2-Year-olds' free play during the COVID-19 pandemic.

Free play is a natural activity in toddlerhood, depending on environmental conditions like available objects and the social environment. The COVID-19 pandemic and its consequences for parents' mental health held the potential to change toddlers' play environment. This cross-sectional study investigated 2-year-olds' (N = 97) free play with objects, and aspects of caregiver mental well-being in three cohorts during the pandemic in Germany. Caregivers reported their positive mental health (PMH), threat perception, perception of current family situation from negative to positive, and workload. We categorized toddlers' behavior in free play sessions in their homes with a fixed set of objects through behavioral coding. Play behavior did not differ between cohorts and did not correlate with caregivers' positive mental health, threat perception, and perception of family situation. A MANOVA revealed a significant main effect of cohort on PMH, threat perception and perception of family situation, qualified by two discriminant functions. Full sample analyses revealed that toddlers of caregivers perceiving a workload increase compared to the time before the pandemic showed less pretend play, and less functional and nonfunctional play. The results provide insights into 2-year-olds' play behavior during a global pandemic and highlight the role of caregiver availability for children's play.

Sleep-dependent memory consolidation of televised content in infants.

Infants face the constant challenge of selecting information for encoding and storage from a continuous incoming stream of data. Sleep might help in this process by selectively consolidating new memory traces that are likely to be of future relevance. Using a deferred imitation paradigm and an experimental design, we asked whether 15- and 24-month-old infants (N = 105) who slept soon after encoding a televised demonstration of target actions would show higher imitation scores (retention) after a 24-h delay than same-aged infants who stayed awake for ≥4 h after encoding. In light of infants' well-known difficulties in learning and remembering information from screens, we tested if increasing the relevance of the televised content via standardised caregiver verbalisations might yield the highest imitation scores in the sleep condition. Regardless of sleep condition, 24-month-olds exhibited retention of target actions while 15-month-olds consistently failed to do so. For 24-month-olds, temporal recall was facilitated by sleep, but not by parental verbalisations. Correlational analyses revealed that more time asleep within 4 h after encoding was associated with better retention of the target actions and their temporal order in 24-months-olds. These results suggest that sleep facilitates memory consolidation of screen-based content in late infancy and that this effect might not hinge on caregivers' verbal engagement during viewing.

The effect of picture book reading on young children's use of an emotion regulation strategy.

Picture book reading is an enjoyable everyday activity for many young children with well-known benefits for language development. The present study investigated whether picture book reading can support young children's social-emotional development by providing a learning opportunity for the usage of emotion regulation strategies. Three-year-old children participated in two waiting situations designed to elicit negative affect. Between these waiting situations they read a picture book. In two experimental conditions, the book depicted how a protagonist (same-aged peer or young adult, respectively) waited for a desired object and distracted herself with toys while waiting. Children in an additional control condition read a picture book that was unrelated to waiting. Use of distraction did not differ between conditions. Parents often read picture book interactively with their children. Therefore, in an additional condition (Exp. 2), the experimenter read the picture book featuring the same-aged peer protagonist in an interactive way intended to facilitate transfer. Apart from the reading style, the design was identical to experiment 1. Experiment 2 intended to test whether changes in reading style lead to differences in three-year old children's social-emotional learning from picture books. When controlling for the children's picture book experience, children in the experimental conditions exhibited an increase in distraction in contrast to children in the control condition. In sum, results suggest that picture book reading could be an ecologically valid and versatile method for supporting 3-year-old children in their use of an age-appropriate adaptive emotion regulation strategies such as distraction.

Stress affects the prediction of others' behavior.

Predicting behavior of other people is vital for successful social interactions. We tested whether a stress-induced cortisol increase affects healthy young men's prediction of another individual's behavior. Forty-two participants were randomly assigned to a stress or to a control condition. Afterwards, they participated in a modified false-belief task that not only tests false-belief understanding but also the tendency to predict another person's future behavior based on his former behavior. Subjective ratings and salivary cortisol concentrations revealed a successful stress induction. Stress did not affect participants' attribution of false beliefs but it increased the probability to predict that a protagonist would act according to his former behavior. Recognizing that stress fosters the interpretation of others' behavior following their former behavior and not their current goals extends previous research showing that stress fosters our own habitual behavior.

