Contingency Learning and Reactivity in Preterm and Full‐Term Infants at 3 Months

Learning difficulties in preterm infants are thought to reflect impairment in arousal regulation. We examined relationships among gestational age, learning speed, and behavioral and physiological reactivity in 55 preterm and 49 full‐term infants during baseline, contingency, and nonreinforcement phases of a conjugate mobile paradigm at 3 months corrected age. For all infants, negative affect, looking duration, and heart rate levels increased during contingency and nonreinforcement phases, whereas respiratory sinus arrhythmia (RSA, an index of parasympathetic activity) decreased and Cortisol did not change. Learners showed greater RSA suppression and less negative affect than nonleamers. This pattern was particularly evident in the preterm group. Overall, preterm infants showed less learning, spent less time looking at the mobile, and had lower Cortisol levels than full‐term infants. Preterm infants also showed greater heart rate responses to contingency and dampened heart rate responses to nonreinforcement compared to full‐term infants. Findings underscore differences in basal and reactivity measures in preterm compared to full‐term infants and suggest that the capacity to regulate parasympathetic activity during a challenge enhances learning in preterm infants.     

The Emergence and Stability of the Attentional Bias to Fearful Faces in Infancy

Several studies have shown that at 7 months of age, infants display an attentional bias toward fearful facial expressions. In this study, we analyzed visual attention and heart rate data from a cross‐sectional study with 5‐, 7‐, 9‐, and 11‐month‐old infants (Experiment 1) and visual attention from a longitudinal study with 5‐ and 7‐month‐old infants (Experiment 2) to examine the emergence and stability of the attentional bias to fearful facial expressions. In both experiments, the attentional bias to fearful faces appeared to emerge between 5 and 7 months of age: 5‐month‐olds did not show a difference in disengaging attention from fearful and nonfearful faces, whereas 7‐ and 9‐month‐old infants had a lower probability of disengaging attention from fearful than nonfearful faces. Across the age groups, heart rate (HR) data (Experiment 1) showed a more pronounced and longer‐lasting HR deceleration to fearful than nonfearful expressions. The results are discussed in relation to the development of the perception and experience of fear and the interaction between emotional and attentional processes.     

Associations between acoustic features of maternal speech and infants’ emotion regulation following a social stressor

Caregiver voices may provide cues to mobilize or calm infants. This study examined whether maternal prosody predicted changes in infants’ biobehavioral state after the still face, a stressor in which the mother withdraws and reinstates social engagement. Ninety-four dyads participated in the study (infant age 4–8 months). Infants’ heart rate and respiratory sinus arrhythmia (measuring cardiac vagal tone) were derived from an electrocardiogram (ECG). Infants’ behavioral distress was measured by negative vocalizations, facial expressions, and gaze aversion. Mothers’ vocalizations were measured via a composite of spectral analysis and spectro-temporal modulation using a two-dimensional fast Fourier transformation of the audio spectrogram. High values on the maternal prosody composite were associated with decreases in infants’ heart rate (β = ?.26, 95% CI: [?0.46, ?0.05]) and behavioral distress (β = ?.23, 95% CI: [?0.42, ?0.03]), and increases in cardiac vagal tone in infants whose vagal tone was low during the stressor (1 SD below mean β = .39, 95% CI: [0.06, 0.73]). High infant heart rate predicted increases in the maternal prosody composite (β = .18, 95% CI: [0.03, 0.33]). These results suggest specific vocal acoustic features of speech that are relevant for regulating infants’ biobehavioral state and demonstrate mother–infant bi-directional dynamics.     

Increases in Arousal are More Long‐Lasting than Decreases in Arousal: On Homeostatic Failures During Emotion Regulation in Infancy

In emotion regulation, negative or undesired emotions are downregulated, but there are also opponent processes to emotion regulation—in which undesired emotions are exacerbated dynamically over time by processes that have an amplifying or upregulating impact. Evidence for such processes has been shown in adults, but little previous work has examined whether infants show similar patterns. To examine this, we measured physiological arousal in 57 typical 12 month olds while presenting a 20‐min mixed viewing battery. Fluctuations in autonomic arousal were measured via heart rate, electrodermal activity, and movement. We reasoned that if transitions in autonomic arousal are random (stochastic), then (1) arousal would be normally distributed across the session, and (2) episodes where arousal exceeded a certain threshold above the mean should be as long‐lived as those where arousal exceeded the same threshold below the mean. In fact we found that (1) heart rate and movement (but not electrodermal activity) were positively skewed, and (2) that increases in arousal have a lower extinction probability than decreases in arousal. Our findings may suggest that increases in arousal are self‐sustaining. These patterns are the opposite of the homeostatic mechanisms predicted by naïve approaches to emotion regulation.     

