14-month-old infants detect a semantic mismatch when occluded objects are mislabeled.

When infants start mastering their first language, they may start to notice when words are used incorrectly. Around 14-months of age, infants detect incorrect labeling when they are presented with an object which is labeled while still visible. However, things that are referred to are often out of sight when we communicate about them. The present study examined infants' detection of semantic mismatch when the object was occluded at the time of labeling. Specifically, we investigated whether mislabeling that referred to an occluded object could elicit a semantic mismatch. We showed 14-month-old Danish-speaking infants events where an onscreen agent showed an object and then hid it in a box. This was followed by another agent's hand pointing at the box, and a concurrent auditory category label played, which either matched or did not match the hidden object. Our results indicate that there is an effect of semantic mismatch with a larger negativity in incongruent trials. Thus, infants detected a mismatch, as indicated by a larger n400, when occluded objects were mislabeled. This finding suggests that infants can sustain an object representation in memory and compare it to a semantic representation of an auditory category label.

An initial but receding altercentric bias in preverbal infants' memory.

Young learners would seem to face a daunting challenge in selecting to what they should attend, a problem that may have been exacerbated in human infants by changes in carrying practices during human evolution. A novel theory proposes that human infant cognition has an altercentric bias whereby early in life, infants prioritize encoding events that are the targets of others' attention. We tested for this bias by asking whether, when the infant and an observing agent have a conflicting perspective on an object's location, the co-witnessed location is better remembered. We found that 8- but not 12-month-olds expected the object to be at the location where the agent had seen it. These findings suggest that in the first year of life, infants may prioritize the encoding of events to which others attend, even though it may sometimes result in memory errors. However, the disappearance of this bias by 12 months suggests that altercentricism is a feature of very early cognition. We propose that it facilitates learning at a unique stage in the life history when motoric immaturity limits infants' interaction with the environment; at this stage, observing others could maximally leverage the information selection process.

Training self-other distinction facilitates perspective taking in young children.

People sometimes commit 'egocentric errors', failing to ignore their own perspective when interpreting others' communication. Training imitation-inhibition, when participants perform the opposite action from another person, facilitates subsequent perspective-taking in adults. This study tested whether imitation-inhibition training also facilitates perspective-taking in 3- to 6-year-olds, an age where egocentric perspective may be particularly influential. Children participated in a 10-min imitation-inhibition, imitation, or non-social-inhibition training (white, n = 25 per condition, 33 female, period: 2018-2021), then the communicative-perspective-taking Director task. Training had a significant effect (F(2, 71) = 3.316, p = .042, η2  = .085): on critical trials, the imitation-inhibition-group selected the correct object more often than the other groups. Imitation-inhibition training specifically enhanced the perspective-taking process possibly by highlighting the distinction between self and other.

3-4-year-old children's memory flexibility allows adaptation to an altered context.

Imitation provides a reliable method to investigate the developing memory functions in childhood. The present study explored whether 3-4-year-old children are able to revise their previous experiences after a 1 week delay in order to adapt to an altered context. We used a combined short-term (Session 1) and delayed (Session 2) imitation paradigm based on a previous study with 2-year-olds. The constraints (target object close/far) and relatedly the relevance of using a tool in a goal attainment task (irrelevant/relevant, respectively) changed between the sessions. We found that children in Session 1 used the tool only when it was needed (relevant/object far context). After the 1 week delay when the tool was previously irrelevant and then became relevant, children remembered the irrelevant act and applied it in the altered context. When the tool lost its relevance after 1 week, children used the tool less than before, but did not fully omit it, despite its reduced efficiency. The present data with 3-year-olds was compared to a pattern of results with 2-year-olds (from a similar previous study), that allowed to discuss possible developmental transitions in memory and imitation. We propose that the flexible restoration of a formerly irrelevant act and the maintenance of a formerly successful solution indicate flexibility of preschooler's memory when guiding imitation. This flexibility, however, interacts with children's tendency to remain faithful to strategies that were previously ostensively demonstrated to them.

Cognitive dissonance from 2 years of age: Toddlers', but not infants', blind choices induce preferences.

