The ‘we-mode’ is defined as an irreducibly collective mode that enables interacting agents to share minds by representing their contributions to a joint action as contributions to something that they are going to pursue together (Gallotti and Frith, 2013, Trends in Cognitive Science, 17, 160–165). This paper reviews the current empirical findings on joint actions upon which the concept ‘we-mode’ relies heavily. Previous investigations on joint actions have demonstrated that sharing task representations allows individuals to predict and monitor their own actions and those of their partners, as well as their combined action outcomes. It has also been shown that performing actions together allows individuals to spontaneously adopt their partner’s level-2 visual and visuospatial perspective. The implications of these findings for research on the we-mode are discussed.

‘We-mode’ cognitive neuroscience aims to elucidate the internal cognitive processes of individuals undergoing interactions with others. This is qualitatively different from the traditional ‘third-person’ social neuroscience, i.e., observation of other’s actions that is accomplished by the so-called mirror neuron system, or the ‘theory of mind’ processes. In the we-mode cognitive neuroscience, it is emphasized that the individual must have a representation that is shared with others to perform joint actions. This shared representation would involve the goal of the task, knowledge about the relevant part of the task for which the individual is responsible, and the perspective of others participating in the ongoing task. In this short comment on the article by Sato, I would like to discuss several potentialities of we-mode cognitive neuroscience, i.e., the we-mode mirror neuron system that is under the influence of a ‘higher’ representation of others, and the we-mode ‘theory of mind’ that is endowed with an automatic and implicit representation of others. It appears promising that we can extend the existing framework of the traditional social cognition studies, in which the mirror neuron system and the theory of minds are thought to reflect different functions of social cognition, by pursuing ‘we-mode’ cognitive neuroscience.

Collaboration, the behavior of cooperating with others to achieve common goals, is a recent major topic in developmental psychology. Previous studies have demonstrated that the ability to collaborate with others develops at approximately 1 to 3 years of age. However, the mechanisms by which collaborations are achieved in young children are not well understood. The present article reviews recent collaboration studies in young children and identifies the importance of action interaction, which provides a basis for collaboration with others, as part of the development of collaboration in young children. Moreover, the authors propose two empirical findings as future research directions: interpersonal synchrony or social contingency and first-person plural cognitive perspective on self-other interactions called “we-mode”. These findings will help to explain the developmental changes that lead to collaboration in young children.

Collaboration is an important social activity, but it is not known how collaboration develops. Furuhata and Itakura (2016) argues that emergent coordination, a key idea explaining interpersonal interactive bodily movements, proposed by Knoblich, Butterfill, and Sebanz (2012), is a gateway to the development of collaboration. In this comment paper, this idea is reviewed favorably from previous adult behavioral studies. The need for integration of shared intention for collaboration is further discussed.

The concept of “we-mode” was recently proposed by Gallotti and Frith (Trends in Cognitive Science, 2013). However, the developmental aspect of we-mode remains unclear. In this article, I have decomposed the concept of we-mode into four perceptual/cognitive components, i.e., body perception, perspective taking, joint action, and bodily synchronization, which have been well studied in development psychology and developmental cognitive neuroscience investigations, and reviewed the typical and atypical developmental perspectives of each cognitive component. I will further discuss how development of these cognitive perceptual/components can shape we-mode.

Hirai (2016) discussed the components of “we-mode” development in detail from the viewpoint of typical/atypical development. However, his reductive approach may overlook important aspects of such development. Herein, I adopt a more holistic perspective in discussing functions of the “we-mode” in development. In doing so, I suggest that the “we-mode” can explain the mechanism of social cognitive development, and highlight its conceptual utility in considering interventions in children with developmental disorders. I hope this complementary discussion will shed additional light for those planning future studies on the “we-mode” development.

Development of social cognition is embedded in real-time social interactions between individuals, i.e., inter-subjectivity. To depict its neural underpinning, we have conducted a multi-brain approach utilizing hyperscanning fMRI that enables depiction of the neural activities of the two brains during a real-time interaction, i.e., joint attention. Hyperscanning fMRI of pairs of adults performing joint attention showed inter-individual neural synchronization in the right inferior frontal gyrus after all of the task-related effects were modeled out. To explore how the joint attention and eye-contact generates the state of shared attention, we conducted hyperscanning fMRI in which pairs of participants performed a real-time mutual gaze, before and after the joint attention task. During the mutual gaze, eye-blink synchronization, a behavioral index of shared attention, increased after the joint attention. The increase of eye-blink synchronization correlated positively with the increase of inter-individual neural synchronization within the right inferior frontal gyrus during mutual gaze. This enhanced neural synchronization also correlated positively with enhanced eye-blink synchronization during the previous joint attention. Thus, shared attention is represented and retained by pair-specific neural synchronization of the right inferior frontal gyrus. Furthermore, we have also successfully treated the two brains as a single unit, in order to understand the neural substrates of inter-subjectivity. We will apply this “two-in-one” strategy to various behavioral milestones of the development of social cognition from mutual imitation to prosocial behavior. Our “two-in-one” strategy using hyperscanning fMRI will become an indispensable and ground-breaking method to open the new field of “inter-subjectivity” social neuroscience.