Does the Organization of Emotional Expression Change Over Time? Facial Expressivity From 4 to 12 Months

Differentiation models contend that the organization of facial expressivity increases during infancy. Accordingly, infants are believed to exhibit increasingly specific facial expressions in response to stimuli as a function of development. This study tested this hypothesis in a sample of 151 infants (83 boys and 68 girls) observed in 4 situations (tickle, sour taste, arm restraint, and masked stranger) at 4 and 12 months of age. Three of the 4 situations showed evidence of increasing specificity over time. In response to tickle, the number of infants exhibiting joy expressions increased and the number exhibiting interest, surprise, and surprise blends decreased from 4 to 12 months. In tasting a sour substance, more infants exhibited disgust and fewer exhibited joy and interest expressions, and fear and surprise blends over time. For arm restraint, more infants exhibited anger expressions and anger blends and fewer exhibited interest and surprise expressions and surprise blends over time. In response to a masked stranger, however, no evidence of increased specificity was found. Overall, these findings suggest that infants increasingly exhibit particular expressions in response to specific stimuli during the 1st year of life. These data provide partial support for the hypothesis that facial expressivity becomes increasingly organized over time.     

Facial Expressivity at 4 Months: A Context by Expression Analysis

The specificity predicted by differential emotions theory (DET) for early facial expressions in response to 5 different eliciting situations was studied in a sample of 4‐month‐old infants (n = 150). Infants were videotaped during tickle, sour taste, jack‐in‐the‐box, arm restraint, and masked‐stranger situations and their expressions were coded second by second. Infants showed a variety of facial expressions in each situation; however, more infants exhibited positive (joy and surprise) than negative expressions (anger, disgust, fear, and sadness) across all situations except sour taste. Consistent with DET‐predicted specificity, joy expressions were the most common in response to tickling, and were less common in response to other situations. Surprise expressions were the most common in response to the jack‐in‐the‐box, as predicted, but also were the most common in response to the arm restraint and masked‐stranger situations, indicating a lack of specificity. No evidence of predicted specificity was found for anger, disgust, fear, and sadness expressions. Evidence of individual differences in expressivity within situations, as well as stability in the pattern across situations, underscores the need to examine both child and contextual factors in studying emotional development. The results provide little support for the DET postulate of situational specificity and suggest that a synthesis of differential emotions and dynamic systems theories of emotional expression should be considered.     

Development of Tactile Responses in Human Preterm and Full‐Term Infants From 30 to 40 Weeks Postconceptional Age

Maturation of tactile sensitivity prior to term was examined in 36 preterm and 13 full‐term infants using a fixed‐trial, habituation procedure. Each infant was presented with a series of 8 habituation (arm stroke), 2 novel (arm lift), and 2 recovery (arm stroke) stimulus trials while heart rate and body movements were recorded. Maturation was observed with a gradual increase in the magnitude of the stimulus‐elicited cardiac acceleration and cardiac‐movement coupling from 30 to 40 weeks postconceptional age. The majority of infants displayed habituation—an excitatory response (heart rate acceleration and body movement)—to the initial presentation of a tactile stimulus, response decline with repeated stimulations, and renewed response to a novel stimulus. A substantial number of infants (40%) failed to respond initially to the tactile stimulus, increased responding over several stimulus presentations, and failed to discriminate the presentation of a novel stimulus. We speculate that these differences in response patterns observed over all ages represent individual difference in the perception of stimulus intensity.     

Young Infants Match Facial and Vocal Emotional Expressions of Other Infants

Research has demonstrated that infants recognize emotional expressions of adults in the first half year of life. We extended this research to a new domain, infant perception of the expressions of other infants. In an intermodal matching procedure, 3.5‐ and 5‐month‐old infants heard a series of infant vocal expressions (positive and negative affect) along with side‐by‐side dynamic videos in which one infant conveyed positive facial affect and another infant conveyed negative facial affect. Results demonstrated that 5‐month‐olds matched the vocal expressions with the affectively congruent facial expressions, whereas 3.5‐month‐olds showed no evidence of matching. These findings indicate that by 5 months of age, infants detect, discriminate, and match the facial and vocal affective displays of other infants. Further, because the facial and vocal expressions were portrayed by different infants and shared no face–voice synchrony, temporal, or intensity patterning, matching was likely based on detection of a more general affective valence common to the face and voice.     

