Intention or expression? Four-month-olds' reactions to a sudden still-face

We addressed whether 4-month-old infants are primarily influenced by the expression or intention underlying a sudden still-face response by an adult social partner. Sixteen dyads of 4-month-old infants interacted with an adult who posed a still-face directed at one of the two infants. Infants' gazing and smiling responses confirm that they are primarily influenced by the emotional and contingency loss rather than the intention underlying the adult's still-face.     

Contribution of facial and vocal cues in the still-face response of 4-month-old infants

The contribution of contingent facial and vocal information in the still-face effect was investigated. Four-month-old infants either saw and heard their mother, only saw their mother, or only heard their mother interacting with them. These interaction periods were followed by the cessation of the mother's interactive face and/or voice. Only infants who observed their mother's face become still and neutral, showed a still-face effect by decreasing their visual attention and positive affect. The findings provide further support that the mother's interactive voice does not contribute to the still-face effect. The developing sensitivity to vocal information in dyadic and triadic contexts is discussed.     

Infant affective responses to mother's still face at 6 months differentially predict externalizing and internalizing behaviors at 18 months

This study investigated (a) stability and change in infant affective responses to the still-face interaction, (b) whether maternal depression affected infant responses, and (c) whether responses to the still-face interaction predicted toddler problem behaviors. Infants (63 girls and 66 boys) of European American mothers (67 depressed and 62 nondepressed) were observed in the still-face interaction at 2, 4, and 6 months. Affect and gaze were coded on a 1-s time base. There were stable individual differences in gazing away and in rates of negative affect. Developmental change occurred only for gazing away, which increased. At 18 months, infants who failed to smile at 6 months in the still-face interaction showed more externalizing-type behaviors than did other toddlers. Infants who failed to cry at 6 months showed fewer internalizing-type behaviors. Mothers' current depressive symptoms and infants' earlier responses to the still-face interaction made independent, comparable contributions to problem behaviors at 18 months.     

Emotional expression and heart rate in high-risk infants during the face-to-face/still-face

In infants, eye constriction—the Duchenne marker—and mouth opening appear to index the intensity of both positive and negative facial expressions. We combined eye constriction and mouth opening that co-occurred with smiles and cry-faces (respectively, the prototypic expressions of infant joy and distress) to measure emotional expression intensity. Expression intensity and heart rate were measured throughout the face-to-face/still-face (FFSF) in a sample of infants with prenatal cocaine exposure who were at risk for developmental difficulties. Smiles declined and cry-faces increased in the still-face episode, but the distribution of eye constriction and mouth opening in smiles and cry-faces did not differ across episodes of the FFSF. As time elapsed in the still face episode potential indices of intensity increased, cry-faces were more likely to be accompanied by eye constriction and mouth opening. During cry-faces there were also moderately stable individual differences in the quantity of eye constriction and mouth opening. Infant heart rate was higher during cry-faces and lower during smiles, but did not vary with intensity of expression or by episode. In sum, infants express more intense negative affect as the still-face progresses, but do not show clear differences in expressive intensity between episodes of the FFSF.     

Intentions make a difference: infant responses to still-face and modified still-face conditions

In two studies, 3-, 6- and 9-month-old infants interacted with their mothers during natural, still-face, and modified still-face (i.e., mothers wearing a mask, or drinking from bottle) conditions. Infants were also presented with matching doll conditions to control for the possibility that their responses might be due to changes in superficial perceptual features. Regardless of age, infants displayed negative affect to the still-face, but, in contrast to recent reports, not to the modified still-face conditions. However, whereas infants' positive affect also depended on their mothers' communicative intentions, these responses changed with cognitive maturation. As expected, infant responses to their mothers were significantly different from those to the doll. The implications of these findings for theories of communication are discussed.     

The still-face response in newborn, 1.5-, and 3-month-old infants

The present study investigated the still-face response to a female stranger in newborn, 1.5-, and 3-month-old infants. The results revealed that 1.5- and 3-month-olds, but not newborns, reliably decreased their visual attention and positive affect when the interaction partner became unresponsive during the still-face period.     

