Interpreting infant emotional expressions: Parenthood has differential effects on men and women

Neither Parents' Sex Nor the Type of Family Modulates Attentional Bias Toward Infant Faces: A Preliminary Study in Different-Sex and Same-Sex Parents

An attentional bias toward infant versus adult faces has been detected in parents and positively associated with sensitive caregiving behaviors. In previous research, the attentional bias has been measured as the difference in attention, in terms of reaction times, captured by infant versus adult faces; the larger the difference, the greater the cognitive engagement that adults deployed to infant faces. However, research so far has been mostly confined to samples of mothers, who have been more represented than fathers. Moreover, new family forms, especially same-sex families of men, have been left out of research. To clarify potential sex differences and extend previous findings to diverse family forms, we implemented a modified Go/no-Go attentional task measuring attentional bias to infant faces in parents with children aged from 2 to 36 months. The sample (N = 86) was matched and included 22 fathers and 22 mothers from different-sex families and 20 fathers and 22 mothers from same-sex families. Overall, the results confirmed that infant faces induced a greater attentional bias compared to adult faces. Moreover, we found that neither the type of family nor parents' sex modulated the attentional bias toward infant faces. The findings are discussed in relation to the importance of understanding the correlates of parental response to infant cues going beyond a heteronormative perspective on parenting.

Attentional Prioritization of Infant Faces in Parents: The Influence of Parents' Experiences of Care

Infant faces are prioritized by the attentional system in parents, resulting in a greater cognitive engagement in terms of response time. However, many biological, contextual and environmental factors relating to this cognitive mechanism have been left unexplored. To fill this gap, this study aims to (i) confirm that infant faces engage more attention compared to adult faces; (ii) investigate whether the attention to infant faces is affected early care experiences of parents; (iii) explore the effect of parents' sex by taking the amount of involvement with early childcare into consideration. 51 mothers and 46 fathers completed a modified Go/no-Go task, a brief sociodemographic questionnaire, the short version of the Adult Parental Acceptance-Rejection scale, and an ad-hoc question relating to the amount of parental involvement with early childcare. Parents' response times were slowed in the presence of infant versus adult faces. Parents whose mother was perceived as more sensitively accepting were more engaged by infant cues. By considering the amount of early parental involvement, the sex of parents did not significantly interact with the type of face. These findings provide new insights on the attention process in response to infant cues in parents and suggest that the investigation of experience-based factors may shed further light on this topic.

Motherhood and theory of mind: increased activation in the posterior cingulate cortex and insulae

Despite growing evidence on effects of parenthood on social understanding, little is known about the influence of parenthood on theory of mind (ToM), the capacity to infer mental and affective states of others. It is also unclear whether any possible effects of parenthood on ToM would generalise to inferring states of adults or are specific to children. We investigated neural activation in mothers and women without children while they predicted action intentions from child and adult faces. Region-of-interest analyses showed stronger activation in mothers in the bilateral posterior cingulate cortex, precuneus (ToM-related areas) and insulae (emotion-related areas). Whole-brain analyses revealed that mothers compared to non-mothers more strongly activated areas including the left angular gyrus and the ventral prefrontal cortex but less strongly activated the right supramarginal gyrus and the dorsal prefrontal cortex. These differences were not specific to child stimuli but occurred in response to both adult and child stimuli and might indicate that mothers and non-mothers employ different strategies to infer action intentions from affective faces. Whether these general differences in affective ToM between mothers and non-mothers are due to biological or experience-related changes should be subject of further investigation.

