Anger and Positive Reactivity in Infancy: Effects on Maternal Report of Surgency and Attention Focusing in Early Childhood

We examined two aspects of temperamental approach in early infancy, positive reactivity and anger, and their unique and combined influences on maternal reports of child surgency and attention focusing at 4 years of age. One hundred and fourteen infants were observed for their positive reactions to novel stimuli at 4 months, and their anger expressions during arm restraint at 9 months. Child surgency and attention focusing at age 4 years were assessed by maternal report. Infants who expressed more anger to restraint were rated higher in surgency during early childhood relative to infants who expressed less anger. The effects of positive reactivity to novelty on attention focusing were moderated by anger to restraint. These findings suggest that infant temperamental approach tendencies are multifaceted and have both unique and combined influences on later maternal report of attention and social behavior.     

Anger and Approach Motivation in Infancy: Relations to Early Childhood Inhibitory Control and Behavior Problems

The relations among infant anger reactivity, approach behavior, and frontal electroencephalogram (EEG) asymmetry, and their relations to inhibitory control and behavior problems in early childhood were examined within the context of a longitudinal study of temperament. Two hundred nine infants’ anger expressions to arm restraint were observed at 4 months of age. Infants’ approach behaviors during play with an unpredictable toy and baseline frontal EEG asymmetry were assessed at 9 months of age. Inhibitory control during a Go/No‐Go task and parent report of behavior problems were evaluated at 4 years of age. High anger‐prone infants with left, but not right, frontal EEG asymmetry showed significantly more approach behaviors and less inhibitory control relative to less anger‐prone infants. Although a link between anger proneness in infancy and behavior problems in early childhood was not found, a combination of low approach behaviors and poor inhibitory control was predictive of internalizing behaviors.     

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.     

Crawling Experience Predicts Avoidance of Real Cliffs and Water Cliffs: Insights from a New Paradigm

This study examined the influence of age, crawling‐onset age, and crawling experience on infants’ adaptive behavior in situations that can lead to dangerous falls. Thirty‐one infants with variable amounts of crawling experience were tested in a new paradigm that used a real cliff and a water cliff, with a harness system to guarantee safety. Consistent with previous findings obtained in studies with real and visual cliffs, infants with more crawling experience were more likely to avoid the real cliff. More importantly, greater crawling experience was associated with a greater likelihood of avoiding the water cliff. The new paradigm offers exciting opportunities to study the development of adaptive behavior in risky environments.     

Does Brief Bradycardia at the Onset of Arm‐Restraint Predict Infants’ Emotional Reactivity During Restraint?

Using electrocardiogram data with 78 six‐month‐old infants, this study examined the presence or absence of brief orienting bradycardia during the onset of maternal arm‐restraint and subsequent differences between infants on behavioral organization during restraint. Results showed that 45 of the infants exhibited brief episodes of bradycardia at the onset of arm‐restraint. Group comparisons showed infants exhibiting bradycardia to have greater emotional reactivity during the arm‐restraint protocol, which included a shorter latency to cry, decreased orientation toward mother, increased escape attempts during restraint, greater intensity of crying, and longer duration of crying than non‐bradycardiac infants. These findings suggest that bradycardia at the outset of a mild perturbation episode may signal infants’ attention to the emotional content of novel dyadic interactions and the disruption of expectancies in ongoing interactions, leading them to become distressed more quickly, turn their attention away from mom, and attempt to escape the restraint with greater vigor.     

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.     

Crawling is Associated with Mental Rotation Ability by 9‐Month‐Old Infants

The present experiment examined whether 9‐month‐old infants’ mental rotation ability was related to their crawling ability. Forty‐eight 9‐month‐old infants were tested; half of them crawled for 7.1 weeks on average. Infants were habituated to a video of a simplified Shepard–Metzler object rotating back and forth through a 240° angle around the longitudinal axis of the object. Infants were tested with videos of the same object rotating through the previously unseen 120° angle and with the mirror image of that display. The results showed that the crawlers looked significantly longer at the mirror object than at the familiar object. The results support the interpretation that crawling experience is associated with 9‐month‐old infants’ mental rotation ability.     