As adults, not only do we choose what we prefer, we also tend to adapt our preferences according to our previous choices. We do this even when choosing blindly and we could not have had any previous preference for the option we chose. These blind choice-induced preferences are thought to result from cognitive dissonance as an effort to reconcile our choices and values. In the present preregistered study, we asked when this phenomenon develops. We reasoned that cognitive dissonance may emerge around 2 years of age in connection with the development of children's self-concept. We presented N = 200 children aged 16 to 36 months with a blind choice between two toys, and then tested whether their choice had induced a preference for the chosen, and a devaluation of the discarded, toy. Indeed, children's choice-induced preferences substantially increased with age. 26- to 36-months-old children preferred a neutral over the previously blindly discarded toy, but the previously chosen over the neutral toy, in line with cognitive dissonance predictions. Younger infants showed evidence against such blind choice-induced preferences, indicating its emergence around 2 years of age. Contrary to our hypotheses, the emergence of blind choice-induced preferences was not related to measures of self-concept development in the second year of life. Our results suggest that cognitive dissonance develops around 2 years. We speculate about cognitive mechanisms that underlie this development, including later-developing aspects of the self-concept and increasingly abstract representational abilities.

Understanding the self in relation to others: Infants spontaneously map another's face to their own at 16-26 months.

The current study probed whether infants understand themselves in relation to others. Infants aged 16-26 months (n = 102) saw their parent wearing a sticker on their forehead or cheek, depending on experimental condition, placed unwitnessed by the child. Infants then received a sticker themselves, and their spontaneous behavior was coded. Regardless of age, from 16 months, all infants who placed the sticker on their cheek or forehead, placed it on the location on their own face matching their parent's placement. This shows that infants as young as 16 months of age have an internal map of their face in relation to others that they can use to guide their behavior. Whether infants placed the sticker on the matching location was related to other measures associated with self-concept development (the use of their own name and mirror self-recognition), indicating that it may reflect a social aspect of children's developing self-concept, namely their understanding of themselves in relation and comparison to others. About half of the infants placed the sticker on themselves, while others put it elsewhere in the surrounding, indicating an additional motivational component to bring about on themselves the state, which they observed on their parent. Together, infants' placement of the sticker in our task suggests an ability to compare, and motivation to align, self and others.

Three cognitive mechanisms for knowledge tracking.

We welcome Phillips et al.'s proposal to separate the understanding of "knowledge" from that of "beliefs." We argue that this distinction is best specified at the level of the cognitive mechanisms. Three distinct mechanisms are discussed: tagging one's own representations with those who share the same reality; representing others' representations (metarepresenting knowledge); and attributing dispositions to provide useful information.

Is motor cortex deactivation during action observation related to imitation in infancy? A commentary on Köster et al., 2020.

Sensorimotor alpha suppression is present both during the observation and execution of actions, and is a commonly used tool to investigate neural mirroring in infancy. Köster et al. (2020) used this measure to investigate infants' motor cortex activation during the observation of action demonstrations and its relationship to subsequent imitation of these actions. Contrary to what is implied in the paper and to common findings in the literature, the study's results appear to suggest that the motor system was deactivated during the observation of the actions, and that greater deactivation during action observation was associated with a greater tendency to copy the action. Here we present potential methodological explanations for these unexpected findings and discuss them in relation to common recommendations in the field.

Seeing the World From Others' Perspective: 14-Month-Olds Show Altercentric Modulation Effects by Others' Beliefs.

Humans have a propensity to readily adopt others' perspective, which often influences their behavior even when it seemingly should not. This altercentric influence has been widely studied in adults, yet we lack an understanding of its ontogenetic origins. The current studies investigated whether 14-month-olds' search in a box for potential objects is modulated by another person's belief about the box's content. We varied the person's potential belief such that in her presence/absence an object was removed, added, or exchanged for another, leading to her true/false belief about the object's presence (Experiment 1, n = 96); or transformed into another object, leading to her true/false belief about the object's identity (i.e., the objects represented under a specific aspect, Experiment 2, n = 32). Infants searched longer if the other person believed that an object remained in the box, showing an altercentric influence early in development. These results suggest that infants spontaneously represent others' beliefs involving multiple objects and raise the possibility that infants can appreciate that others encode the world under a unique aspect.

The flexibility of early memories: Limited reevaluation of action steps in 2-year-old infants.

This study investigated the flexibility of 2-year-old infants' retrieval and reenactment processes. In a delayed imitation paradigm, children were exposed to a constraint change (implemented by the distance of a target object) affecting the relevance of using a tool to obtain a goal (reach the object). In Experiment 1, during demonstration in the first session the tool was either relevant or irrelevant for reaching the goal, and 1 week later it either lost or gained its relevance, respectively. We found that when the tool became unnecessary (relevant to irrelevant change), children used it somewhat less than before and used it less compared with when the tool's relevance remained the same (relevant to relevant, no change). When the tool became necessary after a constraint change (irrelevant to relevant change), children used the tool more than before, but not as much as in the Relevant-Relevant control condition. In Experiment 2, the timing of the constraint change (immediate or delayed) was varied in a modified version of the Irrelevant-Relevant condition, where practice before the constraint change was omitted. Children were not significantly more flexible in the immediate condition than in the delayed condition, and comparisons with Experiment 1 showed that performance did not change if we omitted the practice before the change. These results indicate that although 2-year-olds show considerable mnemonic performance, they face difficulties in adapting to constraint changes. We propose that this inflexibility may stem from infants' inability to revise their evaluations formed in previous events due to their immature episodic memory capacities.