Processing children's faces in the parental brain: A meta-analysis of ERP studies

Event-related potentials (ERPs) are an excellent tool for investigating parental neural responses to child stimuli. Using meta-analysis, we quantified the results of available studies reporting N170 or LPP/P3 ERP responses to children's faces, targeting three questions: 1) Do parents and non-parents differ in ERP responses to child faces? 2) Are parental ERP responses larger to own vs. unfamiliar child faces? 3) Are parental ERP responses to child faces associated with indicators of parenting quality, such as observed parental sensitivity? Across 23 studies (N = 1035), key findings showed 1) larger N170 amplitudes to child faces in parents than in non-parents (r = 0.19), 2) larger LPP/P3 responses to own vs. unfamiliar child faces in parents (r = 0.19), and 3) positive associations between parental LPP/P3 responses to child faces and parenting quality outcomes (r = 0.15). These results encourage further research particularly with the LPP/P3 to assess attentional-motivational processes of parenting, but also highlight the need for larger samples and more systematic assessments of associations between ERPs and parenting.

Family dynamics. An exploration of parental sensitivity and depressive symptoms among mothers and fathers of toddlers

In studies of maternal sensitivity, the influence of mothers’ depressive symptomatology has been consistently highlighted. Additionally, the relevance of both maternal and paternal sensitive responses to children’s development has been recognized. However, literature regarding the dynamics of the mother-father-toddler triad is scarce. This is particularly true when understanding how parental sensitivity may be bidirectionally shaped by both parents’ (i.e., mothers’ and fathers’ depressive symptomatology) and children’s characteristics (i.e., age). Hence, the present study aims to describe and analyse the associations between parental depression, paternal sensitivity and children’s socioemotional difficulties and age with mothers’ sensitive responses to highlight the appropriateness of considering fathers’ depressive symptoms and sensitivity to better understand the impact of maternal depressive symptomatology on mothers’ sensitivity. The participants included 80 Chilean mother-father-child triads in which all children were between 1 and 3 years of age and presented some degree of socioemotional difficulty. The results reveal no differences in maternal and paternal sensitivity or higher depressive symptomatology in mothers than in fathers. Additionally, while mothers’ depression was significantly associated with their sensitivity, this was not the case for fathers. Paternal depressive symptomatology was associated with the mother’s depression. Finally, paternal sensitivity emerged as a mediator between maternal depressive symptoms and sensitivity. This result calls attention to the use of paternal variables to understand how maternal depression impacts mothers’ sensitivity and to thus develop appropriate interventions that expand the scope of such impacts from the dyad to the triad.

Increased activation in the bilateral anterior insulae in response to others in pain in mothers compared to non-mothers

Empathy allows us to share emotions and encourages us to help others. It is especially important in the context of parenting where children's wellbeing is dependent on their parents' understanding and fulfilment of their needs. To date, little is known about differences in empathy responses of parents and non-parents. Using stimuli depicting adults and children in pain, this study focuses on the interaction of motherhood and neural responses in areas associated with empathy. Mothers showed higher activation to both adults and children in pain in the bilateral anterior insulae, key regions of empathy for pain. Additionally, mothers more strongly activated the inferior frontal, superior temporal and the medial superior frontal gyrus. Differences between adult and child stimuli were only found in occipital areas in both mothers and non-mothers. Our results suggest a stronger neural response to others in pain in mothers than non-mothers regardless of whether the person is a child or an adult. This could indicate a possible influence of motherhood on overall neural responses to others in pain rather than motherhood specifically shaping child-related responses. Alternatively, stronger responses to others in pain could increase the likelihood for women to be in a relationship and subsequently to have a child.

Neurocognitive processing of infant stimuli in mothers and non-mothers: psychophysiological, cognitive and neuroimaging evidence

Emerging evidence indicates that mothers and non-mothers show different neurocognitive responses to infant stimuli. This study investigated mothers' psychophysiological, cognitive and neuronal responses to emotional infant stimuli. A total of 35 mothers with 4-month-old infants and 18 control women without young children underwent computerized tests assessing neurocognitive processing of infant stimuli. Their eye gazes and eye fixations, galvanic skin responses (GSRs) and facial expressions towards infant emotional stimuli were recorded during the tasks. Participants underwent functional magnetic resonance imaging during which they viewed pictures of an unknown infant and, for mothers, their own infants. Mothers gazed more and had increased GSR towards infant stimuli and displayed more positive facial expressions to infant laughter, and self-reported more positive ratings of infant vocalizations than control women. At a neural level, mothers showed greater neural response in insula, dorsolateral prefrontal cortex and occipital brain regions within a predefined 'maternal neural network' while watching images of their own vs unknown infants. This specific neural response to own infants correlated with less negative ratings of own vs unknown infants' signals of distress. Differences between mothers and control women without young children could be interpreted as neurocognitive adaptation to motherhood in the mothers.