The Trajectory of Concurrent Motor and Vocal Behaviors Over the Transition to Crawling in Infancy

To document the trajectory of motor and vocal behaviors in real and developmental time, we observed infants at each of four biweekly naturalistic play sessions over the transition to crawling. An exhaustive and mutually exclusive coding scheme documented all vocalizations and postures. Odds ratios of the likelihood of a given posture‐vocalization dyad revealed that vocalization and crawling were significantly unlikely to co‐occur at the session marking the onset of crawling. We speculate that infants’ allocation of attention over the transition to crawling prompted behavioral trade‐offs. During mastery of a novel skill, infants may have had difficulty allocating attention to multiple tasks, but with experience, a decrease in attentional load for the new skill allowed performance of simultaneous behaviors in other domains to occur.     

Relations of Early Goal Blockage Response and Gender to Subsequent Tantrum Behavior

Infants and their mothers participated in a longitudinal study of the sequelae of infant goal blockage responses. Four-month-old infants participated in a standard contingency learning/goal blockage procedure during which anger and sad facial expressions to the blockage were coded. When infants were 12- and 20- months-old, mothers completed a questionnaire about their children's tantrums. Tantrum scores increased with age and boys tended to show more tantrum behavior than girls. Anger expressed to goal blockage at 4 months was unrelated to tantrum behavior. There was a gender by sad expression interaction. Girls who expressed sadness in response to the goal blockage had lower total tantrum scores than boys; otherwise there was no difference. These results suggest that tantrums of infants who display sad, not anger expression, in response to goal blockage, are differentially influenced by children's gender.     

Seven-months-old infants show increased arousal to static emotion body expressions: Evidence from pupil dilation

Human body postures provide perceptual cues that can be used to discriminate and recognize emotions. It was previously found that 7-months-olds’ fixation patterns discriminated fear from other emotion body expressions but it is not clear whether they also process the emotional content of those expressions. The emotional content of visual stimuli can increase arousal level resulting in pupil dilations. To provide evidence that infants also process the emotional content of expressions, we analyzed variations in pupil in response to emotion stimuli. Forty-eight 7-months-old infants viewed adult body postures expressing anger, fear, happiness and neutral expressions, while their pupil size was measured. There was a significant emotion effect between 1040 and 1640 ms after image onset, when fear elicited larger pupil dilations than neutral expressions. A similar trend was found for anger expressions. Our results suggest that infants have increased arousal to negative-valence body expressions. Thus, in combination with previous fixation results, the pupil data show that infants as young as 7-months can perceptually discriminate static body expressions and process the emotional content of those expressions. The results extend information about infant processing of emotion expressions conveyed through other means (e.g., faces).     

The Intensity of Emotional Facial Expressions and Decoding Accuracy

The influence of the physical intensity of emotional facial expressions on perceived intensity and emotion category decoding accuracy was assessed for expressions of anger, disgust, sadness, and happiness. The facial expressions of two men and two women posing each of the four emotions were used as stimuli. Six different levels of intensity of expression were created for each pose using a graphics morphing program. Twelve men and 12 women rated each of the 96 stimuli for perceived intensity of the underlying emotion and for the qualitative nature of the emotion expressed. The results revealed that perceived intensity varied linearly with the manipulated physical intensity of the expression. Emotion category decoding accuracy varied largely linearly with the manipulated physical intensity of the expression for expressions of anger, disgust, and sadness. For the happiness expressions only, the findings were consistent with a categorical judgment process. Sex of encoder produced significant effects for both dependent measures. These effects remained even after possible gender differences in encoding were controlled for, suggesting a perceptual bias on the part of the decoders.     

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).     