Two-month-olds' attention and affective response to maternal still face: a comparison between term and preterm infants in Taiwan

Maternal still face is a robust experimental procedure designed to examine infants’ sensitivity to social contingency and reactivity to its violation. To extend earlier research on the still-face effect on term infants in Western cultures, the present study compared Taiwanese term and preterm infants’ attention and affective response to and recovery from a modified maternal still-face procedure that used an additional still-face reengagement sequence at 2 months of age (corrected age for preterm infants). Infants’ gaze and facial affect were coded from videos. Results showed that preterm infants were as sensitive as term infants to the interruption to social contingency. Both groups of infants reacted with decreased gaze and positive affect across episodes, together with a decreased latency to gaze aversion and an increased latency to positive affect. Both term and preterm infants also demonstrated a W-shaped pattern of decline-followed-by-recovery in their latency to negative affect. However, compared to term infants, preterm infants became distressed faster and stayed in a negative affective state longer after the first exposure to maternal still face. Effects of prematurity on infant attention and affect regulation were discussed. Implications of preterm infants’ heightened affective negativity to mild stress for intervention studies were also addressed.     

Dyadic and triadic skills in preterm and full term infants: a longitudinal study in the first year

This longitudinal study examined dyadic and triadic skills in 26 preterm and 31 full term infants at 3, 6 and 9 months of age. In dyadic interaction, infants engaged with a stranger in face-to-face play interrupted by a still-face episode. In triadic interaction, infants interacted with the adult stranger as she coordinated gaze between the infant and object. Both groups were sensitive for non-contingency in both dyadic and triadic interactions. There were significant group and developmental differences for dyadic and triadic competencies. Compared to full term infants, preterms made less positive elicits during the still-face at 6 months and followed gaze less at 9 months of age. Six-month dyadic skills and 9-month triadic competencies were positively related in preterm and full term infants.     

Newborn preference for a new face vs. a previously seen communicative or motionless face

Newborn infants prefer to look at a new face compared to a known face (still-face). This effect does not happen with the mother-face. The newborns could be attracted by the mother-face because, unlike the still-face, it confirms an expectation of communication.Fifty newborns were video-recorded. Sixteen of them were recruited in the final sample: nine were exposed to a communicative face and seven to a still-face. All the 16 newborns were successively exposed to two preference-tasks where a new face was compared with the known face.Only newborns previously exposed to a still-face preferred to look at a new face instead of the known face. The results suggest that the newborns are able to build a dynamic representation of faces.     

Comparing emotional reactivity and regulation in infants born ELGA and VLGA

Emotional reactivity and regulation behaviors were compared in infants born extremely low gestational age (ELGA) and very low gestational age (VLGA) during the still-face procedure. Infants born ELGA demonstrated greater emotional reactivity and displayed less frequent gaze avoidance, more frequent gestures, and more self-comforting behaviors.     

Learning how to learn from social feedback: The origins of early vocal development

Infants’ prelinguistic vocalizations reliably organize vocal turn-taking with social partners, creating opportunities for learning to produce the sound patterns of the ambient language. This social feedback loop supporting early vocal learning is well-documented, but its developmental origins have yet to be addressed. When do infants learn that their non-cry vocalizations influence others? To test developmental changes in infant vocal learning, we assessed the vocalizations of 2- and 5-month-old infants in a still-face interaction with an unfamiliar adult. During the still-face, infants who have learned the social efficacy of vocalizing increase their babbling rate. In addition, to assess the expectations for social responsiveness that infants build from their everyday experience, we recorded caregiver responsiveness to their infants’ vocalizations during unstructured play. During the still-face, only 5-month-old infants showed an increase in vocalizing (a vocal extinction burst) indicating that they had learned to expect adult responses to their vocalizations. Caregiver responsiveness predicted the magnitude of the vocal extinction burst for 5-month-olds. Because 5-month-olds show a vocal extinction burst with unfamiliar adults, they must have generalized the social efficacy of their vocalizations beyond their familiar caregiver. Caregiver responsiveness to infant vocalizations during unstructured play was similar for 2- and 5-month-olds. Infants thus learn the social efficacy of their vocalizations between 2 and 5 months of age. During this time, infants build associations between their own non-cry sounds and the reactions of adults, which allows learning of the instrumental value of vocalizing.     

Effects of maternal depression in the Still-Face Paradigm: A meta-analysis

The Still-Face Paradigm (SFP) enables researchers to examine the quality of mother-infant interactions. In typical infants, a classic still-face effect (SFE) has been confirmed whereby infants demonstrate reduced positive affect (PA), reduced gaze (GA), and increased negative affect (NA). Recently, the SFP has been used to examine the effect of maternal depression upon infant behaviour. However, the nature and consistency of the behavioural responses of infants of depressed mothers during the SFP remains unclear. In the current meta-analysis, we examined whether or not infants of depressed mothers demonstrate the classic SFE, as well as whether or not these infants display the same levels of PA, NA, and GA as their counterparts with non-depressed mothers. Results revealed that infants of depressed mothers display the classic SFE like infants of their non-depressed counterparts. However, infants of depressed mothers also demonstrated significantly higher levels of PA during the still-face episode. One potential interpretation of this finding is that infants prior experience of similar, depressed interactions with their mothers, encourages them to amplify their positive attachment signals in order to engage maternal attention and response. Alternatively, or additionally, infants of depressed mothers could be using PA in order to regulate their own NA.     