Adults' responses to infant faces: Neutral infant facial expressions elicit the strongest baby schema effect

The effect of the babyface schema includes three typical responses, namely, the preference response, viewing motivation, and attention bias towards infant faces. It has been theorised that these responses are primarily influenced by infants' facial structures. However, recent studies have revealed the moderating role of facial expression, suggesting that the strongest effect of the babyface schema may be related to the neutral facial expression; this hypothesis remains to be tested. In this study, the moderating role of facial expression was assessed in three successive experiments (total N = 402). We used a series of images of the same face with multiple expression-standardised images of infants and adults to control for facial structure. The results indicated that the effect sizes of the babyface schema (i.e., response differences between infants and adults) were different for multiple expressions of the same face. Specifically, the effect sizes of neutral faces were significantly greater than those of happy and sad faces according to the preference response (experiment 1, N = 90), viewing motivation (experiment 2, N = 214), and attentional bias (experiment 3, N = 98). These results empirically confirm that neutral infant facial expressions elicit the strongest effect of the babyface schema under the condition of using adult faces as a comparison baseline and matching multiple expressions of the same face.

It takes two! Exploring sex differences in parenting neurobiology and behaviour

Parents lay the foundation for their children's socio-emotional experiences by sensitively responding to their needs. The hormonal and neurobiological changes that occur during the transition to parenthood importantly contribute to the parents' caregiving behaviour toward their children. Much research has emphasised the relationship between the mother, who is most often the primary caregiver, and her infant, with less focus on the role of fathers in child development. However, recent accounts have suggested that fathers also play an important role in promoting the health, development and psychosocial wellbeing of their children. Evidence from the behavioural literature has indicated that there are significant differences between typical mother-infant versus father-infant interactions. The current review aims to outline differences between maternal and paternal caregiving by discussing the differences in their biological mechanisms. First, we focus on the different hormones that are correlated with sensitive parenting behaviours in mothers and fathers. Next, we discuss the differences between neural bases of motherhood and fatherhood. Lastly, we discuss ways in which parental hormones, parental brain and parental exposure to infant cues interact to shape parental caregiving behaviour. In summary, this review highlights the distinct but complementary nature of maternal and paternal caregiving.

Differential Effects of Infant Vocalizations on Approach-Avoidance Postural Movements in Mothers

Infant vocalization plays a pivotal role in communicating infant mood to parents and thereby motivating parenting responses. Although many psychological and neural responses to infant vocalization have been reported, few studies have examined maternal approach-avoidance behavior in response to infant vocalization. Thus, this research sought to determine how infant emotional vocalization affects maternal behavior. Twenty mothers participated in this behavioral study, all of whom had infants of 24 months old or less. In the experiment, they stood on a Balance Board that collected real-time data regarding center of pressure (COP), while listening to a series of infant vocalizations including cry, laugh, and babbling. They then listened to the same vocalizations for a second time and rated their felt emotions in response to each vocalization. The participants demonstrated significant postural movements of approaching in response to cry stimuli or to stimuli regarded as highly urgent. In contrast, they demonstrated postural movement of avoidance in response to laugh vocalization. These findings suggest that parenting behavior in response to infant emotional vocalization is regulated not by the pleasant-unpleasant axis but by the urgency of the stimulus.