A Comparative Study of Arm‐Restraint Methodology: Differential Effects of Mother and Stranger Restrainers on Infants' Distress Reactivity at 6 and 9 Months of Age

This study examined both differential patterns and the stability of infants' (N = 70) distress reactivity across mother and stranger arm‐restraint conditions when infants were 6 and 9 months of age. Reactivity measures included observational variables for the rise, intensity, and duration of infant distress as well as motor activities associated with escape behaviors. Correlation analyses revealed that infant behaviors during arm restraint were modestly stable across conditions and over time; however, mean comparisons also showed that infants' distress responses appear to be sensitive to protocol parameters (whether restrainer is mother or stranger). At 6 months of age, infants cried more during maternal restraint than with strangers and exhibited escape behaviors more frequently with mothers. Findings further indicate that infants' distress reactivity undergoes developmental alterations from 6 to 9 months of age, with infants crying more quickly, reaching peak intensity of distress faster, and displaying more distress at 9 months compared to 6 months. These changes in infants' reactivity were particularly accentuated during maternal compared to stranger restraint conditions at 9 months of age.     

Experienced crawlers avoid real and water drop-offs,even when they are walking

Crawling experience was recently linked to crawling and walking infants’ avoidance of falling on real and water cliffs, whereas walking experience had no effect on walkers’ avoidance behavior (Burnay et al., 2021). In the current study, the behavior of 25 infants was analyzed on the Real Cliff/Water Cliff apparatus using a longitudinal study design. Infants were tested as experienced crawlers (M_crawling = 2.93 months, SD = 1.07), novice walkers (M_walking = 0.68 months, SD = 0.29), and experienced walkers (M_walking = 4.90 months, SD = 0.92). Infants avoided falling on both cliffs when tested as experienced crawlers and their behavior was not different when tested as novice or experienced walkers. These findings confirmed the effect of crawling experience on crawling and walking infants’ avoidance of falls from heights and into water and the transfer of perceptual learning from crawling to walking postures.     

Gender Differences in Emotion Expression in Low-Income Adolescents Under Stress

Gender roles in mainstream US culture suggest that girls express more happiness, sadness, anxiety, and shame/embarrassment than boys, while boys express more anger and externalizing emotions, such as contempt. However, gender roles and emotion expression may be different in low-income and ethnically diverse families, as children and parents are often faced with greater environmental stressors and may have different gender expectations. This study examined gender differences in emotion expression in low-income adolescents, an understudied population. One hundred and seventy nine adolescents (aged 14–17) participated in the Trier Social Stress Test (TSST). Trained coders rated adolescents’ expressions of happiness, sadness, anxiety, shame/embarrassment, anger, and contempt during the TSST using a micro-analytic coding system. Analyses showed that, consistent with gender roles, girls expressed higher levels of happiness and shame than boys; however, contrary to traditional gender roles, girls showed higher levels of contempt than boys. Also, in contrast to cultural stereotypes, there were no differences in anger between boys and girls. Findings suggest gender-role inconsistent displays of externalizing emotions in low-income adolescents under acute stress, and may reflect different emotion socialization experiences in this group.     

Development of the Movements Impressions Emotions Model: Evaluation of Movements and Impressions Related to the Perception of Emotions in Dance

The purpose of this study is to specify the characteristics that contribute to the perception of emotions expressed through dance movements and to develop an emotional model to show the relationships between impressions and the characteristics of expressive body movements. Six dancers expressed three different emotions through dance: joy, sadness, and anger. Observers (N = 192) rated both their impressions (33 dimensions) and the dance movements (26 characteristics) of 18 dance performances. The results showed that the observers could accurately perceive the emotional meanings expressed in the dances. The impressions of Dynamics, Expansion, and Stability—and the evaluated movements of Frequency and Velocity of Upward Extension, Frequency and Velocity of Downward Movements, Turning or Jumping, and Body Closing—were extracted via factor analysis as determinants of observers’ impressions of emotional expressions in dance. Additionally, covariance structure analysis and discriminant function analysis indicated that the emotional expressions of the dances expressing joy, sadness, and anger are each associated with particular factors. Through these analyses, we developed the Movements Impressions Emotions Model for dance.     