Infant behavioural effects of smartphone interrupted parent-infant interaction

Infants are vulnerable to changes in the dyadic synchrony with their caregivers, as demonstrated in numerous experiments employing the still-face paradigm. The sudden lack of attunement causes infant stress reactions and the still-face literature have suggested potential long-term costs of this in terms of development of social, emotional and cognitive skills. Acknowledging the rapid technological development accompanied by altered practices in the parent-infant interaction, the current study investigates infant behavioural reactions in a similar experimental paradigm, manipulating parental responsiveness and sensitivity in a slightly different manner. In the current study, the parent interrupts the ongoing interaction, simulating occupation with a smartphone, rather than making a ‘still-face’. In a cross-sectional design, infants of six, nine and twelve months display increased levels of protest behaviour in response to the interrupted interaction with their parent, together with lowered levels of positive engagement and social monitoring, suggesting similar behavioural responses as the still-face effect. Implications for infant social and emotional development, as well as for mindful tech habits are discussed.     

Infants' vagal regulation in the still-face paradigm is related to dyadic coordination of mother-infant interaction

The authors investigated relations between mother-infant dyadic coordination and infants' physiological responses. Mothers (N=73) and 3-month-old male and female infants were observed in the still-face paradigm, and mothers' and infants' affective states were coded at 1-s intervals. Synchrony and levels of matching between mother-infant affective states were computed, and infants' heart rate and vagal tone were measured. Infants showed increased negative affect and heart rate and decreased vagal tone during mothers' still-face, indicating physiological regulation of distress. Infants who did not suppress vagal tone during the still-face (nonsuppressors) showed less positive affect, higher reactivity and vagal suppression in normal play and reunion episodes, and lower synchrony in normal play with mothers. The results indicate that infants' physiological regulation in social interaction differs in relation to dyadic coordination of affective behaviors.     

Cocaine exposure is associated with subtle compromises of infants' and mothers' social-emotional behavior and dyadic features of their interaction in the face-to-face still-face paradigm

Prenatal cocaine and opiate exposure are thought to subtly compromise social and emotional development. The authors observed a large sample of 236 cocaine-exposed and 459 nonexposed infants (49 were opiate exposed and 646 nonexposed) with their mothers in the face-to-face still-face paradigm. Infant and maternal behaviors were microanalytically coded. No opiate-exposure effects were detected. However, mothers of cocaine-exposed infants showed more negative engagement than other mothers. The cocaine-exposed dyads also showed higher overall levels of mismatched engagement states than other dyads, including more negative engagement when the infants were in states of neutral engagement. Infants exposed to heavier levels of cocaine showed more passive-withdrawn negative engagement and engaged in more negative affective matching with their mothers than other infants. Although effect sizes were small, cocaine exposure, especially heavy cocaine exposure, was associated with subtly negative interchanges, which may have a cumulative impact on infants' later development and their relationships with their mothers.     

Maternal sensitivity moderates the impact of prenatal anxiety disorder on infant responses to the still-face procedure

Animal studies have demonstrated the interactive effects of prenatal stress exposure and postnatal rearing style on offspring capacity to manage stress. However, little is known about how parenting quality impacts the association between maternal prenatal anxiety and stress reactivity in human infants. This prospective study examined the impact of prenatal anxiety disorder and maternal caregiving sensitivity on infants’ responses to a standardised interactive stressor (still-face procedure). Eighty-four women completed a clinical interview during pregnancy to assess anxiety symptoms meeting DSM-IV diagnostic criteria. At infant age 7 months, maternal sensitivity to infant distress and infant negative affect were observed and coded during the still-face procedure. Maternal postnatal (concurrent) anxiety and depression were also assessed at this time. Results indicated a negative association between maternal sensitivity to infant distress and infant negative affect responses to the still-face procedure. An unexpected finding was a positive association between parity and infant reactivity. The main effect for sensitivity was qualified by a significant interaction, p < .05, suggesting that the impact of sensitivity was particularly marked among infants of women who experienced an anxiety disorder during pregnancy. This finding is consistent with a cumulative risk model suggesting that maternal prenatal anxiety and quality of maternal care act in concert to shape infant outcomes.     

