for our current knowledge of verbal behavior.     

ACKNOWLEDGMENT OF GUEST REVIEWERS

Two‐month‐old infants (N = 29) participated in face‐to‐face interactions with their mothers and with strangers. The contingent responsiveness for smiles and vocalizations, while attending to the partner, was assessed for each partner in both interactions. For smiles and for vocalizations, infants were less responsive to the stranger relative to the mother when the stranger's contingent responsiveness was either more contingent or less contingent than that of the mother. Results are supportive of the hypothesis that young infants develop sensitivities to levels of social contingency present in their maternal interactions, which influence their responsiveness to others.     

An Assessment of Three Procedures to Teach Echoic Responding

The Analysis of Verbal Behavior - The research literature has revealed mixed outcomes on various procedures for increasing vocalizations and echoic responding in persons with disabilities (Miguel,...     

Multiple Coordination Patterns in Infant and Adult Vocalizations

The study of vocal coordination between infants and adults has led to important insights into the development of social, cognitive, emotional, and linguistic abilities. We used an automatic system to identify vocalizations produced by infants and adults over the course of the day for fifteen infants studied longitudinally during the first 2 years of life. We measured three different types of vocal coordination: coincidence‐based, rate‐based, and cluster‐based. Coincidence‐based coordination and rate‐based coordination are established measures in the developmental literature. Cluster‐based coordination is new and measures the strength of matching in the degree to which vocalization events occur in hierarchically nested clusters. We investigated whether various coordination patterns differ as a function of vocalization type, whether different coordination patterns provide unique information about the dynamics of vocal interaction, and how the various coordination patterns each relate to infant age. All vocal coordination patterns displayed greater coordination for infant speech‐related vocalizations, adults adapted the hierarchical clustering of their vocalizations to match that of infants, and each of the three coordination patterns had unique associations with infant age. Altogether, our results indicate that vocal coordination between infants and adults is multifaceted, suggesting a complex relationship between vocal coordination and the development of vocal communication.     

What is the Melody of That Voice? Probing Unbiased Recognition Accuracy with the Montreal Affective Voices

The present study aimed to clarify how listeners decode emotions from human nonverbal vocalizations, exploring unbiased recognition accuracy of vocal emotions selected from the Montreal Affective Voices (MAV) (Belin et al. in Trends Cognit Sci 8:129–135, 2008. doi: 10.1016/j.tics.2004.01.008). The MAV battery includes 90 nonverbal vocalizations expressing anger, disgust, fear, pain, sadness, surprise, happiness, sensual pleasure, as well as neutral expressions, uttered by female and male actors. Using a forced-choice recognition task, 156 native speakers of Portuguese were asked to identify the emotion category underlying each MAV sound, and additionally to rate the valence, arousal and dominance of these sounds. The analysis focused on unbiased hit rates (H_u Score; Wagner in J Nonverbal Behav 17(1):3–28, 1993. doi: 10.1007/BF00987006), as well as on the dimensional ratings for each discrete emotion. Further, we examined the relationship between categorical and dimensional ratings, as well as the effects of speaker’s and listener’s sex on these two types of assessment. Surprise vocalizations were associated with the poorest accuracy, whereas happy vocalizations were the most accurately recognized, contrary to previous studies. Happiness was associated with the highest valence and dominance ratings, whereas fear elicited the highest arousal ratings. Recognition accuracy and dimensional ratings of vocal expressions were dependent both on speaker’s sex and listener’s sex. Further, discrete vocal emotions were not consistently predicted by dimensional ratings. Using a large sample size, the present study provides, for the first time, unbiased recognition accuracy rates for a widely used battery of nonverbal vocalizations. The results demonstrated a dynamic interplay between listener’s and speaker’s variables (e.g., sex) in the recognition of emotion from nonverbal vocalizations. Further, they support the use of both categorical and dimensional accounts of emotion when probing how emotional meaning is decoded from nonverbal vocal cues.     