A matter of habit? Stressful life events and cognitive flexibility in 15-month-olds.

Exposure to chronic stress is associated with habitual learning in adults. We studied the origins of this association by examining the link between stressful life events and infant cognitive flexibility. The final sample consisted of N = 72 fifteen-month-old infants and their mothers. Mothers completed a survey on pre- and postnatal negative life events. To assess chronic stress physiologically, infant and maternal hair cortisol concentrations were determined for cortisol accumulation during the past 3 months. Each infant participated in two cognitive tasks in the laboratory. An instrumental learning task tested infants' ability to disengage from a habituated action when this action became ineffective (Seehagen et al., 2015). An age-adequate version of the A-not-B task tested infants' ability to find a toy at location B after repeatedly finding it at location A. Correlations between cortisol concentrations and postnatal negative life events (number, perceived impact) did not yield significance. Infant and maternal hair cortisol concentrations were not correlated. Infants' ability to shift to a new action in either task, controlled for acute stress, correlated neither with pre- and postnatal negative life events nor with cortisol concentrations. Taken together, these results indicate that the potential link between long-term stress exposure and cognitive flexibility might not be present in samples with low levels of psychosocial stress.

Infant carrying is associated with reduced maternal repetitive negative thinking and increased maternal mental health.

INTRODUCTION: Mental disorders, such as postnatal depression, are common in mothers. Repetitive negative thinking has been identified as a cognitive factor underlying the resulting difficulties in mother-infant interactions. METHOD: The present online survey investigated associations between infant carrying (baby-wearing) and maternal repetitive negative thinking and positive mental health. RESULTS: Repetitive negative thinking was significantly lower, and positive mental health was significantly higher while carrying compared to overall levels. There were no relations between maternal mental health and frequency of carrying. Maternal activities during carrying are portrayed. CONCLUSION: These results are the first indication that carrying could be a low threshold, easily administered intervention method for maternal mental health problems.

The influence of group membership on false-belief attribution in preschool children.

The ability to infer beliefs and thoughts in interaction partners is essential in social life. However, reasoning about other people's beliefs might depend on their characteristics or our relationship with them. Recent studies indicated that children's false-belief attribution was influenced by a protagonist's age and competence. In the current experiments, we investigated whether group membership influences the way children reason about another person's beliefs. We hypothesized that 4-year-olds would be less likely to attribute false beliefs to an ingroup member than to an outgroup member. Group membership was manipulated by accent (Experiments 1-3) and gender (Experiment 4). The results indicated that group membership did not consistently influence children's false-belief attribution. Future research should clarify whether the influence of group membership on false-belief attribution either is absent or depends on other cues that we did not systematically manipulate in our study.

Computer-based mother-infant interaction analysis and mental functioning in postpartum depression.

BACKGROUND: Among mothers suffering from postpartum depression (PD), 10-13% additionally experience a mother-infant interaction disturbance that causes a severe mental health risk for the infant. Besides depressive symptomology, the underlying factors promoting dysfunctional maternal interaction behavior have not yet been sufficiently investigated. Therefore, we examined potential relationships between computer-based mother-infant interaction among postpartum depressed dyads and maternal mental functioning. METHODS: Mother-infant interaction was video-recorded and evaluated via a computer-based micro-interaction analysis program (INTERACT). We included only 25 hospitalized mother-infant dyads that fulfilled the diagnostic criteria of PD and tested mothers on their mental functioning (empathy, theory of mind, meta-cognition and alexithymia). RESULTS: Behavioral interaction analyses indicated that mothers with PD were prone to inactive maternal behavior, less positive maternal behavior along with more rejective behavior and also disengaged affect towards the infant. Distortions in mothers' mental functioning may have had an influence on the dysfunctional patterns of mother-infant dyads. CONCLUSIONS: Cognitive and social functioning could be an influencing factor on dysfunctional maternal interaction behavior. Early detection of distortions of mental processing in expectant mothers might help to inhibit the clinical manifestation of dysfunctional mother-infant bonding and negative child outcome in PD.