Robust patterns and individual variations: Stability and predictors of infant behavior in the still-face paradigm

In the present study we examined key issues regarding infant behavior in the still-face paradigm (SFP) in terms of individual variations, stability, and predictors. The sample consisted of 115 mothers and infants, with assessments at ages 3 and 6 months, including observations of maternal and infant behavior in the SFP, and parent reports of infant temperament. Both robust patterns and individual variations in infant SFP behaviors were found, with only a minority of infants showing the expected patterns for negative affect and gaze. Infant behavior patterns showed no stability from age 3 to 6 months, and infant gaze was related to more pronounced behavior changes across the SFP. Maternal sensitivity in the SFP baseline was related to some aspects of infant SFP behavior. Consistent with the differential susceptibility hypothesis, in infants with a more difficult temperament maternal sensitivity predicted a more pronounced expected pattern of changes in infant positive affect across the SFP, whereas this was not the case for infants with a more easy temperament.     

Individual differences in non-clinical maternal depression impact infant affect and behavior during the still-face paradigm across the first year

Maternal depression can significantly impact mothers’ sensitivity to their infants’ needs as well as infants’ social and emotional development. The still-face paradigm (SFP) is widely used to assess infants’ understanding of the contingency between their own behavior and that of their caregivers, as well as infants’ ability to self-regulate arousal levels during sudden changes in maternal responsiveness. Infants of clinically depressed mothers display blunted levels of negative affect compared to infants of non-depressed mothers during the still-face (SF) phase. However, little is known about whether individual differences in elevated, non-clinical levels of maternal depression similarly affect mother-infant interactions. The current study examines the longitudinal effects of non-clinical maternal depression on infant and maternal behaviors during the SFP. Infants (N = 63) were assessed at 5 and 9 months and maternal depression was assessed at 5 months using the Beck Depression Inventory (BDI). Infants of mothers with elevated levels of depression displayed less negative engagement during the SF phase compared to infants of mothers with lower levels of depression. This effect was present at 5 months, but not at 9 months. Findings demonstrate that non-clinical levels of maternal depressive symptomatology can have a significant impact on infants’ affective regulation during the first half of the first year of life, but this does not necessarily have a long-lasting influence later in infancy. Interventions may want to target mothers with non-clinical depression to promote healthy infant social and emotional development.     

Associations between mother-infant bed-sharing practices and infant affect and behavior during the still-face paradigm

Parents in the United States increasingly report bed-sharing with their infants (i.e., sleeping on a shared sleep surface), but the relationship between bed-sharing and child socioemotional outcomes are not well understood. The current study examines the links between mother-infant bed-sharing at 3 months and infant affect and behavior during a dyadic challenge task at 6 months. Further, we examine nighttime mother-infant contact at 3 months as a possible mechanism that may mediate linkages between bed-sharing and infant outcomes. Using observational data from a sample of 63 mother-infant dyads, we found that infants who bed-shared for any proportion of the observation period at 3 months displayed significantly more self-regulatory behaviors during the still-face episode of the Still-Face Paradigm (SFP) at 6 months, compared to non-bed-sharing infants. Also, infants of mothers who bed-shared for the entire observation period displayed significantly less negativity during the reunion episode than non-bed-sharing infants. There was no evidence that the relations between mother-infant bed-sharing practices and infant affect and behavior during the SFP were mediated through nighttime mother-infant contact. Results suggest that infant regulation at 6 months postpartum may vary based on early nighttime experiences, with bed-sharing potentially promoting more positive and well-regulated behavior during dyadic interaction.     

Mothers who are securely attached in pregnancy show more attuned infant mirroring 7 months postpartum

This study contrasted two forms of mother–infant mirroring: the mother's imitation of the infant's facial, gestural, or vocal behavior (i.e., “direct mirroring”) and the mother's ostensive verbalization of the infant's internal state, marked as distinct from the infant's own experience (i.e., “intention mirroring”). Fifty mothers completed the Adult Attachment Interview (Dynamic Maturational Model) during the third trimester of pregnancy. Mothers returned with their infants 7 months postpartum and completed a modified still-face procedure. While direct mirroring did not distinguish between secure and insecure/dismissing mothers, secure mothers were observed to engage in intention mirroring more than twice as frequently as did insecure/dismissing mothers. Infants of the two mother groups also demonstrated differences, with infants of secure mothers directing their attention toward their mothers at a higher frequency than did infants of insecure/dismissing mothers. The findings underscore marked and ostensive verbalization as a distinguishing feature of secure mothers’ well-attuned, affect-mirroring communication with their infants.