Leader-follower dynamics during early social interactions matter for infant word learning.

We know little about the mechanisms through which leader-follower dynamics during dyadic play shape infants' language acquisition. We hypothesized that infants' decisions to visually explore a specific object signal focal increases in endogenous attention, and that when caregivers respond to these proactive behaviors by naming the object it boosts infants' word learning. To examine this, we invited caregivers and their 14-mo-old infants to play with novel objects, before testing infants' retention of the novel object-label mappings.

The Role of Talking Faces in Infant Language Learning: Mind the Gap between Screen-Based Settings and Real-Life Communicative Interactions.

Over the last few decades, developmental (psycho) linguists have demonstrated that perceiving talking faces audio-visually is important for early language acquisition. Using mostly well-controlled and screen-based laboratory approaches, this line of research has shown that paying attention to talking faces is likely to be one of the powerful strategies infants use to learn their native(s) language(s). In this review, we combine evidence from these screen-based studies with another line of research that has studied how infants learn novel words and deploy their visual attention during naturalistic play.

Proactive or reactive? Neural oscillatory insight into the leader-follower dynamics of early infant-caregiver interaction.

We know that infants' ability to coordinate attention with others toward the end of the first year is fundamental to language acquisition and social cognition. Yet, we understand little about the neural and cognitive mechanisms driving infant attention in shared interaction: do infants play a proactive role in creating episodes of joint attention? Recording electroencephalography (EEG) from 12-mo-old infants while they engaged in table-top play with their caregiver, we examined the communicative behaviors and neural activity preceding and following infant- vs. adult-led joint attention.

Vocal communication is tied to interpersonal arousal coupling in caregiver-infant dyads.

It has been argued that a necessary condition for the emergence of speech in humans is the ability to vocalise irrespective of underlying affective states, but when and how this happens during development remains unclear. To examine this, we used wearable microphones and autonomic sensors to collect multimodal naturalistic datasets from 12-month-olds and their caregivers. We observed that, across the day, clusters of vocalisations occur during elevated infant and caregiver arousal.

Curiosity as a metacognitive feeling.

Curious information-seeking is known to be a key driver for learning, but characterizing this important psychological phenomenon remains a challenge. In this article, we argue that solving this challenge requires qualifying the relationships between metacognition and curiosity. The idea that curiosity is a metacognitive competence has been resisted: researchers have assumed both that young children and non-human animals can be genuinely curious, and that metacognition requires conceptual and culturally situated resources that are unavailable to young children and non-human animals.

Two-Year-Olds' Eye Movements Reflect Confidence in Their Understanding of Words.

We studied the fundamental issue of whether children evaluate the reliability of their language interpretation, that is, their confidence in understanding words. In two experiments, 2-year-olds (Experiment 1: = 50; Experiment 2: = 60) saw two objects and heard one of them being named; both objects were then hidden behind screens and children were asked to look toward the named object, which was eventually revealed. When children knew the label used, they showed increased postdecision persistence after a correct compared with an incorrect anticipatory look, a marker of confidence in word comprehension (Experiment 1).

Studying the Developing Brain in Real-World Contexts: Moving From Castles in the Air to Castles on the Ground.

Most current research in cognitive neuroscience uses standardized non-ecological experiments to study the developing brain. But these approaches do a poor job of mimicking the real-world, and thus can only provide a distorted picture of how cognitive operations and brain development unfold outside of the lab. Here we consider future research avenues which may lead to a better appreciation of how developing brains dynamically interact with a complex real-world environment, and how cognition develops over time.

Cdc42-Specific GTPase-Activating Protein Rga1 Squelches Crosstalk between the High-Osmolarity Glycerol (HOG) and Mating Pheromone Response MAPK Pathways.

Eukaryotes utilize distinct mitogen/messenger-activated protein kinase (MAPK) pathways to evoke appropriate responses when confronted with different stimuli. In yeast, hyperosmotic stress activates MAPK Hog1, whereas mating pheromones activate MAPK Fus3 (and MAPK Kss1). Because these pathways share several upstream components, including the small guanosine-5'-triphosphate phosphohydrolase (GTPase) cell-division-cycle-42 (Cdc42), mechanisms must exist to prevent inadvertent cross-pathway activation.

Knowing How You Know: Toddlers Reevaluate Words Learned From an Unreliable Speaker.

There has been little investigation of the way source monitoring, the ability to track the source of one's knowledge, may be involved in lexical acquisition. In two experiments, we tested whether toddlers (mean age 30 months) can monitor the source of their lexical knowledge and reevaluate their implicit belief about a word mapping when this source is proven to be unreliable. Experiment 1 replicated previous research (Koenig & Woodward, 2010): children displayed better performance in a word learning test when they learned words from a speaker who has previously revealed themself as reliable (correctly labeling familiar objects) as opposed to an unreliable labeler (incorrectly labeling familiar objects).

Distinct signatures of subjective confidence and objective accuracy in speech prosody.

Whether speech prosody truly and naturally reflects a speaker's subjective confidence, rather than other dimensions such as objective accuracy, is unclear. Here, using a new approach combing psychophysics with acoustic analysis and automatic classification of verbal reports, we tease apart the contributions of sensory evidence, accuracy, and subjective confidence to speech prosody. We find that subjective confidence and objective accuracy are distinctly reflected in the loudness, duration and intonation of verbal reports.