Olfactory Familiarization and Discrimination in Preterm and Full‐Term Newborns

The purpose of this study was to observe olfactory detection and discrimination in preterm and full‐term newborns. Infants were familiarized for 10 trials with either vanillin or anethole. On each trial, a cotton swab perfumed with one of the odors was slowly moved in front of the baby's nose for 10 sec. For half of the preterm and full‐term infants, a new odor was presented after the last familiarization trial (experimental groups). For the other half, the same odor as during familiarization was presented (control groups). Facial and head movements for both populations and heart rates for preterm infants were recorded before, during, and after odor presentation. Preterm infants reacted to the scents by increasing facial actions and heart rate but not head movements. Full‐term infants increased facial and head movements. Neither population showed a clear behavioral habituation pattern, but full‐term newborns had a significantly reduced facial reactivity on the last familiarization trial compared to preterm infants. Preterm newborns did, however, show cardiac habituation on the last familiarization trial. Preterm and full‐term infants presented with a new odor after familiarization increased responding compared to infants presented with the same odor, indicating their ability to discriminate between 2 odors. Infants' reactivity and discrimination to odors indicate preterm and full‐term newborns' ability to be attuned to their olfactory environment.     

Infants’ Biological Sensitivity to the Effects of Maternal Social Support: Evidence Among Mexican American Families

The identification of infants who are most susceptible to both negative and positive social environments is critical for understanding early behavioral development. This study longitudinally assessed the interactive effects of infant vagal tone (respiratory sinus arrhythmia; RSA) and maternal social support on behavioral problems and competence among 322 low‐income Mexican American mother–infant dyads (infants: 54.1% female) and explored sex differences. Infant RSA was calculated from resting HR data at 6 weeks of age. Mothers reported on general social support, partner support, and family support at 6 months, and infant behavioral problems and competence at 1 year. Two‐way interactions (RSA × support source) were evaluated to predict behavioral problems and competence, adjusting for covariates. Results indicated higher competence among infants with lower RSA whose mothers reported higher general support or higher partner support. Interactive effects on behavior problems of RSA with maternal partner or family support were only found for female infants: Girls with higher RSA showed more behavior problems when mothers reported low support, but fewer problem levels in the context of high support. Our results suggest that infant RSA is an important moderator of the effects of the early social environment on early development.     

Physiological Reactivity to Infant Crying and Observed Maternal Sensitivity

Relations between maternal sensitivity and physiological reactivity to infant crying were examined using measures of heart rate (HR) and respiratory sinus arrhythmia (RSA) in 49 mothers of second‐born infants. Using the Ainsworth Sensitivity Scale, an independent assessment of maternal sensitivity was made during maternal free play and bathing of their infants. Physiological reactivity was measured while mothers listened to three blocks of infant cry sounds in a standard cry paradigm. Mothers scoring high on sensitivity were compared to less sensitive mothers on both their physiological reactivity to the presented crying sounds and their physiological mean‐level differences. Significant interaction effects were found for both HR and RSA. Highly sensitive mothers showed a larger increase in HR and stronger RSA withdrawal in response to the first block of cry sounds compared to less sensitive mothers. Main effects showed that highly sensitive mothers had lower mean overall HR, and higher mean RSA levels across all three blocks of crying sounds compared to less sensitive mothers. RSA withdrawal and accompanying HR increases are discussed from a polyvagal perspective as indicative of a better capability in responding to infant signals of negative affect.     