Crawling Predicts Infants’ Understanding of Agents’ Navigation of Obstacles

We investigated whether crawling versus noncrawling infants interpret an agent's movements around an obstacle as goal‐directed. Infants (6–9 months) were habituated to a self‐propelled circle jumping over an obstacle to reach a goal. When the obstacle was removed, infants who crawled (n = 13) showed longer looking time to the familiar but now nonrational jumping path versus a novel but rational straight‐line path. Noncrawlers (n = 17) did not discriminate. Looking preference was independent of age and speed of habituation. These findings support the claim that infants’ processing of agency emerges early and applies to all agents, but stress the role of experience in the development of action interpretation.     

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

Research examining infants’ discrimination of affect often uses unfamiliar faces and voices of adults. Recently, research has examined infant discrimination of affect in familiar faces and voices. In much of this research, infants were habituated to the affective expressions using a “standard” 50% habituation criterion. We extend this line of research by examining infants’ discrimination of unfamiliar peers’, that is, 4‐month‐olds, dynamic, facial, and vocal affective expressions and assessing how discrimination is affected by changing the habituation criterion. In two experiments, using an infant‐controlled habituation design, we explored 3‐ and 5‐month‐olds’ discrimination of their peers’ dynamic audiovisual displays of positive and negative expressions of affect. Results of Experiment 1, using a 50% habituation criterion, revealed that 5‐month‐olds, but not 3‐month‐olds discriminated the affective expressions of their peers. In Experiment 2, we examined whether 3‐month‐olds’ lack of discrimination in Experiment 1 was a result of insufficient habituation (i.e., familiarization). Specifically, 3‐month‐olds were habituated using a 70% habituation criterion, providing them with longer familiarization time. Results revealed that using the more stringent habituation criterion, 3‐month‐olds showed longer habituation times, that is increased familiarization, and discriminated their peers’ affective expressions. Results are discussed in terms of infants’ discrimination of affect, the role of familiarization time, and limitations of the 50% habituation criterion.     

Effects of Contingent Reinforcement of Actions on Infants' Object‐Directed Reaching

The role of contingency learning was examined in 3‐month‐old infants' reaching movements. Infants in the experimental group experienced 9 min of active training during which they could move their arms in a reach‐like fashion to pull and move a mobile. Infants in the control group experienced 9 min of passive training during which they watched a mobile move. Prior to (pre‐training) and following the mobile experience (post‐training), infants in both conditions were given an opportunity to interact with a rattle placed within and out of their reach. Compared with infants in the control condition, infants in the experimental condition produced reach‐like movements more frequently during the mobile experience; they also showed a greater increase in reaching attempts from pre‐ to post‐training assessments with the rattle. These findings show that reinforcement of arm extensions and retractions increases the frequency of infants' reaching behaviors. This result suggests that the reinforcement of components of infants' behaviors may contribute to the successful assembly of these behaviors. This process could help keep infants engaged during the lengthy transition from prereaching to independent reaching.     

The Organization of Wariness of Heights in Experienced Crawlers

Most infants with more than 6 weeks of crawling experience completely avoid the deep side of a visual cliff ( Campos, Bertenthal, & Kermoian, 1992 ; Gibson & Walk, 1960 ). However, some experienced crawlers do move onto the transparent surface suspended several feet above the ground. An important question is whether these nonavoiders lack wariness of heights or whether they have a qualitatively different way of showing their wariness than do avoiders of the deep side. The current study addressed this question by measuring heart rate (HR) acceleration upon being lowered on the deep and shallow sides of the visual cliff, latency to crawl toward the mother, and tactile exploration of the cliff surface. Nonavoiders and avoiders had indistinguishable patterns of HR acceleration, showing greater HR acceleration when lowered onto the deep than when lowered onto the shallow side of the cliff. Nonavoiders also showed more tactile exploration and longer latencies than did a comparable group of infants tested on the shallow side. This study illustrates how the same emotion, wariness of heights, can be shown by qualitatively different behaviors, all serving the same function of protecting the individual from falling over a drop‐off.