Listeners' perceptions of the certainty and honesty of a speaker are associated with a common prosodic signature.

The success of human cooperation crucially depends on mechanisms enabling individuals to detect unreliability in their conspecifics. Yet, how such epistemic vigilance is achieved from naturalistic sensory inputs remains unclear. Here we show that listeners' perceptions of the certainty and honesty of other speakers from their speech are based on a common prosodic signature.

Emergent Shared Intentions Support Coordination During Collective Musical Improvisations.

Human interactions are often improvised rather than scripted, which suggests that efficient coordination can emerge even when collective plans are largely underspecified. One possibility is that such forms of coordination primarily rely on mutual influences between interactive partners, and on perception-action couplings such as entrainment or mimicry. Yet some forms of improvised joint actions appear difficult to explain solely by appealing to these emergent mechanisms.

Vocal signals only impact speakers' own emotions when they are self-attributed.

Emotions are often accompanied by vocalizations whose acoustic features provide information about the physiological state of the speaker. Here, we ask if perceiving these affective signals in one's own voice has an impact on one's own emotional state, and if it is necessary to identify these signals as self-originated for the emotional effect to occur. Participants had to deliberate out loud about how they would feel in various familiar emotional scenarios, while we covertly manipulated their voices in order to make them sound happy or sad.

Musical coordination in a large group without plans nor leaders.

A widespread belief is that large groups engaged in joint actions that require a high level of flexibility are unable to coordinate without the introduction of additional resources such as shared plans or hierarchical organizations. Here, we put this belief to a test, by empirically investigating coordination within a large group of 16 musicians performing collective free improvisation-a genre in which improvisers aim at creating music that is as complex and unprecedented as possible without relying on shared plans or on an external conductor. We show that musicians freely improvising within a large ensemble can achieve significant levels of coordination, both at the level of their musical actions (i.

CLEESE: An open-source audio-transformation toolbox for data-driven experiments in speech and music cognition.

Over the past few years, the field of visual social cognition and face processing has been dramatically impacted by a series of data-driven studies employing computer-graphics tools to synthesize arbitrary meaningful facial expressions. In the auditory modality, reverse correlation is traditionally used to characterize sensory processing at the level of spectral or spectro-temporal stimulus properties, but not higher-level cognitive processing of e.g.

Cysteine proteases as digestive enzymes in parasitic helminths.

We briefly review cysteine proteases (orthologs of mammalian cathepsins B, L, F, and C) that are expressed in flatworm and nematode parasites. Emphasis is placed on enzyme activities that have been functionally characterized, are associated with the parasite gut, and putatively contribute to degrading host proteins to absorbable nutrients [1-4]. Often, gut proteases are expressed as multigene families, as is the case with Fasciola [5] and Haemonchus [6], presumably expanding the range of substrates that can be degraded, not least during parasite migration through host tissues [5].

Behavioral and Neural Indices of Metacognitive Sensitivity in Preverbal Infants.

Humans adapt their behavior not only by observing the consequences of their actions but also by internally monitoring their performance. This capacity, termed metacognitive sensitivity [1, 2], has traditionally been denied to young children because they have poor capacities in verbally reporting their own mental states [3-5]. Yet, these observations might reflect children's limited capacities for explicit self-reports, rather than limitations in metacognition per se.

Cysteine and Aspartyl Proteases Contribute to Protein Digestion in the Gut of Freshwater Planaria.

Proteases perform numerous vital functions in flatworms, many of which are likely to be conserved throughout the phylum Platyhelminthes. Within this phylum are several parasitic worms that are often poorly characterized due to their complex life-cycles and lack of responsiveness to genetic manipulation. The flatworm Schmidtea mediterranea, or planaria, is an ideal model organism to study the complex role of protein digestion due to its simple life cycle and amenability to techniques like RNA interference (RNAi).

Infants ask for help when they know they don't know.

Uncertainty monitoring is a core property of metacognition, allowing individuals to adapt their decision-making strategies depending on the state of their knowledge. Although it has been argued that other animals share these metacognitive abilities, only humans seem to possess the ability to explicitly communicate their own uncertainty to others. It remains unknown whether this capacity is present early in development, or whether it emerges later with the ability to verbally report one's own mental states.

Inducing task-relevant responses to speech in the sleeping brain.

Falling asleep leads to a loss of sensory awareness and to the inability to interact with the environment [1]. While this was traditionally thought as a consequence of the brain shutting down to external inputs, it is now acknowledged that incoming stimuli can still be processed, at least to some extent, during sleep [2]. For instance, sleeping participants can create novel sensory associations between tones and odors [3] or reactivate existing semantic associations, as evidenced by event-related potentials [4-7].

Dynamic localization of Fus3 mitogen-activated protein kinase is necessary to evoke appropriate responses and avoid cytotoxic effects.

Cellular responses to many external stimuli are mediated by mitogen-activated protein kinases (MAPKs). We investigated whether dynamic intracellular movement contributes to the spatial and temporal characteristics of the responses elicited by a prototypic MAPK, Fus3, in the mating pheromone response pathway in budding yeast (Saccharomyces cerevisiae). Confining Fus3 in the nucleus, via fusion to a histone H2B, reduced MAPK activation and diminished all responses (pheromone-induced gene expression, cell cycle arrest, projection formation, and mating).