The Relationship between Crawling and Emotion Discrimination in 9- to 10-Month-Old Infants.

The present study examined whether infants' crawling experience is related to their sensitivity to fearful emotional expressions. Twenty-nine 9- to 10-month-old infants were tested in a preferential looking task, in which they were presented with different pairs of animated faces on a screen displaying a 100% happy facial expression and morphed facial expressions containing varying degrees of fear and happiness. Regardless of their crawling experiences, all infants looked longer at more fearful faces. Additionally, infants with at least 6 weeks of crawling experience needed lower levels of fearfulness in the morphs in order to detect a change from a happy to a fearful face compared to those with less crawling experience. Thus, the crawling experience seems to increase infants' sensitivity to fearfulness in faces.

Developmental Changes in Gaze Behavior and the Effects of Auditory Emotion Word Priming in Emotional Face Categorization.

Social interactions often require the simultaneous processing of emotions from facial expressions and speech. However, the development of the gaze behavior used for emotion recognition, and the effects of speech perception on the visual encoding of facial expressions is less understood. We therefore conducted a word-primed face categorization experiment, where participants from multiple age groups (six-year-olds, 12-year-olds, and adults) categorized target facial expressions as positive or negative after priming with valence-congruent or -incongruent auditory emotion words, or no words at all. We recorded our participants' gaze behavior during this task using an eye-tracker, and analyzed the data with respect to the fixation time toward the eyes and mouth regions of faces, as well as the time until participants made the first fixation within those regions (time to first fixation, TTFF). We found that the six-year-olds showed significantly higher accuracy in categorizing congruently primed faces compared to the other conditions. The six-year-olds also showed faster response times, shorter total fixation durations, and faster TTFF measures in all primed trials, regardless of congruency, as compared to unprimed trials. We also found that while adults looked first, and longer, at the eyes as compared to the mouth regions of target faces, children did not exhibit this gaze behavior. Our results thus indicate that young children are more sensitive than adults or older children to auditory emotion word primes during the perception of emotional faces, and that the distribution of gaze across the regions of the face changes significantly from childhood to adulthood.

A Multimodal Comparison of Emotion Categorization Abilities in Children With Developmental Language Disorder.

Purpose Current research has demonstrated that behavioral, emotional, and/or social difficulties often accompany developmental language disorder (DLD). It is an open question to what degrees such difficulties arise as consequence of impaired language and communicative skills, or whether they might also be driven by deficits in verbal and nonverbal emotion processing (e.g., the reduced ability to infer and verbalize emotional states from facial expressions). Regarding the existence of nonverbal deficits, previous research has yielded inconsistent findings. This study was aimed at gaining deeper knowledge of the basic aspects of emotion understanding in children with DLD by comparing their performance on nonverbal and verbal emotion categorization tasks to that of typically developing children. Method Two verbal tasks (Lexical Decision and Valence Decision With Emotion Terms) and two nonverbal tasks (Face Decision and Valence Decision With Facial Expressions) were designed to parallel each other as much as possible, and conducted with twenty-six 6- to 10-year-old children diagnosed with DLD. The same number of typically developed children, carefully matched by age and gender, served as a control group. Results The children with DLD showed lower performance in both verbal tasks and exhibited noticeable problems in the nonverbal emotion processing task. In particular, they achieved lower accuracy scores when they categorized faces by their valence (positive or negative), but did not differ in their ability to distinguish these faces from pictures displaying animals. Conclusions This study provides evidence for the hypothesis that problems in emotion processing in children with DLD might be multimodal. Therefore, the results support the idea of mutual influences in the development of language and emotion skills and contribute to the current debate about the domain specificity of DLD (formerly referred to as specific language impairment).

The Role of Emotional Valence for the Processing of Facial and Verbal Stimuli-Positivity or Negativity Bias?

Emotional valence is predominately conveyed in social interactions by words and facial expressions. The existence of broad biases which favor more efficient processing of positive or negative emotions is still a controversial matter. While so far this question has been investigated separately for each modality, in this narrative review of the literature we focus on valence effects in processing both words and facial expressions. In order to identify the factors underlying positivity and negativity effects, and to uncover whether these effects depend on modality and age, we present and analyze three representative overviews of the literature concerning valence effects in word processing, face processing, and combinations of word and face processing. Our analysis of word processing studies points to a positivity bias or a balanced processing of positive and negative words, whereas the analysis of face processing studies showed the existence of separate positivity and negativity biases depending on the experimental paradigm. The mixed results seem to be a product of the different methods and types of stimuli being used. Interestingly, we found that children exhibit a clear positivity advantage for both word and face processing, indicating similar processing biases in both modalities. Over the course of development, the initial positivity advantage gradually disappears, and in some face processing studies even reverses into a negativity bias. We therefore conclude that there is a need for future research that systematically analyses the impact of age and modality on the emergence of these valence effects. Finally, we discuss possible explanations for the presence of the early positivity advantage and its subsequent decrease.

Investigating the Effects of Embodiment on Emotional Categorization of Faces and Words in Children and Adults.