Altercentric Cognition: How Others Influence Our Cognitive Processing.

Humans are ultrasocial, yet, theories of cognition have often been occupied with the solitary mind. Over the past decade, an increasing volume of work has revealed how individual cognition is influenced by the presence of others. Not only do we rapidly identify others in our environment, but we also align our attention with their attention, which influences what we perceive, represent, and remember, even when our immediate goals do not involve coordination. Here, we refer to the human sensitivity to others and to the targets and content of their attention as 'altercentrism'; and aim to bring seemingly disparate findings together, suggesting that they are all reflections of the altercentric nature of human cognition.

Encoding third-person epistemic states contributes to episodic reconstruction of memories.

We propose an extension to Mahr & Csibra's (M&C's) theory. For successful episodic memory formation, potentially relevant aspects of a situation need to be identified and encoded online and retained for prospective interactions. To be maximally convincing, the communicator not only has to encode not just any contextual detail, but also has to track information in relation to social partners.

Nonverbal components of Theory of Mind in typical and atypical development.

To successfully navigate the human social world one needs to realize that behavior is guided by mental states such as goals and beliefs. Humans are highly proficient in using mental states to explain and predict their conspecific's behavior, which enables adjusting one's own behavior in online social interactions. Whereas according to recent studies even young infants seem to integrate others' beliefs into their own behavior, it is unclear what processes contribute to such competencies and how they may develop. Here we analyze a set of possible nonverbal components of theory of mind that may be involved in taking into account others' mental states, and discuss findings from typical and atypical development. To track an agent's belief one needs to (i) pay attention to agents that might be potential belief holders, and identify their focus of attention and their potential belief contents; (ii) keep track of their different experiences and their consequent beliefs, and (iii) to make behavioral predictions based on such beliefs. If an individual fails to predict an agent's behavior depending on the agent's beliefs, this may be due to a problem at any stage in the above processes. An analysis of the possible nonverbal processes contributing to belief tracking and their functioning in typical and atypical development aims to provide new insights into the possible mechanisms that make human social interactions uniquely rich.

Neural signatures for sustaining object representations attributed to others in preverbal human infants.

A major feat of social beings is to encode what their conspecifics see, know or believe. While various non-human animals show precursors of these abilities, humans perform uniquely sophisticated inferences about other people's mental states. However, it is still unclear how these possibly human-specific capacities develop and whether preverbal infants, similarly to adults, form representations of other agents' mental states, specifically metarepresentations. We explored the neurocognitive bases of eight-month-olds' ability to encode the world from another person's perspective, using gamma-band electroencephalographic activity over the temporal lobes, an established neural signature for sustained object representation after occlusion. We observed such gamma-band activity when an object was occluded from the infants' perspective, as well as when it was occluded only from the other person (study 1), and also when subsequently the object disappeared, but the person falsely believed the object to be present (study 2). These findings suggest that the cognitive systems involved in representing the world from infants' own perspective are also recruited for encoding others' beliefs. Such results point to an early-developing, powerful apparatus suitable to deal with multiple concurrent representations, and suggest that infants can have a metarepresentational understanding of other minds even before the onset of language.

Do infants bind mental states to agents?

Recent findings suggest that infants understand others' preferential choice and can use the perspectives and beliefs of others to interpret their actions. The standard interpretation in the field is that infants understand preferential choice as a dispositional state of the agent. It is possible, however, that these social situations trigger the acquisition of more general, not person-specific knowledge. In a looking-time study we showed an Agent A demonstrating a choice, that only could have been interpreted as preferential based on the perspective (and thus the belief) of the agent, not the observer. Then we introduced a new agent (Agent B), who chose consistently or inconsistently with Agent A; also varying whether Agent B was an adult or a child. Results show that infants expected Agent B (both the adult and the child) to choose as Agent A, but only in the condition where according to Agent A's knowledge two objects were present in familiarization(confirming previous evidence on the importance of contrastive choice). We interpret these results in the following way: (1) infants do not encode the perspectives of other agents as person-specific sources of knowledge and (2) they learn about the object, rather than the agent's disposition towards that object. We propose that early theory of mind processes lack the binding of belief content to the belief holder. However, such limitation may in fact serve an important function, allowing infants to acquire information through the perspectives of others in the form of universal access to general information.