Capacities for meta-cognition, social cognition, and alexithymia in postpartum depression.

Postpartum depression (PPD), a female-specific disorder, is the most common medical complication associated with childbirth (10-20%). The pathological relevance of emotion processing, meta-cognition, alexithymia, and social cognition to PPD is unclear. We tested 25 mothers with PPD (mean age: 30.72 ± 5.76 years) and 25 healthy mothers (mean age: 32.03 ± 3.54 years) for alexithymia (Toronto Alexithymia Scale) and evaluated cognitive empathy (Faux Pas Test), affective empathy (Interpersonal Reactivity Index), meta-cognition (Meta-Cognitions Questionnaire), sociodemographic and clinical-psychometric characteristics and personality dimensions. Mothers with PPD showed higher levels of neuroticism and more anxiety-depressive characteristics. Their metacognitive abilities were significantly altered and they more often had alexithymia. Significant correlations between alexithymia and meta-cognition, trait anxiety, and neuroticism were found. Alexithymia, neurotic personality traits, and dysfunctional meta-cognition appear more frequently in PPD women than healthy women. Social cognition abilities were not significantly altered. Alexithymia and metacognitive distortions play important roles in the pathogenesis of PPD. Dysfunctional meta-cognition, neuroticism, and alexithymia may be risk factors that should be detected early in expectant mothers to prevent the development of PPD.

The role of prior sleep for divergent thinking in infants.

Higher-order cognitive functions seem particularly vulnerable to disruptions in prior sleep in school-aged children and adult populations. This study tested whether divergent thinking in infants varied as a function of prior sleep. Forty-three infants aged 13-16 months participated in a behavioural assessment of divergent thinking. Length of wakefulness since last sleep was experimentally manipulated. In addition, potential relations between divergent thinking and sleep quantity and quality during the night immediately before the assessment, as well as during three consecutive nights preceding the assessment, were examined using actigraphy recordings in combination with parent diaries. Divergent thinking was not impaired by lack of sleep within the previous 4 h. Divergent thinking was consistently related to night-time sleep quality and quantity prior to the assessment. These results suggest that timing of prior naturally occurring daytime sleep is less relevant for emergent divergent thinking capacity than quality and quantity of preceding night-time sleep.

Can you teach me not to be angry? Relations between temperament and the emotion regulation strategy distraction in 2-year-olds.

Little is known about toddlers' acquisition of specific emotion regulation (ER) strategies, and how early ER is shaped by temperament. This study investigated if 24-month-old German toddlers, predominantly from families with high levels of parental education (N = 96, n = 49 male), learned the ER strategy distraction through observational learning, and its interaction with temperament. Increased use of distraction correlated with reduced negative affect. Use of distraction increased through observational learning. Highly active toddlers tended to use active playing activities to distract themselves in a frustrating situation, whereas toddlers with a less active temperament used calmer activities. Toddlers' learning to apply distraction through observational learning was independent of a match between their own temperament and the model's actions.

Prior sleep timing and visual recognition of emotional faces in 6-month-old infants.

Face recognition is an important mnemonic ability for infants when navigating the social world. While age-related changes in face processing abilities are relatively well documented, less is known about short-term intra-individual fluctuations in this ability. Given that sleep deprivation in adults leads to impairments in information processing, we assessed the role of prior sleep on 6-month-old infants' (N = 17) visual recognition of faces showing three emotional expressions (neutral, sad, angry). Visual recognition was inferred by assessing novelty preferences for unfamiliar relative to familiarized faces in a visual recognition memory paradigm. In a within-subject design, infants participated once after they had recently woken up from a nap (nap condition) and once after they had been awake for an extended period of time (awake condition). Infants failed to show visual recognition for the neutral faces in either condition. Infants showed recognition for the sad and angry faces when tested in the awake condition, but not in the nap condition. This suggests that timing of prior sleep shapes how effectively infants process emotionally relevant information in their environment.

The effect of napping and nighttime sleep on memory in infants.