The facial feedback hypothesis (FFH) indicates that besides being involved in the production of facial expressions, the musculature of the face also influences one's perception of emotional stimuli. Recently, this effect has been the focus of increased scrutiny as efforts to replicate a key study with adult participants supporting this hypothesis, using the so-called "pen-in-the-mouth" task, have not been successful at several labs. Our series of experiments attempted to investigate whether the assumed embodiment effect can be reproduced in a simplified emotional categorization task for emotional faces and words. We also wanted to test whether the embodiment effect can be detected in children because it is assumed that their bodily processes are especially closely linked with their sensory and cognitive processes. Our experiments involved child and adult participants categorizing faces and words as positive or negative as quickly as possible, while inducing a positive or negative facial or bodily state (holding a straw in the mouth such that a smile or a frown was generated, or creating a positive or negative body posture). The positive or negative facial and bodily states could therefore be either congruent or incongruent with the valence of the target face and word stimuli. Our results did not show any significant differences between the congruent and incongruent conditions in either children or adults. This suggests that embodiment effects either do not significantly impact valence-based categorization or are not strong enough to be detected by our approach considering the sample size in the present study.

Developmental changes in the categorical processing of positive and negative facial expressions.

Categorical biases in the processing of emotional facial expression have been the subject of much debate in the literature. Opposing views on this topic claim either that positive or negative facial expressions enjoy improved processing in the human brain. The developmental changes in the processing advantages of positive and negative facial expressions are also disputed, with studies using varying paradigms showing seemingly contradictory results. Therefore, to further investigate the development of categorical processing and extraction of emotional information from faces, we tested 6-, 9-, and 12-year-old children, as well as adults, on their ability to categorize various facial expressions as positive or negative as quickly as possible. This was a simplified paradigm designed to explicitly contrast the processing efficiency of positive and negative facial expressions on the broader level of those emotional valence categories, rather than specific single emotional expressions. Our results show an early age processing advantage for positive facial expressions, which disappears in adults who show no such differences in the case of response time measures. In the case of accuracy measures, the early advantage for positive facial expressions gradually disappears and is reversed into a negativity advantage in adults. These findings demonstrate that category-based positive and negative processing advantages are strongly modulated by age over the course of development, and can exhibit opposite effects depending on the developmental stage of the participant.

Auditory Emotion Word Primes Influence Emotional Face Categorization in Children and Adults, but Not Vice Versa.

In order to assess how the perception of audible speech and facial expressions influence one another for the perception of emotions, and how this influence might change over the course of development, we conducted two cross-modal priming experiments with three age groups of children (6-, 9-, and 12-years old), as well as college-aged adults. In Experiment 1, 74 children and 24 adult participants were tasked with categorizing photographs of emotional faces as positive or negative as quickly as possible after being primed with emotion words presented via audio in valence-congruent and valence-incongruent trials. In Experiment 2, 67 children and 24 adult participants carried out a similar categorization task, but with faces acting as visual primes, and emotion words acting as auditory targets. The results of Experiment 1 showed that participants made more errors when categorizing positive faces primed by negative words versus positive words, and that 6-year-old children are particularly sensitive to positive word primes, giving faster correct responses regardless of target valence. Meanwhile, the results of Experiment 2 did not show any congruency effects for priming by facial expressions. Thus, audible emotion words seem to exert an influence on the emotional categorization of faces, while faces do not seem to influence the categorization of emotion words in a significant way.

Age-Dependent Positivity-Bias in Children's Processing of Emotion Terms.

Emotions play an important role in human communication, and the daily-life interactions of young children often include situations that require the verbalization of emotional states with verbal means, e.g., with emotion terms. Through them, one can express own emotional states and those of others. Thus, the acquisition of emotion terms allows children to participate more intensively in social contexts - a basic requirement for learning new words and for elaborating socio-emotional skills. However, little is known about how children acquire and process this specific word category, which is positioned between concrete and abstract words. In particular, the influence of valence on emotion word processing during childhood has not been sufficiently investigated. Previous research points to an advantage of positive words over negative and neutral words in word processing. While previous studies found valence effects to be influenced by factors such as arousal, frequency, concreteness, and task, it is still unclear if and how valence effects are also modified by age. The present study compares the performance of children aged from 5 to 12 years and adults in two experimental tasks: lexical decision (word or pseudoword) and emotional categorization (positive or negative). Stimuli consisted of 48 German emotion terms (24 positive and 24 negative) matched for arousal, concreteness, age of acquisition, word class, word length, morphological complexity, frequency, and neighborhood density. Results from both tasks reveal two developmental trends: First, with increasing age children responded faster and more correctly, suggesting that emotion vocabulary gradually becomes more stable and differentiated during middle childhood. Second, the influence of valence varied with age: younger children (5- and 6-year-olds) showed significantly higher performance levels for positive emotion terms compared to negative emotion terms, whereas older children and adults did not. This age-related valence effect in emotion word processing will be discussed with respect to linguistic and methodological aspects.