Studies using hyperscanning have reported coordination of behaviors among 2 persons who ­performed interactive tasks. Synchronization of brain activity is an underlying mechanism of behavioral coordination. This article proposes a mathematical model (the “Kuramoto model”) which describes a phenome­non called entrainment of oscillator to explain how synchronization of brain activity emerges and which factors affect brain synchronization. A model, including 4 oscillators (inferior frontal gyri and middle temporal gyri in 2 persons) suggested that 1) similarity of oscillation frequencies in brain regions is critical for synchronization of brain activity, 2) patients on the autism spectrum might have different oscillation frequencies in their brain regions resulting in impairment of fluent communication, and 3) learning of important pathways from one person to another person can facilitate synchronization of brain activity, and thus probably can improve communication and behavioral coordination.

By examining the communication scenes that occur between people, we consider the nature of we-mode that occurs in individual-to-individual interactions. First, we consider the basis of we-mode emergence from the perspective of speech acts and various communicative functions within the framework of verbal communication. Next, we examine the psycholinguistic models of verbal communication, referring to Levelt (1989), in order to describe the mechanisms of dialogue. Subsequently, we focus on the interactive alignment found in dialogue as a form of we-mode that arises in verbal communication and consider we-mode by examining the phenomenon of linguistic priming. In addition, after investigating whether this linguistic priming arises in communication between learners of foreign languages, as well as between native speakers, we refer to various foreign language teaching methodologies and second language acquisition theories to consider how communication has been viewed in foreign language education in the past and attempt to understand the identity and role of we-mode in verbal communication and foreign language acquisition.”

In this article, “We-mode theory” is discussed from the viewpoint of social cognition. Furthermore, the mental conditions that should be observed in the relationship between We-mode and non-humans, not humans, will also be examined. Ideas of how a deep understanding of others should be created will be introduced, based on the theory of interactionism seen in social cognition. The possibility of human and non-human coexistence should also be illustrated; i.e., the possibility of coexistence between the human-like robot “Astro Boy” and the disc-shaped vacuum cleaner robot “Roomba”.

I aim to implement ‘we-mode’ in cyberspace by connecting several physical spaces. The we-mode is a special cognitive mode to intimately cooperate with others, and enhance human cognitive abilities and behavioral performances beyond the individual’s ability and performance. Studies on self-body perception, illusory body-ownership (e.g. rubber hand illusion, out-of-body experience, virtual embodiment), social interactions with others (e.g. Mutual gaze), changing one’s own body image, and its social and psychological impacts in cyberspace using virtual reality technologies as well as in physical space are reviewed. Based on those findings I consider how to induce or create we-mode in cyberspace and what can be realized by the cyberspace we-mode compared with the physical-space we-mode.

The possibility of implementing ‘we-mode’ among users in cyber spaces, which is proposed by Kitazaki, is discussed by reviewing the studies on body ownership and the sense of agency, both of which are strongly involved in self-body perception and recognition. The movement of a body in cyber space should strongly correlate with that in the physical space, but not necessary be rendered as realistic. Furthermore, the interaction and relationship between the spaces from the point of view of both a sense of realistic self-body in a cyber space and behavior changes after an experience in a cyber space are discussed to consider the possibility of creating ‘we-mode’ bridging of the physical and cyber spaces.

In recent years, human-robot interactions (HRIs) have been increasing in importance with the increased use of communication robots throughout the world. The traditional approach in robotics has been to read a person’s mental state and react to it. We focus on the next approach, “we-mode” through which the robot generates the atmosphere for smooth interactions. We-mode is one mode of cognition in which each member of a group shares the others’ mental state through their interactions. Consequently, it is anticipated that they would perform beyond the sum of each performance. In the future, this mode will become necessary in HRIs. While the social contingency between a person and a robot is key to the expression of we-mode, existing robots are not designed to realize the three-term contingency. In this paper, we review and analyze the recent trends in robot-design and propose the need for a drastic overhaul of robot-design.

Hayashi (2016) proposed that “we-mode” could be a new way to study human-robot interactions. Although many researchers have envisioned future robots as peers and partners to humans, I believe that the concept of “we-mode” in the human-robot relationship could be a challenging and interesting research target. In response to the article by Hayashi (2016), I discuss how “we-mode” could contribute to the design of robots that interact with people.