Affective and Autonomic Responses to Erotic Images: Evidence of Disgust-Based Mechanisms in Female Sexual Interest/Arousal Disorder

Disgust has recently been implicated in the development and maintenance of female sexual dysfunction, yet most empirical studies have been conducted with a sexually healthy sample. The current study contributes to the literature by expanding the application of a disgust model of sexual functioning to a clinically relevant sample of women with low sexual desire/arousal and accompanying sexual distress. Young women (mean age = 19.12 years) with psychometrically defined sexual dysfunction (i.e., female sexual interest/arousal disorder [FSIAD] group) and a healthy control group were compared in their affective (i.e., facial electromyography [EMG] and self-report) and autonomic (i.e., heart rate and electrodermal activity) responses to disgusting, erotic, positive, and neutral images. Significant differences were predicted in responses to erotic images only. Specifically, it was hypothesized that the FSIAD group would display affective and autonomic responses consistent with a disgust response, while responses from the control group would align with a general appetitive response. Results largely supported study hypotheses. The FSIAD group displayed significantly greater negative facial affect, reported more subjective disgust, and recorded greater heart rate deceleration than the control group in response to erotic stimuli. Greater subjective disgust response corresponded with more sexual avoidance behavior. Planned follow-up analyses explored correlates of subjective disgust responses.     

Infants scan static and dynamic facial expressions differently

Despite being inherently dynamic phenomena, much of our understanding of how infants attend and scan facial expressions is based on static face stimuli. Here we investigate how six-, nine-, and twelve-month infants allocate their visual attention toward dynamic-interactive videos of the six basic emotional expressions, and compare their responses with static images of the same stimuli. We find infants show clear differences in how they attend and scan dynamic and static expressions, looking longer toward the dynamic-face and lower-face regions. Infants across all age groups show differential interest in expressions, and show precise scanning of regions “diagnostic” for emotion recognition. These data also indicate that infants' attention toward dynamic expressions develops over the first year of life, including relative increases in interest and scanning precision toward some negative facial expressions (e.g., anger, fear, and disgust).     

Categorical Representation of Facial Expressions in the Infant Brain

Categorical perception, demonstrated as reduced discrimination of within‐category relative to between‐category differences in stimuli, has been found in a variety of perceptual domains in adults. To examine the development of categorical perception in the domain of facial expression processing, we used behavioral and event‐related potential (ERP) methods to assess discrimination of within‐category (happy‐happy) and between‐category (happy‐sad) differences in facial expressions in 7‐month‐old infants. Data from a visual paired‐comparison test and recordings of attention‐sensitive ERPs showed no discrimination of facial expressions in the within‐category condition, whereas reliable discrimination was observed in the between‐category condition. The results also showed that face‐sensitive ERPs over occipital‐temporal scalp (P400) were attenuated in the within‐category condition relative to the between‐category condition, suggesting a potential neural basis for the reduced within‐category sensitivity. Together, these results suggest that the neural systems underlying categorical representation of facial expressions emerge during the early stages of postnatal development, before acquisition of language.     

Young Infants' Behavioral Reactivity to Mild Perturbation: Developmental Continuity,Stability, and Organization

This study investigated the developmental continuity, stability, and organization of infants' behavioral response to mild stress from 1 to 3 months of age. Changes in infant stress reactivity were expected to coincide with a suspected neurobiological shift around the 2nd month. A total of 53 infants and their mothers participated in this study. At 1 and 3 months, infants' stress reactivity to mild perturbation was assessed by withdrawing a pacifier during nonnutritive sucking. Infant baseline heart rate activity and maternal reports of infant temperament were also obtained. Focusing on facial and vocal negativity, behavioral measures of infant reactivity to pacifier withdrawal were coded from videos. Results showed that developmental continuity and individual instability characterized changes in infant stress reactivity over the 2nd‐month transition. Developmental reorganization was also evidenced by changes in the direction and magnitude of infant stress reactivity in relation to baseline heart period and maternal temperament ratings, respectively. These findings provide direct supporting evidence for the contention that changes in infant stress reactivity to mild perturbation may be a function of developmental shifts in underlying neurobiological mechanisms in early infancy.     

Relations Between Mother‐Child Interactions and the Neural Correlates of Face Processing in 6‐Month‐Olds

Developmental studies of face processing have revealed age‐related changes in how infants allocate neurophysiological resources to the face of a caregiver and an unfamiliar adult. We hypothesize that developmental changes in how infants interact with their caregiver are related to the changes in brain response. We studied 6‐month‐olds because this age is frequently noted in the behavioral and neurophysiological literature as a time of transition in which infants begin to discriminate more readily between caregivers and unfamiliar adults. We used infants' behavioral responses to an original behavioral paradigm to predict event‐related potential (ERP) responses to pictures of the mother's face and a stranger's face in the same group of participants. Our results suggest that individual differences in infants' proximity‐seeking behaviors during interactions with the mother correlate with their neurophysiological responses to the mother's face as opposed to an unfamiliar face for the Nc component of the ERP. These results have implications for understanding the role of the changing infant‐caregiver relationship on the development of the face processing system in early infancy.     