During the first year of life, infants devote the majority of their time to sleep. Research in adults has shown that sleep supports a variety of memory processes. Surprisingly, sleep's function for infant memory has only started to receive attention in research. In this chapter, we will describe age-related changes in sleep and in memory processing over the first years of life, as well as methods to capture both sleep and memory. Then, we will review current findings on the effects of sleep on memory processing in infants. Lastly, we will also point out gaps in current knowledge and describe potential avenues for future research. Overall, the results of recent experimental studies provide evidence that timely, extended napping is involved in how memories are encoded and stored in the long-term and contribute to the formation of knowledge networks in infants.

State-Dependent Memory in Infants.

Why do infants remember some things and not others? Human infants frequently cycle through different states such as calm attentiveness, wakeful activity, and crying. Given that cognitive processes do not occur in isolation, such fluctuations in internal state might influence memory processing. In the present experiment, declarative memory in 9-month-old infants (N = 96) was heavily state dependent. Infants exhibited excellent retention of a deferred imitation task after a 15-min delay if their state at encoding was identical to their state at retrieval (e.g., calm). Infants failed to exhibit retention if their state at encoding was different from their state at retrieval (e.g., calm vs. animated). Infant memory processing depends on internal cues.

A New 3-Day Standardized Eyeblink Conditioning Protocol to Assess Extinction Learning From Infancy to Adulthood.

Associative learning can be observed from the neonatal period onward, providing opportunities to examine changes in basic learning and memory abilities. One method that is suitable to study associative learning is classical eyeblink conditioning (EBC) which is dependent on the cerebellum. Extinction learning can be systematically investigated in this paradigm by varying the context during learning and extinction. Because of methodological difficulties and ethical challenges, no studies have compared extinction learning using EBC across human development. Our goal was to test feasibility of a 3-day delay EBC paradigm that can be used from infancy to adulthood. Acceptance/safety was tested especially for infancy by investigating attrition rates and parental report on infant wellbeing. On a paradigm side, we tested if the paradigm leads to successful acquisition and extinction. An air puff served as unconditional stimulus (US) and a tone as conditional stimulus (CS). On day 1 during acquisition, participants received 36 US-CS pairings in context A. On day 2, participants received 12 acquisition trials in context A to consolidate association learning, followed by 48 extinction trials (tone alone presentations) in context B. Renewal was assessed on day 3 and incorporated 12 CS alone trials presented in both the acquisition context and the extinction context. Eyeblink responses were videotaped and coded offline. The protocol was tested with 12-36-months-old infants (N = 72), adolescents (N = 8), and adults (N = 8). Concerning the acceptance/safety side, attrition ranged from 21 to 58% in infant samples due to the complex preparation of the children for the paradigm. However, attrition is equal to or lower than other infant learning paradigms. Parents of infant samples were very interested in the paradigm and reported low levels of infant stress, exhaustion, and negative feelings during the sessions. Data quality was very high, and no participant had to be excluded because of insufficient data. Concerning the paradigm side, participants showed successful acquisition and extinction as a group. The procedure is ethically sound, feasible, tolerated by many infants, and acceptable among parents. The data show successful acquisition and extinction rates, making the paradigm a valuable tool for investigating developmental changes in extinction learning over the lifespan.

Wait and See: Observational Learning of Distraction as an Emotion Regulation Strategy in 22-Month-Old Toddlers.

Emotion regulation strategies have been linked to the development of mental disorders. In this experiment, we investigated if imitation is an effective way of learning to increase the usage of the emotion regulation strategy 'distraction' for 22-month-old toddlers. Toddlers in two experimental conditions participated in two waiting situations intended to elicit frustration, with a modeling situation between the first and the second waiting situation. In the modeling situation, toddlers observed how either a familiar model (parent) or an unfamiliar model (experimenter) demonstrated the use of distraction as a strategy to cope with a frustrating situation. Toddlers in an additional age-matched control condition did not witness any modeling between the two waiting situations. Analyses revealed that toddlers in both experimental conditions combined distracted themselves more in the second waiting situation than did toddlers in the control condition. There were no differences with regard to the familiarity of the model. These results suggest that providing structured observational learning situations may be a useful way to teach toddlers about the use of specific emotion regulation strategies.

