Infants Discriminate the Affective Expressions of their Peers: The Roles of Age and Familiarization Time

Effects of conflicting emotional cues on toddlers' emotion perception

The communication of emotion is dynamic and occurs across multiple channels, such as facial expression and tone of voice. When cues are in conflict, interpreting emotion can become challenging. Here, we examined the effects of incongruent emotional cues on toddlers' interpretation of emotions. We presented 33 children (22-26 months, Mage = 23.8 months, 15 female) with side-by-side images of faces along with sentences spoken in a tone of voice that conflicted with semantic content. One of the two faces matched the emotional tone of the audio, whereas the other matched the semantic content. For both congruent and incongruent trials, toddlers showed no overall looking preference to either type of face stimuli. However, during the second exposure to the sentences of incongruent trials, older children tended to look longer to the face matching semantic content when listening to happy vs. angry content. Results inform our understanding of the early development of complex emotion understanding.

Somatovisceral influences on emotional development

Frameworks of emotional development have tended to focus on how environmental factors shape children's emotion understanding. However, individual experiences of emotion represent a complex interplay between both external environmental inputs and internal somatovisceral signaling. Here, we discuss the importance of afferent signals and coordination between central and peripheral mechanisms in affective response processing. We propose that incorporating somatovisceral theories of emotions into frameworks of emotional development can inform how children understand emotions in themselves and others. We highlight promising directions for future research on emotional development incorporating this perspective, namely afferent cardiac processing and interoception, immune activation, physiological synchrony, and social touch.

Face Processing in Early Development: A Systematic Review of Behavioral Studies and Considerations in Times of COVID-19 Pandemic

Human faces are one of the most prominent stimuli in the visual environment of young infants and convey critical information for the development of social cognition. During the COVID-19 pandemic, mask wearing has become a common practice outside the home environment. With masks covering nose and mouth regions, the facial cues available to the infant are impoverished. The impact of these changes on development is unknown but is critical to debates around mask mandates in early childhood settings. As infants grow, they increasingly interact with a broader range of familiar and unfamiliar people outside the home; in these settings, mask wearing could possibly influence social development. In order to generate hypotheses about the effects of mask wearing on infant social development, in the present work, we systematically review N = 129 studies selected based on the most recent PRISMA guidelines providing a state-of-the-art framework of behavioral studies investigating face processing in early infancy. We focused on identifying sensitive periods during which being exposed to specific facial features or to the entire face configuration has been found to be important for the development of perceptive and socio-communicative skills. For perceptive skills, infants gradually learn to analyze the eyes or the gaze direction within the context of the entire face configuration. This contributes to identity recognition as well as emotional expression discrimination. For socio-communicative skills, direct gaze and emotional facial expressions are crucial for attention engagement while eye-gaze cuing is important for joint attention. Moreover, attention to the mouth is particularly relevant for speech learning. We discuss possible implications of the exposure to masked faces for developmental needs and functions. Providing groundwork for further research, we encourage the investigation of the consequences of mask wearing for infants' perceptive and socio-communicative development, suggesting new directions within the research field.

Rule learning transfer across linguistic and visual modalities in 7-month-old infants

Rule learning (RL) refers to infants' ability to extract high-order, repetition-based rules from a sequence of elements and to generalize them to new items. RL has been demonstrated in both the auditory and the visual modality, but no studies have investigated infants' transfer of learning across these two modalities, a process that is fundamental for the development of many complex cognitive skills. Using a visual habituation procedure within a cross-modal RL task, we tested 7-month-old infants' transfer of learning both from speech to vision (auditory-visual-AV-condition) and from vision to speech (visual-auditory-VA-condition). Results showed a transfer of learning in the AV condition, but only for those infants who were able to efficiently extract the rule during the learning (habituation) phase. In contrast, in the VA condition infants provided no evidence of RL. Overall, this study indicates that 7-month-old infants can transfers high-order rules across modalities with an advantage for transferring from speech to vision, and that this ability is constrained by infants' individual differences in the way they process the to-be-learned rules.

Infants' learning of non-adjacent regularities from visual sequences

Tracking adjacent (AD) and non-adjacent (NAD) dependencies in a sequence of elements is critical for the development of many complex abilities, such as language acquisition and social interaction. While learning of AD in infancy is a domain-general ability that is functioning across different domains, infants' processing of NAD has been reported only for speech sequences. Here, we tested 9- to 12- and 13- to 15-month-olds' ability to extract AxB grammars in visual sequences of unfamiliar elements. Infants were habituated to a series of 3-visual arrays following an AxB grammar in which the first element (A) predicted the third element (B), while intervening X elements changed continuously. Following habituation, infants were tested with 3-item arrays in which initial and final positions were switched (novel) or kept consistent with the habituation phase (familiar). Older infants successfully recognized the familiar AxB grammar at test, whereas the younger group showed some sensitivity to extract to NAD, albeit in a less robust form. This finding provides the first evidence that the ability to track NAD is a domain-general ability that is present also in the visual domain and that the sensitivity to such dependencies is related to developmental changes, as demonstrated in the auditory domain.

Emotional facial expressions affect visual rule learning in 7- to 8-month-old infants

Rule learning (RL) is an implicit learning mechanism that allows infants to detect and generalize rule-like repetition-based patterns (such as ABB and ABA) from a sequence of elements. Increasing evidence shows that RL operates both in the auditory and the visual domain and is modulated by the perceptual expertise with the to-be-learned stimuli. Yet, whether infants' ability to detect a high-order rule from a sequence of stimuli is affected by affective information remains a largely unexplored issue. Using a visual habituation paradigm, we investigated whether the presence of emotional expressions with a positive and a negative value (i.e., happiness and anger) modulates 7- to 8-month-old infants' ability to learn a rule-like pattern from a sequence of faces of different identities. Results demonstrate that emotional facial expressions (either positive and negative) modulate infants' visual RL mechanism, even though positive and negative facial expressions affect infants' RL in a different manner: while anger disrupts infants' ability to learn the rule-like pattern from a face sequence, in the presence of a happy face infants show a familiarity preference, thus maintaining their learning ability. These findings show that emotional expressions exert an influence on infants' RL abilities, contributing to the investigation on how emotion and cognition interact in face processing during infancy.

Do Preverbal Infants Understand Discrete Facial Expressions of Emotion?

An ongoing debate in affective science concerns whether certain discrete, “basic” emotions have evolutionarily based signals (facial expressions) that are easily, universally, and (perhaps) innately identified. Studies with preverbal infants (younger than 24 months) have the potential to shed light on this debate. This review summarizes what is known about preverbal infants’ understanding of discrete emotional facial expressions. Overall, while many studies suggest that preverbal infants differentiate positive and negative facial expressions, few studies have tested whether infants understand discrete emotions (e.g., anger vs. disgust). Moreover, results vary greatly based on methodological factors. This review also (a) discusses how language may influence the development of emotion understanding, and (b) proposes a new developmental hypothesis for infants’ discrete emotion understanding.