Maternal Depressive Symptoms and 6‐Month‐Old Infants' Sensitivity to Facial Expressions

We examined 6‐month‐old infants' abilities to discriminate smiling and frowning from neutral stimuli. In addition, we assessed the relationship between infants' preferences for varying intensities of smiling and frowning facial expressions and their mothers' history of depressive symptoms. Forty‐six infants were presented pairs of facial expressions, and their preferential looking time was recorded. They also participated in a 3‐min interaction with their mothers for which duration of both mother and infant gazing and smiling were coded. Analyses revealed that the infants reliably discriminated between varying intensities of smiling and frowning facial expressions and a paired neutral expression. In addition, infants' preferences for smiling and frowning expressions were related to self‐reports of maternal depressive symptoms experienced since the birth of the infant. Potential implications for social cognitive development are discussed.     

Do Infants Show Distinct Negative Facial Expressions for Fear and Anger? Emotional Expression in 11‐Month‐Old European American,Chinese, and Japanese Infants

Do infants show distinct negative facial expressions for different negative emotions? To address this question, European American, Chinese, and Japanese 11‐month‐olds were videotaped during procedures designed to elicit mild anger or frustration and fear. Facial behavior was coded using Baby FACS, an anatomically based scoring system. Infants' nonfacial behavior differed across procedures, suggesting that the target emotions were successfully elicited. However evidence for distinct emotion‐specific facial configurations corresponding to fear versus anger was not obtained. Although facial responses were largely similar across cultures, some differences also were observed. Results are discussed in terms of functionalist and dynamical systems approaches to emotion and emotional expression.     

Cry Babies and Pollyannas: Infants Can Detect Unjustified Emotional Reactions

Infants are attuned to emotional facial and vocal expressions, reacting most prominently when they are exposed to negative expressions. However, it remains unknown if infants can detect whether a person's emotions are justifiable given a particular context. The focus of the current paper was to examine whether infants react the same way to unjustified (e.g., distress following a positive experience) and justified (e.g., distress following a negative experience) emotional reactions. Infants aged 15 and 18 months were shown an actor experiencing negative and positive experiences, with one group exposed to an actor whose emotional reactions were consistently unjustified (i.e., did not match the event), while the other saw an actor whose emotional reactions were justified (i.e., always matched the event). Infants' looking times and empathic reactions were examined. Only 18‐month‐olds detected the mismatching facial expressions: Those in the unjustified group showed more hypothesis testing (i.e., checking) across events than the justified group. Older infants in the justified group also showed more concerned reactions to negative expressions than those in the unjustified group. The present findings indicate that infants implicitly understand how the emotional valence of experiences is linked to subsequent emotional expressions.     

Affective and Behavioral Features of Jealousy Protest: Associations with Child Temperament,Maternal Interaction Style,and Attachment

This study explored variation in affective and behavioral components of infants’ jealousy protests during an eliciting condition in which mother and an experimenter directed differential attention exclusively toward a rival. Variation was examined in relation to child temperamental emotionality, maternal interaction style, and attachment security. At 45 weeks, intensity of infants’distress and durations of mother‐ and stranger‐directed behavioral responses, including gaze, touch, and proximity‐seeking, were observed in the eliciting condition. We also assessed infants’positive emotionality (PE) and negative emotionality (NE) and maternal interaction styles of sensitivity and engagement. At 54 weeks, attachment security was measured in the Strange Situation Procedure. Findings revealed that distress differed with temperamental emotionality and maternal interaction style. Specifically, distress was greater in infants with lower PE and having mothers who displayed less sensitivity and engagement. Analyses on behavioral responses toward the experimenter revealed linkages with maternal interaction style. Specifically, experimenter‐directed gaze and touch were greater among infants of mothers who demonstrated less sensitivity and engagement. Behavioral responses toward mother were found associated with quality of attachment. Specifically, mother‐directed proximity and touch were highest among infants later judged insecure resistant and lowest among those later judged insecure/avoidant; with infants later judged secure displaying moderate durations of mother‐directed proximal contact.