Enacting Gustatory Pleasure on Behalf of Another: The Multimodal Coordination of Infant Tasting Practices

Tasting as a social practice can be enacted on behalf of others through precisely positioned nonlexical vocalizations as gustatory mmms. This paper uses multimodal interaction analysis to detail the coordination of parents and infants while starting to feed solid foods; data are from families in Scotland. The analysis focuses on the organization of parental mmms in relation to eye gaze, sequentiality, and the temporal coordination of hands, food, and mouths to demonstrate their use in beginning, continuing, and refocusing on taste. The paper proposes that in order to fully understand the sociality of tasting, infant feeding research should include real‐time vocal and embodied behavior, which is also key to the functional analysis of sensoriality‐related vocalizations at the margins of language.     

Cocaine-Exposed Toddler-Caregiver Dyads During Free Play at 24 Months

Some women continue to use cocaine during pregnancy, placing their fetus at risk for developmental problems. While gross problems are not evident after controlling for experimental flaws, subtle effects continue to be found. Social interactions of cocaine-exposed and nonexposed toddlers and their caregivers were assessed during a Free Play test to determine if psychobehavioral deficits were clinically observable. Risk factors were evaluated to assess whether the child’s socioemotional-behavioral behaviors were related to exposure and/or interactions with caregivers or the environment. Twenty-four-month-old cocaine-exposed and nonexposed toddlers were evaluated with the Child Behavior Check List while they played with their caregivers. Caregivers’ vocalizations were scored as contingent pairs if they occurred within 3 seconds of the child’s. The proportion of pairs was compared by group. Quality of caregivers’ vocalizations was rated as positive or negative based on approval, encouragement, and criticism. General linear model analyses indicate that cocaine-exposed children showed more dysfunctional behaviors than noncocaine-exposed children. Deficits increased when income and number of dependents were included. Caregivers in the drug group emitted fewer vocalizations during play before receiving a toy, indicating fewer opportunities for learning. No effect of quality of caregiver communication or gender by cocaine exposure interaction emerged. Cocaine exposure predicts poor developmental outcomes, but the toddler-caregiver relationship and reduced access to resources are additional risks that had previously been attributed to cocaine exposure. Early intervention services are needed to reduce the impact of low income, increase preschool readiness, and optimize functioning of these fragile families.     

Auditory Distress Signals Potentiate Attentional Bias to Fearful Faces: Evidence for Multimodal Facilitation of Spatial Attention by Emotion

Unimodal emotionally salient visual and auditory stimuli capture attention and have been found to do so cross-modally. However, little is known about the combined influences of auditory and visual threat cues on directing spatial attention. In particular, fearful facial expressions signal the presence of danger and capture attention. Yet, it is unknown whether human auditory distress signals that accompany fearful facial expressions potentiate their capture of attention. It was hypothesized that the capture of attention by fearful faces would be enhanced when co-presented with auditory distress signals. To test this hypothesis, we used a modified multimodal dot-probe task where fearful faces were paired with three sound categories: no sound control, non-distressing human vocalizations, and distressing human vocalizations. Fearful faces captured attention across all three sound conditions. In addition, this effect was potentiated when fearful faces were paired with auditory distress signals. The results provide initial evidence suggesting that emotional attention is facilitated by multisensory integration.     

Maternal education influences Australian infants’ language experience from six months

Disparities in children's early language skills associated with socioeconomic factors have led to many studies examining children's early language environments, but few as yet in the first year of life. This longitudinal study assessed the home language environments of 50 Australian infants, who varied in maternal education (university education, or not). Full‐day audio recordings were collected and analyzed using the LENA system when infants were aged 6–9 months and 12–15 months. Using the device‐specific analysis software, we assessed 12‐h projected counts of (1) adult speech input, (2) conversational interactions, and (3) child vocalizations. At both ages, higher maternal education was associated with higher counts of adult words and conversational turns, but not child vocalizations. The study adds to the literature by demonstrating disparities in the infants’ language experience within the first year of life, related to mothers’ education, with implications for early intervention and parenting supports.