Subjective ratings and emotional recognition of children's facial expressions from the CAFE set

Access to validated stimuli depicting children's facial expressions is useful for different research domains (e.g., developmental, cognitive or social psychology). Yet, such databases are scarce in comparison to others portraying adult models, and validation procedures are typically restricted to emotional recognition accuracy. This work presents subjective ratings for a sub-set of 283 photographs selected from the Child Affective Facial Expression set (CAFE [1]). Extending beyond the original emotion recognition accuracy norms [2], our main goal was to validate this database across eight subjective dimensions related to the model (e.g., attractiveness, familiarity) or the specific facial expression (e.g., intensity, genuineness), using a sample from a different nationality (N = 450 Portuguese participants). We also assessed emotion recognition (forced-choice task with seven options: anger, disgust, fear, happiness, sadness, surprise and neutral). Overall results show that most photographs were rated as highly clear, genuine and intense facial expressions. The models were rated as both moderately familiar and likely to belong to the in-group, obtaining high attractiveness and arousal ratings. Results also showed that, similarly to the original study, the facial expressions were accurately recognized. Normative and raw data are available as supplementary material at https://osf.io/mjqfx/.

Maternal nurturing experience affects the perception and recognition of adult and infant facial expressions

The perception and recognition of facial expressions are crucial for parenting. This study investigated whether and how maternal nurturing experience and trait anxiety influence the perception and recognition of infant and adult facial expressions. This was assessed by comparing the performance of primiparous mothers (n = 25) and non-mothers (n = 28) on an emotional face perception task. Trait anxiety was measured using the Japanese version of the State-Trait Anxiety Inventory (STAI). We found that mothers had higher recognition accuracy for facial expressions, but only of adults, not infants. Moreover, as trait anxiety increased, so did mothers’ sensitivity in perceiving facial expressions of both infants and adults. These findings suggest that maternal nurturing experience does enhance the recognition of adult emotional expressions, and an optimal level of maternal trait anxiety may enhance mothers’ sensitivity toward infants’ and adults’ emotional signals.

The Tromso Infant Faces Database (TIF): Development, Validation and Application to Assess Parenting Experience on Clarity and Intensity Ratings

Newborns and infants are highly depending on successfully communicating their needs; e.g., through crying and facial expressions. Although there is a growing interest in the mechanisms of and possible influences on the recognition of facial expressions in infants, heretofore there exists no validated database of emotional infant faces. In the present article we introduce a standardized and freely available face database containing Caucasian infant face images from 18 infants 4 to 12 months old. The development and validation of the Tromsø Infant Faces (TIF) database is presented in Study 1. Over 700 adults categorized the photographs by seven emotion categories (happy, sad, disgusted, angry, afraid, surprised, neutral) and rated intensity, clarity and their valance. In order to examine the relevance of TIF, we then present its first application in Study 2, investigating differences in emotion recognition across different stages of parenthood. We found a small gender effect in terms of women giving higher intensity and clarity ratings than men. Moreover, parents of young children rated the images as clearer than all the other groups, and parents rated "neutral" expressions as more clearly and more intense. Our results suggest that caretaking experience provides an implicit advantage in the processing of emotional expressions in infant faces, especially for the more difficult, ambiguous expressions.

On Cuteness: Unlocking the Parental Brain and Beyond

Cuteness in offspring is a potent protective mechanism that ensures survival for otherwise completely dependent infants. Previous research has linked cuteness to early ethological ideas of a 'Kindchenschema' (infant schema) where infant facial features serve as 'innate releasing mechanisms' for instinctual caregiving behaviours. We propose extending the concept of cuteness beyond visual features to include positive infant sounds and smells. Evidence from behavioural and neuroimaging studies links this extended concept of cuteness to simple 'instinctual' behaviours and to caregiving, protection, and complex emotions. We review how cuteness supports key parental capacities by igniting fast privileged neural activity followed by slower processing in large brain networks also involved in play, empathy, and perhaps even higher-order moral emotions.