Sleep-dependent selective imitation in infants.

In adults, sleep selectively consolidates those memories that are relevant for future events. The present study tested whether napping after encoding plays a role in selective memory consolidation in infants. Infants aged 15 and 24 months (n = 48 per age) were randomly assigned to a nap or a no-nap demonstration condition, or a baseline control condition. In the demonstration conditions, infants observed an experimenter perform an irrelevant action followed by a relevant action to achieve a desirable outcome on four different toys. Infant imitation of irrelevant and relevant actions was coded at a test session that occurred after a 24-hr delay. The demonstration and test sessions were scheduled around infants' naturally occurring sleeping patterns. When order of actions was not taken into account, infants in both demonstration conditions exhibited retention of the relevant and irrelevant target actions. Contrary to expectations, infants in the nap condition did not perform the relevant action only more often than infants in the no-nap condition. As expected, only infants in the no-nap condition faithfully reproduced the two actions in the demonstrated order: irrelevant action first, followed by the relevant action. Thus, sleep might help infants to selectively "discard" aspects of a learning experience that they identify as being not useful or relevant in the future.

The course of maternal repetitive negative thinking at the transition to motherhood and early mother-infant interactions: Is there a link?

Potential long-term associations between repetitive negative thinking and mother-infant interactions have received little attention. The current longitudinal study including N = 62 mother-infant dyads investigated both maternal and infant behavior in face-to-face interactions as a function of pre- and postnatal maternal repetitive negative thinking when infants were aged around 4 months. We hypothesised that mothers with a strong tendency to engage in repetitive negative thinking would react less contingently to their infants' behavior compared to mothers with a weak tendency to engage in repetitive negative thinking. Furthermore, we hypothesised that infants of mothers high in repetitive negative thinking would differ from infants of mothers low in repetitive negative thinking in their reactions in the still-face task. Contrary to expectations, there was no difference in maternal contingency between mothers high versus low in repetitive negative thinking. However, infant behavior in the still-face task differed as a function of maternal repetitive negative thinking status. Specifically, infants of mothers high in repetitive negative thinking spent more time with object/environment engagement than infants of mothers who were low in repetitive negative thinking, and they also protested less frequently. These findings are discussed in terms of their relevance for the intergenerational transmission of mental disorders.

Overrated adults: 4-year-olds' false belief understanding is influenced by the believer's age.

Children perceive adults as more knowledgeable than peers. We tested whether this general preconception influences preschoolers' performance in a false-belief task. Children (4- and 5-year-olds; N = 146) watched videos showing a peer protagonist or an adult protagonist experiencing events that should lead the protagonist to hold a false belief. Then children were asked to infer the protagonist's perception of the situation. Age of the protagonist influenced 4-year-olds' judgments but not 5-year-olds' judgments. Specifically, 4-year-olds' performance was at chance when presented with a peer protagonist. Their performance dropped further when presented with an adult protagonist and was significantly below chance. Children aged around 5 years performed above chance level regardless of whether they were presented with an adult or peer protagonist. This suggests that in the younger age group, children's tendency to regard adults as experts in general knowledge undermined their ability to accurately judge the possibility that an adult could hold a false belief.

"Should I or shouldn't I?" Imitation of undesired versus allowed actions from peer and adult models by 18- and 24-month-old toddlers.

Imitation is a common way of acquiring novel behaviors in toddlers. However, little is known about toddlers' imitation of undesired actions. Here we investigated 18- and 24-month-olds' (N=110) imitation of undesired and allowed actions from televised peer and adult models. Permissiveness of the demonstrated actions was indicated by the experimenter's response to their execution (angry or neutral). Analyses revealed that toddlers' imitation scores were higher after demonstrations of allowed versus undesired actions, regardless of the age of the model. In agreement with prior research, these results suggest that third-party reactions to a model's actions can be a powerful cue for toddlers to engage in or refrain from imitation. In the context of the present study, third-party reactions were more influential on imitation than the model's age. Considering the relative influence of different social cues for imitation can help to gain a fuller understanding of early observational learning.